The mistakes of Amelia Earhart’s final flight, and the physics that could have saved her. Use code VERITASIUM to get 50% off your 1st club crate when you join a club for kids aged 3+ or go to https://kiwico.com/veritasium 00:00 Amelia Earhart’s fatal flight 01:52 How Earhart prepared for her final mission 03:33 Who was Amelia Earhart? 05:36 The flight plan 07:13 How celestial navigation works 09:16 Invention of radio technology 12:02 Radio waves explained 22:44 Earhart makes her critical decision 24:55 Communication failures 28:30 “Gas is running low” 31:39 Her desperate final message 33:01 The small detail that could have saved her Special thanks to Clifford Heath for his help putting together the radio demo, and the folks at the Victorian ARDF group for connecting us. Thank you to Brian Harrison and Michael Murphy with the AWA Communication Technologies Museum for their assistance with early research. Thank you to Peter Bevelacqua over at Antenna Theory for help filling in some missing details. Sharp-eyed viewers might notice there doesn't seem to be a loop antenna in the flight simulation shots. It sadly wasn't included in the simulator's model of Earhart's Electra, but it features prominently in old photos. The Secret Life of Radio video credits: Tim Hunkin - https://www.youtube.com/watch?si=4AyDKVi6brMqSIMD&v=LMxate9gegg&feature=youtu.be Join us on Patreon for early access videos, bonus content, and to support Veritasium! https://ve42.co/PatreonDE Patrons: Adam Foreman, Albert Wenger, Alexander Tamas, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, Greg Scopel, I. H., John H. Austin, Jr., Juan Benet, KeyWestr, Kirill Shore, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, Michael Krugman, Orlando Bassotto, Paul Peijzel, Reed Spilmann, Richard Sundvall, Sam Lutfi, TTST, Tj Steyn, Ubiquity Ventures, gpoly, john kiehl, meg noah, wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV References: https://ve42.co/RefsEarhart Directed by Sulli Yost and Derek Muller Written by Sulli Yost and Derek Muller Edited by Peter Nelson Animated by David Szakaly, Fabio Albertelli, Maria Gusakovich, Ivy Tello, Mike Radjabov, Mohamed Alhaj Illustrations by Jakub Misiek, Emma Wright Filmed by Derek Muller and Bernard Lau Additional Research by Gabriel Bean, Geeta Thakur Produced by Sulli Yost, Derek Muller, Rob Beasley Spence, Emily Lazard, Tori Brittain, Umar Ijaz Thumbnail contributions by Peter Sheppard, Ren Hurley Additional video/photos supplied by Getty Images and Story Blocks Music from Epidemic Sound and Johnny Hyman

Glass is one of the most important materials humans have ever made. Try out Saily by heading to https://saily.com/veritasium and remember to use coupon code veritasium to get 15% off your first purchase. 00:00 Glass and our place in the universe 01:23 How Gorilla Glass works 04:35 What is glass? 05:15 Is glass a liquid? 07:29 Different types of glass 09:59 Invention of transparent glass 11:56 Why is some glass transparent? 14:54 Invention of glass lenses 15:52 Development of magnification 18:02 How to make glass more durable ▀▀▀ Join us on Patreon for early access videos, bonus content, and to support Veritasium! https://ve42.co/PatreonDE Patrons: Adam Foreman, Albert Wenger, Alexander Tamas, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, Greg Scopel, I. H., John H. Austin, Jr., Juan Benet, KeyWestr, Kirill Shore, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, Michael Krugman, Orlando Bassotto, Paul Peijzel, Reed Spilmann, Richard Sundvall, Sam Lutfi, TTST, Tj Steyn, Ubiquity Ventures, gpoly, john kiehl, meg noah, wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: https://ve42.co/V ▀▀▀ Directed by Petr Lebedev Written by Petr Lebedev and Derek Muller Edited by Nick Lear Animated by Fabio Albertelli, Ivy Tello, David Szakaly and Rokas Viksraitis Illustrated by Jakub Misiek, Emma Wright, and Maria Gusakovich Filmed by Petr Lebedev, Sulli Yost and Miranda Prise Additional research by Gabe Bean Produced by Petr Lebedev, Derek Muller, Rob Beasley Spence, Gabe Bean, and Tori Brittain Thumbnail contributions by Jakub Misiek, Ren Hurley and Peter Sheppard Additional video/photos supplied by Getty Images, Storyblocks Music from Epidemic Sound

Being better at math can make you worse at math problems, and it’s completely rational. Get all sides of every story at https://groundnews.com/Ve and read the news with a data-driven approach. Subscribe through my link for 50% off unlimited access– their biggest discount of the year. 00:00 This research paper has fascinated me for years 00:21 The skin cream question 04:20 How politics influences our reasoning 5:10 The gun control question 8:42 Are people rational decision makers? 9:27 Why people think tribally 10:38 What can we do about political polarisation? ▀▀▀ Join us on Patreon for early access videos and exclusive bonus content https://ve42.co/PatreonDE Patrons: Adam Foreman, Albert Wenger, Alexander Tamas, Anton Ragin, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, Greg Scopel, I. H., John H. Austin, Jr., Juan Benet, KeyWestr, Kirill Shore, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, Michael Krugman, Orlando Bassotto, Paul Peijzel, Reed Spilmann, Richard Sundvall, Sam Lutfi, TTST, Tj Steyn, Ubiquity Ventures, gpoly, john kiehl, meg noah, wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: Kahan D, M. et al. (Sept 3, 2014). Motivated numeracy and enlightened self-government. Behavioural public policy, 1(1), 54-86 - https://ve42.co/Kahan2017 TEDx Talks. (Dec 10, 2018). Are Smart People Ruining Democracy? via Youtube - https://ve42.co/KahanTedx Cardiff University. (Mar 6, 2014). The Science Communication Environment via Youtube - https://ve42.co/KahanCardiff spitfirestrategies. (Nov 21, 2012). How cultural values shape beliefs and perceptions of risk via Youtube - https://ve42.co/KahanSpirit Images & Video: TEDx Talks. (Dec 10, 2018). Are Smart People Ruining Democracy? via Youtube - https://ve42.co/KahanTedx ▀▀▀ Directed by Wylie Overstreet and Derek Muller Written by Wylie Overstreet and Derek Muller Edited by Trenton Oliver Animated by Fabio Albertelli, James Cheetham Illustrated by Jakub Misiek, Emma Wright, and Maria Gusakovich Filmed by Derek Muller and Wylie Overstreet Additional research by Gabe Bean Produced by Wylie Overstreet, Derek Muller, Rob Beasley Spence, Gabe Bean, Gregor Čavlović, and Tori Brittain Thumbnail contributions by Jakub Misiek, Ren Hurley and Peter Sheppard Additional video/photos supplied by Getty Images, Storyblocks Music from Epidemic Sound

The single principle that underpins all of physics. Head to https://brilliant.org/veritasium to start your free 30-day trial and get 20% off an annual premium subscription. A massive thank you to Prof. Steven Strogatz for his expertise and enthusiasm. A huge thank you to Prof. Haithem Taha, Prof. Anthony Bloch, Dr. Carl-Fredrik Nyberg Brodda, Dr. Sarah Millholland, and Dr. Andrew Mitchell for all their help with finding the story and getting it right. A special thanks to Dr. Aurèle Adam, Ron Haaksman, Marc Serra Peralta, and everyone at the Delft Makerspace for their help with preparing and performing experiments. 00:00 One rule that replaces all of physics 00:51 The problem of fastest descent 05:09 Fermat's principle 07:17 Bernoulli's solution 10:38 Maupertuis' principle 12:28 Maupertuis attacked and ridiculed 14:01 Euler & Lagrange to the rescue 17:22 The general approach to solving these problems 19:32 Writing the principle into its modern form 23:17 Why the principle works 27:08 Another way to do mechanics 30:19 A “spooky” breakthrough ▀▀▀ Join us on Patreon for early access videos and exclusive bonus content https://ve42.co/PatreonDE Patrons: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Burt Humburg, Chris Harper, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Martin, Matthias Wrobel, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, Toni , TTST, Ubiquity Ventures, wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ Key references: A fantastic book on the history of the Principle of Least Action: Rojo, A. and Bloch, A. The Principle of Least Action: History and Physics. - https://ve42.co/Bloch2018 Coopersmith, J. (2017). The lazy universe: an introduction to the principle of least action. Oxford University Press. - https://ve42.co/LazyU 3Blue1Brown. The Brachistochrone, with Steven Strogatz via Youtube - https://ve42.co/Brach3B1B Vsauce. The Brachistochrone via Youtube - https://ve42.co/BrachV PBS Space Time. Is ACTION The Most Fundamental Property in Physics? via Youtube - https://ve42.co/PBSAction Full list of references: https://ve42.co/T Images & Video: Voltaire. (1753). Diatribe du Docteur Akakia. - https://ve42.co/DiatribeAkakia Philosophical Transactions cover. via Wikimedia Commons - https://ve42.co/PhilTransImage Kids Fun Science. (Jun 28, 2017). Refraction of Light with a arrow experiment via Youtube - https://ve42.co/RefractionFunSci Physics with Simon Poliakoff. Refraction demonstration with water and laser via Youtube - https://ve42.co/SimonPoliakoff Mercury Transit Across Sun. via Nasa.gov - https://ve42.co/MercTransit ▀▀▀ Directed by Casper Mebius Written by Casper Mebius and Derek Muller Edited by Trenton Oliver Animated by Fabio Albertelli, Ivy Tello, Mike Radjabov, Gregor Čavlović, Emma Wright, James Finnemore and David Szakaly Illustrated by Jakub Misiek, Emma Wright, and Maria Gusakovich Filmed by Derek Muller and Casper Mebius Additional research by Gabe Bean, Gregor Čavlović, and Geeta Thakur Produced by Casper Mebius, Derek Muller, Rob Beasley Spence, Gabe Bean, Gregor Čavlović, and Tori Brittain Thumbnail contributions by Jakub Misiek, Ren Hurley and Peter Sheppard Additional video/photos supplied by Getty Images, Storyblocks, and NASA SVS Music from Epidemic Sound

Europa Clipper is looking for signs of alien life in a very deadly place. Head to http://80000hours.org/veritasium to start planning a career that can help change the world for the better. A massive thank you to Dr. Robert Pappalardo for his expertise and time. A huge thank you to Gretchen McCartney and Cynthia B. Phillips at NASA JPL for their help. For more on hydrothermal vents, check out NaturalWorldFacts on YouTube - @NaturalWorldFacts 00:00 ATTEMPT NO LANDING. 01:06 Jupiter’s deadly radiation belts 03:56 Europa’s secret 06:15 Why Europa isn’t completely frozen 08:03 Effects of tidal flexing 09:13 Why alien life could exist 10:39 How Europa Clipper detects signs of life 11:34 Why not Enceladus? 13:01 Europa Clipper’s instruments 15:13 Launch date and first results ▀▀▀ Special thanks to our Patreon supporters! Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE Adam Foreman, Albert Wenger, Anton Ragin, Ayush Agrawal, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., Jack Cuprill, John H. Austin, Jr., john kiehl, Juan Benet, KeyWestr, Kirill Shore, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Reed Spilmann, Richard Sundvall, Sam Lutfi, Shiroyasha, Tj Steyn, TTST, Ubiquity Ventures and wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: Europa Clipper via Wikipedia - https://ve42.co/ECWiki Magnetosphere of Jupiter via Wikipedia - https://ve42.co/JupiterMagWiki Europa Clipper (2024) via Nasa.gov - https://ve42.co/ECNasa Extraterrestrial Cycloids - Why Are They on Europa? via minutephysics on YouTube - https://ve42.co/MinPhysCycloid Hand, K. P. & Carlson, R. W. (2015). Europa’s surface color suggests an ocean rich with sodium chloride. Geophysical research letters - https://ve42.co/Carlson2015 Dalton, J. B. et al. (2003). Near-Infrared Detection of Potential Evidence for Microscopic Organisms on Europa. Astrobiology - https://ve42.co/Dalton2003 Europa Clipper: Exploring Jupiter's Ocean World (2024, May 24) via Youtube - https://ve42.co/PappalardoLec Carr, M., Belton, M., Chapman, C. et al. (1998). Evidence for a subsurface ocean on Europa. Nature 391, 363–365 - https://ve42.co/Carr1998 New Findings Support Prospect of Life on Jupiter’s Moon Europa (2024) via Nasa.gov - https://ve42.co/NasaEuropaLife Meitzler, R., Jun, I., Blase, R. et al. (2023). Investigating Europa’s Radiation Environment with the Europa Clipper Radiation Monitor. Space Sci Rev 219, 61 - https://ve42.co/Meitzler2023 Images & Video: 2010: The Year We Make Contact - https://ve42.co/2010Contact CGI animations via NASA - https://ve42.co/NasaCGI NASA Eyes on the Solar System - https://ve42.co/NasaEyes Jupiter's magnetosphere via Chandra X-Ray Center - https://ve42.co/JupiterMagChandra Io's Volcanoes via BBC Earth Science - https://ve42.co/IoBBCEarth Clipper ships via Wikipedia - https://ve42.co/ClipperShipWiki Various moon images via NASA - https://ve42.co/NasaMoons Hydrothermal vent animation from NaturalWorldFacts - https://ve42.co/NWFVentAnims Hydrothermal vent footage by Monterey Bay Aquarium Research Institute - https://ve42.co/ARIVent Snotbot footage from VICE News - https://ve42.co/SnotBotVice Plate tectonics on Europa by Noah Kroese - https://ve42.co/KroeseTectonics JUICE CGI animations via ESA - https://ve42.co/JUICECGIESA Arthur C. Clarke photo via ITU Pictures under the CC 2.0 license - https://ve42.co/ClarkePhoto ▀▀▀ Directed by Gregor Čavlović Written by Gregor Čavlović and Derek Muller Edited by Jack Saxon Animated by Mike Radjabov, Fabio Albertelli, and Jack Saxon Illustrated by Jakub Misiek Filmed by Derek Muller, Petr Lebedev and Gregor Čavlović Additional research by Gabriel Bean Produced by Derek Muller, Gregor Čavlović, Rob Beasley Spence, Tori Brittain, Luke Lewis, Barbara Abraul, Gabriel Bean, Petr Lebedev, and Casper Mebius Thumbnail contributions by Ren Hurley, Peter Sheppard, and Jakub Misiek Additional video/photos supplied by Getty Images and Storyblocks Music from Epidemic Sound

The world’s first look inside a thermite reaction. Use code veritasium at https://incogni.com/veritasium to get an exclusive 60% off an annual Incogni plan. A massive thank you to everyone at Goldschmidt for making this possible. With special thanks to Dr. Axel Hoeschen, Christof Gassmann and Claudia Koch. 00:00 What is thermite? 00:51 Hans Goldschmidt and the first thermite reaction 05:55 The reaction as it’s never been seen before 14:57 How thermite welding works 17:43 I destroyed a laptop! 26:44 How thermite is made 31:11 Blow-torching thermite to show how reactive it is If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically. https://snatoms.com/ ▀▀▀ References: Archives from Goldschmidt Thermite via Wikipedia - https://ve42.co/WikiThermite From the past to the present. via goldschmidt.com - https://ve42.co/Past2Present Hans Goldschmidt via Wikipedia - https://ve42.co/HansGWiki Goldschmidt, H. (1914). Gesammelte Veröffentlichungen (1st Ed.). Springer-Verlag - https://ve42.co/HGoldschmit1914 Menzies, J. (2015, January 8). Mechanic's Toolbox: Thermite Welding. SFMTA. - https://ve42.co/ThermiteWelding Kirshenbaum, A. D., & Cahill, J. A. (1960). The density of liquid aluminium oxide. Journal of Inorganic and Nuclear Chemistry - https://ve42.co/CahillA1960 Reichstag fire via Wikipedia - https://ve42.co/ReichstagFireWiki Images & Video: Karl Goldschmidt - https://ve42.co/KGoldschmidt Goldschmidt Chemical Factory - https://ve42.co/GSFabrik Henry Treffry Dunn Rossetti and Dunton at 16 Cheyne Walk - https://ve42.co/Treffry The Green Gown - https://ve42.co/GreenGown Arsenic Green Dress - https://ve42.co/ArsenicGreenDress Kersting, Die Stickerin - https://ve42.co/Fassung Too Early Tissot Detail - https://ve42.co/Tissot Death Skull - https://ve42.co/Skull British uniforms - https://ve42.co/BritishUniforms Thermit in Practice - https://ve42.co/SKallee Thermite Ship Shaft Welding 1 - https://ve42.co/ShipShaft1 Thermite Ship Shaft Welding 2 - https://ve42.co/ShipShaft2 Using Incendiary Grenade to Destroy German Antitank Gun by OkraJoe - https://youtu.be/RTSiq5QYHGo?si=Va_6dPimFuaQfFp5 Reichstagsbrand - https://ve42.co/RTBrand Ruins of the Reichstagsbrand - https://ve42.co/RTBrand2 The Thermite Kettle by colinfurze - https://youtu.be/mg3bFxdAZsY?si=BmBIYPUlP1Wfpuoj ▀▀▀ Special thanks to our Patreon supporters: Albert Wenger, Anton Ragin, Ayush Agrawal, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, I. H., Jack Cuprill, John H. Austin, Jr., Juan Benet, KeyWestr, Kirill Shore, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, Michael Krugman, Orlando Bassotto, Paul Peijzel, Reed Spilmann, Richard Sundvall, Sam Lutfi, TTST, Tj Steyn, Ubiquity Ventures, gpoly, john kiehl, meg noah, wolfee ▀▀▀ Directed by Derek Muller Written by Derek Muller Edited by Trenton Oliver Animated by Fabio Albertelli, Rokas Vikšraitis and Mike Radjabov Illustrations by Jakub Misiek Filmed by Derek Muller, David Bochmann, Casper Mebius, Luise Dietert, Henning Fischer and Harald Schweiger Additional Research by Gregor Čavlović and Gabriel Bean Produced by Gregor Čavlović, Derek Muller, Casper Mebius, Rob Beasley Spence, Emily Lazard and Tori Brittain Thumbnail contributions by Peter Sheppard, Ren Hurley and Casper Mebius Additional video/photos supplied by Getty Images and Story Blocks Music from Epidemic Sound

How do QR codes work? The checkerboard patterns taking over the world, demystified. Go to https://Saily.com/veritasium and use the code ‘veritasium’ to get an exclusive 15% off your first purchase. Special thanks to Mashiro Hara and Yuki Watanabe. 00:00 I was wrong 00:49 How Morse Code revolutionized communication 03:57 How barcodes work 10:34 How QR codes store information 18:16 Why damaged QR codes still work 29:54 Why are QR codes so common? 31:21 How safe are QR codes? 32:25 The future of QR codes If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically. https://snatoms.com/ ▀▀▀ References: https://ve42.co/O Images & Video: 1940’s grocery store - H.I.C - https://ve42.co/1940sShop Why Americans Are Obsessed With Peanut Butter via Youtube - https://ve42.co/PeanutButter1 Jif Peanut Butter 90s Commercial (1998) via Youtube - https://ve42.co/PeanutButter2 Vericode Symbol via Youtube - https://ve42.co/VericodeSymbol Oreo introduces Sour Patch Kids cookies via YouTube - https://ve42.co/OreaSour BSE - Changes in Behaviour via YouTube - https://ve42.co/BSE QR Code with Drones | Firefly Drone Show via YouTube - https://ve42.co/DroneQRCode Damaged barcode 1 by christiaangpr via Reddit - https://ve42.co/DamagedBarcode1 Damaged barcode 2, Midcom service group https://ve42.co/DamagedBarcode2 Oskana, G and Petkova, A. (2020 July 1). Testing a nano-barcodes marking technology for identification and protection of the mechanical products, Fig. 1 - https://ve42.co/MatrixCodes NASA Celebrates 40 Years of the Voyager Mission via Nasa.gov - https://ve42.co/Voyager40Yr Apollo footage via Nasa.gov - https://ve42.co/ApolloFootage Snake in a QR code by MattKC via mattkc.com - https://ve42.co/SnakeQR Scratched CD by Ice3yes via Reddit - https://ve42.co/ScratchedCD Alfred Vail Portrait via si.edu - https://ve42.co/AlfredVail Bernard Silver Portrait vai invent.org - https://ve42.co/BernardSilver Norman Joseph Woodland Portrait via usatoday.com https://ve42.co/NormanWoodland Masahiro Hara portrait via denso.com https://ve42.co/MasahiroPhoto Cooke and Wheatstone telegraph patents via Wikipedia: https://ve42.co/TelegraphPatent1 https://ve42.co/TelegraphPatent2 https://ve42.co/TelegraphPatent3 https://ve42.co/TelegraphPatent4 https://ve42.co/TelegraphPatent5 https://ve42.co/TelegraphPatent6 5 needle telegraph via cachesleuth.com- https://ve42.co/NeedleTelegraph ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Albert Wenger, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, I. H., Jack Cuprill, John H. Austin, Jr., Juan Benet, KeyWestr, Kirill Shore, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, Michael Krugman, Orlando Bassotto, Paul Peijzel, Reed Spilmann, Richard Sundvall, Sam Lutfi, TTST, Tj Steyn, Ubiquity Ventures, gpoly, john kiehl, meg noah, wolfee ▀▀▀ Directed by Sumeet Kulkarni and Derek Muller Written by Sumeet Kulkarni Edited by Peter Nelson and Luke Molloy Animated by David Szakaly, Fabio Albertelli, James Finnemore, Ivy Tello Illustrations by Jakub Misiek, Emma Wright Filmed by Derek Muller Additional Research by Gabriel Bean Produced by Sumeet Kulkarni, Derek Muller, Rob Beasley Spence, Emily Lazard, Tori Brittain, Emily Zhang Thumbnail contributions by Peter Sheppard, Ren Hurley, David Szakaly, Gregor Čavlović Additional video/photos supplied by Getty Images and Story Blocks Music from Epidemic Sound

Can you trust your phone? Head to https://brilliant.org/veritasium to start your free 30-day trial and get 20% off an annual premium subscription. A huge thank you to Linus Sebastian and the team at Linus Tech Tips - check them out at @LinusTechTips A massive thank you to Alexandre De Oliveira and Karsten Nohl making this demo possible. A special thanks to Crofton Black, Cathal Mc Daid, and James Hobson at Hacksmith Industries. 00:00 I hacked Linus! 00:59 How Steve Jobs and Steve Wozniak hacked the telephone network 02:22 Early history of the telephone 07:08 The kidnapping of Sheikha Latifa 08:41 How Signalling System No. 7 works 11:03 Why SS7 is vulnerable to hacking 12:15 How hackers gain access to phones 16:17 How I was able to spy on Linus’ phone 18:09 How hackers can intercept text messages 21:04 How your location can be tracked via SS7 29:03 How to protect your phone from hacking ▀▀▀ Special thanks to our Patreon supporters! Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE Adam Foreman, Albert Wenger, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Burt Humburg, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., Jack Cuprill, John H. Austin, Jr., john kiehl, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Tj Steyn, TTST, Ubiquity Ventures and wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: Black, C. (2020). Spy companies using Channel Islands to track phones around the world. The Bureau of Investigative Journalism - https://ve42.co/SpyTBIJ It is dangerously easy to hack the world’s phones via The Economist - https://ve42.co/EconHack Blake, H. (2023). The Fugitive Princesses of Dubai. The New Yorker - https://ve42.co/DubaiNY McDaid, C. (2021). How Surveillance Companies Track You Using Mobile Networks. media.ccc.de - https://ve42.co/McDaid2021 Engel, T. (2014). SS7: Locate. Track. Manipulate. media.ccc.de - https://ve42.co/Engel2014 Nohl, K. (2014). Mobile self-defense. media.ccc.de - https://ve42.co/Nohl2014 How Cell Service Actually Works via WendoverProductions - https://ve42.co/CellWendover How Telephone Phreaking Worked via The 8-Bit Guy - https://ve42.co/8BitGuy Transmission Lines: Part 1 An Introduction via TheSiGuy - https://ve42.co/TheSiGuy The Step-By-Step Switch via AT&T Tech Channel - https://ve42.co/SwitchATNT Hacking Your Phone via 60 Minutes - https://ve42.co/60minHack Rosenbaum, R. (1971). Secrets of the Little Blue Box. The Esquire Magazine - https://ve42.co/Rosenbaum1971 Black, C. et. al. (2023). Ghost in the network. Lighthouse Reports - https://ve42.co/Black2023 Kerr, D. (2019). The step-by-step telephone switching system. dougkerr.net - https://ve42.co/Kerr2019 Ecall and 2G/3G Network Obsolescence via PFA Plateforme Automobile - https://ve42.co/PFAAuto2021 Images & Video: All references can be found here: https://ve42.co/PhoneSpyingImageVideo ▀▀▀ Directed by Henry van Dyck Written by Henry van Dyck Edited by Laura Mills Animated by Fabio Albertelli, Ivy Tello, David Szakaly, and Jakub Misiek Filmed by Derek Muller and Linus Media Group Team Additional research by Gabe Bean Produced by Derek Muller, Henry van Dyck, Rob Beasley Spence, Tori Brittain, Emily Lazard, Luke Lewis, Gregor Čavlović, and Emily Zhang Thumbnail contributions by Ren Hurley and Peter Sheppard Additional video/photos supplied by Getty Images and Storyblocks Music from Epidemic Sound

Myths and misconceptions about planes. Go to https://groundnews.com/Ver to see through media misconceptions and get all sides of every story. Subscribe to save 40% off unlimited access through our link. A massive thank you to Petter Hörnfeldt for his expertise and time. Check out @MentourPilot. A huge thank you to Baz Collins, Nick Woods, Val Bukmanis, and everyone at the Queensland Air Museum for hosting us and making this shoot possible - https://ve42.co/QLDAir A special thanks to Roddy McNamee for helping out with the script - https://ve42.co/RMcN A big thank you to Emily Zhang, Petr Lebedev, and Casper Mebius for their help and guidance! 00:00 Can plane doors be opened mid-flight? 00:28 How high do planes fly? 02:31 How do jet engines work? 04:43 Airplanes before cabin pressurization 05:34 Why don’t pressurized planes need door locks? 07:07 Do people fart more in planes? 07:57 The story of Aloha Airlines Flight 243 09:21 The story of Asiana Airlines Flight AA8124 09:57 Is “airplane mode” on phones real? 13:53 Why does airplane food taste bad? 15:07 Why do people drink tomato juice on planes? 16:15 How safe is air travel? ▀▀▀ Special thanks to our Patreon supporters! Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE Adam Foreman, Albert Wenger, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Burt Humburg, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, I. H., Jack Cuprill, John H. Austin, Jr., Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, TTST, Tj Steyn, Ubiquity Ventures, gpoly, john kiehl, meg noah, wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: Pilot’s Handbook of Aeronautical Knowledge via the FAA - https://ve42.co/LiftandDragEqs Compressor efficiency by Roddy McNamee - https://ve42.co/Compressor Garrido, E. et. al. (2019). Breathless and dying on Mount Everest. The Lancet Respiratory Medicine - https://ve42.co/Everest3min Cabin Pressurization via Wikipedia - https://ve42.co/CabinPressure B737 door specifications by Chris Brady - https://ve42.co/737door Aloha Airlines 243 Accident Report by the NTSB - https://ve42.co/AlohaAirline Boeing 737-297 Specifications via the FAA - https://ve42.co/AlohaCycles (PED) Aviation Rulemaking Committee via the FAA - https://ve42.co/AirplaneMode Ritchie, C. (1996). Potential Liability from Electromagnetic Interference. Journal of Air Law and Commerce - https://ve42.co/Ritchie1996 FAA restrictions via eCFR - https://ve42.co/FAArules Is Phone Interference Phony? via Wired - https://ve42.co/FCCTesting Sabatini N. (2005). Statement before the Subcommittee of Aviation. U.S. Department of Transportation - https://ve42.co/FCCquote EU rules on Airplane Mode via euronews.com - https://ve42.co/EUAPM Mayer, F. et al. (2022). Indoor Air Quality in Commercial Air Transportation. Handbook of Indoor Air Quality - https://ve42.co/PlaneHumid Burdack-Freitag, et al. (2010). Odor and taste perception in a simulated aircraft cabin. Journal of Consumer Protection and Food Safety. - https://ve42.co/SmellTaste Spence, C. (2017). Tasting in the air: A review. International Journal of Gastronomy and Food Science - https://ve42.co/PlaneFoodTaste Yan, K. S., & Dando, R. (2015). A crossmodal role for audition in taste perception. Journal of Experimental Psychology. - https://ve42.co/ChordaTympani Images & Video: Passenger Opens Emergency Exit via 10 News First - https://ve42.co/Jetstar Airplane-Door OPENS Mid-flight! by Mentour Pilot - https://ve42.co/MentourAsia A320 Door by Captain Time - https://ve42.co/A320Door B737 Door by Abdulrahman Ismail - https://ve42.co/B737Door The Miracle Landing Of Aloha Airlines Flight 243 by Wonder - https://ve42.co/Wonder243 Terrifying video shows Asiana flight door open in mid-air by National Post - https://ve42.co/PlaneDoorOpen Faraday Cage by Radwell International - https://ve42.co/Faraday Anatomy of the Inner Ear model by Annie Campbell, Now Medical Studios - https://ve42.co/EarAnatomy ▀▀▀ Directed by Gregor Čavlović and Derek Muller Written by Gregor Čavlović, Derek Muller, Petr Lebedev, Emily Zhang, and Casper Mebius Edited by Jack Saxon Animated by Mike Radjabov, Fabio Albertelli, Ivy Tello, David Szakaly, and Jack Saxon Illustrated by Jakub Misiek Filmed by Chase Brockett, Charles Clement, and Derek Muller Additional research by Gabriel Bean Produced by Derek Muller, Gregor Čavlović, Rob Beasley Spence, Tori Brittain, Owen Maher, Emily Lazard, Luke Lewis, Petr Lebedev, Emily Zhang, and Casper Mebius Thumbnail contributions by Ren Hurley, Peter Sheppard, Mike Radjabov, and Igant Barbeci Additional video/photos supplied by Getty Images and Storyblocks Music from Epidemic Sound

Democracy might be mathematically impossible – here’s why. Head to https://brilliant.org/veritasium to start your free 30-day trial and get 20% off an annual premium subscription. If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically. https://snatoms.com/ ▀▀▀ Massive thanks to Prof. Eric Maskin for helping with the script. Thanks to Chris Dong for inspiring this video. Massive thanks to Latif Nasser for being part of this video. ▀▀▀ A few great proofs of Arrow’s impossibility theorem: Yu, N. N. (2012). A one-shot proof of Arrow's impossibility theorem. Economic Theory, 523-525.- https://ve42.co/Yu2012 Geanakoplos, J. (2005). Three brief proofs of Arrow’s impossibility theorem. Economic Theory, 26(1), 211-215. - https://ve42.co/Geanakoplos2005 References: Arrow, K. J. (2012). Social choice and individual values (Vol. 12). Yale university press. - https://ve42.co/Arrow2012 Arrow, K. J. (1950). A Difficulty in the Concept of Social Welfare. Journal of Political Economy - https://ve42.co/Arrow1950 Black, D. (1948). On the rationale of group decision-making. Journal of political economy, 56(1), 23-34. - https://ve42.co/Black1948 Black, D. (1969). On Arrow's impossibility theorem. The Journal of Law and Economics, 12(2), 227-248. - https://ve42.co/Arrow1969 Maskin, E., & Sen, A. (2014). The Arrow impossibility theorem. Columbia University Press. - https://ve42.co/Maskin2014 Gehrlein, W. V., & Valognes, F. (2001). Condorcet efficiency: A preference for indifference. Social Choice and Welfare - https://ve42.co/Gehrlein2001 Dardanoni, V. (2001). A pedagogical proof of Arrow's Impossibility Theorem. Social Choice and Welfare, 18(1), 107-112. - https://ve42.co/Dardanoni2001 McCune, D., & Wilson, J. (2023). Ranked-choice voting and the spoiler effect. Public Choice, 196(1), 19-50. - https://ve42.co/McCune2023 Santucci, J. (2021). Variants of ranked-choice voting from a strategic perspective. Politics and Governance, 9(2), 344-353. - https://ve42.co/Santucci2021 Kaminski, M. M. (2018). Spoiler effects in proportional representation systems: evidence from eight Polish parliamentary elections, 1991–2015. Public Choice, 176(3), 441-460. - https://ve42.co/Kaminski2018 Brams, S. J., & Fishburn, P. C. (1978). Approval voting. American Political Science Review, 72(3), 831-847. - https://ve42.co/Brams1978 Other references and election results - https://ve42.co/IODRefs Images & Video: Minneapolis 2013 Debate Images: https://ve42.co/Minn2013Debate 4 Images from this article: https://ve42.co/MinnDebateMPR Arrow Nobel Prize Image from NYT Article: https://ve42.co/ArrowNYT ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Burt Humburg, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, I. H., Jack Cuprill, John H. Austin, Jr., Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, TTST, Tj Steyn, Ubiquity Ventures, gpoly, john kiehl, meg noah, wolfee ▀▀▀ Directed by Petr Lebedev and Derek Muller Written by Petr Lebedev and Derek Muller Edited by Trenton Oliver Animated by Fabio Albertelli, Jakub Misiek and Ivy Tello Filmed by Derek Muller Additional Research by Gabriel Bean Produced by Petr Lebedev, Derek Muller, Gabriel Bean, Rob Beasley Spence, Emily Lazard, Luke Lewis Thumbnail contributions by Jakub Misiek, Ren Hurley, Peter Sheppard Additional video/photos supplied by Getty Images Music from Epidemic Sound

Audio illusions show us that hearing is about more than just sensing frequency. Which ones trick you every time? Head to https://brilliant.org/veritasium to start your free 30-day trial and get 20% off an annual premium subscription. If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically. https://snatoms.com/ ▀▀▀ A big thank you to Titus Grenyer over at Pep Organ for showing us around the Sydney Town Hall Organ, to Dr. Diana Deutsch for providing her illusions and insight into the field, to Casey Connor for advice on building sound illusions, and to Dr. Michael Bach for providing the motion-bounce illusion. ▀▀▀ References: https://ve42.co/AudioIllusionsRefs Images & Video: Aircraft Detection before radar, 1917-1940 - https://ve42.co/e Women’s Auxiliary Air Force operator Denise Miley - https://ve42.co/f Daventry Experiment Van, operated by “Jock” Herd - https://ve42.co/g Perfect fifth - https://ve42.co/h Denge acoustic mirrors - The original uploader was Jksolomon at English Wikipedia. - https://ve42.co/q Denge sound mirrors | Sound Mirrors https://ve42.co/u Mayer telescope in 1880, US patent number 224199. NAE Website - Acoustic Source Localization Techniques and Their Applications https://ve42.co/s Professor Mayer’s Topophone - https://ve42.co/t ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Burt Humburg, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, TTST, Tj Steyn, Ubiquity Ventures, wolfee ▀▀▀ Directed by Sulli Yost and Derek Muller Hosted by Derek Muller Written by Sulli Yost and Derek Muller Edited by Jack Saxon and Peter Nelson Animated by Fabio Albertelli, David Szakaly, and Ivy Tello Illustrations by Jakub Misiek Filmed by Derek Muller Produced by Sulli Yost, Derek Muller, Rob Beasley Spence, Emily Lazard, Tori Brittain, Emily Zhang, Petr Lebedev, Gregor Čavlović, and Gabe Bean Thumbnail contributions by Peter Sheppard and Ren Hurley Additional video/photos supplied by Getty Images, Storyblocks, and Envato Music from GarageBand, Virtual Piano, and Epidemic Sound

The robots of our future may look nothing like humans at all. Head to https://brilliant.org/veritasium to start your free 30-day trial and get 20% off an annual premium subscription. Huge thanks to Dr. Elliot Hawkes for giving us the updates on his robots, and for showing them to us over the years! Our videos in this supercut: https://www.youtube.com/watch?v=qevIIQHrJZg https://www.youtube.com/watch?v=daaDuC1kbds https://www.youtube.com/watch?v=ZMQbHMgK2rw https://www.youtube.com/watch?v=97t7Xj_iBv0 https://www.youtube.com/watch?v=058hRtaCWC0 0:00 - Intro 2:04 - Unstoppable Vine Robot 15:13 - Update on Vine Robot! 20:24 - Highest Jumping Robot 32:15 - Update on the Jumper! 38:26 - Micromouse Competition 1:02:15 - Benefit of non-humanoid robots 1:02:48 - Brilliant 1:04:24 - Bendy Machines 1:16:26 - Soft Robots 1:25:55 - Conclusion ▀▀▀ Special thanks to our Patreon supporters! Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE Adam Foreman, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Burt Humburg, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Tj Steyn, TTST, Ubiquity Ventures, wolfee, and Yar If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ Images & Video: All New Atlas via Boston Dynamics on YouTube - https://ve42.co/NewAtlas Farewell to HD Atlas via Boston Dynamics on YouTube - https://ve42.co/HDAtlas C-3PO via Cinemax on YouTube - https://ve42.co/C3PO I, Robot via Movieclips on YouTube - https://ve42.co/iRobot I, Robot No via ukery on YouTube - https://ve42.co/iRobotNo Big Hero 6 via Flick Society on YouTube - https://ve42.co/BH6 Big Hero 6 via 茶茶君 on YouTube - https://ve42.co/2ndBH6 Roomba via iRobot on YouTube - https://ve42.co/Roomba ▀▀▀ Filmed by Derek Muller Edited by Trenton Oliver and Peter Nelson Produced by Emily Zhang, Gregor Čavlović, Rob Beasley Spence, and Emily Taylor Thumbnail contributions by Ignat Berbeci, Ren Hurley, and Peter Sheppard Additional video/photos supplied by Getty Images Music from Epidemic Sound

We experimented to see how much pain our volunteers could handle. Go to https://headspace-web.app.link/e/vstm to try Headspace for free using the code VERITASIUM Studies on Headspace - https://ve42.co/Headspace A massive thank you to Rayner Moss for recreating the experiment equipment and making this shoot happen. ▀▀▀ Special thanks to our Patreon supporters! Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE Adam Foreman, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Burt Humburg, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., John H. Austin, Jr., John Kiehl, Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Max Paladino, Meekay, Meg Noah, Michael Krugman, Name, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, Toni, TTST, Ubiquity Ventures, Wolfee. If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: Kahneman, D. et al. (1993). When More Pain Is Preferred to Less: Adding a Better End. Psychological Science - https://ve42.co/Kahneman1993 Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux - https://ve42.co/FastAndSlow Fredrickson, B. L., Kahneman, D. (1993). Duration neglect in retrospective evaluations of affective episodes. Journal of personality and social psychology - https://ve42.co/Fredrickson1993 Kahneman, D., Tversky, A. (1972). Subjective probability: A judgment of representativeness. Cognitive Psychology - https://ve42.co/Kahneman1972 Diener, E. et al. (2001). End Effects of Rated Life Quality: The James Dean Effect. Psychological Science - https://ve42.co/Deiner2001 Redelmeier, D. A. et al. (2003). Memories of colonoscopy: a randomized trial. Pain - https://ve42.co/Redelmeier2003 Kemp, S. et al. (2008). A test of the peak-end rule with extended autobiographical events. Memory & Cognition - https://ve42.co/Kemp2008 Images & Video: Daniel Kahneman via UNSW - https://ve42.co/ImgKahneman Barbara Fredrickson via UNC - https://ve42.co/ImgFredrickson Stephen Gould via achievement.org - https://ve42.co/ImgGould Amos Tversky via LGT - https://ve42.co/ImgTversky ▀▀▀ Directed by Petr Lebedev Written by Petr Lebedev and Derek Muller Edited by Peter Nelson Animated by Fabio Albertelli and Ivy Tello Illustrated by Jakub Misiek Filmed by Derek Muller and Bernard Lau Produced by Petr Lebedev, Derek Muller, Rob Beasley Spence, Owen Maher, David Szasz, Emily Taylor, Gregor Čavlović and Alistair Dann Thumbnail contributions by Ren Hurley and Peter Sheppard Additional video/photos supplied by Getty and Storyblocks Music from Epidemic Sound

How jumping spiders reveal an entire secret world of colors. Let BetterHelp connect you to a therapist who can support you - all from the comfort of your own home. Visit https://betterhelp.com/veritasium and enjoy a special discount on your first month. A massive thank you to everyone at Day’s Edge Productions for making this documentary happen. Check them out at https://daysedge.com/. You can watch the full-length documentary “The World According to Jumping Spiders” on Curiosity Stream - coming soon. ▀▀▀ Special thanks to our Patreon supporters! Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE Adam Foreman, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Bruce, Burt Humburg, Chris Harper, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Martin, Matthias Wrobel, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, Toni, TTST, Ubiquity Ventures, wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ Directed by Neil Losin Written by Neil Losin Edited by Neil Losin, Andy Laub, and Alan Saunders Animated by Root House Studio and David Hutchinson Filmed by Neil Losin, Nate Dappen, Alex Wiles, Andy Laub, and Barend van der Watt Produced by Day’s Edge Productions Repurposed for YouTube by Derek Muller, Casper Mebius, Petr Lebedev, Peter Nelson, Trenton Oliver, Emily Zhang, Giovanna Utichi, Rob Beasley Spence, Emily Taylor, and Gregor Čavlović Thumbnail contributions by Ren Hurley and Peter Sheppard Video/photos supplied by Day’s Edge Productions and Storyblocks Music by Adrian Younge, PBS, Epidemic Sound, and Jonny Hyman

Avalanches are beautiful, majestic, and completely terrifying – this is a video all about the science of avalanches. Head to https://brilliant.org/veritasium to start your free 30-day trial, and get 20% off an annual premium subscription. A massive thank you to everyone at Whistler Blackcomb for making this shoot happen – Dane Gergovich, David Iles, Alastair Collis, Erin Taylor, and everyone else on the ski patrol team. Thank you for keeping us safe! A massive thank you to Bruce Tremper, Niko Schirmer, and Mark Smiley for their expertise and help with this video. We are truly grateful for your time and expertise. If you have any intention of going into the backcountry, you have to read Bruce’s book – Staying Alive in Avalanche Terrain. It’s the Bible for this stuff, and the book that inspired us to make this video. ▀▀▀ Special thanks to our Patreon supporters! Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE Adam Foreman, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Burt Humburg, Chris Harper, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Martin, Matthias Wrobel, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, Toni , TTST, Ubiquity Ventures, wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: Tremper, B. (2001). Staying Alive in Avalanche Terrain. Mountaineers Books. - https://ve42.co/Tremper2001 McClung, D. & Schaerer, P. (2006). The Avalanche Handbook. Mountaineers Books. - https://ve42.co/McClung2006 Hopfinger, E. J. (1983). Snow Avalanche Motion and Related Phenomena. Annual Review of Fluid Mechanics. - https://ve42.co/Hopfinger1983 Schweizer, J. et al. (2003). Snow avalanche formation. Reviews of Geophysics. - https://ve42.co/Schweizer2003 Schweizer, J. et al. (2008). Review of spatial variability of snowpack properties and its importance for avalanche formation. Cold Regions Science and Technology. - https://ve42.co/Schweizer2008 Jamieson, B. (2006). Formation of refrozen snowpack layers and their role in slab avalanche release. Reviews of Geophysics. - https://ve42.co/Jamieson2006 Schweizer, J. et al. (2016). Avalance release 101. International Snow Science Workshop Proceeding. - https://ve42.co/Schweizer2016 Schweizer, J. (2008). Snow avalanche formation and dynamics. Cold Regions Science and Technology. - https://ve42.co/Schweizer2008-2 Images & Video: Skiing and snowboarding footage by Niko Schirmer - https://ve42.co/NikoYT World's Biggest Avalanche (c)Thom Goddard/All Star Films Ltd 2015. Thank you to the Thom Goddard Channel for use - https://ve42.co/ThomGoddard Newspaper clippings via Newspapers.com – https://ve42.co/Newspapers Video of a snow slab avalanche via Trottet, B. et al. (2022). Transition from sub-Rayleigh anticrack to supershear crack propagation in snow avalanches. Nature Physics. - https://ve42.co/Trottet2022 Remote Triggered Avalanche via Henry’s Avalanche Talk - Remote Triggering of an Avalanche WW1 images via Brugnara, Y. et al. (2016). December 1916: Deadly Wartime Weather. Geographica Bernensia - https://ve42.co/Brugnara2016 Major Avalanches via Geomorphological Hazards - https://ve42.co/MajorAvi White Friday avalanche illustration via Avalanches WIllow - https://ve42.co/WhiteFriday White Friday aftermath via Lost In History - https://ve42.co/AviGraves Field mass on Marmolada via Austrian National Library - https://ve42.co/AviMass Yungay disaster via NOAA - https://ve42.co/Yungay Yungay aftermath via AMC Museum - https://ve42.co/YungayAMC Bruce Tremper Image via utavy - https://ve42.co/BruceTPic Snowpack via SnowStudies.org - https://ve42.co/SnowStudies Snowpack via Avalanche.org - https://ve42.co/SnowPackAvi Snow crystals via Reiweger, I. (2011). Failure of weak snow layers. ETH. - https://ve42.co/Reiweger2011 ▀▀▀ Directed by Petr Lebedev Written by Petr Lebedev and Derek Muller Edited by Peter Nelson (Additional editing by James Horsley) Animated by Jakub Misiek, Fabio Albertelli, Alex Zepherin, and Alex Drakoulis Additional Research by Gregor Čavloviċ Filmed by Petr Lebedev and Ryan Regehr FPV Drone by Mitch Winton Produced by Petr Lebedev, Derek Muller, Han Evans, Giovanna Utichi, Rob Beasley Spence, Emily Taylor and Gregor Čavloviċ Thumbnail by Ren Hurley and Peter Sheppard Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

Einstein was wrong about black holes, what else? Use code veritasium at the link below to get an exclusive 60% off an annual Incogni plan: https://incogni.com/veritasium A massive thank you to Prof. Geraint F. Lewis and Prof. Juan Maldacena for their expertise and help with this video. A huge thank you to those who helped us understand this complicated topic: Dr. Suddhasattwa Brahma, Prof. Carlo Rovelli, Dr. Hal Haggard, Prof. Martin Bojowald, Dr. Francesca Vidotto, Prof. Andrew Hamilton, and Dr. Carl-Fredrik Nyberg Brodda. A special thanks to Alessandro Roussel from ScienceClic for his spectacular simulations and feedback on the video. Check out his channel here: https://ve42.co/ScienceClic An excellent book on this topic and an inspiration for this video: Cox, B., & Forshaw, J. (2023). Black holes: the key to understanding the universe. ▀▀▀ Special thanks to our Patreon supporters! Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE Adam Foreman, Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Burt Humburg, Chris Harper, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, I. H., John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Martin, Matthias Wrobel, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, Toni , TTST, Ubiquity Ventures, wolfee If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: Thorne, K. (1995). Black Holes & Time Warps: Einstein's Outrageous Legacy. Relativity Playlist by ScienceClic - https://ve42.co/SCPlaylist Hamilton, A. J. S. (2021). General Relativity, Black Holes, and Cosmology - https://ve42.co/Hamilton2021 Black Hole Events by PBS Space Time - https://youtu.be/vNaEBbFbvcY?list=PLsPUh22kYmNBl4h0i4mI5zDflExXJMo_x Newton’s Letters via The Newton Project - https://ve42.co/NewtonMail Einstein, A. (1915). Die feldgleichungen der gravitation. - https://ve42.co/Einstein1915 Why Time and Space Swap by ScienceClic - https://youtu.be/GQZ3R81iyE0 Schwarzschild, K. (1916). Über das Gravitationsfeld eines Massenpunktes nach der Einsteinschen Theorie. - https://ve42.co/Schwarzschild1916 Wali, K. C. (1982). Chandrasekhar vs. Eddington—an unanticipated confrontation. - https://ve42.co/Wali1982 How to Build a Black Hole by PBS Space Time - https://www.youtube.com/watch?v=xx4562gesw0 Oppenheimer, J. R., & Volkoff, G. M. (1939). On massive neutron cores. - https://ve42.co/TOVLimit Oppenheimer, J. R., & Snyder, H. (1939). On continued gravitational contraction. - https://ve42.co/Oppenheimer1939 Schwarzschild Geometry by Andrew Hamilton - https://ve42.co/SchwarzGeom Why all world maps are wrong by Vox - https://www.youtube.com/watch?v=kIID5FDi2JQ Hamilton, A. J., & Lisle, J. P. (2008). The river model of black holes. - https://ve42.co/HamiltonLisle2008 Mapping The Multiverse by PBS Space Time - https://www.youtube.com/watch?v=4v9A9hQUcBQ Rotating black hole via Wikipedia - https://ve42.co/WikiRBH Wormhole Travel by PBS Space Time - https://www.youtube.com/watch?v=ldVDM-v5uz0 Morris, M. S., & Thorne, K. S. (1988). Wormholes in spacetime and their use for interstellar travel. - https://ve42.co/MorrisThorne1988 Images & Video: D3 Geo Projection Library by Mike Bostock https://ve42.co/d3geo Interrupted Maps by Jason Davies https://ve42.co/DaviesMaps Kazmierczak, J. et al. (2021). NASA’s NICER Tests Matter’s Limits. - https://ve42.co/NasaNICER Bridgman, T. et al. (2024). M5.1 flare 'Double Whammy', at Active Regions 13559 and 13561. NASA SVS. - https://ve42.co/NasaFlare Schnittman, J. et al. (2019). Black Hole Accretion Disk Visualization. - https://ve42.co/NasaAccrDisk Wiessinger, S. et al. (2020). A Decade of Sun. NASA SVS. - https://ve42.co/NasaSunDecade Skelly, C. et al. (2017). What is a Neutron Star? NASA SVS. - https://ve42.co/NasaNeutron What would we see if we fell into a black hole by ScienceClic - https://youtu.be/4rTv9wvvat8 Earth texture - https://ve42.co/NASAEarth First image of Sgr A* - https://ve42.co/EHT1 Image of M87 - https://ve42.co/EHT2 Polarized light image of Sgr A* - https://ve42.co/EHT3 ▀▀▀ Directed by Casper Mebius Written by Casper Mebius, Derek Muller and Will Wood Edited by Trenton Oliver Animated by Fabio Albertelli, Ivy Tello, Mike Radjabov, David Szakaly, Jonny Hyman, and Alessandro Roussel Illustrated by Jakub Misiek Filmed by Derek Muller Additional research by Gregor Čavlović Produced by Casper Mebius, Derek Muller, Will Wood, Giovanna Utichi, Rob Beasley Spence, Gregor Čavlović, and Emily Taylor Thumbnail contributions by Jakub Misiek, Ren Hurley and Peter Sheppard Additional video/photos supplied by Getty Images, Storyblocks, and NASA SVS Music from Epidemic Sound

The number 37 is on your mind more than you think. Head to https://brilliant.org/veritasium to start your free 30-day trial and get 20% off an annual premium subscription. Huge thanks to Tom Magliery for sharing his 37 collection with us. Support http://thirty-seven.org by sharing your own 37 sightings to [email protected]! Thanks to Dr. Todd Landman, the Academic Magician, for sharing his footage of the 37 Force. - https://www.todd-landman.com/ ▀▀▀ Special thanks to our Patreon supporters! Join this list to help us keep our videos free, forever: https://ve42.co/PatreonDE Sam Lutfi, Lee Redden, Juan Benet, Richard Sundvall, Paul Peijzel, Gnare, Michael Krugman, Meekay, Ubiquity Ventures, Marinus Kuivenhoven, Bill Linder, Evgeny Skvortsov, Burt Humburg, Dave Kircher, Diffbot, john kiehl, Blake Byers, Stephen Wilcox, John H. Austin, Jr., Josh Hibschman, TTST, Orlando Bassotto, Anton Ragin, David Johnston, KeyWestr, Tj Steyn, meg noah, Chris Harper, Adam Foreman, Max Paladino, Balkrishna Heroor, I. H., Garrett Mueller, Bertrand Serlet, Kyi, wolfee, Matthias Wrobel If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ References: Simon, W. E. (1972). “Blue Seven Phenomenon” in Elementary and Jr. High Children. Psychological Reports - https://ve42.co/Simon1972 Trueman, J. (1979). Existence & Robustness of Blue Seven Phenomena. The Journal of General Psychology - https://ve42.co/Trueman1979 Saito, M. (1999). “Blue and Seven Phenomena” in Japanese Students. Perceptual & Motor Skills - https://ve42.co/Saito1999 Philbrick, J. L. (1976). Blue seven in East Africa: Preliminary report. Perceptual & Motor Skills - https://ve42.co/Philbrick1976 Hargreaves, S. (2009). The psychology of randomness. - https://ve42.co/Hargreaves2009 The 37 Force via The Magician’s Forum - https://ve42.co/37Force1 Fulves, K. (1979) Self-Working Mental Magic. Dover Publications, Inc. - https://ve42.co/Fulves1979 Random numbers via The Jargon File at catb.org - https://ve42.co/Jargon Random Number Survey by MahoganyForest via Reddit - https://ve42.co/RedditRndm Prime number theorem via Wikipedia - https://ve42.co/WikiPNT Grossack, C. (2023). A truly incredible fact about the number 37. Grossack.site - https://ve42.co/Grossack2023 Least prime factor of n via oeis.org - https://ve42.co/LeastPrime Fry, H. (2017). When should you settle down? ideas.ted.com - https://ve42.co/Fry2017 Choosing Toilets by Numberphile - https://www.youtube.com/watch?v=XIOoCKO-ybQ Seaton, R. (2014). The Secretary Problem Explained: Dating Mathematically. rs.io - https://ve42.co/Seaton2014 Images & Video: Just 37 by Tom Magliery - https://ve42.co/Just37 R4000 Processor via Molecular Expressions - https://ve42.co/micro37 The “37” Cluster by Noel Carboni - https://ve42.co/NGC2169 Charles Fleischer via Wikimedia - https://ve42.co/Fleischer ▀▀▀ Directed by Emily Zhang Written by Emily Zhang and Derek Muller Edited by Peter Nelson Asst edited by Luke Molloy Animated by Fabio Albertelli, Ivy Tello, and Leigh Williamson Illustrated by Jakub Misiek Filmed by Emily Zhang, Casper Mebius, Derek Muller, Michael Cimpher, and David Szasz Additional research by Gregor Čavlović Produced by Emily Zhang, Giovanna Utichi, Han Evans, and Emily Taylor Thumbnail contributions by Ignat Berbeci, Ren Hurley, and Peter Sheppard Additional video/photos supplied by Getty Images and Storyblocks Music from Epidemic Sound

This is a video about how Japanese samurai swords, aka katanas, are made – from the gathering of the iron sand, to the smelting of the steel, to the forging of the blade. Head over to https://hensonshaving.com/veritasium and enter code 'Veritasium' for 100 free blades with the purchase of a razor. Make sure to add both the razor and the blades to your cart for the code to take effect. Special thanks to our Patreon supporters! Join this list to help us keep our videos free, forever: https://ve42.co/PatreonDEB If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ A massive thank you to John McBride for making this entire project happen. This would not have been possible without John. Please check out his japan walking tours https://walkjapan.com/ Massive thanks to Craig Mod, Inoue-san, everyone in the Tanabe family, and Takanashi-san. Also a massive thank you to Kevin Cashen – https://cashenblades.com/ ▀▀▀ References: Tanii, H., Inazumi, T., & Terashima, K. (2014). Mineralogical study of iron sand with different metallurgical characteristic to smelting with use of Japanese classic iron-making furnace “Tatara”. ISIJ international, 54(5), 1044-1050. Tate, M. (2005). History of Iron and Steel Making Technology in Japan Mainly on the smelting of iron sand by Tatara. Tetsu-to-Hagane, 91(1), 2-10. Krauss, G. (1999). Martensite in steel: strength and structure. Materials science and engineering: A, 273, 40-57. Krauss, G., & Marder, A. R. (1971). The morphology of martensite in iron alloys. Metallurgical Transactions, 2, 2343-2357. Yalçın, Ü. (1999). Early iron metallurgy in Anatolia. Anatolian Studies, 49, 177-187. Kapp, L., Kapp, H., & Yoshihara, Y. (1987). The craft of the Japanese sword. Kodansha International. Matsumoto, C., Das, A. K., Ohba, T., Morito, S., Hayashi, T., & Takami, G. (2013). Characteristics of Japanese sword produced from tatara steel. Journal of Alloys and Compounds, 577, S673-S677. Inoue, T. (2010). Tatara and the Japanese sword: the science and technology. Acta Mechanica, 214(1), 17-30. Images & Video: Great video from NHK – https://ve42.co/NHK ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bill Linder, Blake Byers, Burt Humburg, Chris Harper, Dave Kircher, David Johnston, Diffbot, Evgeny Skvortsov, Garrett Mueller, Gnare, I.H., John H. Austin, Jr. ,john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Petr Lebedev Written by Petr Lebedev and Derek Muller Edited by Trenton Oliver, Jack Saxon, Peter Nelson Animated by Fabio Albertelli, Jakub Misiek, David Szakaly Filmed by Petr Lebedev and Lui Kimishima Produced by Petr Lebedev, Derek Muller, Han Evans, Giovanna Utichi, Emily Taylor Additional research by Gregor Čavlović Thumbnail by Peter Sheppard Additional video/photos supplied by Getty Images Music from Epidemic Sound

Do odd perfect numbers exist? Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV A massive thank you to Prof. Pace Nielsen for all his time and help with this video. A big thank you to Dr. Asaf Karagila, Pascal Ochem, Prof. Tianxin Cai, and Prof. William Dunham for their expertise and help. To try GIMPS out yourself: https://ve42.co/GIMPS These sources were particularly helpful: Perfect numbers via MacTutor - https://ve42.co/MTPerfect Cai, T. (2022). Perfect numbers and fibonacci sequences. World Scientific. - https://ve42.co/Cai2022 Dunham, W. (2022). Euler: The master of us all (Vol. 22). American Mathematical Society. - https://ve42.co/Dunham2022 ▀▀▀ References: https://www.youtube.com/watch?v=T0xKHwQH-4I&pp=ygUPcGVyZmVjdCBudW1iZXJz https://www.youtube.com/watch?v=q8n15q1v4Xo&pp=ygUPcGVyZmVjdCBudW1iZXJz Dickson, L. E. (1919). History of the Theory of Numbers.. (Vol. 1). Carnegie Institution of Washington. Knill, O. (2007). The oldest open problem in mathematics. NEU Math Circle, December2. - https://ve42.co/Knill2007 Perfect number via Wikipedia - https://ve42.co/WikiPerfect Introduction to Arithmetic via HalthiTrust - https://ve42.co/IntroArithmetic Nicomachus of Gerasa via MacTutor - https://ve42.co/MTNicomachus Sonja, B. (1988). The First Perfect Numbers and Three Types of Amicable Numbers in a Manuscript on Elementary Number Theory by Ibn Fellûs. Erdem, c. IV, 11. - https://ve42.co/Sonja1988 Ibn Fallus via Wikipedia - https://ve42.co/WikiFallus Mersenne prime via Wikipedia - https://ve42.co/WikiMP List of Known Mersenne Prime Numbers - https://ve42.co/ListOfMP Marin Mersenne via MacTutor - https://ve42.co/MTMersenne Leonhard Euler via Wikipedia - https://ve42.co/WikiEuler Frank Nelson Cole via Wikipedia - https://ve42.co/WikiFNCole GIMPS History via Mersenne.org - https://ve42.co/GIMPSHistory EFF Cooperative Computing Awards via EFF - https://ve42.co/EFFAwards Jonathan Pace via Primewiki - https://ve42.co/PWikiPace Book with just one number sells out in Japan via BastillePost - https://ve42.co/PrimeBook Predicted distribution of Mersenne primes via John D. Cook - https://ve42.co/JDCookMP Euler’s Odd Perfect Numbers Theorem via Cantor's Paradise - https://ve42.co/EulerOPN A Perfect (Math) Mystery via Medium - https://ve42.co/Machado2024 Brent, R. P., Cohen, G. L., & te Riele, H. J. (1991). Improved techniques for lower bounds for odd perfect numbers. Mathematics of Computation, 57(196), 857-868. - https://ve42.co/Brent1991 Ochem, P., & Rao, M. (2012). Odd perfect numbers are greater than 10¹⁵⁰⁰. Mathematics of Computation, 81(279), 1869-1877. - https://ve42.co/Ochem2012 Mathematicians Open a New Front on an Ancient Number Problem via Quantamagazine - https://ve42.co/QuantaSpoofs Descartes number via Wikipedia - https://ve42.co/WikiDescartesNumber Andersen, N., Durham, S., Griffin, M. J., Hales, J., Jenkins, P., Keck, R., ... & Wu, D. (2022). Odd, spoof perfect factorizations. Journal of Number Theory, 234, 31-47. - https://ve42.co/Andersen2022 Pomerance’s Heuristic that Odd Perfect Numbers are Unlikely via OddPerfect.org - https://ve42.co/Heuristic Images & Video: Clip of Piergiorgio Odifreddi - https://www.youtube.com/watch?v=y0paHEA8-gA Euclid’s Elements 1 via Claymath - https://ve42.co/CM1 Euclid’s Elements 2 via Claymath - https://ve42.co/CM2 Euclid’s Elements 3 via Claymath - https://ve42.co/CM3 Diophanti - https://ve42.co/Diophanti Gauss book - https://ve42.co/GaussDis Euler’s Archive 1 - https://ve42.co/Euler1 Euler’s Archive 2 - https://ve42.co/Euler2 ▀▀▀ Special thanks to our Patreon supporters: Anton Ragin, Balkrishna Heroor, Bertrand Serlet, Bill Linder, Blake Byers, Burt Humburg, Chris Harper, Dave Kircher, David Johnston, Diffbot, Evgeny Skvortsov, Garrett Mueller, Gnare, I.H., John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures, wolfee ▀▀▀ Directed by Casper Mebius Written by Casper Mebius and Derek Muller Edited by Peter Nelson Illustrated by Jakub Misiek Animated by Fabio Albertelli, Ivy Tello, David Szakaly, Alondra Vitae, Alex Drakoulis, and Leigh Williamson Filmed by Derek Muller, Raquel Nuno, and Peter Nelson Additional research by Aaron Santos, Camilla Machado, and Gregor Čavlović Produced by Casper Mebius, Gregor Čavlović, Han Evans, and Derek Muller Thumbnail by Ren Hurley Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

The most famous equation in finance, the Black-Scholes/Merton equation, came from physics. It launched an industry worth trillions of dollars and led to the world’s best investments. Go to https://www.eightsleep.com/veritasium and use the code Veritasium for $200 off your Pod Cover. If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV ▀▀▀ A huge thank you to Prof. Andrew Lo (MIT) for speaking with us and helping with the script. We would also like to thank the following: Prof. Amanda Turner (University of Leeds) Owen Maher (Electrify Video Partners) ▀▀▀ References: The Man Who Solved the Market: How Jim Simons launched the quant revolution, Gregory Zuckerman. Penguin Publishing Group. - https://ve42.co/GZuckerman The Physics of Finance: Predicting the Unpredictable: Can Science Beat the Market? James Owen Weatherall. Short Books. - https://ve42.co/FinancePhysics The Statistical Mechanics of Financial Markets, J.Voigt. Springer. - https://ve42.co/Springer Black, F., & Scholes, M. (1973). The pricing of options and corporate liabilities. Journal of political economy, 81(3), 637-654. - https://ve42.co/BlackScholes Cornell, B. (2020). Medallion fund: The ultimate counterexample?. The Journal of Portfolio Management, 46(4), 156-159. - https://ve42.co/Medallion Images & Video: Ed Thorp on The Tim Ferris Show - https://www.youtube.com/watch?v=CNvz91Jyzbg Jim Simons on TED - https://www.youtube.com/watch?v=U5kIdtMJGc8 Jim Simons on Numberphile - https://www.youtube.com/watch?v=QNznD9hMEh0 ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bill Linder, Blake Byers, Burt Humburg, Chris Harper, Dave Kircher, David Johnston, Diffbot, Evgeny Skvortsov, Garrett Mueller, Gnare, I.H., John H. Austin, Jr. ,john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Will Wood and Derek Muller Written by Will Wood, Emily Zhang, Petr Lebedev and Derek Muller Camera operation by Raquel Nuno Additional research by Gregor Čavlović Edited by Jack Saxon and Trenton Oliver Animated by Fabio Albertelli, Jakub Misiek, Ivy Tello, David Szakaly and Will Wood Produced by Will Wood, Han Evans and Derek Muller Thumbnail by Ren Hurley Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

The blue LED was supposed to be impossible—until a young engineer proposed a moonshot idea. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV Huge thanks to the UC Santa Barbara Materials Dept (https://ssleec.ucsb.edu/) for taking us around. Thanks to Álvaro Bermejillo Seco for reviewing the science. Thanks to these especially helpful sources: Nobel Prize Biography - Shuji Nakamura - https://ve42.co/NakamuraNobel Johnstone, B. (2015). Brilliant!. Prometheus Books. - https://ve42.co/Johnstone2015 Nakamura, S., Pearton, S., & Fasol, G. (2010). The Blue Laser Diode: The Complete Story. Springer. - https://ve42.co/Nakamura2010 ▀▀▀ References: https://www.youtube.com/watch?v=O8M2z2hIbag https://www.youtube.com/watch?v=TGUteH93xNo https://www.youtube.com/watch?v=idwKHQEw78g https://www.youtube.com/watch?v=yoTALRhAqWc Touchstone, L. A. (2022). Nick Holonyak Jr. University of Illinois. - https://ve42.co/Touchstone2022 Perry, T. S. (1995). The Unsung Inventor. IEEE Spectrum. - https://ve42.co/Perry1995 Chabay, R. & Sherwood, B. (2011). Matter & interactions (4th ed.), S2: Semiconductors. Wiley. - https://ve42.co/ChabaySherwood How MOCVD Works via Aixtron - https://ve42.co/MOCVD Vangala, S. R., et al. (2019). Epitaxial growth of ZnSe on GaAs. Journal of Crystal Growth. - https://ve42.co/Vangala2019 Nakamura, S. (1991). GaN Growth Using GaN Buffer Layer. JJAP. - https://ve42.co/Nakamura3rd1991 Amano, H., et al. (1989). P-Type Conduction in Mg-Doped GaN w/ LEEBI. JJAP. - https://ve42.co/Amano1989 Huang, M., et al. (2021). Defects in Mg–H‐Codoped GaN. Physica Status Solidi. - https://ve42.co/Huang2021 Schubert, E. F. (2006). Light Emitting Diodes, Ch 4: LED basics. Cambridge University Press. - https://ve42.co/RPI-LEDs Kitada, C. (2001). Blue About Japan. Japan Inc. - https://ve42.co/Kitada2001 Whitaker, T. (2002). Nakamura loses Nichia patent battle. Optics.org. - https://ve42.co/NichiaSales3 Pirates Osaka. (2014). Nakamura awarded Nobel Prize in Physics. Hatena Blog. - https://ve42.co/NichiaSales1 Growth Bozu via Twitter. - https://ve42.co/NichiaSales2 Rose, J. (2014). Blue LEDs – Filling the world with new light. The Royal Swedish Academy of Sciences. - https://ve42.co/Rose2014 Pattison, P. M., et al. (2017). LED lighting efficacy. Comptes Rendus Physique. - https://ve42.co/Pattison2017 Electricity pricing via EIA - https://ve42.co/ElectricityPricing Lane, K., et al. (2023). Lighting. IEA. - https://ve42.co/LightingIEA LED Footprint via The Climate Group - https://ve42.co/ClimateGroupLED Nichia’s History via Nichia - https://ve42.co/NichiaHistory Shuji Nakamura via Wikipedia - https://ve42.co/NakamuraWiki Images & Video: Lighting the World via UCTVInsight on YouTube - https://ve42.co/UCTVep2 & https://ve42.co/UCTVep3 Palo Alto Times 1971 Article via Newspapers.com - https://ve42.co/Newspapers Nick Holonyak, Jr. and the LED via UIUC on YouTube - https://ve42.co/HolonyakIllinois The Original Blue LED via Science History Institute on YouTube - https://ve42.co/OGBlueLED Maxfield, M. (2022). Compound Semiconductors. EE Journal. - https://ve42.co/Maxfield2022 M. Stutzmann, et al. (2001). Playing with Polarity. pss (b). - https://ve42.co/Stutzman2001 Isamu Akasaki in 1995 via Andrey Nikolaev on YouTube - https://ve42.co/AsakiNikolaev Pioneer TX-610 Stereo Tuner via Ian Marino on YouTube - https://ve42.co/StereoMarino Shuji Nakamura via EPO on YouTube - https://ve42.co/NakamuraEPO Nichia Campus via Nichia on LinkedIn - https://ve42.co/NichiaHQ Nichia via TDElektronik on YouTube - https://ve42.co/NichiaTDE Violeds Sterilization of COVID-19 via Seoul Viosys - https://ve42.co/SterilizationUV ▀▀▀ Special thanks to our Patreon supporters: Chris Harper, Max Paladino, Balkrishna Heroor, Adam Foreman, Orlando Bassotto, Tj Steyn, meg noah, KeyWestr, TTST, John H. Austin, Jr., john kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Juan Benet, David Johnston, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Sam Lutfi ▀▀▀ Directed by Emily Zhang Written by Emily Zhang, Ricky Nathvani, and Derek Muller Edited by Trenton Oliver Illustrated by Jakub Misiek Animated by Fabio Albertelli, Mike Radjabov, David Szakaly, Ivy Tello, and Alondra Vitae Filmed by Derek Muller, Raquel Nuno, and Trenton Oliver Additional research by Gregor Čavlović Produced by Emily Zhang, Han Evans, Gregor Čavlović, and Derek Muller Thumbnail by Ren Hurley Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

How a rainfall simulator saves millions of lives. Get exclusive NordVPN deal here ➵ https://NordVPN.com/veritasium. It’s risk free with Nord’s 30 day money-back guarantee! If you’re looking for a molecular modeling kit, try Snatoms – a kit I invented where the atoms snap together magnetically – https://ve42.co/SnatomsV ▀▀▀ Huge thanks to Okouchi-San and Dr. Sakai and everyone at NIED and the Large Scale Rainfall Simulator for their time, expertise and access to this amazing facility. A big thank you to Prof. Olga Mavrouli and Prof. Bill Schulz for their invaluable expertise on the mechanisms of landslides. ▀▀▀ References: Ulbrich, C. W. (1983). Natural variations in the analytical form of the raindrop size distribution. Journal of climate and applied meteorology, 1764-1775. – https://ve42.co/Ulbrich83 Van Boxel, J. H. (1997, November). Numerical model for the fall speed of rain drops in a rain fall simulator. In Workshop on wind and water erosion (Vol. 5, pp. 77-85). – https://ve42.co/Boxel87 Canuti, P., Focardi, P., & Garzonio, C. (1985). Correlation between rainfall and landslides. Bulletin of Engineering Geology & the Environment, 32(1). Tsaparas, I., Rahardjo, H., Toll, D. G., & Leong, E. C. (2002). Controlling parameters for rainfall-induced landslides. Computers and geotechnics, 29(1), 1-27. – https://ve42.co/Tsaparas2002 Nakamura, H., & Oosawa, M. (2021, March). Effects of the underground discharge channel/reservoir for small urban rivers in the Tokyo area. In IOP Conference Series: Earth and Environmental Science (Vol. 703, No. 1, p. 012029). IOP Publishing. – https://ve42.co/Nakamura21 Guthrie, R. H., & Evans, S. G. (2004). Magnitude and frequency of landslides triggered by a storm event, Loughborough Inlet, British Columbia. Natural Hazards and Earth System Sciences, 4(3), 475-483. – https://ve42.co/Guthrie2004 Images & Video: Miyako, Iwate Tsunami via ANNnewsCH - https://ve42.co/Miyako2011 Mount Onake Volcano via BBC News - https://ve42.co/BBCOnake Typhoon Jebi via Al Jazeera - https://ve42.co/TyphoonJebi East Asia Typhoons via CBC News - https://ve42.co/TyphoonCBC Atami Landslide via The Quint - https://ve42.co/Atami2021 Atami Landslide via news.com.au - https://ve42.co/2ndAtami2021 Sendai Earthquake via ANNnewsCH - https://ve42.co/SendaiQuake Nagasaki Mudslide via The Telegrap - https://ve42.co/NagasakiMudslide Wajima Landslide via Guardian News - https://ve42.co/WajimaLandslide Drone Rainfall Test via AIZAWAchan - https://ve42.co/DroneRain Car Rainfall Test via TIER IV - https://ve42.co/CarRainTest Rainfall Simulator via NIED - https://ve42.co/RainfallSim1 External Footage of Simulator via NIED - https://ve42.co/RainfallSim2 Landslide Simulations via NIED - https://ve42.co/RainfallSim3 Typhoon Prapiroon via Force Thirteen - https://ve42.co/TyphoonPrapiroon Yanohigashi Floods via CNA - https://ve42.co/YanohigashiFloods Japan Floods via The Telegraph - https://ve42.co/TelegraphFlood Japan Floods via euronew - https://ve42.co/EuroNewsFlood Typhoon Hagibis via Guardian News - https://ve42.co/TyphoonHagibis Typhoon Hagibis via SCMP - https://ve42.co/TyphoonHagibisSCMP Satellite Imagery of Hagibis via Force Thirteen - https://ve42.co/HagibisSatellite Tokyo Flood Control System via NikkeiAsia.com - https://ve42.co/FloodControl Landslides Footage via Underworld - https://ve42.co/MonsterLandslides Norway Landslide via ABC7 - https://ve42.co/NorwayLandslide Planet Destruction via BBC - https://ve42.co/BBCDestruction B.C. Climate Change Danger via CBC News - https://ve42.co/BCClimateChange Canada’s Logging Roads via CBC News - https://ve42.co/CBCLogging ▀▀▀ Special thanks to our Patreon supporters: Chris Harper, Max Paladino, Balkrishna Heroor, Adam Foreman, Orlando Bassotto, Tj Steyn, meg noah, KeyWestr, TTST, John H. Austin, Jr., john kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Juan Benet, David Johnston, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Sam Lutfi ▀▀▀ Directed by Petr Lebedev Written by Petr Lebedev Edited by Peter Nelson Additional Research by Gregor Čavlović Animated by Fabio Albertelli Illustrations by Jakub Misiek Filmed by Petr Lebedev, Emily Zhang, Derek Muller Produced by Petr Lebedev, Han Evans and Gregor Čavlović Thumbnail by Peter Sheppard Additional video/photos supplied by Getty Images Music from Epidemic Sound

People don’t understand the scale of the Universe. There’s a data driven way to read the news: go to https://ground.news/veritasium to get 30% off the Vantage plan and see through sensationalized reporting. If you’re looking for a molecular modeling kit, try Snatoms – a kit I invented where the atoms snap together magnetically – https://ve42.co/SnatomsV ▀▀▀ A huge thank you to Dr. Ashmeet Singh for his expert feedback on this video. ▀▀▀ References: Fun video by RealLifeLore about the scale of the Universe - https://www.youtube.com/watch?v=Iy7NzjCmUf0&pp=ygUkcmVhbCBsaWZlIGxvcmUgc2NhbGUgb2YgdGhlIHVuaXZlcnNl Moon Facts via NASA - https://ve42.co/NASAMoon Titan Facts via NASA - https://ve42.co/Titan Mercury Facts via NASA - https://ve42.co/Mercury Why Pluto is no Longer a Planet, BBC News via YouTube - https://www.youtube.com/watch?v=iIk29MnzZWA&pp=ygUYcGx1dG8gbm8gbG9uZ2VyIGEgcGxhbmV0 Pluto, Wikipedia - https://ve42.co/WikiPluto Eris, Wikipedia - https://ve42.co/WikiEris Brown, M. E., & Schaller, E. L. (2007). The mass of dwarf planet Eris. Science, 316(5831), 1585-1585. - https://ve42.co/Brown2007 Trans-Neptunian object, Wikipedia - https://ve42.co/WikiTNO IAU 2006 General Assembly Press Release, via IAU - https://ve42.co/IAU2006 Solar System Moons via NASA - https://ve42.co/NASAMoons Solar System Asteroids via NASA - https://ve42.co/Asteroids Solar System, Wikipedia - https://ve42.co/WikiSolarSystem How many stars are in the Universe via ESA - https://ve42.co/ESAStars Catalog of Exoplanets via exoplanet - https://ve42.co/ExoplanetCatalog Crowther, T. W., Glick, H. B., Covey, K. R., Bettigole, C., Maynard, D. S., Thomas, S. M., ... & Bradford, M. A. (2015). Mapping tree density at a global scale. Nature, 525(7568), 201-205. - https://ve42.co/Crowther2015 Galaxy, Wikipedia - https://ve42.co/WikiGalaxy Counting Galaxies with the Hubble Space Telescope via NASA - https://ve42.co/CountingGalaxies Conselice, C. J., Wilkinson, A., Duncan, K., & Mortlock, A. (2016). The evolution of galaxy number density at z8 and its implications. The Astrophysical Journal, 830(2), 83. - https://ve42.co/Conselice2016 Sagan, C., & Druyan, A. (2011). Pale blue dot: A vision of the human future in space. Ballantine books. Images & Video: Clip of Titan’s Surface, NASA via YouTube - https://www.youtube.com/watch?v=xn3-0a19sC8 Clips of Pluto Had it Coming, The Late Show with Stephen Colbert via YouTube - https://www.youtube.com/watch?v=5nqT7XrYRPc Image of Solar System Objects - https://ve42.co/SolarSystemObjects ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bill Linder, Blake Byers, Burt Humburg, Chris Harper, Dave Kircher, David Johnston, Diffbot, Evgeny Skvortsov, Gnare, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Max Paladino, Meekay, meg noah, Michael Krugman, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Casper Mebius Written by Casper Mebius and Derek Muller Additional research & fact checking by Gregor Čavlović Edited by Peter Nelson Animated by Ivy Tello and Alondra Vitae Filmed by Derek Muller, Raquel Nuno and Zyan Treadwell Produced by Derek Muller, Casper Mebius and Han Evans Additional video/photos supplied by Getty Images, StoryBlocks and by courtesy of NASA, NASA's Goddard Space Flight Center/SDO, NASA JPL, NASA/JPL-Caltech NASA GSFC, NASA HQ, NASA's Scientific Visualization Studio, NCSA, A. Kritsuk, M. Norman Music from Epidemic Sound Thumbnail by Peter Sheppard

This is a video about the most famous problem in Game Theory, the Prisoner’s Dilemma. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. If you’re looking for a molecular modeling kit, try Snatoms – a kit I invented where the atoms snap together magnetically – https://ve42.co/SnatomsV ▀▀▀ A massive thank you to Prof. Robert Axelrod and Prof. Steven Strogatz for their expertise and time. To read more about Prof. Axelrod’s Passion for Cooperation visit: https://ve42.co/Axelrod2023 A massive thanks to the wonderful Nicky Case. Nicky’s “The Evolution of Trust” game was a huge inspiration for this video. We highly recommend you play this excellent game yourself, over at: https://ncase.me/trust/ A huge thank you to those who helped us understand and fact check different parts of this topic - Dr. Christian Hilbe, Dr. Vincent Knight, Dr. Jelena Grujic, Prof. Andreas Diekmann, and Dr. Alexander Stewart. ▀▀▀ References: Excellent game on the evolution of trust by Nicky Case - https://ve42.co/Case2023 Summary of Axelrod’s work by This Place - https://www.youtube.com/watch?v=BOvAbjfJ0x0 How to outsmart the Prisoner’s Dilemma by TED-Ed - https://www.youtube.com/watch?v=emyi4z-O0ls&pp=ygUScHJpc29uZXIncyBkaWxlbW1h Tit for Tat by radiolab - https://ve42.co/T4T The Golden Rule by radiolab - https://ve42.co/GoldenRule Axelrod, R. (1984). The Evolution of Cooperation. Dawkins, R. (2016). The selfish gene. Oxford university press. Poundstone, W. (1992). Prisoner's Dilemma. William Poundstone. Nowak, M. A., & Highfield, R. (2011). Supercooperators. Edinburgh: Canongate. Binmore, K. (2007). Game theory: a very short introduction. OUP Oxford. Northrup, L. & Rock, D. (1966). The Detection of Joe I. - https://ve42.co/JOE1 Prisoner’s dilemma, Wikipedia - https://ve42.co/WikiPD Prisoner’s Dilemma, Stanford - https://ve42.co/StanfordPD Flood, M. M. (1952). Some experimental games. - https://ve42.co/Flood1952 Historical nuclear weapons stockpiles, Wikipedia - https://ve42.co/WikiNWS Goodwin, I. (1998). The Price of Victory in Cold War - https://ve42.co/Goodwin1998 Cold war: How it happened. - https://ve42.co/CW2014 Axelrod, R. (1980). Effective choice in the prisoner's dilemma. Journal of conflict resolution, 24(1), 3-25. - https://ve42.co/Axelrod1980a Axelrod, R. (1980). More effective choice in the prisoner's dilemma. Journal of conflict resolution, 24(3), 379-403. - https://ve42.co/Axelrod1980b Axelrod, R., & Hamilton, W. D. (1981). The evolution of cooperation. science, 211(4489), 1390-1396. https://ve42.co/Axelrod1981 Stanislav Petrov, Wikipedia - https://ve42.co/WikiSP Wu, J., & Axelrod, R. (1995). How to cope with noise in the iterated prisoner's dilemma. Journal of Conflict resolution, 39(1), 183-189. - https://ve42.co/Wu1995 INF Treaty - https://ve42.co/INF START Treaties - https://ve42.co/START START I, Wikipedia - https://ve42.co/WikiSTART Images & Video: RAND Historical images via rand.org - https://ve42.co/RAND Golden Balls - https://www.youtube.com/watch?v=S0qjK3TWZE8 Zotti, G., et al. (2021). The Simulated Sky: Stellarium for Cultural Astronomy Research - https://ve42.co/Stellarium Newspapers from 1980s via Newspapers.com – https://ve42.co/Newspapers Decommisioned nuke image via The Moscow Times - https://ve42.co/MT2012 Soviet inspection image via Bulletin of the Atomic Scientists - https://ve42.co/Krzyzaniak2019 Decommissioning nuclear weapon via ShareAmerica - https://ve42.co/Kaufman2014 ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Amadeo Bee, Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, Jesse Brandsoy, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Mario Bottion, Max Maladino, Meekay, meg noah, Michael Krugman, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Casper Mebius Written by Casper Mebius, Derek Muller, Petr Lebedev, and Ashley Hamer Additional research and fact checking by Gregor Čavlović and Will Wood Edited by Peter Nelson Animated by Fabio Albertelli, Ivy Tello and Alondra Vitae Illustrations by Jakub Misiek Filmed by Derek Muller Produced by Casper Mebius, Derek Muller, Gregor Čavlović and Han Evans Additional video/photos supplied by Getty Images Music from Epidemic Sound Thumbnail by Peter Sheppard

This is the world’s largest earthquake simulator, here’s how it works. For a free trial to Shopify go to https://www.shopify.com/veritasium. If you’re looking for a molecular modeling kit, head to https://ve42.co/SnatomsV to try Snatoms – a kit I invented where the atoms snap together magnetically. ▀▀▀ A massive thank you to everyone at NIED for allowing access to their facility. Massive thanks to Okouchi-san for arranging this shoot. A huge thank you to Dr. Yohsuke Kawamata for the tour of E-defense and for sharing his deep expertise. ▀▀▀ References: Nakashima, M., et al. (2018). Experiences, accomplishments, lessons, and challenges of E‐defense. Tests using world's largest shaking table. Japan Architectural Review, 1(1), 4-17. - https://ve42.co/Nakashima Suganuma, K. (2005). 3-D Full-Scale Earthquake Testing Facility (E-Defense). NISTEP Science & Technology Foresight Center. - https://ve42.co/Suganuma Ohtani, K., et al. (2004). Construction of E-Defense (3-D full-scale earthquake testing facility). In Thirteenth World Conference on Earthquake Engineering (Vol. 189). - https://ve42.co/Ohtani Horiuchi, T., et al. (2022). Contributions of E-Defense Shaking Table to Earthquake Engineering and its Future. Journal of Disaster Research, 17(6), 985-999. - https://ve42.co/Horiuchi Nakamura, I., et al. (2008). E-Defense experiments on full-scale wooden houses. In Proceedings of the 14th World conference on earthquake engineering, Beijing, China (pp. 12-17). - https://ve42.co/Nakamura Japan: The Next Big Quake. Financial Times. - https://ve42.co/BigQuake Images & Video: Kobe earthquake compilation - https://ve42.co/Kobe ▀▀▀ Special thanks to our Patreon supporters: carrotcypher, Chris Harper, Max Paladino, Balkrishna Heroor, Adam Foreman, Orlando Bassotto, Tj Steyn, meg noah, KeyWestr, TTST, John H. Austin, Jr., john kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Juan Benet, David Johnston, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Sam Lutfi. ▀▀▀ Directed by Will Wood and Petr Lebedev Written by Will Wood, Petr Lebedev and Derek Muller Edited by Jack Saxon and Trenton Oliver Animated by Fabio Albertelli, Ivy Tello, Leigh Williamson, David Szakaly Filmed by Petr Lebedev, Lui Kimishima and Derek Muller Produced by Will Wood, Petr Lebedev, Han Evans and Derek Muller Thumbnail by Ren Hurley Additional video/photos supplied by Getty Images and NIED (E-defense) Music from Epidemic Sound

How an SAT question became a mathematical paradox. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. I invented Snatoms, a molecule modeling kit where the atoms snap together magnetically. Try it at https://ve42.co/SnatomsV Huge thanks to Dr. Doug Jungreis for taking the time to speak with us about this SAT question. Thanks to Stellarium, a wonderful free astronomy simulator – https://ve42.co/Stellarium Thanks to Newspapers.com, a database of historical newspapers – https://ve42.co/Newspapers ▀▀▀ References: Summary of this problem by MindYourDecisions – https://www.youtube.com/watch?v=kN3AOMrnEUs More cool math about this problem by Kyle Hill – https://www.youtube.com/watch?v=_zCDbB9wvrc Murtagh, J. (2023). The SAT Problem That Everybody Got Wrong. Scientific American – https://ve42.co/SATSciAm United Press International (1982). Error Found in S.A.T. Question. New York Times – https://ve42.co/SAT-NYT Yang (2020). What's the hardest SAT math problem that you've seen? Quora – https://ve42.co/SATQuora Coin rotation paradox via Wikipedia – https://ve42.co/CoinParadox Simmons, B. (2015). Circle revolutions rolling around another circle. MathStackExchange. – https://ve42.co/CircleRoll Sidereal time via Wikipedia – https://ve42.co/SiderealWiki Solar Time vs. Sidereal Time via Las Cumbres Observatory – https://ve42.co/SiderealLCO Images & Video: Zotti, G., et al. (2021). The Simulated Sky: Stellarium for Cultural Astronomy Research - https://ve42.co/Stellarium Newspapers from 1980s - 1990s via Newspapers.com – https://ve42.co/Newspapers SAT Practice Test via the College Board – https://ve42.co/PracticeSAT Revolution Definition via NASA – https://ve42.co/RevolutionNASA Revolution Definition via Merriam-Webster – https://ve42.co/RevolutionWebster Earth motion animation via NASA – https://ve42.co/OrbitNASA Satellite animation via NASA – https://ve42.co/SatNASA ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Chris Harper, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Emily Zhang Written by Emily Zhang and Gregor Čavlović Edited by Peter Nelson Animated by Ivy Tello and Fabio Albertelli Filmed by Derek Muller Produced by Emily Zhang, Gregor Čavlović, and Derek Muller Thumbnail by Ren Hurley Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

Sewing machines are mechanical marvels – here’s how they work. Get your first month of KiwiCo FREE at https://www.kiwico.com/veritasium ▀▀▀ A huge thanks to Prof. Andy Ruina for suggesting this video topic, guiding us in the research, and giving deeply insightful notes. Massive thanks to Noah Johnson and Tina Vines for teaching Derek how to chain-stitch, and letting us shoot with your embroidery machine! Please check out stitchrite and tina_vines on instagram if you're interested in seeing more of their gorgeous chain stitch embroidery. Thanks to Denny Stanley and the whole crew at Las Vegas Props for building the large replica model of the sewing machine. https://www.vegasprops.net ▀▀▀ References: Parton, J. (1870). History of the Sewing-machine. Howe Machine Company, No. 38, N. Charles St.. -- https://ve42.co/Patron1870 Gregory, J. M. (2006). A History of the Sewing Machine to 1880. Transactions of the Newcomen Society, 76(1), 127-144. -- https://ve42.co/Gregory2006 How America Spends Money: 100 Years In the Life of the Family Budget, The Atlantic -- https://ve42.co/Budget1 Buckman, J. (2016). Unraveling the Threads: The Life, Death and Resurrection of the Singer Sewing Machine Company, America’s First Multi-National Corporation. Dog Ear Publishing. Lewton, F. L. (1930). The servant in the house: a brief history of the sewing machine (Vol. 3056). US Government Printing Office. -- https://ve42.co/Lewton1930 ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Chris Harper, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Petr Lebedev Written by Petr Lebedev, Derek Muller, Felicity Nelson Edited by Trenton Oliver Animated by Mike Radjabov, Fabio Albertelli and Jakub Misiek Filmed by Derek Muller, Raquel Nuno, Gene Nagata and Taylor Cody Aditional Research by Gregor Čavlović Produced by Petr Lebedev, Han Evans, and Derek Muller Additional video/photos supplied by Getty Images and Storyblocks Music from Epidemic Sound

How to lead a happier and longer life. Check out our sponsor: https://betterhelp.com/veritasium to get matched with a professional therapist who will listen and help. ▀▀▀ A huge thanks to Prof. Robert Waldinger for all his help with this video. To learn more about what makes for a good life, visit: https://the-good-life-book.com/ and https://www.youtube.com/watch?v=8KkKuTCFvzI&pp=ygUJd2FsZGluZ2Vy A special thanks to Prof. Julianne Holt-Lunstad for her expert advice on the importance of social connections and the detrimental effects of loneliness and social isolation. ▀▀▀ Additional Videos: Family Reacts to Winning CA$1 Million Lotto, NowThisNews via YouTube - https://ve42.co/CA1Lottery Woman claims to be $1 billion Powerball winner, KTLA 5 via YouTube - https://ve42.co/1BilLottery Old Lottery Winner Meets Young Lottery Winner | The Gap, LADbible TV via YouTube - https://ve42.co/LADBibleLottery Why eyewitnesses get it wrong - Scott Fraser, TED-Ed via Youtube - https://ve42.co/TEDFraser Surgeon General discusses health risks of loneliness and steps to help connect with others, PBS NewsHour via YouTube - https://ve42.co/PBS-SG ▀▀▀ References: Waldinger, R., & Schulz, M. (2023). The Good Life: Lessons from the World's Longest Scientific Study of Happiness. Simon and Schuster. Lindqvist et al. (2020). Long-run effects of lottery wealth on psychological well-being. The Review of Economic Studies. - https://ve42.co/Lindqvist2020 Wen et al. (2011). Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study. The lancet. - https://ve42.co/Wen2011 Nocon et al. (2008). Association of physical activity with all-cause and cardiovascular mortality: a systematic review and meta-analysis. European Journal of Preventive Cardiology. - https://ve42.co/Nocon2008 Blondell et al. (2014). Does physical activity prevent cognitive decline and dementia?: A systematic review and meta-analysis of longitudinal studies. BMC public health. - https://ve42.co/Blondell2014 Office of the Surgeon General. (2023). Our Epidemic of Loneliness and Isolation: The US Surgeon General’s Advisory on the Healing Effects of Social Connection and Community. - https://ve42.co/LonelinessEpidemic Holt-Lunstad et al. (2010). Social relationships and mortality risk: a meta-analytic review. PLoS medicine. - https://ve42.co/Holt-Lunstad2010 Valtorta et al. (2016). Loneliness and social isolation as risk factors for coronary heart disease and stroke: systematic review and meta-analysis of longitudinal observational studies. Heart. - https://ve42.co/Valtorta2016 Shovestul et al. (2020). Risk factors for loneliness: The high relative importance of age versus other factors. PloS one. - https://ve42.co/Shovestul2020 Donovan et al. (2017). Loneliness, depression and cognitive function in older US adults. International journal of geriatric psychiatry. - https://ve42.co/Donovan2017 Lara et al. (2019). Does loneliness contribute to mild cognitive impairment and dementia? A systematic review and meta-analysis of longitudinal studies. Ageing research reviews. - https://ve42.co/Lara2019 Holt-Lunstad et al. (2015). Loneliness and social isolation as risk factors for mortality: a meta-analytic review. Perspectives on psychological science. - https://ve42.co/Holt-Lunstad2015 McIntyre et al. (2015). Compulsive Internet use and relations between social connectedness, and introversion. Computers in Human Behavior. - https://ve42.co/McIntyre2015 Kahneman & Deaton. (2010). High income improves evaluation of life but not emotional well-being. Proceedings of the national academy of sciences. - https://ve42.co/Kahneman2010 Killingsworth. (2021). Experienced well-being rises with income, even above $75,000 per year. Proceedings of the National Academy of Sciences. - https://ve42.co/Killingsworth2021 Killingsworth et al. (2023). Income and emotional well-being: A conflict resolved. Proceedings of the National Academy of Sciences. - https://ve42.co/Killingsworth2023 ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Chris Harper, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Casper Mebius Written by Casper Mebius, Petr Lebedev, and Derek Muller Edited by Peter Nelson Animated by Fabio Albertelli and Ivy Tello Filmed by Derek Muller, Emily Zhang, and Zyan Treadwell Produced by Casper Mebius, Petr Lebedev, Han Evans, and Derek Muller Additional video/photos supplied by Getty Images and Storyblocks Music from Epidemic Sound Thumbnail by Ren Hurley

We visited the US Navy to test the best night vision goggles in the world. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. If you’re looking for a molecular modeling kit, head to https://ve42.co/SnatomsV to try Snatoms – a kit I invented where the atoms snap together magnetically. Huge thanks to Dr. Ben Conley and the entire team at the Naval Surface Warfare Center, Crane Division. ▀▀▀ Video References: Tyson, J. (2001). How Night Vision Works. How Stuff Works. – https://ve42.co/HSWNightVision Montoro, H. P. Image Intensification: The Technology of Night Vision. Photonics. – https://ve42.co/PhotonicsTech Brain Stuff - HowStuffWorks via YouTube – https://ve42.co/HSWVideo Photonis via YouTube – https://ve42.co/Photonis Operator Drewski via YouTube – https://ve42.co/NVGaming Night-vision device via Wikipedia – https://ve42.co/NVWiki Image intensifier via Wikipedia – https://ve42.co/Intensifier Lodriguss, J. How Digital Cameras Work. AstroPix. –https://ve42.co/AstroPix Kinka-Byo. (2019). What is the physical cause of increasing noise at high ISO? StackExchange. – https://ve42.co/PhotoISO Macias, A. (2015). The secret NVGs SEAL Team Six wore on the Bin Laden raid. Business Insider. – https://ve42.co/BINightVision Van Dommelen, L. Thermionic Emis­sion. Quan­tum Me­chan­ics for En­gi­neers. – https://ve42.co/Thermoionic Nave, R. (2016). Blackbody Radiation. HyperPhysics. – https://ve42.co/BlackBody Night Vision Terminology - Generations. ModArmory. – https://ve42.co/ModArmory NASA (2018). X-ray Detectors - Electrical Current Detections. – https://ve42.co/NASAXRay Images & Video: Osama Bin Laden report, via CNN on YouTube - https://ve42.co/CNNOBL Sicario Night Raid Scene, via Movieclips on YouTube - https://ve42.co/Sicario Splinter Cell footage, via Ubisoft on YouTube - https://ve42.co/SplinterCell Step Brothers Night Vision Scene, via masusockvevo on YouTube - https://ve42.co/StepBrothers Ukraine report, via CNN on YouTube - https://ve42.co/CNNUkraine FLIR K2 Thermal Imaging Camera footage, via Teledyne FLIR on YouTube - https://ve42.co/FLIRK2 Chandra X-ray Observatory imagery, via NASA - https://ve42.co/NASAChandra ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Chris Harper, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Mario Bottion, Max Maladino, Meekay, meg noah, Michael Krugman, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Emily Zhang Written by Emily Zhang and Derek Muller Edited by Trenton Oliver Animated by Mike Radjabov, Fabio Albertelli, and Ivy Tello Filmed by Trenton Oliver, Emily Zhang, Derek Muller, and Raquel Nuno Produced by Emily Zhang and Derek Muller Thumbnail by Ren Hurley Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

To kickstart your business or online store with a free trial of Shopify, go to https://shopify.com/veritasium If you’re looking for a molecular modeling kit, try Snatoms – a kit I invented where the atoms snap together magnetically – https://ve42.co/SnatomsV ▀▀▀ Huge thanks to Carlo Rovelli: https://t.co/FF5ohRQB8R And Geraint Lewis: https://www.geraintflewis.com/ ▀▀▀ Images and references: Holographic wormhole, via Nature - https://ve42.co/Holographic ‘Did physicists create a wormhole in a quantum computer?’ by Davide Castelvecchi, via Nature - https://ve42.co/NatureWormhole Traversable Holographic Wormhole by Sarag Wells, via Vice - https://ve42.co/ViceWormhole ‘Quantum teleportation opens a ‘wormhole in space–time’’ by Martijn Boerkamp, via Physics World - https://ve42.co/PWTeleportation ‘Physicists Create a Holographic Wormhole’ by Natalie Wolchover, via Quanta - https://ve42.co/QuantaWormhole ‘the Smallest, Crummiest Wormhole You Can Imagine’, via The New York Times - https://ve42.co/NYTWormhole ‘How Physicists Created a Holographic, via Quanta - https://ve42.co/QuantaYTWormhole Quantum computer imagery, via Quantumai - https://ve42.co/Quantumai ‘Nuclear fusion breakthrough’, via Sky News - https://ve42.co/SkyWormhole ‘NASA scientist explains why images from new telescope astounded him’, via CNN on YouTube - https://ve42.co/CNNWormhole ‘Neutrino Faster Than Speed of Light’, via Associated Press - https://ve42.co/APWormhole ‘Michio Kaku on Quantum Computing’, via PowerfulJRE - https://ve42.co/JRE AskScience AMA Series, via r/askscience on Reddit - https://ve42.co/ClimateAMA ‘Professor Andrei Linde celebrates physics breakthrough’, via Stanford - https://ve42.co/AndreiLinde ‘Gravitational waves turn to dust’ by Ian Sample, via The Guardian - https://ve42.co/Waves2Dust ‘The First Room-Temperature Ambient-Pressure Superconductor’, Sukbae Lee, Ji-Hoon Kim, Young-Wan Kwon, 2023, via arXiv - https://ve42.co/Superconductor ‘What's the buzz about LK-99?’, via Global News - https://ve42.co/GlobalLK99 Meissner effect, via @andrewmccalip on Twitter - https://ve42.co/Meissner ‘Will LK99 Superconductor CHANGE THE WORLD?’, via Breaking Points on YouTube - https://ve42.co/BreakingPoints ‘Superconductor Breakthroughs’, via WSJ - https://ve42.co/WSJSuperconductor LK99 claims forum post, via Spacebattles - https://ve42.co/KL99Forum Copper graph, via Handbook of Electromagnetic Materials - https://ve42.co/CopperGraph LK-99 Superconductor ​showing levitation - https://ve42.co/Levitation ‘Unreliable social science research’ by Cathleen O’Grady, via Science - https://ve42.co/SocialScience Tiny Neutrinos article by Dennis Overbye, via The NYT - https://ve42.co/NYTNeutrinos ‘The Crisis in Cosmology’ by Astrophysics in Process, via Medium - https://ve42.co/CosmoCrisis ‘Some scientists speak of a “crisis in cosmology.”’ by Adam Frank, via Big Think - https://ve42.co/BigThinkCosmo ‘Why is there a 'crisis' in cosmology?’ by Paul Sutter, via Space - https://ve42.co/SpaceCosmo ‘Breakthrough in nuclear fusion, via PBS NewsHour on YouTube - https://ve42.co/PBSBreakthrough DOE National Lab press conference, via U.S. Department of Energy on YouTube - https://ve42.co/DOEPress ‘Nuclear fusion breakthrough’ by Catherine Clifford, via CNBC - https://ve42.co/CNBCFusion ‘US officials announce nuclear fusion breakthrough’, via CNN - https://ve42.co/CNNFusion Nuclear fusion article, via CNN - https://ve42.co/CNNNuclear Climate catastrophe article by Robin McKie, via The Guardian - https://ve42.co/GuardianClimate Nuclear fusion article by Nicola Davis, via The Guardian - https://ve42.co/GuardianFusion Fusion breakthrough article, via Imperial College London - https://ve42.co/ImperialFusion Wednesday briefing by Archive Bland, via The Guardian - https://ve42.co/GuardianBriefing Sky Sport News Bulletin, via Sky Sport NZ on YouTube - https://ve42.co/SkyBulletin Alien Probe Ignored Us article by Ed Mazza, via Huffington Post - https://ve42.co/AlienProbe Attempts to scan the mysterious Oumuamua 'comet' article by Shivali Best, via MailOnline - https://ve42.co/Oumuamua ‘Have Aliens Found Us?’ by Isaac Chotiner, via The New York Times - https://ve42.co/NYTAliens ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Amadeo Bee, Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Chris Harper, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, Jesse Brandsoy, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Mario Bottion, Max Maladino, Meekay, meg noah, Michael Krugman, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Written by Derek Muller Edited by Peter Nelson Filmed by Derek Muller Produced by Derek Muller Additional video/photos supplied by Getty Images and Storyblocks Music from Epidemic Sound Thumbnail by Geoff Barrett

Discover strange new universes that turn up at the core of Einstein’s General Relativity. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. If you’re looking for a molecular modeling kit, try Snatoms – a kit I invented where the atoms snap together magnetically – https://ve42.co/SnatomsV If you want to play around in hyperbolic space then check out: https://3-dimensional.space/geometries/hyp/ ▀▀▀ A massive thank you to Prof. Alex Kontorovich for all his help with this video. A huge thank you to Prof. Geraint Lewis and Dr. Ashmeet Singh for helping us understand the applications of Non-Euclidean geometry in astronomy/cosmology. Lastly, a big thank you to Dr. Henry Segerman and Dr. Rémi Coulon for helping us visualize what it’s like to be inside hyperbolic space and helping us understand hyperbolic geometry. ▀▀▀ Images: Euclid via Science Museum Group - https://ve42.co/Euclid Geodesy survey via ams - https://ve42.co/Geodesy John Wheeler via NAS Online - https://ve42.co/Wheeler ▀▀▀ References: Dunham, W. (1991). Journey through Genius: Great Theorems of Mathematics. John Wiley & Sons. Bonola, R. (1955). Non-Euclidean geometry: A critical and historical study of its development. Courier Corporation. Library of Congress. (n.d.). The Library of Congress. - https://ve42.co/LibofCongress Euclid’s Elements, Wikipedia - https://ve42.co/Elements The History of Non-Euclidean Geometry, Extra History via YouTube - https://ve42.co/ExtraHistory We (could) live on a 4D Pringle - Physics for the Birds via YouTube - https://ve42.co/4DPringle Parallel Postulate, Wikipedia - https://ve42.co/Parallel Prékopa, A., & Molnár, E. (Eds.). (2006). Non-euclidean geometries: János Bolyai memorial volume (Vol. 581). Springer Science & Business Media. St Andrews, University of. (n.d.). Bolyai. MacTutor History of Mathematics. - https://ve42.co/Bolyai Bolyai, J. (1896). The Science Absolute of Space.. (Vol. 3). The Neomon. Gauss, Wikipedia - https://ve42.co/Gauss Landvermessung, D. Z. (1929). Abhandlungen ueber Gauss' wissenschaftliche Taetigkeit auf den Gebieten der Geodaesie, Physik und Astronomie Bd. 11, Abt. - https://ve42.co/Landvermessung Nikolai Lobachevsky, Wikipedia - https://ve42.co/Lobachevsky Lobachevskiĭ, N. I. (1891). Geometrical researches on the theory of parallels. University of Texas. A Problem with the Parallel Postulate, Numberphile via YouTube - https://ve42.co/NumberphileParallel Riemann, B. (2016). On the hypotheses which lie at the bases of geometry. Birkhäuser. - https://ve42.co/Riemann Einstein, A. (1905). On the electrodynamics of moving bodies. Annalen der physik, 17(10), 891-921. - https://ve42.co/Einstein1905 Why Gravity is NOT a Force, Veritasium via YouTube - https://www.youtube.com/watch?v=XRr1kaXKBsU ESA/Hubble. (n.d.). Hubblecast 90: The final frontier of the Frontier Fields. ESA/Hubble. - https://ve42.co/Einstein1905 Agazie, G., et al. (2023). The NANOGrav 15 yr data set: Constraints on supermassive black hole binaries from the gravitational-wave background. - https://ve42.co/NANOGrav Secrets of the Cosmic Microwave Background, PBS Spacetime via YouTube - https://ve42.co/PBSCMB Wood, C. (2020). How Ancient Light Reveals the Universe's Contents. Quanta Magazine. - https://ve42.co/AncientLight Collaboration (2014). Planck 2013 results. XVI. Cosmological parameters. A&A, 571, A16. - https://ve42.co/Planck2013 WMAP Science Team, NASA. (2014). Matter in the Universe. WMAP, NASA. - https://ve42.co/WMAP2014 Shape of the universe, Wikipedia - https://ve42.co/UniverseShape Crocheting Hyperbolic Planes: Daina Taimina by Ted, via YouTube - https://ve42.co/Hyperbolic Hyperbolic Crochet model - https://ve42.co/Crochet ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Amadeo Bee, Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, Jesse Brandsoy, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Mario Bottion, Max Maladino, Meekay, meg noah, Michael Krugman, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Casper Mebius Written by Casper Mebius, Petr Lebedev, Emily Zhang and Derek Muller Edited by Jack Saxon Animated by Fabio Albertelli, Ivy Tello, and Mike Radjabov Illustrations by Jakub Misiek and Celia Bode Filmed by Derek Muller Produced by Casper Mebius, Derek Muller, and Han Evans Additional video/photos supplied by Getty Images, Pond5, and by courtesy of: NASA, NASA's Goddard Space Flight Center, NASA Goddard Flight Lab/ CI Lab, NASA’s WMAP science teams, ESO, and ESA/Hubble. Music from Epidemic Sound Thumbnail by Ren Hurley

YES, THIS IS A REUPLOAD. The original was age-restricted and demonetized. To support the channel directly, you can buy Snatoms: https://ve42.co/snatoms1 https://ve42.co/amzn or support on Patreon: https://ve42.co/p Fritz Haber is the scientist who arguably most transformed the world. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ A huge thanks to Dan Charles for writing a fantastic biography of Fritz Haber, for taking the time to talk to us about it, and providing valuable feedback. This video would not be what it is without his contributions. http://site.danielcharles.us https://ve42.co/Charles Thanks to Tom de Prinse from Explosions and Fire for helping us with the chemistry of explosives. If you like explosions and/or fire, you will love his channel. https://www.youtube.com/c/ExplosionsFire2 Thanks to Michael Kuiper of CSIRO for the animation of the composition of air - https://www.youtube.com/watch?v=j9JvX58aRfg Special thanks to Sonya Pemberton, Karl Kruszelnicki, Mary Dobbie, Olivia McRae, and the patreon supporters for giving us feedback on the earlier version of this video. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: The primary reference used is Vaclav Smil’s excellent book, Enriching The Earth – Smil, V. (2004). Enriching the earth: Fritz Haber, Carl Bosch, and the transformation of world food production. MIT press. – https://ve42.co/Smil Mastermind: The Rise and Fall of Fritz Haber, the Nobel Laureate Who Launched the Age of Chemical Warfare, by Dan Charles – https://ve42.co/Charles Stoltzenberg, D. (2004). Fritz Haber: Chemist, Nobel Laureate, German, Jew. Chemical Heritage Foundation. – https://ve42.co/Stoltzenberg Postgate, J. R. (1982). The fundamentals of nitrogen fixation. CUP Archive. – https://ve42.co/postgate Miles, A. G. (1992). Biological nitrogen fixation. – https://ve42.co/Miles Friedrich, B., & Hoffmann, D. (2017). Clara Immerwahr: A life in the shadow of Fritz Haber. In One Hundred Years of Chemical Warfare: Research, Deployment, Consequences(pp. 45-67). Springer, Cham. – https://ve42.co/Friedrich2017 Da Silva, G. (2020). What is ammonium nitrate, the chemical that exploded in Beirut. Sci Am, 5. – https://ve42.co/Silva Rodrigues, P., & Micael, J. (2021). The importance of guano birds to the Inca Empire and the first conservation measures implemented by humans. – https://ve42.co/rodrigues Allison, F. E. (1957). Nitrogen and soil fertility. Soil, the, 85-94. – https://ve42.co/Allison Crookes, W. (1898). Address of the President before the British Association for the Advancement of Science, Bristol, 1898. Science, 8(200), 561-575. – https://ve42.co/Crookes ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: RayJ Johnson, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, Julian Lee, Inconcision, TTST, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, john kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Timothy O’Brien, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Petr Lebedev, Derek Muller, Felicity Nelson and Kovi Rose Edited by Trenton Oliver Animation by Jakub Mistek, Fabio Albertelli, Ivy Tello, Alex Drakoulis, Nils Ramses Kullack, and Charlie Davies SFX by Shaun Clifford Filmed by Petr Lebedev, Derek Muller and Raquel Nuno Photo of nitrogen deficiency in rice from https://ve42.co/rice Additional video/photos supplied by Getty Images Music from Epidemic Sound: https://ve42.co/music

This is how people can hold their breath for tens of minutes. Check out our sponsor: https://betterhelp.com/veritasium to get matched with a professional therapist who will listen and help. ▀▀▀ A huge thanks to Brandon Birchak for all his help with this video: https://eliteperformancedesign.uscreen.io/ A special thanks to Juan Valdivia for his expert advice on the science of extreme breath holding. ▀▀▀ References: U.S. Department of Health and Human Services. (n.d.). How your body controls breathing. National Heart Lung and Blood Institute. - https://ve42.co/BodyBreathing Anatomy, autonomic nervous system - statpearls - NCBI bookshelf. (n.d.-a). - https://ve42.co/ANS Biochemistry, oxidative phosphorylation - statpearls - NCBI bookshelf. (n.d.-c). - https://ve42.co/ncbiATP Acidosis. Acidosis - an overview | ScienceDirect Topics. (n.d.). - https://ve42.co/Acidosis Evaluation of respiratory alkalosis. Evaluation of respiratory alkalosis - Differential diagnosis of symptoms | BMJ Best Practice US. (n.d.). - https://ve42.co/Alkalosis Wilmshurst, P. (1998, October 10). Diving and Oxygen. BMJ (Clinical research ed.). - https://ve42.co/DivingO López-Barneo, J., Ortega-Sáenz, P., Pardal, R., Pascual, A., & Piruat, J. I. (2008). Carotid body oxygen sensing. European Respiratory Journal, 32(5), 1386-1398. - https://ve42.co/Barneo2008 Jeff, & Huffy. (2022, November 17). The Bolt score test: Measure your breathing volume capacity. Marathon Handbook. - https://ve42.co/BOLT Lindholm, P., & Lundgren, C. E. (2009). The physiology and pathophysiology of human breath-hold diving. Journal of Applied Physiology, 106(1), 284-292. - https://ve42.co/Lindholm2009 Physiology, lung capacity - statpearls - NCBI bookshelf. (n.d.-c). - https://ve42.co/LungCapacity Panneton, W. M., & Gan, Q. (2020). The mammalian diving response: inroads to its neural control. Frontiers in Neuroscience, 14, 524. - https://ve42.co/Panneton2020 Baković, D., Eterović, D., Saratlija‐Novaković, X., Palada, I., Valic, Z., Bilopavlović, N., & Dujić, X. (2005). Effect of human splenic contraction on variation in circulating blood cell counts. Clinical and experimental pharmacology and physiology, 32(11), 944-951. https://ve42.co/Bakovic2005 Gooden, B. (1971). The diving response in man, rat and echidna (Doctoral dissertation). - https://ve42.co/Gooden1971 Longest duration breath hold - freediving static apnea (male). Guinness World Records. (n.d.). - https://ve42.co/DivingRecord What’s the longest a human can hold their breath underwater? BBC Science Focus Magazine. (n.d.). - https://ve42.co/Southwell2023 ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Amadeo Bee, Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, Jesse Brandsoy, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Mario Bottion, Max Paladino, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Derek Muller Written by Felicity Nelson and Derek Muller Edited by Trenton Oliver Animated by Ivy Tello Filmed by Derek Muller Produced by Derek Muller Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

This is a video about some of the many times we have nearly blown up the world. Part of this video is brought to you by Henson -- head over to https://hensonshaving.com/veritasium and enter code 'Veritasium' for 100 free blades with the purchase of a razor. Make sure to add both the razor and the blades to your cart for the code to take effect. ▀▀▀ References: List of Broken Arrows -- https://ve42.co/AtomicArchive https://ve42.co/BrokenArrowsReport Declassified Goldsboro Report -- https://ve42.co/Goldsboro Operation ChromeDome -- https://ve42.co/OperationChromeDome CIA website -- https://ve42.co/CIA Cataclysmic cargo: The hunt for four missing nuclear bombs after a B-52 crash -- https://ve42.co/WoPo THE LAST FLIGHT OF HOBO 28 -- https://ve42.co/lastflight The Voice of Larry Messinger is from this documentary -- https://ve42.co/Messinger Even Without Detonation, 4 Hydrogen Bombs From ’66 Scar Spanish Village -- https://ve42.co/NYTPalomares Decades Later, Sickness Among Airmen After a Hydrogen Bomb Accident -- https://ve42.co/NYTPalomares2 Picture of ReVelle -- https://ve42.co/JackReVelle1 Great NPR where the audio of ReVelle is from -- https://ve42.co/JackReVelle2 CIA Website -- https://ve42.co/CIA ▀▀▀ Special thanks to our Patreon supporters: Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, Jesse Brandsoy, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Mario Bottion, MaxPal, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Petr Lebedev Written by Petr Lebedev and Derek Muller Edited by Peter Nelson Animated by Fabio Albertelli, Jakub Misiek, Ivy Tello and Mike Radjabov Filmed by Derek Muller Produced by Petr Lebedev and Derek Muller Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

There is an entire branch of math simply devoted to knots – and it has changed the world. We’ll rope you in. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. ▀▀▀ Huge thanks to Prof. Colin Adams for his excellent help guiding us through the world of knots. Many thanks to Prof. Doug Smith, Dorian Raymer, Prof. David Leigh, and Prof. Dorothy Buck for helping us understand applications of knot theory. Many thanks to Prof. Dan Silver & Prof. Jim Hoste for speaking with us about the history and tabulation of knots. If you want to learn more about knots and play with them yourself, check out: The amazing KnotPlot tool — https://knotplot.com/. Thanks to Rob Scharein for providing technical help as well! A table of knots and all their invariants — https://knotinfo.math.indiana.edu/ The Knot Atlas for general info on knots — http://katlas.org/wiki/Main_Page ▀▀▀ Knot Theory Video References – https://ve42.co/KnotTheoryRefs Images & Video: Alexander Cutting the Gordian Knot by Donato Creti via Fine Art America - https://ve42.co/GordianCut Indus Valley tablet via Quora - https://ve42.co/IndusValley Pages from the Book of Kells via National Trust of Scotland - https://ve42.co/BookOfKells Medieval Celtic designs from @thebookofkellsofficial via Instagram - https://ve42.co/KellsInsta Chinese knotwork by YWang9174 via Wikimedia Commons - https://ve42.co/Panchang Quipu cords by Pi3.124 via Wikimedia Commons - https://ve42.co/Quipu Borromeo heraldry via Terre Borromeo - https://ve42.co/Borromeo Birman/Jones letter via Celebratio Mathematica - https://ve42.co/JonesBirman Molecular trefoil knot by M stone via Wikimedia Commons - https://ve42.co/TrefoilMolecule X-ray structure of trefoil knot by Ll0103 via Wikimedia Commons - https://ve42.co/XrayTrefoil Bacteria animation from Your Body's Molecular Machines by Drew Berry via the Walter and Eliza Hall Institute of Medical Research - http://wehi.tv Topoisomerase and knots from Orlandini et al. Synergy of topoisomerase. PNAS, vol. 116, no. 17, 2019, pp. 8149–8154. – https://ve42.co/Orlandini2019 KnotProt 2.0: A database of proteins with knots and slipknots - https://ve42.co/Knotprot ▀▀▀ Special thanks to our Patreon supporters: Anton Ragin, Balkrishna Heroor, Bernard McGee, Bill Linder, Burt Humburg, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, Jesse Brandsoy, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Mario Bottion, MaxPal, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Directed by Emily Zhang Written by Emily Zhang and Derek Muller Edited by Trenton Oliver Animated by Fabio Albertelli, Ivy Tello, Jakub Misiek, and Mike Radjabov Filmed by Derek Muller, Raquel Nuno, and Emily Zhang Produced by Emily Zhang and Derek Muller Thumbnail by Ignat Berbeci and Mike Radjabov Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound

Will we see a new generation of airships roaming our skies? Head to https://www.odoo.com/r/veritasium to start building your own website for free. If you’re looking for a molecular modeling kit, try Snatoms – a kit I invented where the atoms snap together magnetically – https://ve42.co/SnatomsV ▀▀▀ Thank you to Eli Dourado for letting us explore the argument he describes in his article: https://ve42.co/Dourado A huge thank you to Dan Grossman and Nick Allman for their time, help, and expertise. Also a massive thank you to those who helped us understand the world of modern airships, and provided valuable feedback - Prof. Barry Prentice, Gennadiy Verba, Prof. Christoph Pflaum, Heather Roszczyk, Dr. Casey Handmer, Richard Van Trueren, & Thibault Proux. We are also grateful for the collaboration of the companies who are working hard to make this comeback happen - Atlas LTA, Buoyant Aircraft Systems International, Hybrid Air Vehicles, LTA Research, & Flying Whales. ▀▀▀ References: How Airships Could Overcome a Century of Failure, Bloomberg Originals via YouTube - https://ve42.co/AirshipsCoF Why the Airship May Be the Future of Air Travel, Undecided with Matt Ferrell via YouTube - https://ve42.co/FutureAirships Airship, Wikipedia - https://ve42.co/AirshipWiki Handmer, C. (2020). A quick note on airships. Casey Handmer’s Blog - https://ve42.co/Handmer2020 UNCTAD (2020). Review of Maritime Transport 2020 - https://ve42.co/RMT2020 National Transportation Research Center (2023). Freight Analysis Framework Version 5 (FAF5) - https://ve42.co/FAF5 Hybrid Air Vehicles (2023). HAV - https://ve42.co/HAV LTA Research (2023). Lighter Than Air (LTA) Research - https://ve42.co/LTAResearch OceanSkyCruises (2023). North Pole Expedition - OceanSkyCruises - https://ve42.co/NPExpedition Flying Whales (2023). Flying Whales - https://ve42.co/FlyingWhales Buoyant Aircraft Systems International (2023). BASI - https://ve42.co/BASI Atlas LTA (2023). Atlas Electric Airships | Atlas LTA Airships - https://ve42.co/AtlasLTA Prentice, B. (2021). Hydrogen gas-fuelled airships could spur development in remote communities. The Conversation - https://ve42.co/HydrogenAirships Grossman, D. (2009). The Hindenburg Disaster. Airships - https://ve42.co/Hindenburg1 Hindenburg Disaster, Wikipedia - https://ve42.co/HindenburgWiki What happened to the Hindenburg?, Jared Owen via Youtube - https://ve42.co/Owen2019 National Museum of the U.S. Navy. USS Akron (ZRS-4) - https://ve42.co/USSAkron USS Akron, Wikipedia - https://ve42.co/USSAkronWiki ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Amadeo Bee, Anton Ragin, Balkrishna Heroor, Benedikt Heinen, Bernard McGee, Bill Linder, Burt Humburg, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, Jesse Brandsoy, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Mario Bottion, MaxPal, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Written by Casper Mebius & Derek Muller Directed by Casper Mebius Edited by Jack Saxon Filmed by Derek Muller, Jamie MacLeod, Han Evans, & Raquel Nuno Animation by Mike Radjabov & Fabio Albertelli Additional video/photos supplied by Getty Images, Pond5, & Envato Elements Music from Epidemic Sound & Pond5 Produced by Casper Mebius, Derek Muller, & Han Evans More footage & photos from: Thermite Rail Welding video by dulevoz via YouTube - https://www.youtube.com/watch?v=rNjosF789X4 O’Rourke, T. (2016). Chronicle Covers: When the Hindenburg burst into flames. San Francisco Chronicle - https://ve42.co/Hindenburg2 Wind turbine blade transport video by DOLL Fahrzeugbau via YouTube - https://www.youtube.com/watch?v=5aPXuap0LZw Wind turbine blade transport through mountains video by CGTN via Youtube - https://www.youtube.com/watch?v=9dtUrY8_1CM Former Airship Hangar by Stefan Kühn - https://ve42.co/Aerium

IQ is supposed to measure intelligence, but does it? Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. If you’re looking for a molecular modeling kit, try Snatoms – a kit I invented where the atoms snap together magnetically – https://ve42.co/SnatomsV ▀▀▀ A huge thank you to Emeritus Professor Cecil R. Reynolds and Dr. Stuart J. Ritchie for their expertise and time. Also a massive thank you to Prof. Steven Piantadosi and Prof. Alan S. Kaufman for helping us understand this complicated topic. As well as to Jay Zagrosky from Boston University's Questrom School of Business for providing data from his study. ▀▀▀ References: Kaufman, A. S. (2009). IQ testing 101. Springer Publishing Company. Reynolds, C. R., & Livingston, R. A. (2021). Mastering modern psychological testing. Springer International Publishing. Ritchie, S. (2015). Intelligence: All that matters. John Murray. Spearman, C. (1961). " General Intelligence" Objectively Determined and Measured. - https://ve42.co/Spearman1904 Binet, A., & Simon, T. (1907). Le développement de l'intelligence chez les enfants. L'Année psychologique, 14(1), 1-94.. - https://ve42.co/Binet1907 Intelligence Quotient, Wikipedia - https://ve42.co/IQWiki Radiolab Presents: G. - https://ve42.co/RadioLabG McDaniel, M. A. (2005). Big-brained people are smarter: A meta-analysis of the relationship between in vivo brain volume and intelligence. Intelligence, 33(4), 337-346. - https://ve42.co/McDaniel2005 Deary, I. J., Strand, S., Smith, P., & Fernandes, C. (2007). Intelligence and educational achievement. Intelligence, 35(1), 13-21. - https://ve42.co/Deary2007 Lozano-Blasco, R., Quílez-Robres, A., Usán, P., Salavera, C., & Casanovas-López, R. (2022). Types of Intelligence and Academic Performance: A Systematic Review and Meta-Analysis. Journal of Intelligence, 10(4), 123. - https://ve42.co/Blasco2022 Kuncel, N. R., & Hezlett, S. A. (2010). Fact and fiction in cognitive ability testing for admissions and hiring decisions. Current Directions in Psychological Science, 19(6), 339-345. - https://ve42.co/Kuncel2010 Laurence, J. H., & Ramsberger, P. F. (1991). Low-aptitude men in the military: Who profits, who pays?. Praeger Publishers. - https://ve42.co/Laurence1991 Gregory, H. (2015). McNamara's Folly: The Use of Low-IQ Troops in the Vietnam War; Plus the Induction of Unfit Men, Criminals, and Misfits. Infinity Publishing. Gottfredson, L. S., & Deary, I. J. (2004). Intelligence predicts health and longevity, but why?. Current Directions in Psychological Science, 13(1), 1-4. - https://ve42.co/Gottfredson2004 Sanchez-Izquierdo, M., Fernandez-Ballesteros, R., Valeriano-Lorenzo, E. L., & Botella, J. (2023). Intelligence and life expectancy in late adulthood: A meta-analysis. Intelligence, 98, 101738. - https://ve42.co/Izquierdo2023 Zagorsky, J. L. (2007). Do you have to be smart to be rich? The impact of IQ on wealth, income and financial distress. Intelligence, 35(5), 489-501. - https://ve42.co/Zagorsky2007 Strenze, T. (2007). Intelligence and socioeconomic success: A meta-analytic review of longitudinal research. Intelligence, 35(5), 401-426. - https://ve42.co/Strenze2007 Deary, I. J., Pattie, A., & Starr, J. M. (2013). The stability of intelligence from age 11 to age 90 years: the Lothian birth cohort of 1921. Psychological science, 24(12), 2361-2368. - https://ve42.co/Deary2013 Flynn, J. R. (1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological bulletin, 101(2), 171. - https://ve42.co/Flynn1987 Why our IQ levels are higher than our grandparents' | James Flynn, TED via YouTube - https://www.youtube.com/watch?v=9vpqilhW9uI Duckworth, A. L., Quinn, P. D., Lynam, D. R., Loeber, R., & Stouthamer-Loeber, M. (2011). Role of test motivation in intelligence testing. Proceedings of the National Academy of Sciences, 108(19), 7716-7720. - https://ve42.co/Duckworth2011 Kulik, J. A., Bangert-Drowns, R. L., & Kulik, C. L. C. (1984). Effectiveness of coaching for aptitude tests. Psychological Bulletin, 95(2), 179. - https://ve42.co/Kulik1984 ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Amadeo Bee, Anton Ragin, Balkrishna Heroor, Benedikt Heinen, Bernard McGee, Bill Linder, Burt Humburg, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, MaxPal, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Written by Derek Muller, Casper Mebius, & Petr Lebedev Edited by Trenton Oliver Filmed by Derek Muller, Han Evans, & Raquel Nuno Animation by Fabio Albertelli & Ivy Tello Additional video/photos supplied by Getty Images & Pond5 Music from Epidemic Sound Produced by Derek Muller, Casper Mebius, & Han Evans

J. Robert Oppenheimer forever changed the course of history. He may be the most important physicist to have ever lived. Part of this video is sponsored by Wren. Offset your carbon footprint on Wren: ​https://www.wren.co/start/veritasium1 For the first 100 people who sign up, I will personally pay for the first month of your subscription! If you want to learn more about Oppeheimer, I strongly recommend the book “American Prometheus” By Kai Bird and Martin Sherwin. It is a remarkable book, very much deserving of the Pulitzer prize it received. If you’re looking for a molecular modeling kit, try Snatoms – a kit I invented where the atoms snap together magnetically – https://ve42.co/SnatomsV ▀▀▀ A huge thank you to Dr. Martin Rohde and Dr. Antonia Denkova from the TU Delft for proofreading the script and providing valuable feedback. ▀▀▀ References: Bird, K., & Sherwin, M. J. (2021). American Prometheus: the triumph and tragedy of J. Robert Oppenheimer. Atlantic Books. Smith, A. K., & Weiner, C. (1980). Robert Oppenheimer: letters and recollections. Bulletin of the Atomic Scientists, 36(5), 19-27. - https://ve42.co/Smith1980 Combes, J. M., Duclos, P., & Seiler, R. (1981). The born-oppenheimer approximation. Rigorous atomic and molecular physics, 185-213. - https://ve42.co/Combes1981 Rhodes, R. (2012). The making of the atomic bomb. Simon and Schuster. Oppenheimer, J. R., & Volkoff, G. M. (1939). On massive neutron cores. Physical Review, 55(4), 374. - https://ve42.co/Oppenheimer1939b Oppenheimer, J. R. (1927). Bemerkung zur Zerstreuung der α-Teilchen. Zeitschrift für Physik, 43(5-6), 413-415. - https://ve42.co/Oppenheimer1927 Oppenheimer, J. R. (1927). Zur quantenmechanik der richtungsentartung. Zeitschrift für Physik, 43(1-2), 27-46. - https://ve42.co/Oppenheimer1927b Born, M., & Oppenheimer, R. (1927). Zur Quantentheorie der Molekeln Annalen der Physik, v. 84. - https://ve42.co/Born1927 Oppenheimer, J. R. (1928). Three notes on the quantum theory of aperiodic effects. Physical review, 31(1), 66. Oppenheimer, J. R. (1928). On the quantum theory of the capture of electrons. Physical review, 31(3), 349. Oppenheimer, J. R. (1931). Note on light quanta and the electromagnetic field. Physical Review, 38(4), 725. Furry, W. H., & Oppenheimer, J. R. (1934). On the theory of the electron and positive. Physical Review, 45(4), 245. - https://ve42.co/Oppenheimer1934 Oppenheimer, J. R. (1935). Note on charge and field fluctuations. Physical Review, 47(2), 144. - https://ve42.co/Oppenheimer1935 Oppenheimer, J. R., & Snyder, H. (1939). On continued gravitational contraction. Physical Review, 56(5), 455. - https://ve42.co/Oppenheimer1939 Oppenheimer, J. R., & Phillips, M. (1935). Note on the transmutation function for deuterons. Physical Review, 48(6), 500. - https://ve42.co/Oppenheimer1935b Malik, J. (1985). Yields of the Hiroshima and Nagasaki nuclear explosions (No. LA-8819). Los Alamos National Lab.(LANL), Los Alamos, NM (United States). - https://ve42.co/Malik1985 Ignition of the atmosphere with nuclear bombs -- https://ve42.co/Konopinski46 ▀▀▀ Special thanks to our Patreon supporters: Adam Foreman, Amadeo Bee, Anton Ragin, Balkrishna Heroor, Benedikt Heinen, Bernard McGee, Bill Linder, Blake Byers, Burt Humburg, Dave Kircher, Diffbot, Evgeny Skvortsov, Gnare, John H. Austin, Jr., john kiehl, Josh Hibschman, Juan Benet, KeyWestr, Lee Redden, Marinus Kuivenhoven, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Stephen Wilcox, Tj Steyn, TTST, Ubiquity Ventures ▀▀▀ Written by Petr Lebedev & Derek Muller Edited by Trenton Oliver & Katrina Jackson Filmed by Derek Muller Animation by Fabio Albertelli, Ivy Tello, & Mike Radjabov Illustration by Jakub Misiek and Celia Bode Additional video/photos supplied by Getty Images & Pond5 Music from Epidemic Sound

This is the biggest, brightest, hottest video there is about the science of fireworks. This video is brought to you by Kiwico – go to https://kiwico.com/veritasium for your first month free! If you're looking for a molecular modeling kit, try Snatoms - a kit I invented where the atoms snap together magnetically: https://snatoms.com Check out Gene’s channel here -- @PotatoJet Massive thanks to Mike Tockstein from Pyrotechnic Innovations @PyroInnovations and Will Scott from Las Vegas Display Fireworks Inc, for all your pyro knowledge and keeping us safe. ▀▀▀ Massive thanks to Gene Nagata from PotatoJet for filming this episode – check out his wonderful channel for more videos about cameras and FPV drones. Thanks to Brandon Williams for helping with the chemistry and sourcing of materials. Thanks to Matthew Tosh for the help with the chemistry conversation about fireworks. Thanks to Simon Werrett for the help with the history of fireworks. ▀▀▀ Werrett, S. (2010). Fireworks: pyrotechnic arts and sciences in European history. University of Chicago Press ▀▀▀ Special thanks to our Patreon supporters: Emil Abu Milad, Tj Steyn, meg noah, Bernard McGee, KeyWestr, Amadeo Bee, TTST, Balkrishna Heroor, John H. Austin, Jr., john kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Sam Lutfi. ▀▀▀ Written by Derek Muller Edited by Trenton Oliver Animated by Ivy Tello and Fabio Albertelli Filmed by Derek Muller, Hunter Peterson, Gene Nagata, Raquel Nuno Production by Hunter Peterson and Stephanie Castillo Additional video/photos supplied by Mike Tockstein/Pyrotechnic Innovations Music from Epidemic Sound & Jonny Hyman Produced by Derek Muller, Petr Lebedev, Emily Zhang, & Casper Mebius

One of the most important, yet least understood, concepts in all of physics. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. If you're looking for a molecular modeling kit, try Snatoms - a kit I invented where the atoms snap together magnetically: https://snatoms.com ▀▀▀ A huge thank you to those who helped us understand different aspects of this complicated topic - Dr. Ashmeet Singh, Supriya Krishnamurthy, Dr. Jos Thijssen, Dr. Bijoy Bera, Dr. Timon Idema, and Dr. Misha Titov. ▀▀▀ References: Carnot, S. (1824). Reflections on the motive power of heat: and on machines fitted to develop that power. - https://ve42.co/Carnot1890 Harnessing The True Power Of Atoms | Order And Disorder Documentaries, Spark via YouTube - https://ve42.co/OrderDisorder A better description of entropy, Steve Mould via YouTube - https://ve42.co/Mould2016 Dugdale, J. S. (1996). Entropy and its physical meaning. CRC Press. - https://ve42.co/Dugdale1996 Schroeder, D. V. (1999). An introduction to thermal physics. - https://ve42.co/Schroeder2021 Fowler, M. Heat Engines: the Carnot Cycle, University of Virginia. - https://ve42.co/Fowler2023 Chandler, D.L. (2010). Explained: The Carnot Limit, MIT News - https://ve42.co/Chandler2010 Entropy, Wikipedia - https://ve42.co/EntropyWiki Clausius, R. (1867). The mechanical theory of heat. Van Voorst. - https://ve42.co/Clausius1867 What is entropy? TED-Ed via YouTube - https://ve42.co/Phillips2017 Thijssen, J. (2018) Lecture Notes Statistical Physics, TU Delft. Schneider, E. D., & Kay, J. J. (1994). Life as a manifestation of the second law of thermodynamics. Mathematical and computer modelling, 19(6-8), 25-48. - https://ve42.co/Schneider1994 Lineweaver, C. H., & Egan, C. A. (2008). Life, gravity and the second law of thermodynamics. Physics of Life Reviews, 5(4), 225-242. - https://ve42.co/Lineweaver2008 Michaelian, K. (2012). HESS Opinions" Biological catalysis of the hydrological cycle: life's thermodynamic function". Hydrology and Earth System Sciences, 16(8), 2629-2645. - https://ve42.co/Michaelian2012 England, J. L. (2013). Statistical physics of self-replication. The Journal of chemical physics, 139(12), 09B623_1. - https://ve42.co/England2013 England, J. L. (2015). Dissipative adaptation in driven self-assembly. Nature nanotechnology, 10(11), 919-923. - https://ve42.co/England2015 Wolchover, N. (2014). A New Physics Theory of Life, Quantamagazine - https://ve42.co/Wolchover2014 Lineweaver, C. H. (2013). The entropy of the universe and the maximum entropy production principle. In Beyond the Second Law: Entropy Production and Non-equilibrium Systems (pp. 415-427). Berlin, Heidelberg: Springer Berlin Heidelberg. - https://ve42.co/LineweaverEntropy Bekenstein, J.D. (1972). Black holes and the second law. Lett. Nuovo Cimento 4, 737–740. - https://ve42.co/Bekenstein1972 Carroll, S.M. (2022). The Biggest Ideas in the Universe: Space, Time, and Motion. Penguin Publishing Group. - https://ve42.co/Carroll2022 Black hole thermodynamics, Wikipedia - https://ve42.co/BlackHoleTD Cosmology and the arrow of time: Sean Carroll at TEDxCaltech, TEDx Talks via YouTube - https://ve42.co/CarrollTEDx Carroll, S. M. (2008). The cosmic origins of time’s arrow. Scientific American, 298(6), 48-57. - https://ve42.co/Carroll2008 The Passage of Time and the Meaning of Life | Sean Carroll (Talk + Q&A), Long Now Foundation via YouTube - https://ve42.co/CarrollLNF ▀▀▀ Special thanks to our Patreon supporters: Emil Abu Milad, Tj Steyn, meg noah, Bernard McGee, KeyWestr, Amadeo Bee, TTST, Balkrishna Heroor, John H. Austin, Jr., john kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Sam Lutfi. ▀▀▀ Written by Casper Mebius & Derek Muller Edited by Trenton Oliver & Jamie MacLeod Animated by Mike Radjabov, Ivy Tello, Fabio Albertelli and Jakub Misiek Filmed by Derek Muller, Albert Leung & Raquel Nuno Molecular collisions video by CSIRO's Data61 via YouTube: Simulation of water freezing into ice Additional video/photos supplied by Getty Images, Pond5 and by courtesy of NASA, NASA's Goddard Space Flight Center, NASA Goddard Flight Lab/ CI Lab, NASA/SDO and the AIA, EVE, HMI, and WMAP science teams. As well as the Advanced Visualization Laboratory at the National Center for Supercomputing Applications, B. Robertson, L. Hernquist Music from Epidemic Sound & Jonny Hyman Produced by Derek Muller, Petr Lebedev, Emily Zhang, & Casper Mebius

Go to our sponsor https://betterhelp.com/veritasium to get matched with a professional therapist who will listen and help. ▀▀▀ Huge thanks to the Australian Reptile Park for having us over to film – special thanks to Jake Meney for showing us the spiders and Caitlin Vine for organizing the shoot. https://www.reptilepark.com.au Huge thanks to Dr Timothy Jackson with his help and answering our questions. Thanks to Seqirus Australia for providing B-roll footage of the antivenom production process. ▀▀▀ References: Pineda, S. S., Sollod, B. L., Wilson, D., Darling, A., Sunagar, K., Undheim, E. A., ... & King, G. F. (2014). Diversification of a single ancestral gene into a successful toxin superfamily in highly venomous Australian funnel-web spiders. BMC genomics, 15(1), 1-16 - https://ve42.co/Pineda2014 Isbister, G. K., Gray, M. R., Balit, C. R., Raven, R. J., Stokes, B. J., Porges, K., ... & Fisher, M. M. (2005). Funnel-web spider bite: a systematic review of recorded clinical cases. Medical journal of Australia, 182(8), 407-411 - https://ve42.co/Isbister2005 Herzig, V., Sunagar, K., Wilson, D. T., Pineda, S. S., Israel, M. R., Dutertre, S., ... & Fry, B. G. (2020). Australian funnel-web spiders evolved human-lethal δ-hexatoxins for defense against vertebrate predators. Proceedings of the National Academy of Sciences, 117(40), 24920-24928 - https://ve42.co/Herzig2020 Nicholson, G. M., & Graudins, A. (2002). Spiders of medical importance in the Asia–Pacific: Atracotoxin, latrotoxin and related spider neurotoxins. Clinical and experimental pharmacology and physiology, 29(9), 785-794 - https://ve42.co/Nicholson2002 Fletcher, J. I., Chapman, B. E., Mackay, J. P., Howden, M. E., & King, G. F. (1997). The structure of versutoxin (δ-atracotoxin-Hv1) provides insights into the binding of site 3 neurotoxins to the voltage-gated sodium channel. Structure, 5(11), 1525-1535 - https://ve42.co/Fletcher1997 Australian Reptile Park. (2022). Snake and Spider First Aid - https://ve42.co/ARPFirstAid The Australian Museum. (20 ). Spider facts - https://ve42.co/SpiderFacts ▀▀▀ Special thanks to our Patreon supporters: Orlando Bassotto, Tj Steyn, meg noah, Bernard McGee, KeyWestr, Amadeo Bee, TTST, Balkrishna Heroor, John H. Austin, Jr., john kiehl, Anton Ragin, Benedikt Heinen, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, and Sam Lutfi ▀▀▀ Written by Katie Barnshaw & Derek Muller Edited by Trenton Oliver Filmed by Petr Lebedev, Derek Muller and Jason Tran Animation by Ivy Tello, Jakub Misiek and Fabio Albertelli Neuron animation by Reciprocal Space – https://www.reciprocal.space Additional video/photos supplied from Getty Images, Pond5 B-roll supplied by Seqirus Australia Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, Emily Zhang & Katie Barnshaw

There's a strange number system, featured in the work of a dozen Fields Medalists, that helps solve problems that are intractable with real numbers. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. If you're looking for a molecular modeling kit, try Snatoms - a kit I invented where the atoms snap together magnetically: https://snatoms.com ▀▀▀ References: Koblitz, N. (2012). p-adic Numbers, p-adic Analysis, and Zeta-Functions (Vol. 58). Springer Science & Business Media. Amazing intro to p-adic numbers here: https://youtu.be/3gyHKCDq1YA Excellent series on p-adic numbers: https://youtu.be/VTtBDSWR1Ac Great videos by James Tanton: @JamesTantonMath ▀▀▀ Special thanks to our Patreon supporters: Emil Abu Milad, Tj Steyn, meg noah, Bernard McGee, KeyWestr, Amadeo Bee, TTST, Balkrishna Heroor, John H. Austin, Jr., john kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Sam Lutfi. ▀▀▀ Written by Derek Muller and Alex Kontorovich Edited by Trenton Oliver Animated by Mike Radjabov, Ivy Tello, Fabio Albertelli and Jakub Misiek Filmed by Derek Muller Additional video/photos supplied by Getty Images & Pond5 Music from Epidemic Sound & Jonny Hyman Produced by Derek Muller, Petr Lebedev, & Emily Zhang

Welcome to Micromouse, the fastest maze-solving competition on Earth. Join Onshape’s community of over 3 million CAD users by creating a free account here: https://Onshape.pro/Veritasium. ▀▀▀ A huge thank you to Peter Harrison for all of his help introducing us to the world of Micromouse – check out https://ukmars.org & https://micromouseonline.com. Thank you to David Otten, APEC, and the All-Japan Micromouse Competition for having us. Thank you to Juing-Hei (https://www.youtube.com/@suhu9379) & Derek Hall (https://www.youtube.com/@MicroMouse) for usage of their micromouse videos. Thank you to John McBride, Yusaku Kanagawa, and Katie Barnshaw for their help with Japanese translations. ▀▀▀ References: Claude Shannon Demonstrates Machine Learning, AT&T Tech Channel Archive - https://ve42.co/ClaudeShannon Mighty mouse, MIT News Magazine - https://ve42.co/MightyMouse History, Micromouse Online Blog - https://ve42.co/MMHistory Christiansen, D. (1977). Spectral lines: Announcing the Amazing Micro-Mouse Maze Contest. IEEE Spectrum, vol. 14, no. 5, pp. 27-27 - https://ve42.co/Christiansen1977 Allan, R. (1979). Microprocessors: The amazing micromice: See how they won: Probing the innards of the smartest and fastest entries in the Amazing Micro-Mouse Maze Contest. IEEE Spectrum, vol. 16, no. 9, pp. 62-65, - https://ve42.co/Allan1979 1977-79 – “MOONLIGHT SPECIAL” Battelle Inst. (American), CyberNetic Zoo - https://ve42.co/MoonlightSpecial Christiansen, D. (2014). The Amazing MicroMouse Roars On. Spectral Lines - https://ve42.co/Christiansen2014 1986 - MicroMouse history, competition & how it got started in the USA, via YouTube - https://ve42.co/MMArchiveYT The first World Micromouse Contest in Tsubuka, Japan, August 1985 [1/2] by TKsTclip via YouTube - https://ve42.co/MMTsukubaYT IEEE. (2018). Micromouse Competition Rules - https://ve42.co/IEEERules Tondra, D. (2004). The Inception of Chedda: A detailed design and analysis of micromouse. University of Nevada - https://ve42.co/Tondra2004 Braunl, T. (1999). Research relevance of mobile robot competitions. IEEE Robotics & Automation Magazine, vol. 6, no. 4, pp. 32-37 - https://ve42.co/Braunl1999 All Japan Micromouse 2017 by Peter Harrison, Micromouse Online - https://ve42.co/RedComet Winning record of the national competition micromouse (half size) competition. mm3sakusya @ wiki (Google translated from Japanese) - https://ve42.co/JapanFinishTimes The Fosbury Flop—A Game-Changing Technique, Smithsonian Magazine - https://ve42.co/FosburyFlop Gold medal winning heights in the Men's and Women's high jump at the Summer Olympics from 1896 to 2020, Statistica - https://ve42.co/HighJump Zhang, H., Wang, Y., Wang, Y., & Soon, P. L. (2016). Design and realization of two-wheel micro-mouse diagonal dashing. Journal of Intelligent & Fuzzy Systems, 31(4), 2299-2306. - https://ve42.co/Zhang2016 Micromouse Turn List, Keri’s Lab - https://ve42.co/MMTurns Green Ye via YouTube - https://ve42.co/Greenye Classic Micromouse, Excel 9a. Demonstrate fan suction, by TzongYong Khiew via YouTube - https://ve42.co/MMFanYT Vacuum Micromouse by Eliot, HACKADAY - https://ve42.co/MMVacuum ▀▀▀ Special thanks to our Patreon supporters: Emil Abu Milad, Tj Steyn, meg noah, Bernard McGee, KeyWestr, Amadeo Bee, TTST, Balkrishna Heroor, John H. Austin, Jr., john kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Sam Lutfi. ▀▀▀ Written by Tom Lum and Emily Zhang Edited by Trenton Oliver Animated by Ivy Tello Coordinated by Emily Zhang Filmed by Yusaku Kanagawa, Emily Zhang, Derek Muller, and Raquel Nuno Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound Thumbnail by Ren Hurley and Ignat Berbeci References by Katie Barnshaw Produced by Derek Muller, Petr Lebedev, and Emily Zhang

Lightbulbs might be the best idea ever – just not for light. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. A huge thanks to David Lovett for showing me his awesome relay and vacuum tube based computers. Check out his YouTube channel @UsagiElectric ▀▀▀ References: Herring, C., & Nichols, M. H. (1949). Thermionic emission. Reviews of modern physics, 21(2), 185. – https://ve42.co/Herring1949 Goldstine, H. H., & Goldstine, A. (1946). The electronic numerical integrator and computer (eniac). Mathematical Tables and Other Aids to Computation, 2(15), 97-110. – https://ve42.co/ENIAC Shannon, C. E. (1938). A symbolic analysis of relay and switching circuits. Electrical Engineering, 57(12), 713-723. – https://ve42.co/Shannon38 Boole, G. (1847). The mathematical analysis of logic. Philosophical Library. – https://ve42.co/Boole1847 The world’s first general purpose computer turns 75 – https://ve42.co/ENIAC2 Dylla, H. F., & Corneliussen, S. T. (2005). John Ambrose Fleming and the beginning of electronics. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 23(4), 1244-1251. – https://ve42.co/Dylla2005 Stibitz, G. R. (1980). Early computers. In A History of Computing in the Twentieth Century (pp. 479-483). Academic Press. ENIAC’s Hydrogen Bomb Calculations – https://ve42.co/ENIAC3 ▀▀▀ Special thanks to our Patreon supporters: Emil Abu Milad, Tj Steyn, meg noah, Bernard McGee, KeyWestr, Amadeo Bee, TTST, Balkrishna Heroor, John H. Austin, Jr., john kiehl, Anton Ragin, Benedikt Heinen, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy ‘kkm’ K’Nelson, Sam Lutfi. ▀▀▀ Written by Petr Lebedev, Derek Muller and Kovi Rose Edited by Trenton Oliver Animated by Mike Radjabov, Ivy Tello and Fabio Albertelli Filmed by Derek Muller & Raquel Nuno Additional video/photos supplied by Getty Images & Pond5 Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, & Emily Zhang Thumbnail by Ignat Berbeci

NASA have made a wheel capable of withstanding tough Martian terrain, but just how indestructible is it? Head to https://hensonshaving.com/veritasium and enter code 'Veritasium' for 100 free blades with the purchase of a razor. Make sure to add both the razor and the blades to your cart for the code to take effect. ▀▀▀ A huge thanks to everyone at NASA Glenn Research Center for having us at the SLOPE Lab, showing their work on this indestructible tire, and helping with the science and animation. A huge thanks to everyone at Smart Tire Co for showing us around their facility, teaching us about nitinol, and letting us flatten their tires. ▀▀▀ References: Steel Rod Footage - https://ve42.co/SteelRod H. Föll. 8.4.1 - Martensite. University of Kiel, Faculty of Engineering - https://ve42.co/Foell Bhattacharya, K. (1998). Theory of martensitic microstructure and the shape-memory effect - https://ve42.co/Bhattacharya1998 Bhattacharya, K. (2003). Microstructure of martensite: why it forms and how it gives rise to the shape-memory effect (Vol. 2). Oxford University Press. - https://ve42.co/MartensiteBook Shaw, J. A. (2008). Tips and tricks for characterizing shape memory alloy wire: part 1—differential scanning calorimetry and basic phenomena. Experimental Techniques - https://ve42.co/Shaw2008 Buehler, W. J., Gilfrich, J. V., & Wiley, R. C. (1963). Effect of low‐temperature phase changes on the mechanical properties of alloys near composition TiNi. Journal of applied physics, 34(5), 1475-1477. ▀▀▀ Special thanks to our Patreon supporters: Emil Abu Milad, Tj Steyn, meg noah, Bernard McGee, KeyWestr, Amadeo Bee, TTST, Balkrishna Heroor, John H. Austin, Jr., john kiehl, Anton Ragin, Benedikt Heinen, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy ‘kkm’ K’Nelson, Sam Lutfi. ▀▀▀ Written by Derek Muller, Katie Barnshaw, & Emily Zhang Edited by Trenton Oliver Animated by Mike Radjabov & Ivy Tello Coordinated by Emily Zhang Filmed by Derek Muller, Emily Zhang & Raquel Nuno Additional video/photos supplied by Getty Images & Pond5 Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, & Emily Zhang Thumbnail by Ignat Berbeci

Concrete = cement + sand + gravel. Cement is the most important man-made material on Earth. Offset your carbon footprint on Wren: https://wren.co/veritasium . For the first 100 people who sign up, I will personally pay for the first month of your subscription! ▀▀▀ A huge thank you to Nevada Ready Mix for being willing to bury me in concrete, especially Elu Chavez and Mike Sherwood. https://www.nevadareadymix.com And to Brandon Birchak of Six Foot Productions for providing the big fish bowl, safety equipment, planning and filming: https://www.sixfootcreations.com ▀▀▀ References: Instant stone (just add water), Roots of Progress, https://rootsofprogress.org/instant-stone-just-add-water https://rootsofprogress.org/cement-redux Cement Chemistry and Sustainable Cementitious Materials https://www.youtube.com/@cementchemistryandsustaina9629 Ahmad, S., Lawan, A., & Al-Osta, M. (2020). Effect of sugar dosage on setting time, microstructure and strength of Type I and Type V Portland cements. Case Studies in Construction Materials, 13, e00364. – https://ve42.co/Ahmad2020 Seymour, L. M., Maragh, J., Sabatini, P., Di Tommaso, M., Weaver, J. C., & Masic, A. (2023). Hot mixing: Mechanistic insights into the durability of ancient Roman concrete. Science advances, 9(1), eadd1602. -- https://ve42.co/Seymour2023 ▀▀▀ Special thanks to our Patreon supporters: Emil Abu Milad, Tj Steyn, meg noah, Bernard McGee, KeyWestr, Amadeo Bee, TTST, Balkrishna Heroor, John H. Austin, Jr., Eric Sexton, john kiehl, Anton Ragin, Benedikt Heinen, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi. ▀▀▀ Written by Derek Muller Edited by Trenton Oliver Filmed by Raquel Nuno, Austin Bradley and Bryson Animated by Ivy Tello & Mike Radjabov Additional video/photos supplied by Getty Images & Pond5 Music from Epidemic Sound & Jonny Hyman: the Bill Wurtz inspired ‘Skyscrapers are made of sea shells’ Produced by Derek Muller, Petr Lebedev, & Emily Zhang

A quantum computer in the next decade could crack the encryption our society relies on using Shor's Algorithm. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 people get 20% off an annual premium subscription. ▀▀▀ A huge thank you to those who helped us understand this complex field and ensure we told this story accurately - Dr. Lorenz Panny, Prof. Serge Fehr, Dr. Dustin Moody, Prof. Benne de Weger, Prof. Tanja Lange, PhD candidate Jelle Vos, Gorjan Alagic, and Jack Hidary. A huge thanks to those who helped us with the math behind Shor’s algorithm - Prof. David Elkouss, Javier Pagan Lacambra, Marc Serra Peralta, and Daniel Bedialauneta Rodriguez. ▀▀▀ References: Joseph, D., et al. (2022). Transitioning organizations to post-quantum cryptography. Nature, 605(7909), 237-243. - https://ve42.co/Joseph2022 Bernstein, D. J., & Lange, T. (2017). Post-quantum cryptography. Nature, 549(7671), 188-194. - https://ve42.co/Bernstein2017 An Insight, An Idea with Sundar Pichai - Quantum Computing, Wold Economic Forum via YouTube - https://ve42.co/QCWEFyt Migrating to Post-Quantum Cryptography, The White House - https://ve42.co/PQCWhiteHouse Kotas, W. A. (2000). A brief history of cryptography. University of Tennessee - https://ve42.co/Kotas2000 Hellman, M. (1976). New directions in cryptography. IEEE transactions on Information Theory, 22(6), 644-654. - https://ve42.co/Hellman1976 Rivest, R. L., Shamir, A., & Adleman, L. (1978). A method for obtaining digital signatures and public-key cryptosystems. Communications of the ACM, 21(2), 120-126. - https://ve42.co/Rivest1978 Kak, A. (2023). Lecture 12: Public-Key Cryptography and the RSA Algorithm - https://ve42.co/Kak2023 Calderbank, M. (2007). The RSA Cryptosystem: History, Algorithm, Primes. University of Chicago. - https://ve42.co/Calderbank2007 Cryptographic Key Length Recommendation, Keylength - https://ve42.co/KeyLength Coppersmith, D. (2002). An approximate Fourier transform useful in quantum factoring. arXiv preprint quant-ph/0201067. - https://ve42.co/Coppersmith2002 Quantum Fourier Transform, Qiskit - https://ve42.co/Qiskit Shor, P. W. (1994, November). Algorithms for quantum computation: discrete logarithms and factoring. In Proceedings 35th annual symposium on foundations of computer science (pp. 124-134). IEEE. - https://ve42.co/Shor1994 Shor’s algorithm, Wikipedia - https://ve42.co/ShorWiki Euler’s totient function, Wikipedia - https://ve42.co/EulerWiki Asfaw, A. (2020). Shor’s Algorithm Lecture Series, Qiskit Summer School - https://ve42.co/ShorYT How Quantum Computers Break Encryption, minutephysics via YouTube - https://ve42.co/PQCmpyt Breaking RSA Encryption - an Update on the State-of-the-Art, QuintessenceLabs - https://ve42.co/QuintessenceLabs O'Gorman, J., & Campbell, E. T. (2017). Quantum computation with realistic magic-state factories. Physical Review A, 95(3), 032338. - https://ve42.co/OGorman2017 Gidney, C., & Ekerå, M. (2021). How to factor 2048 bit RSA integers in 8 hours using 20 million noisy qubits. Quantum, 5, 433. - https://ve42.co/Gidney2021 2021 Quantum Threat Timeline Report, Global Risk Institute - https://ve42.co/QuantumRisk The IBM Quantum Development Roadmap, IBM - https://ve42.co/IBMQC Post-Quantum Cryptography, Computer Security Resource Center (NIST) - https://ve42.co/CSRCPQC Alagic, G., et al. (2022). Status report on the third round of the NIST post-quantum cryptography standardization process. US Department of Commerce, NIST. - https://ve42.co/Alagic2022 Thijs, L. (2015). Lattice cryptography and lattice cryptanalysis - https://ve42.co/Thijs2015 ▀▀▀ Special thanks to our Patreon supporters: Tj Steyn, Meg Noah, Bernard McGee, KeyWestr, Elliot Miller, Jerome Barakos, M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin, Jr., Eric Sexton, john kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi. ▀▀▀ Written by Casper Mebius & Derek Muller Edited by Trenton Oliver Filmed by Raquel Nuno Animated by Ivy Tello & Mike Radjabov Additional video/photos supplied by Getty Images & Pond5 Music from Epidemic Sound & Jonny Hyman Produced by Derek Muller, Petr Lebedev, & Emily Zhang

The world's strongest magnet is a million times stronger than Earth's magnetic field. Learn more about sustainability and Google’s efforts at sustainability.google. Part of this video was sponsored by Google. Trends insights for the past year are based on Google Trends data from 2/10/2022 - 2/10/2023, U.S. ▀▀▀ Thanks to the entire NHMFL team - especially Tim, Stephen, Caroline, Kristin, Sam, Lance, and everyone who helped with the demos - for the great visit. The NHMFL is funded by the National Science Foundation and the State of Florida. Special thanks to Henry from Minutephysics for lending his magnet animations from our magnet collaboration: https://youtu.be/hFAOXdXZ5TM ▀▀▀ References: Liu, Y., Zhu, D. M., Strayer, D. M., & Israelsson, U. E. (2010). Magnetic levitation of large water droplets and mice. Advances in Space Research, 45(1), 208-213. Simon, M. D., & Geim, A. K. (2000). Diamagnetic levitation: Flying frogs and floating magnets. Journal of applied physics, 87(9), 6200-6204. Berry, M. V., & Geim, A. K. (1997). Of flying frogs and levitrons. European Journal of Physics, 18(4), 307. ▀▀▀ Special thanks to our Patreon supporters: Tj Steyn, Meg Noah, Bernard McGee, James Sanger, Elliot Miller, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin Jr., Eric Sexton, John Kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi ▀▀▀ Written by Derek Muller Edited and Motion Graphics by Trenton Oliver Coordinated by Emily Zhang and Derek Muller Filmed by Derek Muller, Trenton Oliver, and Emily Zhang Additional video/photos supplied by Pond5 & Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

For decades, the Sleeping Beauty Problem has divided people between two answers. Head to https://brilliant.org/veritasium to start your free 30-day trial, and the first 200 of you will get 20% off an annual premium subscription. ▀▀▀ Many thanks to Dr. Mike Titelbaum and Dr. Adam Elga for their insights into the problem. ▀▀▀ References: Elga, A. (2000). Self-locating belief and the Sleeping Beauty problem. Analysis, 60(2), 143-147. - https://ve42.co/Elga2000 Lewis, D. (2001). Sleeping beauty: reply to Elga. Analysis, 61(3), 171-176. - https://ve42.co/Lewis2001 Winkler, P. (2017). The sleeping beauty controversy. The American Mathematical Monthly, 124(7), 579-587. - https://ve42.co/Winkler2017 Titelbaum, M. G. (2013). Ten reasons to care about the Sleeping Beauty problem. Philosophy Compass, 8(11), 1003-1017. - https://ve42.co/Titelbaum2013 Mutalik, P. (2016). Solution: ‘Sleeping Beauty’s Dilemma’, Quanta Magazine - https://ve42.co/MutalikQ2016 Rec.Puzzles - Some “Sleeping Beauty” Postings - https://ve42.co/SBRecPuzzles The Sleeping Beauty Paradox, Statistics SE - https://ve42.co/SBPSSE The Sleeping Beauty Problem, Reddit - https://ve42.co/SBPReddit Sleeping Beauty paradox explained, GameFAQs - https://ve42.co/SBPGameFAQ The Sleeping Beauty Problem, Physics Forums - https://ve42.co/SBPPhysicsForums ▀▀▀ Special thanks to our Patreon supporters: Tj Steyn, Meg Noah, Bernard McGee, KeyWestr, Elliot Miller, Brian Busbee, Jerome Barakos, M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin, Jr., Eric Sexton, john kiehl, Anton Ragin, Benedikt Heinen, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, jim buckmaster, Juan Benet, Ubiquity Ventures, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi. ▀▀▀ Written by Emily Zhang, Derek Muller, Tamar Lichter Blanks Edited by Fabio Albertelli Animation by Ivy Tello, Fabio Albertelli, Jakub Misiek Additional video/photos supplied by Getty Images & Pond5 Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, Emily Zhang

Adhesives based on gecko skin can hold huge weights – without sticking to anything. Head to https://brilliant.org/Veritasium to start your free trial. The first 200 of you will get 20% off Brilliant’s annual premium subscription. ▀▀▀ Thanks to Dr. Mark Cutkosky, Tony Chen, Amar Hajj-Ahmad, and the rest of the Biomimetics and Dexterous Manipulation Lab at Stanford University for showing us the power of gecko adhesives. ▀▀▀ References: Russell, A. P., Stark, A. Y., & Higham, T. E. (2019). The integrative biology of gecko adhesion: historical review, current understanding, and grand challenges. Integrative and comparative biology, 59(1), 101-116. – https://ve42.co/Russell2019 Hajj-Ahmad, A., Suresh, S. A., and Cutkosky, M. R. (June 6, 2021). "Cutting to the Point: Directly Machined Metal Molds for Directional Gecko-Inspired Adhesives." ASME. J. Micro Nano-Manuf. doi: https://doi-org.stanford.idm.oclc.org/10.1115/1.4051406 Kerst, Capella F., "Gecko inspired adhesives : permanent practical manufacturing, new materials, and applications," PhD Thesis, Stanford Universisty, December 2020. Suresh, S.A. "Engineering Gecko-Inspired Adhesives." Ph.D. thesis, Stanford University, 2020. [Online]. Available: https://purl.stanford.edu/cp134gr3166. Suresh, S.A., Kerst, C.F., Cutkosky, M.R., Hawkes, E.W. "Spatially variant microstructured adhesive with one-way friction." Journal of the Royal Society Interface. 2019. doi: 10.1098/rsif.2018.0705 Glick, P., Suresh, S.A., Ruffatto III, D., Cutkosky, M.R., Tolley, M.T., and Parness, A. "A soft robotic gripper with gecko-inspired adhesive." Robotics and Automation Letters. 2018. doi:10.1109/LRA.2018.2792688. Christensen, D.L., Hawkes, E.W., Suresh, S.A., Ladenheim, K. and Cutkosky, M.R., "µTugs: Enabling Microrobots to Deliver Macro Forces with Controllable Adhesives," IEEE/ICRA 2015 (preprint). Hawkes, E. W., "Applying Dry Adhesives to the Real World," Ph.D. thesis, Stanford University, 2015. ▀▀▀ Special thanks to our Patreon supporters: Meg Noah, Bernard McGee, James Sanger, Elliot Miller, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin Jr., Eric Sexton, John Kiehl, Anton Ragin, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, Jim Buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi ▀▀▀ Written by Derek Muller & Petr Lebedev Edited by Trenton Oliver Animation by Ivy Tello Filmed by Derek Muller, Raquel Nuno & Albert Leung Additional video/photos supplied by Pond5 & Getty Images Music from Epidemic Sound Exec. Produced by Derek Muller, Petr Lebedev, and Emily Zhang

In this lab, they use different flow visualization techniques to help detect contraband, residues, and develop trace particle detection methods. Part of this video was sponsored by Caseta by Lutron. Find out more at https://casetawireless.com/veritasium ▀▀▀ Thanks to Rich Press and NIST for the great visit. Thanks to Matt Staymates for taking us around his lab and showing us the fascinating research being done with flow visualization. You can check out all the cool work going on at NIST here: https://www.nist.gov/ ▀▀▀ Check out these Lutron products: https://www.homedepot.com/p/Lutron-Caseta-Wireless-Smart-Lighting-Dimmer-Switch-and-Remote-Kit-for-Wall-and-Ceiling-Lights-White-P-PKG1W-WH-R/206754146 https://www.homedepot.com/p/Lutron-Caseta-Wireless-Smart-Lighting-Dimmer-Switch-Starter-Kit-P-BDG-PKG1W/205582770 https://www.homedepot.com/p/Lutron-Caseta-Wireless-Smart-Lighting-Dimmer-Switch-2-Count-Starter-Kit-P-BDG-PKG2W-HD/301783649 https://www.homedepot.com/p/Lutron-Caseta-Wireless-Smart-Lighting-Dimmer-Switch-for-Wall-and-Ceiling-Lights-White-PD-6WCL-WH-R/206828225 https://www.homedepot.com/p/Lutron-Caseta-Wireless-Smart-Lighting-Switch-for-All-Bulb-Types-or-Fans-White-PD-5ANS-WH-R/305090201 https://www.homedepot.com/p/Lutron-Caseta-Smart-Switch-3-Way-Kit-2-Points-of-Control-with-Pico-Remote-Wallplate-and-Bracket-White-P-PKG1WS-WH/314328501?keyword=P-PKG1WS-WH&semanticToken=323t00r011220000_36acc44414963ab909697567725ec5ae_1601584501254+323t00r011220000+%3E++cnn%3A%7B0%3A0%7D+cnp%3A%7B10%3A0%7D+cnd%3A%7B4%3A0%7D+cne%3A%7B8%3A0%7D+cns%3A%7B5%3A0%7D+cnx%3A%7B3%3A0%7D+cnq%3A%7B0%3A0%7D+cnw%3A%7B0%3A0%7D+cnv%3A%7B0%3A0%7D+st%3A%7Bp-pkg1ws-wh%7D%3Ast+oos%3A%7B1%3A1%7D+rt%3A%7Bp-pkg1ws-wh%7D%3Art+dln%3A%7B563900%7D+tgr%3A%7BSkuExactMatch%7D+smf%3A%7Bca%2Cbr%7D%3Asmf+nf%3A%7B1%7D%3Anf+qu%3A%7Bp-pkg1ws-wh%7D%3Aqu https://www.homedepot.com/s/P-BDG-PKG2WS-WH?NCNI-5 https://www.homedepot.com/p/Lutron-Caseta-Wireless-Pico-Wall-Mounting-Kit-White-PJ2-WALL-WH-L01/204718234 https://www.homedepot.com/p/Lutron-Single-Pole-Caseta-Wireless-Smart-Fan-Speed-Control-White-PD-FSQN-WH-R/308675064 https://www.homedepot.com/p/Lutron-Caseta-Wireless-Single-Pole-3-Way-Smart-Lighting-Lamp-Dimmer-and-Remote-Kit -White-P-PKG1P-WH-R/206792507 ▀▀▀ References: Staymates, M.E., (2020). My Stay-at-Home Lab Shows How Face Coverings Can Slow the Spread of Disease. NIST. – https://ve42.co/FaceMaskNIST Staymates, M. E., et al. (2016). Biomimetic sniffing improves the detection performance of a 3D printed nose of a dog and a commercial trace vapor detector. Scientific reports, 6(1), 1-10. – https://ve42.co/Staymates2016 NIST. (2022). Surface and Trace Chemical Analysis Group. – https://ve42.co/NISTgroup ▀▀▀ Special thanks to our Patreon supporters: Bernard McGee, James Sanger, Elliot Miller, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin Jr., OnlineBookClub.org, Eric Sexton, John Kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, Jim Buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi ▀▀▀ Written by Derek Muller and Emily Zhang Edited by Trenton Oliver Animation by Ivy Tello Filmed by Derek Muller, Raquel Nuno, Trenton Oliver, and Emily Zhang Additional video/photos supplied by Pond5 & Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

An engineer came up with a plan to drop tungsten telephone poles from space - the idea has been seriously considered on multiple occasions, so we tested it. This video is sponsored by Brilliant. You can get started for free, or the first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Massive thanks to Archisand for building such a beautiful sandcastle. https://www.youtube.com/@GregLeBon Thanks to Inland Empire Film Services and the San Bernardino County Film Office for portions of the video shot in the County of San Bernardino. Huge thanks to John and Angie Miller for helping us with securing the shooting location and going above and beyond to make this shoot happen – http://highdesertlocations.com/ Massive thanks to Dr David Wright for the interview and providing invaluable guidance during the research for this video. Here’s a great video about space-based missile defense – https://www.ucsusa.org/resources/space-based-missile-defense-not-good-idea Massive thanks to Adam Savage for being part of this video Additional photos from NASA and ESA ▀▀▀ References: USAF. (2003). The US Air Force transformation flight plan. Preston, R., Johnson, D. J., Edwards, S. J., Miller, M. D., & Shipbaugh, C. (2002). Space weapons earth wars. Rand Corporation. Wright, D., Grego, L., & Gronlund, L. (2005). The physics of space security. A Reference Manual, Cambridge. DeBlois, B. M., Garwin, R. L., Kemp, R. S., & Marwell, J. C. (2004). Space weapons: crossing the US Rubicon. International Security, 50-84. Baucom, D. R. (2017). The Rise and Fall of Brilliant Pebbles 1. In United States Military History 1865 to the Present Day (pp. 329-376). Routledge. Hitchens, T., & Samson, V. (2004). Space-based interceptors: still not a good idea. Georgetown journal of international affairs, 21-29. National Research Council. (2012). Making sense of ballistic missile defense: An assessment of concepts and systems for US boost-phase missile defense in comparison to other alternatives. National Academies Press. Borger, J. (2005). Bush likely to back weapons in space. The Guardian, 19. ▀▀▀ Special thanks to: Bernard McGee, James Sanger, Elliot Miller, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin Jr., OnlineBookClub.org, Eric Sexton, John Kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, Jim Buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi ▀▀▀ Written by Petr Lebedev, Derek Muller, and Emily Zhang Filmed by Trenton Oliver, Derek Muller, Petr Lebedev, Emily Zhang, Raquel Nuno and Eddie Lopez Animation by Mike Radjabov, Fabio Albertelli and Jonny Hyman Edited by Trenton Oliver Slow Motion Camera: Shawn Sanders and Anthony Corrales Sandcastle Timelapse by Greg LeBon and Archisand Phantom rental from Panny Hire LA Helicopter Pilots: Rick Shuster and Cliff Fleming Helicopter Safety Officer: Ryan Hosking FPV Drone Pilots: Sammie Saing and Josh Ewalt Production Assistants: Roman Bacvic and Eddie Lopez Intern: Katie Barnshaw Additional video/photos supplied by Pond5 and Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

This lab measures the tiniest forces in the universe. This video is sponsored by Brilliant. You can get started for free, or the first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. ▀▀▀ Thanks to Rich Press and NIST for the great visit. Thanks to Dr. Gordon Shaw for showing us around his lab and teaching us about measuring tiny forces. You can check out all the cool work going on at NIST here: https://www.nist.gov/ ▀▀▀ References: Lee, J. (2016). Measuring Tiny Forces With Light. NIST. – https://ve42.co/Lee2016 Melcher, J., Stirling, J., Guzman, F., Pratt, J. & Shaw, G. (2014). A self-calibrating optomechanical force sensor with femtonewton resolution. Applied Physics Letters. – https://ve42.co/Melcher2014 ▀▀▀ Special thanks to our Patreon supporters: Bernard McGee, James Sanger, Elliot Miller, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin Jr., OnlineBookClub.org, Eric Sexton, John Kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, Jim Buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi ▀▀▀ Written by Derek Muller Edited by Trenton Oliver Animation by Ivy Tello Filmed by Derek Muller, Trenton Oliver, and Emily Zhang Additional video/photos supplied by Pond5 & Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

The US Navy has an indoor ocean that can simulate any wave in the world. This video is sponsored by Brilliant. You can get started for free, or the first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. ▀▀▀ Thanks to Kelley Stirling and the Naval Surface Warfare Center, Carderock Division for the visit. Thanks to Miguel Quintero and Capt. Todd E. Hutchison for talking to us about the important work going on in the Maneuvering and Seakeeping Basin. Thanks to Dr. Georgy Manucharyan at the University of Washington for his help in understanding ocean waves. ▀▀▀ References: Webb, P. (2017). Introduction to Oceanography. Chapter 10: Waves. Online OER textbook. – https://ve42.co/Webb2017 Stewart, R. (2008). Introduction to Physical Oceanography. – https://ve42.co/Stewart2008 van den Bremer, T. S. & Breivik, Ø. (2018). Stokes drift. Phil. Trans. R. Soc. A. – https://ve42.co/Bremer2017 Monismith, S. (2020). Stokes drift: Theory and experiments. Journal of Fluid Mechanics, 884, F1. – https://ve42.co/Monismith2020 Young, I. R. (1999). Wind Generated Ocean Waves. Elsevier. p. 83. – https://ve42.co/Young1999 Wright, P. Island Physics. 4.2 Formation of Waves – https://ve42.co/IslandPhysics American Bureau of Shipping. (2016). Guidance Notes on Selecting Design Wave by Long Term Stochastic Method. – https://ve42.co/ABS2016 James, S. & Stull, R. (2019). Wave Characteristics. UBC ATSC 113 - Weather for Sailing, Flying & Snow Sports. – https://ve42.co/James2019 Garrison, T. (2009). Oceanography: An Invitation to Marine Science (7th ed). – https://ve42.co/Garrison2009 ▀▀▀ Special thanks to our Patreon supporters: James Sanger, Louis Lebbos, Elliot Miller, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, John Kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, Jim Buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi ▀▀▀ Written by Derek Muller & Emily Zhang Edited by Fabio Albertelli Animation by Ivy Tello & Mike Radjabov Filmed by Derek Muller & Emily Zhang Additional video/photos supplied by Pond5 & Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

This government warehouse keeps our entire society up to standard. Part of this video was sponsored by Google Domains. Take the first step to get online with a domain name from Google Domains - go to domains.google/veritasium to get 20% off your first year. #GoogleDomains ▀▀▀ Thanks to Rich Press and NIST for the great visit. Thanks to Dr. Steve Choquette, Dr. Ben Place, and Dr. Johanna Camara for teaching us about the world of Standard Reference Materials. You can check out all the cool work going on at NIST here: https://www.nist.gov/ ▀▀▀ References: NIST (2022). Standard Reference Materials. – https://ve42.co/WhyStandard2022 Montgomery, R. & Bercik, I. (2022). NIST Standard Reference Materials 2022 Catalog. – https://ve42.co/SRMCatalog Vincent, J. (2022). Made to measure: why we can’t stop quantifying our lives. The Guardian – https://ve42.co/Vincent2022 Proffitt, A. (2022). NIST Develops Monkeypox Reference Materials, Sees Growing Role in Outbreak Response. Diagnostics World. – https://ve42.co/Proffitt2022 ▀▀▀ Special thanks to our Patreon supporters: James Sanger, Louis Lebbos, Elliot Miller, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, John Kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, Jim Buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi ▀▀▀ Written by Derek Muller & Emily Zhang Edited by Trenton Oliver Animation by Ivy Tello & Mike Radjabov Filmed by Derek Muller, Trenton Oliver, and Emily Zhang Additional video/photos supplied by Pond5 & Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

People have witnessed supernovae for millennia, but what threat do they pose to life on Earth? This video is sponsored by Brilliant. You can get started for free, or the first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. ▀▀▀ A massive thanks to Prof. Hans-Thomas Janka for helping us with the physics of supernovae and GRBs. A massive thanks to Prof. Brian Thomas for all of his help with the terrestrial effects of supernovae and GRBs. This video would not have been possible without them. Also thanks to Dr. Luke Barnes for his initial help with the literature search. Hydrogen bomb vs Supernova fact was taken from this great article by xkcd/Randall Munroe – https://what-if.xkcd.com/73/ (based on the calculation by Andrew Karam, 2002) Cosmic bubble footage from https://www.cfa.harvard.edu/news/1000-light-year-wide-bubble-surrounding-earth-source-all-nearby-young-stars Neutrino driven SN explosion simulations from https://iopscience.iop.org/article/10.1088/2041-8205/808/2/L42 ▀▀▀ References: Melott, A. et al. (2019). Hypothesis: Muon radiation dose and marine megafaunal extinction at the End-Pliocene supernova. Astrobiology, 19(6), 825-830. – https://ve42.co/Melott1 Thomas, B. C. et al. (2016). Terrestrial effects of nearby supernovae in the early Pleistocene. The Astrophysical Journal Letters, 826(1), L3 – https://ve42.co/Thomas1 Melott, A. L., & Thomas, B. C. (2019). From cosmic explosions to terrestrial fires?. The Journal of Geology, 127(4), 475-481. – https://ve42.co/Melott2 Fields, B. et al. (2019). Near-Earth supernova explosions: Evidence, implications, and opportunities. arXiv preprint arXiv:1903.04589. – https://ve42.co/Fields1 Thomas, B. C., Atri, D., & Melott, A. L. (2021). Gamma-ray bursts: not so much deadlier than we thought. Monthly Notices of the Royal Astronomical Society, 500(2), 1970-1973. – https://ve42.co/Thomas2 Melott, A. et al. (2004). Did a gamma-ray burst initiate the late Ordovician mass extinction?. International Journal of Astrobiology, 3(1), 55-61. – https://ve42.co/Melott3 Firestone, R. B. (2014). Observation of 23 supernovae that exploded less than 300 pc from Earth during the past 300 kyr. The Astrophysical Journal, 789(1), 29. – https://ve42.co/firestone1 Janka, H. T. (2017). Neutrino emission from supernovae. arXiv preprint arXiv:1702.08713. – https://ve42.co/Janka1 Janka, H. T., & Hillebrandt, W. (1989). Neutrino emission from type II supernovae-an analysis of the spectra. Astronomy and astrophysics, 224, 49-56. – https://ve42.co/Janka2 Janka, H. T. (2017). Neutrino-driven explosions. arXiv preprint arXiv:1702.08825. – https://ve42.co/Janka3 Karam, P. A. (2002). Gamma and neutrino radiation dose from gamma ray bursts and nearby supernovae. Health physics, 82(4), 491-499. – https://ve42.co/Karam1 Melott, A. L., Thomas, et al.. (2017). A supernova at 50 pc: effects on the Earth's atmosphere and biota. The Astrophysical Journal, 840(2), 105. – https://ve42.co/Melott4 Ludwig, P., et al. (2016). Time-resolved 2-million-year-old supernova activity discovered in Earth’s microfossil record. Proceedings of the National Academy of Sciences, 113(33), 9232-9237. – https://ve42.co/Ludwig1 Gritschneder, et al. (2011). The supernova triggered formation and enrichment of our solar system. The Astrophysical Journal, 745(1), 22. – https://ve42.co/Gritschneder1 Motizuki, Y., Takahashi, et al. (2009). An Antarctic ice core recording both supernovae and solar cycles. arXiv preprint arXiv:0902.3446. – https://ve42.co/Motizuki Zucker, C. et al. (2022). Star formation near the Sun is driven by expansion of the Local Bubble. Nature, 601(7893), 334-337. – https://ve42.co/Zucker1 Hirata, K. et al.(1987). Observation of a neutrino burst from the supernova SN1987A. Physical Review Letters, 58(14), 1490. – https://ve42.co/Hirata1 ▀▀▀ Special thanks to our Patron supporters: James Sanger, Louis Lebbos, Elliot Miller, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin, Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, John Kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, jim buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi ▀▀▀ Written by Petr Lebedev & Derek Muller Edited by Fabio Albertelli Animation by Fabio Albertelli, Jakub Misiek, Alex Drakoulis, Ivy Tello, Mike Radjabov, and Charlie Davies Filmed by Derek Muller Additional Research by Kovi Rose & Katie Barnshaw Video/photos supplied by NASA, ESA, Pond5, and Getty Images Music from Epidemic Sound & Jonny Hyman Produced by Derek Muller, Petr Lebedev, and Emily Zhang

The Fast Fourier Transform is used everywhere but it has a fascinating origin story that could have ended the nuclear arms race. This video is sponsored by 80,000 Hours. Head to http://80000hours.org/veritasium to sign up for their newsletter and get sent a free copy of their in-depth career guide. A huge thank you to Dr. Richard Garwin for taking the time to speak with us. Thanks to Dr. Steve Brunton of the University of Washington for his help with understanding the Fast Fourier Transform. Thanks to Dr. Cliff Thurber of the University of Wisconsin-Madison, Dr. Paul Richards of Columbia University, and Dr. Steven Gibbons of the Norwegian Geotechnical Institute for their expertise. Thanks to Grant Sanderson of 3Blue1Brown for his helpful feedback on the script. His great video on the Fourier Transform is here - https://youtu.be/spUNpyF58BY ▀▀▀ References: Kristensen, H.M., Korda, M. (2022). Status of World Nuclear Forces. Federation of American Scientists (FAS). https://ve42.co/Stockpile2022 Barth, K. H. (1998). Science and politics in early nuclear test ban negotiations. Physics Today, 51(3), 34-39. - https://ve42.co/Barth1998 Schmalberger, T. (1991). In pursuit of a nuclear test ban treaty - https://ve42.co/Schmalberger1991 Bowers, D., & Selby, N. D. (2009). Forensic seismology and the comprehensive nuclear-test-ban treaty. Annual Review of Earth and Planetary Sciences, 37, 209-236 - https://ve42.co/Bowers2009 Incorporated Research Institutions for Seismology (IRIS). (2022). How Often Do Earthquakes Occur? https://ve42.co/IRIS2022 Kimball, D. (2022). The Nuclear Testing Tally. Arms Control Association. https://ve42.co/TestTally2022 Kværna, T., & Ringdal, F. (2013). Detection capability of the seismic network of the International Monitoring System for the Comprehensive Nuclear Test Ban Treaty. Bulletin of the Seismological Society of America, 103(2A), 759-772 - https://ve42.co/Kvrna2013 Sykes, L. R., & Evernden, J. F. (1982). The verification of a comprehensive nuclear test ban. Scientific American, 247(4), 47-55 - https://ve42.co/Sykes1982 Peterson, J., & Hutt, C. R. (2014). World-wide standardized seismograph network: a data users guide (p. 82). US Department of the Interior, US Geological Survey. - https://ve42.co/Peterson2014 Richards, P. G., & Kim, W. Y. (2009). Monitoring for nuclear explosions. Scientific American, 300(3), 70-77 - https://ve42.co/Richards2009 Jacobsen, L. L., Fedorova, I., & Lajus, J. (2021). The seismograph as a diplomatic object: The Soviet–American exchange of instruments, 1958–1964. Centaurus, 63(2), 277-295 - https://ve42.co/Jacobsen2021 Schwartz S. I. (1998). The Hidden Costs Of Our Nuclear Arsenal: Overview Of Project Findings. The Brookings Institution - https://ve42.co/Schwartz1998 Ricón, J.L. (2016). The Soviet Union: Military Spending. Nintil - https://ve42.co/Nintil2016 Heideman, M. T., Johnson, D. H., & Burrus, C. S. (1985). Gauss and the history of the fast Fourier transform. Archive for history of exact sciences, 265-277 - https://ve42.co/Heideman1985 Ford, D. (2004). Richard Garwin - Session IV. American Institute of Physics (AIP). - https://ve42.co/Ford2004 Aaserud, F. (1986). Richard Garwin - Session I. American Institute of Physics (AIP). - https://ve42.co/Aaserud1986 Goldstein, A. (1997). James W. Cooley, an oral history. IEEE History Center, Piscataway, NJ, USA - https://ve42.co/Goldstein1997 Cooley, J., Garwin, R., Rader, C., Bogert, B., & Stockham, T. (1969). The 1968 Arden House workshop on fast Fourier transform processing. IEEE Transactions on Audio and Electroacoustics, 17(2), 66-76 - https://ve42.co/Cooley1969 ▀▀▀ Special thanks to Patreon supporters: Louis Lebbos, Elliot MIller, RayJ Johnson, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin, Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, John Kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, jim buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Derek Muller & Felicity Nelson Filmed by Derek Muller & Raquel Nuno Animation by Ivy Tello, Jakub Misiek, Alex Drakoulis, and Fabio Albertelli Edited by Albert Leung & Derek Muller Research Assistant: Katie Barnshaw Additional video/photos supplied by Pond5 and Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

I always thought Florida seemed like a terrible place to launch anything from.

This video is sponsored by Brilliant. You can get started for free, or the first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Check out Adam Savage's video: https://youtu.be/h_zytOcMwys A massive thanks to Adam Savage and the whole Tested Crew – especially Kristen Lomasney, Ryan Kiser, and Joey Fameli. Thank you so much for coming out to the desert with us, and for inviting us to your cave! Check out the video we made with them on their channel – https://youtu.be/h_zytOcMwys Another huge thanks to iFly Ontario for letting us shoot in your amazing windtunnel. Special thanks to Diana Rios, Treasa Telle, Michelle Brumley for having us and Anthony and Torrell for being great instructors. iFly run STEM education trips, where you can experience terminal velocity first hand – https://www.iflyworld.com/programs/stem-field-trips/ Thanks to Inland Empire Film Services and the San Bernardino County Film Office for portions of the video shot in the County of San Bernardino. The raindrop video is from Alistair McClymont’s gorgeous artwork “Raindrop” – ​​https://alistairmcclymont.com/artwork/raindrop/ Video of the raindrop breaking apart is from the coolest paper i’ve read in a while – Villermaux, E., & Bossa, B. (2009). Single-drop fragmentation determines size distribution of raindrops. Nature physics, 5(9), 697-702. – https://ve42.co/Villermaux ▀▀▀ References: Altair. (2019). Digital Debunking: Could a Penny Dropped Off the Top of the Empire State Building Actually Kill You? - https://ve42.co/Altair2019 Braeunig, R.A. Atmosphere Properties. - https://ve42.co/AtmosProp The Guardian. (2014). Brutal winter weather brings new challenge: ice falling from skyscrapers - https://ve42.co/WTCicicle NASA. (2018). The Apollo 15 Hammer-Feather Drop - https://ve42.co/NASAmoondrop Red Bull Stratos - https://ve42.co/RBStratos Quealy, K., Sanger-KatzIn, M. (2015). In Other Countries, You’re as Likely to Be Killed by a Falling Object as by a Gun. New York Times. - https://ve42.co/NYTFallingObject National Safety Council. (2022). Struck by Objects. - https://ve42.co/NSCStruck Williams, A. (2019). What are your chances of being killed by hail in the US? - https://ve42.co/Williams2019 NewScientist. (2021). Can bullets fired upwards cause injuries when they return to earth? - https://ve42.co/CelebratoryGunFire Chambers, J. (2020). Meet the Flechette – the Deadliest Weapon of World War I? - https://ve42.co/Flechette Wikipedia. Lazy Dog (bomb). - https://ve42.co/LazyDog Gläser, N., Kneubuehl, B. P., Zuber, S., Axmann, S., Ketterer, T., Thali, M. J., & Bolliger, S. A. (2011). Biomechanical examination of blunt trauma due to baseball bat blows to the head. Journal of Forensic Biomechanics, 2 - https://ve42.co/Glaser2011 Yoganandan, N., Pintar, F. A., SANCES JR, A. N. T. H. O. N. Y., Walsh, P. R., Ewing, C. L., Thomas, D. J., & Snyder, R. G. (1995). Biomechanics of skull fracture. Journal of neurotrauma, 12(4), 659-668. New York Times. (2014). Falling Tape Measure Kills Man at Jersey City Construction Site - The New York Times - https://ve42.co/NYTTapeMeasure IMDb. (2006). "MythBusters" Bullets Fired Up (TV Episode). - https://ve42.co/MBgunfire ▀▀▀ Special thanks to: Elliot MIller, Louis Lebbos, RayJ Johnson, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin, Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, john kiehl, Nathan Lanza, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Robert Blum, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Petr Lebedev, Derek Muller, and Emily Zhang Filmed by Derek Muller, Trenton Oliver, Petr Lebedev, Emily Zhang, Raquel Nuno and Eddie Lopez Animation by Ivy Tello, Mike Radjabov, Fabio Albertelli, and Jakub Misiek Edited by Trenton Oliver and Derek Muller FPV Drone Pilots: Sammie Saing and Josh Ewalt Slow Motion Camera: Shawn Sanders and Anthony Corrales Helicopter Pilots: Rick Shuster and Cliff Fleming Helicopter Safety Officer: Ryan Hosking Production Assistants: Roman Bacvic and Eddie Lopez Research Assistant: Katie Barnshaw Additional video/photos supplied by Pond5 and Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

This tiny robot can jump higher than anything else in the world. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Huge thanks to Dr. Elliot Hawkes and the rest of the group - Charles Xiao, Chris Keeley, Dr. Morgan Pope, and Dr. Günter Niemeyer - for having us at UCSB and showing us their high-flying jumper. ▀▀▀ References: Hawkes, E.W., Xiao, C., Peloquin, R., Keeley, C., Begley, M.R., Pope, M.T., & Niemeyer, G. (2022). Engineered jumpers overcome biological limits via work multiplication. Nature, 604, 657-661. – https://ve42.co/Hawkes2022 Fernandez, S. (2022). Hitting New Heights. The Current, UC Santa Barbara. – https://ve42.co/Fernandez2022 Bushwick, S. (2022). Record-Breaking Jumping Robot Can Leap a 10-Story Building. Engineering, Scientific American. – https://ve42.co/Bushwick2022 Mack, E. (2022). This Robot Can Leap Nine Stories in One Jump, Will Go Even Higher on Moon. Science, CNET. – https://ve42.co/Mack2022 Ashby, M. (2020). Materials Selection in Mechanical Design (4th edition). Elsevier. Jumping robot leaps to record heights. Nature Video - https://ve42.co/NatureJumper MultiMo-Bat Robot - https://ve42.co/MultiMoBat Galago Jump - https://ve42.co/GalagoJump Slingshot Spider - https://ve42.co/SlingshotSpider ▀▀▀ Special thanks to Patreon supporters: RayJ Johnson, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin, Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, john kiehl, Nathan Lanza, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Robert Blum, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Emily Zhang and Derek Muller Filmed by Derek Muller and Trenton Oliver Animation by Mike Radjabov and Ivy Tello Edited by Trenton Oliver Additional video/photos supplied by Pond5 and Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

Which experts have real expertise? This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. ▀▀▀ Chase, W. G., & Simon, H. A. (1973). Perception in chess. Cognitive psychology, 4(1), 55-81. – https://ve42.co/chess1 Calderwood, R., Klein, G. A., & Crandall, B. W. (1988). Time pressure, skill, and move quality in chess. The American Journal of Psychology, 481-493. – https://ve42.co/chess2 Hogarth, R. M., Lejarraga, T., & Soyer, E. (2015). The two settings of kind and wicked learning environments. Current Directions in Psychological Science, 24(5), 379-385. – https://ve42.co/Hogarth Ægisdóttir, S., White, M. J., Spengler, P. M., Maugherman, A. S., Anderson, L. A., Cook, R. S., ... & Rush, J. D. (2006). The meta-analysis of clinical judgment project: Fifty-six years of accumulated research on clinical versus statistical prediction. The Counseling Psychologist, 34(3), 341-382. – https://ve42.co/anderson1 Ericsson, K. A. (2015). Acquisition and maintenance of medical expertise: a perspective from the expert-performance approach with deliberate practice. Academic Medicine, 90(11), 1471-1486. – https://ve42.co/anderson2 Goldberg, S. B., Rousmaniere, T., Miller, S. D., Whipple, J., Nielsen, S. L., Hoyt, W. T., & Wampold, B. E. (2016). Do psychotherapists improve with time and experience? A longitudinal analysis of outcomes in a clinical setting. Journal of Counseling Psychology, 63(1), 1. – https://ve42.co/goldberg1 Ericsson, K. A., Krampe, R. T., & Tesch-Römer, C. (1993). The role of deliberate practice in the acquisition of expert performance. Psychological Review, 100(3), 363. – https://ve42.co/anderson3 Egan, D. E., & Schwartz, B. J. (1979). Chunking in recall of symbolic drawings. Memory & Cognition, 7(2), 149-158. – https://ve42.co/chunking1 Tetlock, P. E. (2017). Expert political judgment. In Expert Political Judgment. Princeton University Press. – https://ve42.co/Tetlock Melton, R. S. (1952). A comparison of clinical and actuarial methods of prediction with an assessment of the relative accuracy of different clinicians. Unpublished Ph.D. thesis, University of Minnesota. Meehl, E. P. (1954). Clinical versus Statistical Prediction: A Theoretical Analysis and a Review of the Evidence. University of Minnesota Press. – https://ve42.co/Meehl1954 Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux. – https://ve42.co/Kahneman ▀▀▀ Special thanks to Patreon supporters: RayJ Johnson, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, Julian Lee, Inconcision, TTST, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, john kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Timothy O’Brien, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Derek Muller and Petr Lebedev Animation by Ivy Tello and Fabio Albertelli Filmed by Derek Muller and Raquel Nuno Additional video/photos supplied by Getty Images Music from Epidemic Sound (https://ve42.co/music) Produced by Derek Muller, Petr Lebedev, and Emily Zhang

Fritz Haber is the scientist who arguably most transformed the world. Part of this video is sponsored by Wren. Offset your carbon footprint on Wren: ​https://www.wren.co/start/veritasium1. For the first 100 people who sign up, I will personally pay for the first month of your subscription! ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ A huge thanks to Dan Charles for writing a fantastic biography of Fritz Haber, for taking the time to talk to us about it, and providing valuable feedback. This video would not be what it is without his contributions. http://site.danielcharles.us https://ve42.co/Charles Huge thanks to Tom de Prinse from Explosions and Fire for helping us with the chemistry of explosives. If you like explosions and/or fire, you will love his channel. https://www.youtube.com/c/ExplosionsFire2 Special thanks to Sonya Pemberton, Karl Kruszelnicki, Mary Dobbie, Olivia McRae, and the patreon supporters for giving us feedback on the earlier version of this video. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: The primary reference used is Vaclav Smil’s excellent book, Enriching The Earth – Smil, V. (2004). Enriching the earth: Fritz Haber, Carl Bosch, and the transformation of world food production. MIT press. – https://ve42.co/Smil Mastermind: The Rise and Fall of Fritz Haber, the Nobel Laureate Who Launched the Age of Chemical Warfare, by Dan Charles – https://ve42.co/Charles Stoltzenberg, D. (2004). Fritz Haber: Chemist, Nobel Laureate, German, Jew. Chemical Heritage Foundation. – https://ve42.co/Stoltzenberg Postgate, J. R. (1982). The fundamentals of nitrogen fixation. CUP Archive. – https://ve42.co/postgate Miles, A. G. (1992). Biological nitrogen fixation. – https://ve42.co/Miles Friedrich, B., & Hoffmann, D. (2017). Clara Immerwahr: A life in the shadow of Fritz Haber. In One Hundred Years of Chemical Warfare: Research, Deployment, Consequences(pp. 45-67). Springer, Cham. – https://ve42.co/Friedrich2017 Da Silva, G. (2020). What is ammonium nitrate, the chemical that exploded in Beirut. Sci Am, 5. – https://ve42.co/Silva Rodrigues, P., & Micael, J. (2021). The importance of guano birds to the Inca Empire and the first conservation measures implemented by humans. – https://ve42.co/rodrigues Allison, F. E. (1957). Nitrogen and soil fertility. Soil, the, 85-94. – https://ve42.co/Allison Crookes, W. (1898). Address of the President before the British Association for the Advancement of Science, Bristol, 1898. Science, 8(200), 561-575. – https://ve42.co/Crookes ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: RayJ Johnson, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, Julian Lee, Inconcision, TTST, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, john kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Timothy O’Brien, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Petr Lebedev, Derek Muller, Felicity Nelson and Kovi Rose Edited by Trenton Oliver Animation by Jakub Mistek, Fabio Albertelli, Ivy Tello, Alex Drakoulis, Nils Ramses Kullack, and Charlie Davies SFX by Shaun Clifford Filmed by Petr Lebedev, Derek Muller and Raquel Nuno Photo of nitrogen deficiency in rice from https://ve42.co/rice Additional video/photos supplied by Getty Images Music from Epidemic Sound: https://ve42.co/music

The 100 Prisoners Riddle feels completely impossible even once you know the answer. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Special thanks to Destin of Smarter Every Day (https://ve42.co/SED), Toby of Tibees (https://ve42.co/Tibees), and Jabril of Jabrils (https://ve42.co/Jabrils) for taking the time to think about this mind bending riddle. Huge thanks to Luke West for building plots and for his help with the math. Huge thanks to Dr. Eugene Curtin and Dr. Max Warshauer for their great article on the problem and taking the time to help us understand it: https://ve42.co/CurtinWarshauer Thanks to Dr. John Baez for his help with finding alternate ways to do the calculations. Thanks to Simon Pampena for his input and analysis. Other 100 Prisoners Riddle videos: minutephysics: https://www.youtube.com/watch?v=C5-I0bAuEUE Vsauce2: https://www.youtube.com/watch?v=kOnEEeHZp94 Stand-up Maths: https://www.youtube.com/watch?v=a1DUUnhk3uE TED-Ed: https://www.youtube.com/watch?v=vIdStMTgNl0 ▀▀▀ References: Original paper: Gál, A., & Miltersen, P.B. (2003). The Cell Probe Complexity of Succinct Data Structures. BRICS, Department of Computer Science, University of Aarhus. All rights reserved. – https://ve42.co/GalMiltersen Winkler, P. (2006). Seven Puzzles You Think You Must Not Have Heard Correctly. – https://ve42.co/Winkler2006 The 100 Prisoners Problem – https://ve42.co/100PWiki Golomb, S. & Gaal, P. (1998). On the Number of Permutations on n Objects with Greatest Cycle Length k. Advances in Applied Mathematics, 20(1), 98-107. – https://ve42.co/Golomb1998 Lamb, E. (2012). Puzzling Prisoners Presented to Promote North America's Only Museum of Math. Observations, Scientific American. – https://ve42.co/Lamb2012 Permutations – https://ve42.co/PermutationsWiki Probability that a random permutation of n elements has a cycle of length k greater than n/2, Math SE. – https://ve42.co/BaezProbSE Counting Cycle Structures in Sn, Math SE. – https://ve42.co/CountCyclesSE What is the distribution of cycle lengths in derangements? In particular, expected longest cycle, Math SE. – https://ve42.co/JorikiSE The Manim Community Developers. (2021). Manim - Mathematical Animation Framework (Version v0.13.1). – https://www.manim.community/ ▀▀▀ Special thanks to Patreon supporters: RayJ Johnson, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, Julian Lee, Inconcision, TTST, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Matthew Gonzalez, Eric Sexton, john kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Timothy O’Brien, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Derek Muller and Emily Zhang Filmed by Derek Muller and Petr Lebedev Animation by Ivy Tello and Jesús Rascón Edited by Trenton Oliver Additional video/photos supplied by Getty Images Music from Epidemic Sound and Jonny Hyman Produced by Derek Muller, Petr Lebedev, and Emily Zhang

This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Astronomers think there should be 5 times as much dark matter as ordinary matter – a shadow universe that makes up most of the mass in the universe. But after decades of trying, no experiments have found any trace of dark matter – except one. A massive thanks to the wonderful people at the ARC Centre of Excellence for Dark Matter Physics https://www.centredarkmatter.org for showing us around and being on camera – Fleur Morrison, A/Prof Phillip Urquijo, Prof Elisabetta Barberio, Madeleine Zurowski and Grace Lawrence. Thanks to Leo Fincher-Johnson and everyone at the Stawell gold mine for having us. Massive thanks to Prof. Geraint Lewis – Geraint has been Veritasium’s go-to expert for anything astrophysics and cosmology related. Please check out his website, and buy his books, they’re great – https://www.geraintflewis.com Thanks to Prof. Timothy Tait for the help to make sure we got the science right. ▀▀▀ Galaxy cluster simulation from IllustrisTNG – https://www.tng-project.org Venn Diagram of Dark Matter from Tim Tait – https://ve42.co/venn The Bullet Cluster Image from Magellan, Hubble and Chandra telescopes – https://ve42.co/BC2 Bullet cluster animation from Andrew Robertson / Institute for Computational Cosmology / Durham University – https://ve42.co/BC3 ▀▀▀ Bernabei, R., Belli, P., Cappella, F., Cerulli, R., Dai, C. J., d’Angelo, A., ... & Ye, Z. P. (2008). First results from DAMA/LIBRA and the combined results with DAMA/NaI. The European Physical Journal C, 56(3), 333-355. – https://ve42.co/DAMA2008 Zwicky, F. (1933). Die rotverschiebung von extragalaktischen nebeln. Helvetica physica acta, 6, 110-127. – https://ve42.co/Zwicky1 Zwicky, F. (1937). On the Masses of Nebulae and of Clusters of Nebulae. The Astrophysical Journal, 86, 217. – https://ve42.co/Zwicky2 Rubin, V. C., & Ford Jr, W. K. (1970). Rotation of the Andromeda nebula from a spectroscopic survey of emission regions. The Astrophysical Journal, 159, 379. – https://ve42.co/Rubin1 Bosma, A., & Van der Kruit, P. C. (1979). The local mass-to-light ratio in spiral galaxies. Astronomy and Astrophysics, 79, 281-286. – https://ve42.co/Bosma1 Milgrom, M. (1983). A modification of the Newtonian dynamics as a possible alternative to the hidden mass hypothesis. The Astrophysical Journal, 270, 365-370. – https://ve42.co/mond1 Sanders, R. H., & McGaugh, S. S. (2002). Modified Newtonian dynamics as an alternative to dark matter. Annual Review of Astronomy and Astrophysics, 40(1), 263-317. – https://ve42.co/Mond2 M. Markevitch; A. H. Gonzalez; D. Clowe; A. Vikhlinin; L. David; W. Forman; C. Jones; S. Murray & W. Tucker (2004). "Direct constraints on the dark matter self-interaction cross-section from the merging galaxy cluster 1E0657-56". Astrophys. J. 606 (2): 819–824. – https://ve42.co/BC1 Great website about the CMB – http://background.uchicago.edu/~whu/intermediate/driving2.html Galli, S., Iocco, F., Bertone, G., & Melchiorri, A. (2009). CMB constraints on dark matter models with large annihilation cross section. Physical Review D, 80(2), 023505. – https://ve42.co/CMB1 Antonello, M., Barberio, E., Baroncelli, T., Benziger, J., Bignell, L. J., Bolognino, I., ... & Xu, J. (2019). The SABRE project and the SABRE Proof-of-Principle. The European Physical Journal C, 79(4), 1-8. – https://ve42.co/SABRE1 ▀▀▀ Special thanks to Patreon supporters: Inconcision, Kelly Snook, TTST, Ross McCawley, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Dmitry Kuzmichev, Matthew Gonzalez, Eric Sexton, john kiehl, Anton Ragin, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Derek Muller and Petr Lebedev Edited by Trenton Oliver Animation by Ivy Tello and Mike Radjabov Filmed by Derek Muller and Petr Lebedev Additional video/photos supplied by Getty Image B-roll supplied by Stawell Gold Mine Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

This is an image of the supermassive black hole, Sagittarius A*, at the center of our Milky Way galaxy. Visit https://www.kiwico.com/veritasium30 to get 30% off your first month of any crate! ▀▀▀ Image of Sgr A* from EHT collaboration Event Horizon Telescope collaboration: https://ve42.co/EHT Animations from The Relativistic Astrophysics group, Institute for Theoretical Physics, Goethe-Universität Frankfurt. Massive thanks to Prof. Luciano Rezzolla, Dr Christian Fromm and Dr Alejandro Cruz-Osorio. A huge thanks to Prof. Peter Tuthill and Dr Manisha Caleb for feedback on earlier versions of this video and helping explain VLBI. Great video by Thatcher Chamberlin about VLBI here – https://youtu.be/Y8rAHTvpJbk Animations and simulations with English text: L. R. Weih & L. Rezzolla (Goethe University Frankfurt) https://youtu.be/jvftAadCFRI Video of stars going around Sgr A* from European Southern Observatory https://www.eso.org/public/videos/eso1825e/ Video zooming into the center of our galaxy from European Southern Observatory https://www.youtube.com/watch?v=dXAU0gzsPOw Video of observation of M87 courtesy of: C. M. Fromm, Y. Mizuno & L. Rezzolla (Goethe University Frankfurt) https://youtu.be/meOKmzhTcIY Video of observation of SgrA* courtesy of C. M. Fromm, Y. Mizuno & L. Rezzolla (Goethe University Frankfurt) Z. Younsi (University College London) https://youtu.be/VnsZj9RvhFU Video of telescopes in the array 2017: C. M. Fromm & L. Rezzolla (Goethe University Frankfurt) https://youtu.be/Ame7fzBuFnk Animations and simulations (no text): L. R. Weih & L. Rezzolla (Goethe University Frankfurt) https://youtu.be/XmvpKFSvB7A ▀▀▀ Special thanks to Patreon supporters: Inconcision, Kelly Snook, TTST, Ross McCawley, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Dmitry Kuzmichev, Matthew Gonzalez, Eric Sexton, john kiehl, Anton Ragin, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Derek Muller Animation by Ivy Tello, Mike Radjabov, Maria Raykova Filmed by Petr Lebedev

This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Special thanks to: Bruce Sherwood, Ruth Chabay, Aaron Titus, and Steve Spicklemore https://matterandinteractions.org VPython simulation: http://tinyurl.com/SurfaceCharge Richard Abbott from Caltech Electrical Engineering YouTubers: Electroboom: https://www.youtube.com/c/Electroboom Alpha Phoenix: https://www.youtube.com/c/AlphaPhoenixChannel eevblog: https://www.youtube.com/c/EevblogDave Ben Watson: https://www.youtube.com/channel/UCgZUVIEtBnnBpFWJuxl_E5g Big Clive: https://www.youtube.com/c/Bigclive Z Y: https://www.youtube.com/user/ZongyiYang Further analysis of the large circuit is available here: https://ve42.co/bigcircuit Special thanks to Dr Geraint Lewis for bringing up this question in the first place and discussing it with us. Check out his and Dr Chris Ferrie’s new book here: https://ve42.co/Universe2021 ▀▀▀ References: A great video about the Poynting vector by the Science Asylum: https://youtu.be/C7tQJ42nGno Sefton, I. M. (2002). Understanding electricity and circuits: What the text books don’t tell you. In Science Teachers’ Workshop. -- https://ve42.co/Sefton Feynman, R. P., Leighton, R. B., & Sands, M. (1965). The feynman lectures on physics; vol. Ii, chapter 27. American Journal of Physics, 33(9), 750-752. -- https://ve42.co/Feynman27 Hunt, B. J. (2005). The Maxwellians. Cornell University Press. Müller, R. (2012). A semiquantitative treatment of surface charges in DC circuits. American Journal of Physics, 80(9), 782-788. -- https://ve42.co/Muller2012 Galili, I., & Goihbarg, E. (2005). Energy transfer in electrical circuits: A qualitative account. American journal of physics, 73(2), 141-144. -- https://ve42.co/Galili2004 Deno, D. W. (1976). Transmission line fields. IEEE Transactions on Power Apparatus and Systems, 95(5), 1600-1611. -- https://ve42.co/Deno76 ▀▀▀ Special thanks to Patreon supporters: Inconcision, Kelly Snook, TTST, Ross McCawley, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Dmitry Kuzmichev, Matthew Gonzalez, Eric Sexton, john kiehl, Anton Ragin, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Derek Muller Edited by Derek Muller Filmed by Trenton Oliver and Petr Lebedev Animation by Mike Radjabov and Ivy Tello Additional video/photos supplied by Getty Images Music from Epidemic Sound and Jonny Hyman Produced by Derek Muller, Petr Lebedev, and Emily Zhang

A part of this video is sponsored by Wren. Offset your carbon footprint on Wren: ​https://www.wren.co/start/veritasium. For the first 100 people who sign up, I will personally pay for the first month of your subscription! Massive thanks to Prof. Francois Tissot for suggesting we make a video on the topic of isotope geochemistry. Huge thanks to Prof. Bruce Lanphear for consulting with us on lead and cardiovascular diseases. Thanks to Vincent Mai for lending us your Snatoms kit. Thanks to the Caltech Archives for the audio of Patterson’s interview. Thanks to Rayner Moss for help with the fire piston. ▀▀▀ Other great resources you should check out: Bill Bryson has a chapter in his fantastic “A Short History of Nearly Everything” Radiolab have a wonderful podcast: https://www.wnycstudios.org/podcasts/radiolab/articles/heavy-metal Cosmos: A Spacetime Odyssey has a wonderful episode – S1E7 which does a great job of telling the story of Clair Patterson A fantastic Mental floss article – https://www.mentalfloss.com/article/94569/clair-patterson-scientist-who-determined-age-earth-and-then-saved-it ▀▀▀ References: Much of the lead-crime hypothesis data is from Rick Nevin’s work – https://ricknevin.com/ WHO factsheet on lead poisoning – https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health WHO press release about the end of leaded gasoline https://news.un.org/en/story/2021/08/1098792 UNICEF report – https://ve42.co/UNICEF Needleman, H. (2004). Lead poisoning. Annu. Rev. Med., 55, 209-222. https://ve42.co/Needleman1 Needleman, H. L. (1991). Human lead exposure. CRC Press. https://ve42.co/Needleman2 Needleman, H. L. et al. (1979). Deficits in psychologic and classroom performance of children with elevated dentine lead levels. New England journal of medicine, 300(13), 689-695. – https://ve42.co/Needleman3 Needleman, H. L. et al. (1996). Bone lead levels and delinquent behavior. Jama, 275(5), 363-369. https://ve42.co/Needleman4 Kovarik, W. J. (1993). The ethyl controversy: the news media and the public health debate over leaded gasoline, 1924-1926 https://ve42.co/Kovarik2 Edelmann, F. T. (2016). The life and legacy of Thomas Midgley Jr. In Papers and Proceedings of the Royal Society of Tasmania https://ve42.co/Edelmann More, A. F. et al. (2017). Next‐generation ice core technology reveals true minimum natural levels of lead (Pb) in the atmosphere: Insights from the Black Death. GeoHealth, 1(4), 211-219. https://ve42.co/More1 McFarland, M. J., et al. (2022). PNAS 119(11), e2118631119. https://ve42.co/McFarland Kovarik, W. (2005). Ethyl-leaded gasoline. International Journal of Occupational and Environmental Health, 11(4), 384-397. https://ve42.co/Kovarik3 Nevin, R. (2007). Understanding international crime trends: the legacy of preschool lead exposure. Environmental research, 104(3), 315-336. – https://ve42.co/Nevin2007 Ericson, J. E., et al. (1979). Skeletal concentrations of lead in ancient Peruvians. New England Journal of Medicine, 300(17), 946-951. – https://ve42.co/Ericson1 Patterson, Claire. The Isotopic Composition of Trace Quantities of Lead and Calcium https://ve42.co/Patterson1 Boutron, C. F., & Patterson, C. C. (1986). Lead concentration changes in Antarctic ice during the Wisconsin/Holocene transition. Nature, 323(6085), 222-225. – https://ve42.co/Boulton1 Patterson, C. (1956). Age of meteorites and the earth. Geochimica et Cosmochimica Acta, 10(4), 230-237. – https://ve42.co/Patterson2 Lanphear, B. P. et al (2018). Low-level lead exposure and mortality in US adults: a population-based cohort study. The Lancet Public Health, 3(4), e177-e184. – https://ve42.co/Lanphear1 Schaule, B. K., & Patterson, C. C. (1981). Lead concentrations in the northeast Pacific: evidence for global anthropogenic perturbations. Earth and Planetary Science Letters, 54(1), 97-116. – https://ve42.co/Schaule1 ▀▀▀ Special thanks to Patreon supporters: Inconcision, Kelly Snook, TTST, Ross McCawley, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Dmitry Kuzmichev, Matthew Gonzalez, Eric Sexton, john kiehl, Anton Ragin, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Petr Lebedev, Derek Muller, Chris Stewart and Katie Barnshaw Edited by Trenon Oliver Filmed by Petr Lebedev Animation by Fabio Albertelli, Jakub Misiek, Iván Tello and Mike Radjabov, Caleb Worcester Additional video/photos supplied by Getty Images Patterson’s 1995 interview audio Courtesy of the Archives, California Institute of Technology Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. To make antivenom, you first need to collect venom from the world’s most deadly snakes. Huge thanks to the Australian Reptile Park for having us over to film – special thanks to Zac Bower for milking all of these snakes for us and Caitlin Vine for organizing the shoot. Absolute legends. https://www.reptilepark.com.au Huge thanks to Dr Timothy Jackson from the Australian Venom Research Unit for answering our questions, and fact checking the script. This video would not have been the same without you. Thanks to Seqirus Australia for providing B-roll footage of the horses and the antivenom production. ▀▀▀ References: Calmette, A. (1896). Le venin des serpents: Physiologie de l'envenimation, traitement des morsures venimeuses par le sérum des animaux vaccinés. Paris: Société d'éditions scientifiques. Broad, A. J., Sutherland, S. K., & Coulter, A. R. (1979). The lethality in mice of dangerous Australian and other snake venom. Toxicon, 17(6), 661-664. – https://ve42.co/Broad79 WHO Expert Committee on Biological Standardization. (2016). WHO guidelines for the production, control and regulation of snake antivenom immunoglobulins. Geneve, Switzerland. – https://ve42.co/WHO2016 Calmette, A. (1896). The treatment of animals poisoned with snake venom by the injection of antivenomous serum. British medical journal, 2(1859), 399. – https://ve42.co/Calmette1896 Hawgood, B. J. (1999). Doctor Albert Calmette 1863–1933: founder of antivenomous serotherapy and of antituberculous BCG vaccination. Toxicon, 37(9), 1241-1258. – https://ve42.co/Hawgood99 Pucca, M. B., Cerni, F. A., Janke, R., Bermúdez-Méndez, E., Ledsgaard, L., Barbosa, J. E., & Laustsen, A. H. (2019). History of envenoming therapy and current perspectives. Frontiers in immunology, 1598. – https://ve42.co/Pucca19 Kang, T. S., Georgieva, D., Genov, N., Murakami, M. T., Sinha, M., Kumar, R. P., ... & Kini, R. M. (2011). Enzymatic toxins from snake venom: structural characterization and mechanism of catalysis. The FEBS journal, 278(23), 4544-4576. – https://ve42.co/Kang2011 Hawgood, B. J. (2007). Albert Calmette (1863–1933) and Camille Guerin (1872–1961): the C and G of BCG vaccine. Journal of medical biography, 15(3), 139-146. – https://ve42.co/Hawgood2007 Vonk, F. J., Admiraal, J. F., Jackson, K., Reshef, R., de Bakker, M. A., Vanderschoot, K., ... & Richardson, M. K. (2008). Evolutionary origin and development of snake fangs. Nature, 454(7204), 630-633. – https://ve42.co/vonk2008 Bochner, R. (2016). Paths to the discovery of antivenom serotherapy in France. Journal of Venomous Animals and Toxins including Tropical Diseases, 22. – https://ve42.co/Bochner2016 Young, B. A., Herzog, F., Friedel, P., Rammensee, S., Bausch, A., & van Hemmen, J. L. (2011). Tears of venom: hydrodynamics of reptilian envenomation. Physical review letters, 106(19), 198103. – https://ve42.co/Young2011 Madras Medical Journal, Volume Second, July-December 1870. Page 355 ▀▀▀ Special thanks to Patreon supporters: Inconcision, Kelly Snook, TTST, Ross McCawley, Balkrishna Heroor, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Dmitry Kuzmichev, Matthew Gonzalez, Eric Sexton, john kiehl, Anton Ragin, Benedikt Heinen, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Petr Lebedev and Derek Muller Edited by Trenton Oliver Filmed by Jason Tran and Petr Lebedev Animation by Fabio Albertelli, Jakub Misiek, Iván Tello and Mike Radjabov. Molecule animation by Reciprocal Space – https://www.reciprocal.space Additional video/photos supplied by Getty Image B-roll supplied by Seqirus Australia Music from Epidemic Sound and Jonny Hyman Produced by Derek Muller, Petr Lebedev, and Emily Zhang

Visit https://brilliant.org/Veritasium/ to get started learning STEM for free, and the first 200 people will get 20% off their annual premium subscription. Digital computers have served us well for decades, but the rise of artificial intelligence demands a totally new kind of computer: analog. Thanks to Mike Henry and everyone at Mythic for the analog computing tour! https://www.mythic-ai.com/ Thanks to Dr. Bernd Ulmann, who created The Analog Thing and taught us how to use it. https://the-analog-thing.org Moore’s Law was filmed at the Computer History Museum in Mountain View, CA. Welch Labs’ ALVINN video: https://www.youtube.com/watch?v=H0igiP6Hg1k ▀▀▀ References: Crevier, D. (1993). AI: The Tumultuous History Of The Search For Artificial Intelligence. Basic Books. – https://ve42.co/Crevier1993 Valiant, L. (2013). Probably Approximately Correct. HarperCollins. – https://ve42.co/Valiant2013 Rosenblatt, F. (1958). The Perceptron: A Probabilistic Model for Information Storage and Organization in the Brain. Psychological Review, 65(6), 386-408. – https://ve42.co/Rosenblatt1958 NEW NAVY DEVICE LEARNS BY DOING; Psychologist Shows Embryo of Computer Designed to Read and Grow Wiser (1958). The New York Times, p. 25. – https://ve42.co/NYT1958 Mason, H., Stewart, D., and Gill, B. (1958). Rival. The New Yorker, p. 45. – https://ve42.co/Mason1958 Alvinn driving NavLab footage – https://ve42.co/NavLab Pomerleau, D. (1989). ALVINN: An Autonomous Land Vehicle In a Neural Network. NeurIPS, (2)1, 305-313. – https://ve42.co/Pomerleau1989 ImageNet website – https://ve42.co/ImageNet Russakovsky, O., Deng, J. et al. (2015). ImageNet Large Scale Visual Recognition Challenge. – https://ve42.co/ImageNetChallenge AlexNet Paper: Krizhevsky, A., Sutskever, I., Hinton, G. (2012). ImageNet Classification with Deep Convolutional Neural Networks. NeurIPS, (25)1, 1097-1105. – https://ve42.co/AlexNet Karpathy, A. (2014). Blog post: What I learned from competing against a ConvNet on ImageNet. – https://ve42.co/Karpathy2014 Fick, D. (2018). Blog post: Mythic @ Hot Chips 2018. – https://ve42.co/MythicBlog Jin, Y. & Lee, B. (2019). 2.2 Basic operations of flash memory. Advances in Computers, 114, 1-69. – https://ve42.co/Jin2019 Demler, M. (2018). Mythic Multiplies in a Flash. The Microprocessor Report. – https://ve42.co/Demler2018 Aspinity (2021). Blog post: 5 Myths About AnalogML. – https://ve42.co/Aspinity Wright, L. et al. (2022). Deep physical neural networks trained with backpropagation. Nature, 601, 49–555. – https://ve42.co/Wright2022 Waldrop, M. M. (2016). The chips are down for Moore’s law. Nature, 530, 144–147. – https://ve42.co/Waldrop2016 ▀▀▀ Special thanks to Patreon supporters: Kelly Snook, TTST, Ross McCawley, Balkrishna Heroor, 65square.com, Chris LaClair, Avi Yashchin, John H. Austin, Jr., OnlineBookClub.org, Dmitry Kuzmichev, Matthew Gonzalez, Eric Sexton, john kiehl, Anton Ragin, Benedikt Heinen, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Michael Schneider, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀ Written by Derek Muller, Stephen Welch, and Emily Zhang Filmed by Derek Muller, Petr Lebedev, and Emily Zhang Animation by Iván Tello, Mike Radjabov, and Stephen Welch Edited by Derek Muller Additional video/photos supplied by Getty Images and Pond5 Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev, and Emily Zhang

Analog computers were the most powerful computers for thousands of years, relegated to obscurity by the digital revolution. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Thanks to Scott Wiedemann for the lego computer instructions – https://www.youtube.com/watch?v=5X_Ft4YR_wU Antikythera Archive & Animations ©2005-2020 Images First Ltd. https://www.youtube.com/watch?v=1ebB0tyrMa8 "The Antikythera Cosmos" (2021) follows the latest developments from the UCL Antikythera Research Team as they recreate a dazzling display of the ancient Greek Cosmos at the front of the Antikythera Mechanism. Tides video from NASA – https://climate.nasa.gov/climate_resources/246/video-global-ocean-tides/ Ship animation from this painting – https://ve42.co/Agamemnon Moore’s Law, the op-amp, and the Norden bombsight were filmed at the Computer History Museum in Mountain View, CA. ▀▀▀ References: Freeth, T., Bitsakis, Y., Moussas, X., Seiradakis, J. H., Tselikas, A., Mangou, H., ... & Edmunds, M. G. (2006). Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism. Nature, 444(7119), 587-591. – https://ve42.co/Freeth2006 Freeth, T., & Jones, A. (2012). The cosmos in the Antikythera mechanism. ISAW Papers. – https://ve42.co/Freeth2012 Cartwright, D. E. (2000). Tides: a scientific history. Cambridge University Press. – https://ve42.co/tides Thomson, W. (2017). Mathematical and physical papers. CUP Archive. – https://ve42.co/Kelvinv6 Parker, B. B. (2007). Tidal analysis and prediction. NOAA NOS Center for Operational Oceanographic Products and Services. - https://ve42.co/Parker2007 Parker, B. (2011). The tide predictions for D-Day. Physics Today, 64(9), 35-40. – https://ve42.co/Parker2011 Small, J. (2013). The Analogue Alternative. Routledge. – https://ve42.co/Small2013 Zorpette, G. (1989). Parkinson's gun director. IEEE Spectrum, 26(4), 43. – https://ve42.co/Zorpette89 Tremblay, M. (2009). Deconstructing the myth of the Norden Bombsight (Doctoral dissertation). – https://ve42.co/Tremblay Gladwell, M. (2021). The Bomber Mafia. Little, Brown and Company. - https://ve42.co/Gladwell2021 Mindell, D. A. (2000). Automation’s finest hour: Radar and system integration in World War II. Systems, Experts, and Computers: The Systems Approach in Management and Engineering, World War II and After. Edited by A. C. Hughes and T. P. Hughes, 27-56. – https://ve42.co/Mindell Haigh, T., Priestley, M., & Rope, C. (2016). ENIAC in Action. The MIT Press. - https://ve42.co/Eniac2016 Soni, J., & Goodman, R. (2017). A mind at play: how Claude Shannon invented the information age. Simon and Schuster. – https://ve42.co/Soni Haigh, T. & Ceruzzi, P. (2021). A New History of Modern Computing. The MIT Press. - https://ve42.co/ModernComputing Rid, T. (2016). Rise of the Machines: a Cybernetic History. Highbridge. - https://ve42.co/Rid2016 Ulmann, B. (2013). Analog computing. Oldenbourg Wissenschaftsverlag. – https://ve42.co/Ulmann2013 ▀▀▀ Special thanks to Patreon supporters: Dmitry Kuzmichev, Matthew Gonzalez, Baranidharan S, Eric Sexton, john kiehl, Daniel Brockman, Anton Ragin, S S, Benedikt Heinen, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Edward Larsen, Burt Humburg, Blak Byers, Dumky, , Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Mac Malkawi, Michael Schneider, Ludovic Robillard, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Stephen Wilcox, Marinus Kuivenhoven, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Written by Derek Muller, Stephen Welch and Emily Zhang Filmed by Derek Muller, Emily Zhang and Raquel Nuno Animation by Fabio Albertelli, Jakub Misiek, Mike Radjabov, Iván Tello, Trenton Oliver Edited by Derek Muller Additional video supplied by Getty Images Music from Epidemic Sound and Jonny Hyman Produced by Derek Muller, Petr Lebedev and Emily Zhang

Dr Ken Libbrecht is the world expert on snowflakes, designer of custom snowflakes, snowflake consultant for the movie Frozen - his photos appear on postage stamps all over the world. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Thanks to Dr Ken Libbrecht for showing us how to grow designer snowflakes. Obviously, this video would not have been possible without his help and his expertise. His website is full of information about snowflakes http://snowcrystals.com. His new book is also available to purchase from here -- https://ve42.co/SnowCrystalsBook ▀▀▀ References: Libbrecht, K. G. (2019). A Quantitative Physical Model of the Snow Crystal Morphology Diagram. arXiv preprint arXiv:1910.09067. -- https://ve42.co/Libbrecht2019 ▀▀▀ Special thanks to Patreon supporters: Luis Felipe, Anton Ragin, Paul Peijzel, S S, Benedikt Heinen, Diffbot, Micah Mangione, Juan Benet, Ruslan Khroma, Richard Sundvall, Lee Redden, Sam Lutfi, MJP, Gnare, Nick DiCandilo, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Ruslan Khroma, Robert Blum, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Ron Neal Written by Derek Muller Filmed by Derek Muller, Raquel Nuno, Trenton Oliver and Emily Zhang Edited by Trenton Oliver Animations by Ivàn Tello and Trenton Oliver Additional video supplied by Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev and Emily Zhang

Why are bicycles stable? The most common answer is gyroscopic effects, but this is not right. This video was sponsored by Kiwico. Get 50% off your first month of any crate at https://kiwico.com/veritasium50 Huge thanks to Rick Cavallaro for creating this bike on short notice. Thanks to all the friends who participated in the filming. Rick was also responsible for the Blackbird Faster Than The Wind Downwind Cart. https://youtu.be/jyQwgBAaBag Great videos on bikes and counter-steering: MinutePhysics: How Do Bikes Stay Up? https://youtu.be/oZAc5t2lkvo MinutePhysics: The Counterintuitive Physics of Turning a Bike: https://youtu.be/llRkf1fnNDM Why Bicycles Do Not Fall - Arend Schwab TED talk: https://youtu.be/2Y4mbT3ozcA Today I Found Out: We Still Don't Know How Bicycles Work https://youtu.be/YWsK6rmsKSI TU Delft - Smart motor in handlebars prevents bicycles from falling over: https://youtu.be/rBOQp2uY_lk Andy Ruina Explains How Bicycles Balance Themselves: https://youtu.be/NcZCzr9ExKk ▀▀▀ More References: TU Delft Bicycle Site: http://bicycle.tudelft.nl/schwab/Bicycle/ Bicycle stability program: http://ruina.tam.cornell.edu/research/topics/bicycle_mechanics/JBike6_web_folder/index.htm ▀▀▀ Special thanks to Patreon supporters: Luis Felipe, Anton Ragin, Paul Peijzel, S S, Benedikt Heinen, Diffbot, Micah Mangione, Juan Benet, Ruslan Khroma, Richard Sundvall, Lee Redden, Sam Lutfi, MJP, Gnare, Nick DiCandilo, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Ruslan Khroma, Robert Blum, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson,Ron Neal ▀▀▀ Written by Derek Muller Filmed by Trenton Oliver, Raquel Nuno and Derek Muller Edited by Derek Muller Music from Epidemic Sound and Jonny Hyman Produced by Derek Muller, Petr Lebedev and Emily Zhang

The misconception is that electrons carry potential energy around a complete conducting loop, transferring their energy to the load. This video was sponsored by Caséta by Lutron. Learn more at https://Lutron.com/veritasium Further analysis of the large circuit is available here: https://ve42.co/bigcircuit Special thanks to Dr Geraint Lewis for bringing up this question in the first place and discussing it with us. Check out his and Dr Chris Ferrie’s new book here: https://ve42.co/Universe2021 Special thanks to Dr Robert Olsen for his expertise. He quite literally wrote the book on transmission lines, which you can find here: https://ve42.co/Olsen2018 Special thanks to Dr Richard Abbott for running a real-life experiment to test the model. Huge thanks to all of the experts we talked to for this video -- Dr Karl Berggren, Dr Bruce Hunt, Dr Paul Stanley, Dr Joe Steinmeyer, Ian Sefton, and Dr David G Vallancourt. ▀▀▀ References: A great video about the Poynting vector by the Science Asylum: https://youtu.be/C7tQJ42nGno Sefton, I. M. (2002). Understanding electricity and circuits: What the text books don’t tell you. In Science Teachers’ Workshop. -- https://ve42.co/Sefton Feynman, R. P., Leighton, R. B., & Sands, M. (1965). The feynman lectures on physics; vol. Ii, chapter 27. American Journal of Physics, 33(9), 750-752. -- https://ve42.co/Feynman27 Hunt, B. J. (2005). The Maxwellians. Cornell University Press. Müller, R. (2012). A semiquantitative treatment of surface charges in DC circuits. American Journal of Physics, 80(9), 782-788. -- https://ve42.co/Muller2012 Galili, I., & Goihbarg, E. (2005). Energy transfer in electrical circuits: A qualitative account. American journal of physics, 73(2), 141-144. -- https://ve42.co/Galili2004 Deno, D. W. (1976). Transmission line fields. IEEE Transactions on Power Apparatus and Systems, 95(5), 1600-1611. -- https://ve42.co/Deno76 ▀▀▀ Special thanks to Patreon supporters: Luis Felipe, Anton Ragin, Paul Peijzel, S S, Benedikt Heinen, Diffbot, Micah Mangione, Juan Benet, Ruslan Khroma, Richard Sundvall, Lee Redden, Sam Lutfi, MJP, Gnare, Nick DiCandilo, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Ruslan Khroma, Robert Blum, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson,Ron Neal Written by Derek Muller and Petr Lebedev Animation by Mike Radjabov and Iván Tello Filmed by Derek Muller and Emily Zhang Footage of the sun by Raquel Nuno Edited by Derek Muller Additional video supplied by Getty Images Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev and Emily Zhang

A general solution to the cubic equation was long considered impossible, until we gave up the requirement that math reflect reality. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Thanks to Dr Amir Alexander, Dr Alexander Kontorovich, Dr Chris Ferrie, and Dr Adam Becker for the helpful advice and feedback on the earlier versions of the script. ▀▀▀ References: Some great videos about the cubic: 500 years of not teaching the cubic formula. -- https://youtu.be/N-KXStupwsc Imaginary Numbers are Real -- https://youtu.be/T647CGsuOVU Dunham, W. (1990). Journey through genius: The great theorems of mathematics. New York. -- https://ve42.co/Dunham90 Toscano, F. (2020). The Secret Formula. Princeton University Press. -- https://ve42.co/Toscano2020 Bochner, S. (1963). The significance of some basic mathematical conceptions for physics. Isis, 54(2), 179-205. -- https://ve42.co/Bochner63 Muroi, K. (2019). Cubic equations of Babylonian mathematics. arXiv preprint arXiv:1905.08034. -- https://ve42.co/Murio21 Branson, W. Solving the cubic with Cardano, -- https://ve42.co/Branson2014 Rothman, T. (2013). Cardano v Tartaglia: The Great Feud Goes Supernatural. arXiv preprint arXiv:1308.2181. -- https://ve42.co/Rothman Vali Siadat, M., & Tholen, A. (2021). Omar Khayyam: Geometric Algebra and Cubic Equations. Math Horizons, 28(1), 12-15. -- https://ve42.co/Siadat21 Merino, O. (2006). A short history of complex numbers. University of Rhode Island. -- https://ve42.co/Merino2006 Cardano, G (1545), Ars magna or The Rules of Algebra, Dover (published 1993), ISBN 0-486-67811-3 Bombelli, R (1579) L’Algebra https://ve42.co/Bombelli ▀▀▀ Special thanks to Patreon supporters: Luis Felipe, Anton Ragin, Paul Peijzel, S S, Benedikt Heinen, Diffbot, Micah Mangione, Juan Benet, Ruslan Khroma, Richard Sundvall, Lee Redden, Sam Lutfi, MJP, Gnare, Nick DiCandilo, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Ruslan Khroma, Robert Blum, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson,Ron Neal Written by Derek Muller, Stephen Welch and Petr Lebedev Animation by Fabio Albertelli, Jakub Misiek, Iván Tello and Jesús Rascón Mathematical animations done with Manim -- thanks Grant Sanderson and the Manim community! SFX by Shaun Clifford Filmed by Derek Muller and Emily Zhang Edited by Derek Muller and Petr Lebedev Additional video supplied by Getty Images Music from Epidemic Sound Additional Music By Jonny Hyman Produced by Derek Muller, Petr Lebedev and Emily Zhang

The story of a controversial physics question on the qualifying exam for the 2014 US Physics Olympiad team. How does a uniform cable beneath a helicopter hang? Visit https://SimpliSafe.com/veritasium to learn more and to get at least 30% off your SimpliSafe security system! Thanks to SimpliSafe for sponsoring a portion of this video. Thanks to Scott Smith and the Perris Valley Airport for hosting us. You can learn more about them at https://skydiveperris.com/. Thanks to Craig Hosking for being our expert helicopter pilot. Thanks to Professor Paul Stanley for the interview and for writing such an interesting question. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: The Exam — https://ve42.co/AAPT2014Exam The Solution — https://ve42.co/AAPT2014Solutions ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: S S, Andrew, Benedikt Heinen, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Mac Malkawi, Michael Schneider, Big Badaboom, Ludovic Robillard, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Derek Muller, Emily Zhang, and Petr Lebedev Filmed by Derek Muller, Trenton Oliver, and Emily Zhang Edited by Trenton Oliver Animation by Mike Radjabov Music from Epidemic Sounds Additional video supplied by Getty Images Produced by Derek Muller, Petr Lebedev, and Emily Zhang

This is a #robot that walks, flies, #skateboards, #slacklines, and might do much more one day. A portion of this video was sponsored by Bluehost. Start building a website with Bluehost today. Use my link to receive more than 65% off: https://bluehost.com/track/veritasium #Bluehost #BHcreator Thanks to Prof. Soon-Jo Chung and everyone at the Aerospace Robotics and Control Lab at Caltech for the tour! https://aerospacerobotics.caltech.edu/ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Kim, K., Spieler, P., Lupu, S., Ramezani, A., Chung, S. (2021). A bipedal walking robot that can fly, slackline, and skateboard. Science Robotics. — https://www.science.org/doi/10.1126/scirobotics.abf8136 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: S S, Andrew, Benedikt Heinen, Diffbot, Micah Mangione, MJP, Gnare, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Mac Malkawi, Michael Schneider, Big Badaboom, Ludovic Robillard, jim buckmaster, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Derek Muller Filmed by Derek Muller, Trenton Oliver, and Emily Zhang Edited by Trenton Oliver Produced by Derek Muller, Petr Lebedev, and Emily Zhang

Your genetic code is probably already in a database, without you ever giving a sample or permission. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ A huge thanks to Paul Holes, Billy Jensen, Brett Williams, Dr Connie Bormans and Dr Doc Edge for being part of this video. Thanks to Verogen and Family Tree DNA for giving me access to film. Thanks to Sonya Pemberton, Joe Hanson, Raquel Nuno, CGP Grey, and numerous Patreon supporters for helpful feedback on an earlier version of this video. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Phillips, C. (2018). The Golden State Killer investigation and the nascent field of forensic genealogy. Forensic Science International: Genetics, 36, 186-188. -- https://ve42.co/Phillips2018 Guerrini, C. J., Robinson, J. O., Petersen, D., & McGuire, A. L. (2018). Should police have access to genetic genealogy databases? Capturing the Golden State Killer and other criminals using a controversial new forensic technique. PLoS biology, 16(10), e2006906. -- https://ve42.co/Guerrini Ram, N., Guerrini, C. J., & McGuire, A. L. (2018). Genealogy databases and the future of criminal investigation. Science, 360(6393), 1078-1079. -- https://ve42.co/Ram2019 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Andrew, Diffbot, Micah Mangione, MJP, Gnare, Nick DiCandilo, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Mac Malkawi, Michael Schneider, Big Badaboom, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Derek Muller Animation by Iván Tello and Another Angle 3D Visuals (www.anotherangle.ee) SFX by Shaun Clifford Filmed by Derek Muller, Raquel Nuno, Shirley Dutoit, and Emily Zhang Edited by Derek Muller Produced by Derek Muller and Casey Rentz Additional video supplied by Getty Images Music from Epidemic Sound https://epidemicsound.com ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

Bowling has been reinvented many times over the past seven thousand years but especially in the last 30. This is the fascinating physics of balls, oil, lane and pins. A portion of this video was sponsored by Salesforce. Go to https://salesforce.com/veritasium to learn more. Huge thanks to Steve Kloempken and all of Storm Bowling for letting us visit and get a glimpse into the crazy world of bowling. Huge thanks to legends Chris Barnes and Pete Weber for taking the time to bowl with us. Thanks to Ron Hatfield and James Freeman for their help with research. Check out their great book, Bowling Beyond the Basics: https://ve42.co/HatfieldFreeman Thanks to the United States Bowling Congress (USBC) and Professional Bowlers Association (PBA) for their help with accessing archival data and footage. Spacial thanks to Rod Cross for physics consultation. Thanks to Bill Guszczo for giving us the idea to make this video in the first place. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Freeman, James, and Ron Hatfield. Bowling beyond the Basics: What's Really Happening on the Lanes, and What You Can Do about It. BowlSmart, 2018. -- https://ve42.co/HatfieldFreeman N. Stremmel, P. Ridenour and S. Sterbenz. “Identifying the Critical Factors That Contribute to Bowling Ball Motion on a Bowling Lane.” United States Bowling Congress, 2008. -- https://ve42.co/BallMotionASQ USBC Equipment Specifications and Certification Team. “Ball Motion Study: Phase I and II Final Report.” United States Bowling Congress, 2008. -- https://ve42.co/USBCBallMotion Brettingen, Patrick, and Nicki Mours. “USBC static weight limits remain relevant.” United States Bowling Congress, 2011. -- https://ve42.co/USBCStaticWeight Article on lane oil origins -- https://ve42.co/OilOrigins Luna, Richard. “Bruce Pluckhahn says there's a little bit of bowling…” United Press International Archives, 1984. -- https://ve42.co/BowlingHistory Johnson, Brody D. “The Physics of Bowling: How good bowlers stay off the straight and narrow.” St. Louis University. -- https://ve42.co/JohnsonPhysicsPpt Talamo, Jim. “The Physics of Bowling Balls.” -- https://ve42.co/TalamoPhysicsPpt Thompson, Ted. “Breakdown and Carrydown - Then and Now.” Kegel. 2012. -- https://ve42.co/ThompsonKegel Frohlich, Cliff. “What Makes Bowling Balls Hook?” American Journal of Physics, vol. 72, no. 9, 2004, pp. 1170–1177., https://doi.org/10.1119/1.1767099. -- https://ve42.co/FrohlichHook Article on bowling’s ranking in participatory sports -- https://ve42.co/BowlingRank Speranza, Dan, and Dave Nestor. “Initial Oil Absorption Results.” United States Bowling Congress, 2016. -- https://ve42.co/USBCOilAbsorption D. Benner, N. Mours, and P. Ridenour. “Pin Carry Study: Bowl Expo 2009.” United States Bowling Congress, 2009. -- https://ve42.co/USBCPinCarry Hopkins, D. C., and J. D. Patterson. “Bowling Frames: Paths of a Bowling Ball.” American Journal of Physics, vol. 45, no. 3, 1977, pp. 263–266., https://doi.org/10.1119/1.11005. -- https://ve42.co/HopkinsPath Normani, Franco. “The Physics of Bowling.” Real World Physics Problems. -- https://ve42.co/NormaniPhysics Horaczek, Stan. “The insides of pro bowling balls will make your head spin.” Popular Science, 2020. -- https://ve42.co/HoraczekSpin House shot oil pattern -- https://ve42.co/HouseOil. Licensed under Creative Commons: By Attribution 4.0. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Andrew, Diffbot, Micah Mangione, MJP, Gnare, Nick DiCandilo, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Mac Malkawi, Michael Schneider, Big Badaboom, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Clayton Greenwell, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Written by Derek Muller and Emily Zhang Animations by Mike Radjabov and Iván Tello Filmed by Derek Muller, Trenton Oliver, and Emily Zhang Edited by Trenton Oliver SFX by Shaun Clifford Additional video supplied by Getty Images Music from Epidemic Sounds Produced by Derek Muller, Petr Lebedev, and Emily Zhang

Under UV light, almost all species of scorpions glow a bright green color, but why? Thanks to Capital One Shopping for sponsoring a portion of this video! Avoid Paying Full Price. Get Capital One Shopping for free using this link: https://capitaloneshopping.com/veritasium A huge thanks to Prof. Carl Kloock for the interview and taking us scorpion hunting at the Panorama Vista Preserve. ▀▀▀ References: Zwicky, K. T. (1968). A light response in the tail of Urodacus, a scorpion. Life Sciences, 7(6), 257-262. --https://ve42.co/Zwicky1968 Kloock, C. T. (2005). Aerial insects avoid fluorescing scorpions. Euscorpius, 2005(21), 1-7. -- https://ve42.co/Kloock2005 Gaffin, D. D., Bumm, L. A., Taylor, M. S., Popokina, N. V., & Mann, S. (2012). Scorpion fluorescence and reaction to light. Animal Behaviour, 83(2), 429-436. -- https://ve42.co/Gaffin2012 Kloock, C. T., Kubli, A., & Reynolds, R. (2010). Ultraviolet light detection: a function of scorpion fluorescence. The Journal of Arachnology, 38(3), 441-445. -- https://ve42.co/Kloock2012 Kloock, C. T. (2009). Reducing scorpion fluorescence via prolonged exposure to ultraviolet light. The Journal of Arachnology, 37(3), 368-370. -- https://ve42.co/Kloock2009 ▀▀▀ Written by Derek Muller, Emily Zhang, Petr Lebedev Animation by Iván Tello Filmed by Derek Muller and Emily Zhang Edited by Brian Kim Additional video supplied by Getty Images Music from Epidemic Sound https://epidemicsound.com And "Sneaky Snitch" by Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/b… Produced by Derek Muller, Emily Zhang and Petr Lebedev

Tiny particles from distant galaxies have caused plane accidents, election interference and game glitches. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. This video was inspired by the RadioLab Podcast "Bit Flip" https://ve42.co/BF -- they're brilliant science storytellers. A Huge thanks to Dr Leif Scheick, Calla Cofield and the JPL Media Relations Team. Thanks to Col Chris Hadfield. Check out his book: https://chrishadfield.ca/books/ ▀▀▀ References: J. F. Ziegler, "Terrestrial cosmic rays," in IBM Journal of Research and Development, vol. 40, no. 1, pp. 19-39, Jan. 1996, doi: 10.1147/rd.401.0019. -- https://ve42.co/Ziegler1996 D. Binder, E. C. Smith and A. B. Holman, "Satellite Anomalies from Galactic Cosmic Rays," in IEEE Transactions on Nuclear Science, vol. 22, no. 6, pp. 2675-2680, Dec. 1975, doi: 10.1109/TNS.1975.4328188 https://ve42.co/Binder1975 Ziegler, J. F., & Lanford, W. A. (1979). Effect of cosmic rays on computer memories. Science, 206(4420), 776-788 https://ve42.co/Ziegler1979 Drury, L. O. C. (2012). Origin of cosmic rays. Astroparticle Physics, 39, 52-60. https://ve42.co/Drury2012 Hess, V. (2018). On the observations of the penetrating radiation during seven balloon flights. arXiv preprint arXiv:1808.02927. --https://ve42.co/Hess2018 Carlson, P., & De Angelis, A. (2011). Nationalism and internationalism in science: the case of the discovery of cosmic rays. The European Physical Journal H, 35(4), 309-329. -- https://ve42.co/Carlson2011 Höeffgen, S. K., Metzger, S., & Steffens, M. (2020). Investigating the effects of cosmic rays on space electronics. Frontiers in Physics, 8, 318. -- https://ve42.co/Hoeffgen2020 Edmonds, L. D., Barnes, C. E., & Scheick, L. Z. (2000). An introduction to space radiation effects on microelectronics. Jet Propulsion Laboratory, National Aeronautics and Space Administration. -- https://ve42.co/Edmonds2000 NASA Mars 2020 website covering the specifications of the Perseverance Rover https://ve42.co/RoverBrains Australian Government Australian Transport Safety Bureau report on QF72 -- https://ve42.co/ASTBQantas Australian Government Australian Transport Safety Bureau summary on QF72 --https://ve42.co/ASTBQantas2 Great Blog post about QF72 -- https://ve42.co/DempseyQantas Michael Barr's report on the Toyota acceleration issue --https://ve42.co/Barr2015 NASA's Report on Toyota -- https://ve42.co/NASAToyota T. C. May and M. H. Woods, "A New Physical Mechanism for Soft Errors in Dynamic Memories," 16th International Reliability Physics Symposium, 1978, pp. 33-40, doi: 10.1109/IRPS.1978.362815. --https://ve42.co/May1978 P. M. O'Neill and G. D. Badhwar, "Single event upsets for Space Shuttle flights of new general purpose computer memory devices," in IEEE Transactions on Nuclear Science, vol. 41, no. 5, pp. 1755-1764, Oct. 1994, doi: 10.1109/23.317386. -- https://ve42.co/ONeill1994 Wikipedia about radiation hardening -- https://ve42.co/RadHardening Toward Monitoring Fault-Tolerant Embedded Systems (Extended Abstract) -- https://ve42.co/Goodloe2009 Article about speed run -- https://ve42.co/BurttSpeedrun Article about speed run -- https://ve42.co/BountySpeedrun Article about redundant systems in spaceflight -- https://ve42.co/NASAComputers Article about the PowerPC750 -- https://ve42.co/Wener-FlignerNASA Fuglesang C, Narici L, Picozza P, Sannita WG. Phosphenes in low earth orbit: survey responses from 59 astronauts. Aviat Space Environ Med. 2006 Apr;77(4):449-52. PMID: 16676658. -- https://ve42.co/Fuglesang2006 Good article about Cosmic Rays causing flashes -- https://ve42.co/AtkinsonEye Good article about radiation resistance -- https://ve42.co/RoverResistance Special thanks to Patreon supporters: Paul Peijzel, Juan Benet, Ruslan Khroma, Richard Sundvall, Lee Redden, Sam Lutfi, MJP, Gnare, Nick DiCandilo, Dave Kircher, Edward Larsen, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Written by Derek Muller and Petr Lebedev Animation by Iván Tello, Mike Radjabov, Fabio Albertelli, Jakub Misiek and Charlie Davies SFX by Shaun Clifford Filmed by Derek Muller, Raquel Nuno, and Emily Zhang Edited by Derek Muller and Petr Lebedev SFX by Shaun Clifford Additional video supplied by Getty Images Rover Footage From NASA/JPL-Caltech QF72 footage from the Smithsonian channel https://youtu.be/H3q5S9PCoJA SM64 footage from https://ve42.co/pannenkoek2012 Music from Epidemic Sound Produced by Derek Muller, Petr Lebedev and Emily Zhang

The title and thumbnail play a huge role in a video's success or failure. Check out http://kiwico.com/Veritasium50 for 50% off your first month of any subscription! ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Alvaro Naranjo, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Derek Muller Animation by Iván Tello Filmed by Derek Muller and Emily Zhang Additional video supplied by Getty Images Produced by Derek Muller, Emily Zhang and Petr Lebedev

3D printed rockets save on up front tooling, enable rapid iteration, decrease part count, and facilitate radically new designs. For your chance to win 2 seats on one of the first Virgin Galactic flights to Space and support a great cause, go to https://www.omaze.com/veritasium Special thanks to Scott Manley for the interview and advising on aerospace engineering. Check out his channel: https://www.youtube.com/user/szyzyg ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Benson, T. (2021). Rocket Parts. NASA. — https://ve42.co/RocketParts Boen, B. (2009). Winter Wonder: Rocket Icicles. NASA. — https://ve42.co/EngineIcicles Hall, N. (2021). Rocket Thrust Equation. NASA. — https://ve42.co/RocketEqn Benson, T. (2021). Rocket Thrust. NASA. — https://ve42.co/RocketThrust Regenerative Cooling — https://ve42.co/RegenCooling How A Gold Bullet Almost Destroyed A Space Shuttle by Scott Manley — https://ve42.co/ManleyEngine ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Derek Muller, Petr Lebedev, and Emily Zhang Animation by Mike Radjabov Filmed by Derek Muller, Raquel Nuno, Trenton Oliver, and Emily Zhang Edited by Trenton Oliver SFX by Shaun Clifford Additional video supplied by Getty Images & Pond5 Produced by Derek Muller, Petr Lebedev, and Emily Zhang

The Collatz Conjecture is the simplest math problem no one can solve — it is easy enough for almost anyone to understand but notoriously difficult to solve. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Special thanks to Prof. Alex Kontorovich for introducing us to this topic, filming the interview, and consulting on the script and earlier drafts of this video. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Lagarias, J. C. (2006). The 3x+ 1 problem: An annotated bibliography, II (2000-2009). arXiv preprint math/0608208. — https://ve42.co/Lagarias2006 Lagarias, J. C. (2003). The 3x+ 1 problem: An annotated bibliography (1963–1999). The ultimate challenge: the 3x, 1, 267-341. — https://ve42.co/Lagarias2003 Tao, T (2020). The Notorious Collatz Conjecture — https://ve42.co/Tao2020 A. Kontorovich and Y. Sinai, Structure Theorem for (d,g,h)-Maps, Bulletin of the Brazilian Mathematical Society, New Series 33(2), 2002, pp. 213-224. A. Kontorovich and S. Miller Benford's Law, values of L-functions and the 3x+1 Problem, Acta Arithmetica 120 (2005), 269-297. A. Kontorovich and J. Lagarias Stochastic Models for the 3x + 1 and 5x + 1 Problems, in "The Ultimate Challenge: The 3x+1 Problem," AMS 2010. Tao, T. (2019). Almost all orbits of the Collatz map attain almost bounded values. arXiv preprint arXiv:1909.03562. — https://ve42.co/Tao2019 Conway, J. H. (1987). Fractran: A simple universal programming language for arithmetic. In Open problems in Communication and Computation (pp. 4-26). Springer, New York, NY. — https://ve42.co/Conway1987 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Alvaro Naranjo, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Derek Muller, Alex Kontorovich and Petr Lebedev Animation by Iván Tello, Jonny Hyman, Jesús Enrique Rascón and Mike Radjabov Filmed by Derek Muller and Emily Zhang Edited by Derek Muller SFX by Shaun Clifford Additional video supplied by Getty Images Produced by Derek Muller, Petr Lebedev and Emily Zhang 3d Coral by Vasilis Triantafyllou and Niklas Rosenstein — https://ve42.co/3DCoral Coral visualisation by Algoritmarte — https://ve42.co/Coral

How close are we to having fully autonomous vehicles on the roads? Are they safe? In Chandler, Arizona a fleet of Waymo vehicles are already in operation. Waymo sponsored this video and provided access to their technology and personnel. Check out their safety report here: https://waymo.com/safety/ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Waymo Safety Reports — https://waymo.com/safety/ Driving Statistics — https://ve42.co/DrivingStats The Real Moral Dilemma of Self-Driving Cars https://ve42.co/SelfDriving ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Alvaro naranjo, Burt Humburg, Blake Byers, Dumky, Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Animation by Fabio Albertelli and Jakub Misiek Edited by Trenton Oliver Audio Mix and SFX by Shaun Clifford Music by Epidemic Sound https://epidemicsound.com Additional video supplied by Getty Images and Pond 5 Produced by Derek Muller, Emily Zhang and Petr Lebedev

This is not just true of slinkies - if you release a steel rod from the top, the top really starts falling before the bottom. If you hit a tennis ball with a racket, a wave has to travel from the strings to your hand before you feel it - and the ball is well on its way to the net by this time. If you hit a golf ball, the ball is well on its way to the hole before you can feel it. Rigid bodies aren't truly rigid and understanding this is essential to understanding the way the world works

You are not a visual learner — learning styles are a stubborn myth. Part of this video is sponsored by Google Search. Special thanks to Prof. Daniel Willingham for the interview and being part of this video. Special thanks to Dr Helen Georigou for reviewing the script and helping with the scientific literature. Special thanks to Jennifer Borgioli Binis for consulting on the script. MinutePhysics video on a better way to picture atoms -- https://ve42.co/Atom ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Pashler, H., McDaniel, M., Rohrer, D., & Bjork, R. (2008). Learning styles: Concepts and evidence. Psychological science in the public interest, 9(3), 105-119. — https://ve42.co/Pashler2008 Willingham, D. T., Hughes, E. M., & Dobolyi, D. G. (2015). The scientific status of learning styles theories. Teaching of Psychology, 42(3), 266-271. — https://ve42.co/Willingham Massa, L. J., & Mayer, R. E. (2006). Testing the ATI hypothesis: Should multimedia instruction accommodate verbalizer-visualizer cognitive style?. Learning and Individual Differences, 16(4), 321-335. — https://ve42.co/Massa2006 Riener, C., & Willingham, D. (2010). The myth of learning styles. Change: The magazine of higher learning, 42(5), 32-35.— https://ve42.co/Riener2010 Husmann, P. R., & O'Loughlin, V. D. (2019). Another nail in the coffin for learning styles? Disparities among undergraduate anatomy students’ study strategies, class performance, and reported VARK learning styles. Anatomical sciences education, 12(1), 6-19. — https://ve42.co/Husmann2019 Snider, V. E., & Roehl, R. (2007). Teachers’ beliefs about pedagogy and related issues. Psychology in the Schools, 44, 873–886. doi:10.1002/pits.20272 — https://ve42.co/Snider2007 Fleming, N., & Baume, D. (2006). Learning Styles Again: VARKing up the right tree!. Educational developments, 7(4), 4. — https://ve42.co/Fleming2006 Rogowsky, B. A., Calhoun, B. M., & Tallal, P. (2015). Matching learning style to instructional method: Effects on comprehension. Journal of educational psychology, 107(1), 64. — https://ve42.co/Rogowskyetal Coffield, Frank; Moseley, David; Hall, Elaine; Ecclestone, Kathryn (2004). — https://ve42.co/Coffield2004 Furey, W. (2020). THE STUBBORN MYTH OF LEARNING STYLES. Education Next, 20(3), 8-13. — https://ve42.co/Furey2020 Dunn, R., Beaudry, J. S., & Klavas, A. (2002). Survey of research on learning styles. California Journal of Science Education II (2). — https://ve42.co/Dunn2002 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Research and Writing by Derek Muller and Petr Lebedev Animation by Iván Tello Filmed by Emily Zhang and Trenton Oliver Edited by Trenton Oliver Music by Epidemic Sound https://epidemicsound.com Additional video supplied by Getty Images ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

A UCLA Physics Professor bet me $10,000 that my video about going downwind faster than the wind was wrong. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. For more information about the Veritasium Science Communication Contest check out -- https://ve42.co/contest ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ The wager agreement: https://ve42.co/wager Prof. Kusenko's slides: https://ve42.co/Kusenko My rebuttal: https://ve42.co/rebuttal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Huge thanks to Xyla Foxlin for building the model cart, and making the instructions so accessible to the public. Check out Xyla's video -- https://youtu.be/VUgajGv4Aok A massive thanks to Bill Nye, Neil DeGrasse Tyson, and Sean Carroll for witnessing the signing of the wager. A huge thanks to Prof. Alexander Kusenko for being a man of honour -- it's a difficult thing to change your mind, especially in a public forum. A huge thanks to Prof. Mark Drela for the interview and help making sure we got the physics right. A massive thanks to Rick Cavallaro for making Blackbird, all your insights, analysis, data, and general help with these videos -- it was so fun to work with you on this crazy project -- check out Rick's channel https://ve42.co/Rick ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References M. Drela. Dead-Downwind Faster Than The Wind (DDWFTTW) Analysis (Jan 2009) -- https://ve42.co/Drela 2013 AAPT United States Physics Olympiad Semifinal Exam -- https://ve42.co/AAPT2013 Rick's treadmill footage -- https://ve42.co/Treadmill Rick's multiple explanations of how Blackbird works -- https://ve42.co/DDWFTTW Blackford, B. L. (1978). The physics of a push‐me pull‐you boat. American Journal of Physics, 46(10), 1004-1006. — https://ve42.co/Blackford1979 Forum discussions -- https://ve42.co/forum Blog -- https://ve42.co/blog1 and retraction https://ve42.co/BlogRetraction Bauer, A. B. (1969, April). Faster than the Wind. In First AIAA Symposium on Sailing. -- https://ve42.co/Bauer1969 Bauer's Obituary -- https://ve42.co/BauerObituary Gaunaa, M., Øye, S., & Mikkelsen, R. F. (2009). Theory and design of flow driven vehicles using rotors for energy conversion. In EWEC 2009 Proceedings online EWEC Md. Sadak Ali Khan, Syed Ali Sufiyan, Jibu Thomas George, Md. Nizamuddin Ahmed. Analysis of Down-Wind Propeller Vehicle. International Journal of Scientific and Research Publications, 3, 4. (April 2013) ISSN 2250-3153. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Bill Linder, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim Buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written and Edited by Derek Muller Animation by Mike Radjabov Manim equations by Jonny Hyman Filmed by Emily Zhang and Raquel Nuno Music from Epidemic Sound https://epidemicsound.com and by Jonny Hyman Additional video supplied by Getty Images Produced by Emily Zhang, Petr Lebedev and Derek Muller

If you ran evolution all over again, would you get humans? How repeatable is #evolution? This video is sponsored by @BountyBrand. #biology #science #QPU #HygieneBeginswithBounty #BountyPartner Special thanks to Prof. Richard Lenski and team for showing me around the lab — it is an honor to be able to witness and document such a historic science experiment. Thanks to Dr Zachary Blount for the help with research and setting up the competition time-lapse, Dr Nkrumah Grant for microscope images of the long-term line cells @NkrumahGrant Devin Lake, Kate Bellgowan, and Dr. Minako Izutsu for being part of this video. Long Live the LTEE! LTEE website — http://myxo.css.msu.edu/ecoli/index.html Intro footage courtesy of the Kishony Lab — https://kishony.technion.ac.il ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Lenski, R. E., & Travisano, M. (1994). Dynamics of adaptation and diversification: a 10,000-generation experiment with bacterial populations. Proceedings of the National Academy of Sciences, 91(15), 6808-6814. — https://ve42.co/Lenski1994 Lenski, R. E., Rose, M. R., Simpson, S. C., & Tadler, S. C. (1991). Long-term experimental evolution in Escherichia coli. I. Adaptation and divergence during 2,000 generations. The American Naturalist, 138(6), 1315-1341. — https://ve42.co/Lenski1991 Good, B. H., McDonald, M. J., Barrick, J. E., Lenski, R. E., & Desai, M. M. (2017). The dynamics of molecular evolution over 60,000 generations. Nature, 551(7678), 45-50. — https://ve42.co/Good2017 Blount, Z. D., Borland, C. Z., & Lenski, R. E. (2008). Historical contingency and the evolution of a key innovation in an experimental population of Escherichia coli. Proceedings of the National Academy of Sciences, 105(23), 7899-7906. — https://ve42.co/Blount2008 Blount, Z. D., Lenski, R. E., & Losos, J. B. (2018). Contingency and determinism in evolution: Replaying life’s tape. Science, 362(6415). — https://ve42.co/Blount2018 Wiser, M. J., Ribeck, N., & Lenski, R. E. (2013). Long-term dynamics of adaptation in asexual populations. Science, 342(6164), 1364-1367. — https://ve42.co/Wiser2013 N, Scharping. (2019). How a 30-Year Experiment Has Fundamentally Changed Our View of How Evolution Works. Discover — https://ve42.co/Scharping ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Mike Tung, Evgeny Skvortsov, Meekay, Ismail Öncü Usta, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Research and Writing by by Derek Muller, Petr Lebedev and Casey Rentz Animation by Iván Tello Filmed by Derek Muller and Emily Zhang Edited by Derek Muller Music from Epidemic Sound https://epidemicsound.com (and Jonny Hyman) Additional video supplied by Getty Images Thumbnail image courtesy of the Kishony Lab Produced by Casey Rentz ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

Everyone will say this craft breaks the laws of physics. This video is sponsored by Kiwico, For 50% off your first month of any subscription crate from KiwiCo (available in 40 countries!) head to https://www.kiwico.com/Veritasium50 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ A HUGE thanks to Rick and Neil for letting me drive Blackbird. Check out Rick's YouTube Channel for more in depth videos and explanations on going faster than the wind downwind -- https://ve42.co/Rick Gene Nagata made the shoot possible. If you’re a video nerd like me, check out his channel, Potato Jet: https://www.youtube.com/c/PotatoJet/featured. Xyla Foxlin for made the model cart used in this video. Xyla builds amazing things like rockets and canoes, check it out! https://www.youtube.com/c/xylafoxlin/ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References Jack Goodman's YouTube video -- https://ve42.co/Goodman Rick's treadmill footage -- https://ve42.co/Treadmill Rick's multiple explanations of how Blackbird works -- https://ve42.co/DDWFTTW Forum discussions -- https://ve42.co/forum Blog -- https://ve42.co/blog1 and retraction https://ve42.co/BlogRetraction ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Bill Linder, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Thanks to James Lincoln for building the initial prototypes for a model blackbird. Written by Derek Muller, James Lincoln, and Petr Lebedev Animation by Mike Radjabov and Iván Tello Filmed by Gene Nagata, Derek Muller, Trenton Oliver, AJ Fillo and Emily Zhang Edited by Trenton Oliver Music from Epidemic Sound https://epidemicsound.com Additional video supplied by Getty Images Produced by AJ Fillo

Not everything that is true can be proven. This discovery transformed infinity, changed the course of a world war and led to the modern computer. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Special thanks to Prof. Asaf Karagila for consultation on set theory and specific rewrites, to Prof. Alex Kontorovich for reviews of earlier drafts, Prof. Toby ‘Qubit’ Cubitt for the help with the spectral gap, to Henry Reich for the helpful feedback and comments on the video. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Dunham, W. (2013, July). A Note on the Origin of the Twin Prime Conjecture. In Notices of the International Congress of Chinese Mathematicians (Vol. 1, No. 1, pp. 63-65). International Press of Boston. — https://ve42.co/Dunham2013 Conway, J. (1970). The game of life. Scientific American, 223(4), 4. — https://ve42.co/Conway1970 Churchill, A., Biderman, S., Herrick, A. (2019). Magic: The Gathering is Turing Complete. ArXiv. — https://ve42.co/Churchill2019 Gaifman, H. (2006). Naming and Diagonalization, from Cantor to Godel to Kleene. Logic Journal of the IGPL, 14(5), 709-728. — https://ve42.co/Gaifman2006 Lénárt, I. (2010). Gauss, Bolyai, Lobachevsky–in General Education?(Hyperbolic Geometry as Part of the Mathematics Curriculum). In Proceedings of Bridges 2010: Mathematics, Music, Art, Architecture, Culture (pp. 223-230). Tessellations Publishing. — https://ve42.co/Lnrt2010 Attribution of Poincare’s quote, The Mathematical Intelligencer, vol. 13, no. 1, Winter 1991. — https://ve42.co/Poincare Irvine, A. D., & Deutsch, H. (1995). Russell’s paradox. — https://ve42.co/Irvine1995 Gödel, K. (1992). On formally undecidable propositions of Principia Mathematica and related systems. Courier Corporation. — https://ve42.co/Godel1931 Russell, B., & Whitehead, A. (1973). Principia Mathematica [PM], vol I, 1910, vol. II, 1912, vol III, 1913, vol. I, 1925, vol II & III, 1927, Paperback Edition to* 56. Cambridge UP. — https://ve42.co/Russel1910 Gödel, K. (1986). Kurt Gödel: Collected Works: Volume I: Publications 1929-1936 (Vol. 1). Oxford University Press, USA. — https://ve42.co/Godel1986 Cubitt, T. S., Perez-Garcia, D., & Wolf, M. M. (2015). Undecidability of the spectral gap. Nature, 528(7581), 207-211. — https://ve42.co/Cubitt2015 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Written by Derek Muller, Adam Becker and Jonny Hyman Animation by Fabio Albertelli, Jakub Misiek, Iván Tello and Jonny Hyman Math City Animation by Another Angle 3D Visuals (www.anotherangle.ee) Filmed by Derek Muller and Raquel Nuno Edited by Derek Muller Music and SFX by Jonny Hyman Additional Music from Epidemic Sound Additional video supplied by Getty Images Thumbnail by Geoff Barrett Associate Producers: Petr Lebedev and Emily Zhang ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

If there's a hotel with infinite rooms, could it ever be completely full? Could you run out of space to put everyone? The surprising answer is yes -- this is important to know if you're the manager of the Hilbert Hotel. ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ References: Ewald, W., & Sieg, W. (2013). David Hilbert's Lectures on the Foundations of Arithmetic and Logic 1917-1933. Springer Berlin Heidelberg. -- https://ve42.co/Ewald2013 Gamow, G. (1988). One, two, three--infinity: facts and speculations of science. Courier Corporation. -- https://ve42.co/Gamow1947 ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Special thanks to Patreon supporters: Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ Animation by JD Pounds and Jonny Hyman Thumbnail by Iván Tello Music by Jonny Hyman and from Epidemic Sound and E's Jammy Jams (Hotel Lavish - Radio Nights, Steps in Time - Golden Age Radio, What Now - Golden Age Radio, Book Bag - E's Jammy Jams, Arabian Sand - E's Jammy Jams, Firefly in a Fairytale - Gareth Coker) Written By Derek Muller and Alex Kontorovich ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

This robot has applications to archaeology, space exploration, and search and rescue — with a simple elegant design inspired by a plant. Sign up to Morning Brew for free today: https://ve42.co/mb Make your own Vine Robot! — https://www.vinerobots.org Special thanks to A/Prof. Elliot Hawkes, Nicholas Naclerio, Margaret Coad, David Haggerty for appearing in this video and showing off your amazing robots. For more info on vine (and other types of) robots check out https://ve42.co/HawkesLab, and https://ve42.co/CHARM B-roll footage of robots from the supplementary materials of (Hawkes et al., 2017) https://ve42.co/VineVideos, and from Stanford University https://ve42.co/StanfordVideo Additional info on the intubation vine robot here: https://www.wardenchem.com/vine References: Hawkes, E. W., Blumenschein, L. H., Greer, J. D., & Okamura, A. M. (2017). A soft robot that navigates its environment through growth. Science Robotics, 2(8). — https://ve42.co/Hawkes2017 Coad, M. M., Blumenschein, L. H., Cutler, S., Zepeda, J. A. R., Naclerio, N. D., El-Hussieny, H., ... & Okamura, A. M. (2019). Vine robots: Design, teleoperation, and deployment for navigation and exploration. IEEE Robotics & Automation Magazine, 27(3), 120-132. — https://ve42.co/Coad2019 Blumenschein, L. H., Coad, M. M., Haggerty, D. A., Okamura, A. M., & Hawkes, E. W. (2020). Design, modeling, control, and application of everting vine robots. Frontiers in Robotics and AI, 7. — https://ve42.co/Blumenschein2020 Haggerty, D. A., Naclerio, N. D., & Hawkes, E. W. (2019, November). Characterizing environmental interactions for soft growing robots. In 2019 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (pp. 3335-3342). IEEE. — https://ve42.co/Haggerty2019 Naclerio, N. D., Hubicki, C. M., Aydin, Y. O., Goldman, D. I., & Hawkes, E. W. (2018, October). Soft robotic burrowing device with tip-extension and granular fluidization. In 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (pp. 5918-5923). IEEE. — https://ve42.co/Naclerio19 Special thanks to Patreon supporters: Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Edited by Trenton Oliver Animation by Ivan Tello Filmed by Derek Muller Thumbnail by Ignat Berbeci Music from Epidemic Sound

How does order spontaneously arise out of chaos? This video is sponsored by Kiwico — go to https://www.kiwico.com/Veritasium50 for 50% off your first month of any crate. An enormous thanks to Prof. Steven Strogatz — this video would not have been possible without him. Much of the script-writing was inspired and informed by his wonderful book Sync, and his 2004 TED talk. He is a giant in this field, and has literally written the book on chaos, complexity, and synchronization. It was hard to find a paper in this field that Steven (or one of his students) didn't contribute to. His Podcast "The Joy of X" is wonderful — please listen and subscribe wherever you get your podcasts https://www.quantamagazine.org/tag/the-joy-of-x Nicky Case's Amazing Firefly Interactive — https://ncase.me/fireflies Great Kuramoto Model Interactive — https://www.complexity-explorables.org/explorables/ride-my-kuramotocycle References: Strogatz, S. H. (2012). Sync: How order emerges from chaos in the universe, nature, and daily life. Hachette UK. — https://ve42.co/Sync Strogatz, S. H. (2000). From Kuramoto to Crawford: exploring the onset of synchronization in populations of coupled oscillators. Physica D: Nonlinear Phenomena, 143(1-4), 1-20. — https://ve42.co/Strogatz2000 Goldsztein, G. H., Nadeau, A. N., & Strogatz, S. H. (2021). Synchronization of clocks and metronomes: A perturbation analysis based on multiple timescales. Chaos: An Interdisciplinary Journal of Nonlinear Science, 31(2), 023109. — https://ve42.co/Goldsztein The Broughton Suspension Bridge and the Resonance Disaster — https://ve42.co/Broughton Bennett, M., Schatz, M. F., Rockwood, H., & Wiesenfeld, K. (2002). Huygens's clocks. Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 458(2019), 563-579. — https://ve42.co/Bennett2002 Pantaleone, J. (2002). Synchronization of metronomes. American Journal of Physics, 70(10), 992-1000. — https://ve42.co/Pantaleone2002 Kuramoto, Y. (1975). Self-entrainment of a population of coupled non-linear oscillators. In International symposium on mathematical problems in theoretical physics (pp. 420-422). Springer, Berlin, Heidelberg. -- https://ve42.co/Kuramoto1975 Great video by Minute Earth about Tidal Locking and the Moon — https://ve42.co/MinuteEarth Strogatz, S. H., Abrams, D. M., McRobie, A., Eckhardt, B., & Ott, E. (2005). Crowd synchrony on the Millennium Bridge. Nature, 438(7064), 43-44. — https://ve42.co/Strogatz2005 Zhabotinsky, A. M. (2007). Belousov-zhabotinsky reaction. Scholarpedia, 2(9), 1435. — https://ve42.co/Zhabotinsky2007 Flavio H Fenton et al. (2008) Cardiac arrhythmia. Scholarpedia, 3(7):1665. — https://ve42.co/Cardiac Cherry, E. M., & Fenton, F. H. (2008). Visualization of spiral and scroll waves in simulated and experimental cardiac tissue. New Journal of Physics, 10(12), 125016. — https://ve42.co/Cherry2008 Tyson, J. J. (1994). What everyone should know about the Belousov-Zhabotinsky reaction. In Frontiers in mathematical biology (pp. 569-587). Springer, Berlin, Heidelberg. — https://ve42.co/Tyson1994 Winfree, A. T. (2001). The geometry of biological time (Vol. 12). Springer Science & Business Media. — https://ve42.co/Winfree2001 Special thanks to Patreon supporters: Mac Malkawi, Oleksii Leonov, Michael Schneider, Jim Osmun, Tyson McDowell, Ludovic Robillard, jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Lyvann Ferrusca, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Written by Derek Muller and Petr Lebedev Animation by Fabio Albe gfx and 3D animation by Jonny Hyman Filmed by Derek Muller and Raquel Nuno Edited by Derek Muller Additional video supplied by Getty Images Thumbnail by Ignat Berbeci More footage from NASA's Scientific Visualization Studio 100 metronome video from https://www.youtube.com/watch?v=suxu1bmPm2g Intro animation by Jorge Cham Thanks for the BZ footage from SteinbockGroup: https://www.youtube.com/watch?v=IJn1ssZEyns and NileRed https://youtu.be/LL3kVtc-4vY Animation of waves in the heart from The Virtual Heart/ EM Cherry/ FH Fenton — https://ve42.co/Cardiac and https://ve42.co/Cherry2008 Chemical materials and protocol provided by Mike Morris and the UCI Chemistry Outreach Program https://www.chem.uci.edu/~jsnowick/outreach/UCI_Outreach/index.html Thanks to Alie Ward for title/thumbnail consultation Thanks to Dr Juliette Becker and Dr James O'Donoghue for the planetary science help Music from Jonny Hyman, Epidemic Sound https://epidemicsound.com "Seaweed" "Deeper Than The Ocean" "Ripple Effect" Music also from Artlist https://artlist.com "Children of Mystery" Thumbnail by Ignat Berbeci

This video is about stuff: light bulbs, printers, phones and why they aren't better. Go to https://NordVPN.com/veritasium and use code VERITASIUM to get a 2-year plan plus 1 additional month with a huge discount. It’s risk free with Nord’s 30 day money-back guarantee! References: The Man in the White Suit — https://ve42.co/Suit London, B. (1932). Ending the depression through planned obsolescence. — https://ve42.co/London32 Slade, G. (2009). Made to break: Technology and obsolescence in America. Harvard University Press — https://ve42.co/madetobreak Krajewski, M. (2014). The great lightbulb conspiracy. IEEE spectrum, 51(10), 56-61. — https://ve42.co/Phoebus Special thanks to Patreon supporters: Mac Malkawi, Oleksii Leonov, Michael Schneider, Jim Osmun, Tyson McDowell, Ludovic Robillard, jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Lyvann Ferrusca, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Written by Derek Muller and Petr Lebedev Animation by Ivan Tello Filmed by Derek Muller and Raquel Nuno Edited by Derek Muller Video supplied by Getty Images Music from https://epidemicsound.com"Particle Emission", "Into the Forest", "Stavselet", "Face of the Earth" Thumbnail by Raquel Nuno and Karri Denise

For thousands of years, mathematicians were calculating Pi the obvious but numerically inefficient way. Then Newton came along and changed the game. This video is sponsored by Brilliant. The first 314 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription. Happy Pi Day! (for a few days ago...) References: Arndt, J., & Haenel, C. (2001). Pi-unleashed. Springer Science & Business Media — https://ve42.co/Arndt2001 Dunham, W. (1990). Journey through genius: The great theorems of mathematics. Wiley — https://ve42.co/Dunham1990 Borwein, J. M. (2014). The Life of π: From Archimedes to ENIAC and Beyond. In From Alexandria, Through Baghdad (pp. 531-561). Springer, Berlin, Heidelberg — https://ve42.co/Borwein2012 Special thanks to Alex Kontorovich, Professor of Mathematics at Rutgers University, and Distinguished Visiting Professor for the Public Dissemination of Mathematics National Museum of Mathematics MoMath for being part of this Pi Day video. Special thanks to Patreon supporters: Jim Osmun, Tyson McDowell, Ludovic Robillard, jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Lyvann Ferrusca, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Written by Derek Muller and Alex Kontorovich Animation by Ivan Tello Filmed by Derek Muller and Raquel Nuno Edited by Derek Muller Music by Jonny Hyman and Petr Lebedev Additional Music from https://epidemicsound.com "Particle Emission", "Into the Forest", "Stavselet", "Face of the Earth", "Firefly in a Fairytale" Thumbnail by Gianmarco Malandra and Karri Denise

Robots of the future may be softer, squishier and bendier than robots today. This could make them ideal for space exploration. Check out http://kiwico.com/Veritasium50 for 50% off your first month of any subscription! On Thursday February 18th, 2021 the NASA Perseverance Rover will land on Mars. It is a wonderful robot, made out of steel and wire — but will future robots look like Perseverance? There is an emerging field of research on "soft robots", where the machines are flexible. These soft robots have many advantages over traditional robots — they're safer, lighter, more flexible and can change their shape and size. NASA is investigating the use of soft robots for space missions. For future visits to Enceladus or Europa, a lander could cut a hole in the ice and then insert a compliant robot through the hole. This robot could then grow and change shape on the other side. References: N. S. Usevitch, Z. M. Hammond, M. Schwager, A. M. Okamura, E. W. Hawkes, S. Follmer, An untethered isoperimetric soft robot. Sci. Robot. 4, https://ve42.co/Hammond2020 — paper about the truss robot https://ve42.co/Usevitch2020 — press release and video about the truss robot Electronics-free pneumatic circuits for controlling soft-legged robots Dylan Drotman1, Saurabh Jadhav, David Sharp, Christian Chan, Michael T. Tolley Sci. Robot. 6, eaay2627 (2021) https://ve42.co/Drotman — paper about the turtle robot Special thanks to Patreon supporters: Jim Osmun, Tyson McDowell, Ludovic Robillard, jim buckmaster, Robert, fanime96, Marc Forand, Juan Benet, Ruslan Khroma, Robert Blum, Grace O'Maille KRON x Arc iOS, Richard Sundvall, Lee Redden, Vincent, Lyvann Ferrusca, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex , Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal, Bryan Baker Thanks to Zachary Hammond for showing me the soft truss robot Filmed by Derek Muller Edited and GFX by Trenton Oliver Animation by Ivan Tello Music by Jonny Hyman Thumbnail by Ignat Berbeci, Dan Meyer

I got the chance to interview Bill Gates so I asked him: Will Covid-19 be the last pandemic? How does he deal with misinformation and conspiracy theories? And what is the next disaster? The Foundation Letter is here: https://ve42.co/BG21 Special thanks to Patreon supporters: Ludovic Robillard, jim buckmaster, Robert, fanime96, Marc Forand, Juan Benet, Robert Blum, Grace O'Maille KRON x Arc iOS, Richard Sundvall, Lee Redden, Vincent, Lyvann Ferrusca, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex , Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal Thanks to Petr Lebedev for early edits and Jonny Hyman for feedback

What are these electric blue ponds in the middle of the Utah desert? And why do they keep changing color?

Thank you so much for an amazing 10 years! If you would like one of the giveaway items, fill out the form: https://ve42.co/10yr (you'll need the password from this video). Any comments posting the password will be blocked. Spanish:https://ve42.co/VeEs Arabic: https://ve42.co/VeAr Thanks to Vorso for the spinning tops https://www.vorsospin.com Huge Thanks to Patreon Supporters: Ludovic Robillard, John Bauer, james, jim buckmaster, Robert, fanime96, Marc Forand, Juan Benet, Ruslan Khroma, Robert Blum, Grace O'Maille KRON x Arc iOS, Richard Sundvall, Lee Redden, Vincent, Lyvann Ferrusca, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Laura Sanborn, Pindex , Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal I also want to say a massive thanks to all my EDUtuber colleagues. Meeting and making great friends over the last decade has been one of the best things about this career.

Ames window illusion illustrates how we don't directly perceive external reality. Special Holiday deal! Go to https://NordVPN.com/veritasium and use code VERITASIUM to get 68% off a 2 year plan plus 4 additional months free. It’s risk free with Nord’s 30 day money-back guarantee! Special thanks to: Prof. Phil Kellman from UCLA Psychology https://kellmanlab.psych.ucla.edu Museum of Illusions in Los Angeles for the use of their Ames Room https://laillusions.com Curiosity Show - Video on Ames Illusion: https://youtu.be/DkVOIJAaWO0 References: Ames, A., Jr. (1951). Visual perception and the rotating trapezoidal window. Psychological Monographs: General and Applied, 65(7), i–32. https://doi.org/10.1037/h0093600 Marcel de Heer & Thomas V. Papathomas (2017) The Ames Window Illusion and Its Variations DOI:10.1093/acprof:oso/9780199794607.003.0014 Oross, Stephen, Francis, Ellie, Mauk, Deborah & Fox, Robert. (1987). The Ames Window Illusion: Perception of Illusory Motion by Human Infants. Journal of Experimental Psychology: Human Perception & Performance, 13(4), 609-613. Behrens, R. (1987). The Life and Unusual Ideas of Adelbert Ames, Jr. Leonardo, 20(3), 273-279. doi:10.2307/1578173 Burnham, C., & Ono, H. (1969). Variables Altering Perception of the Rotating Trapezoidal Illusion. The American Journal of Psychology, 82(1), 86-95. doi:10.2307/1420609 Allport, G. W., & Pettigrew, T. F. (1957). Cultural influence on the perception of movement: The trapezoidal illusion among Zulus. The Journal of Abnormal and Social Psychology, 55(1), 104–113. https://doi.org/10.1037/h0049372 Zenhausern R. Effect of Perspective on Two Trapezoid Illusions. Perceptual and Motor Skills. 1969;28(3):1003-1009. doi:10.2466/pms.1969.28.3.1003 Gehringer, W. L., & Engel, E. (1986). Effect of ecological viewing conditions on the Ames' distorted room illusion. Journal of Experimental Psychology: Human Perception and Performance, 12(2), 181–185. https://doi.org/10.1037/0096-1523.12.2.181 Long, G.M., Toppino, T.C. Adaptation effects and reversible figures: A comment on Horlitz and O’Leary. Perception & Psychophysics 56, 605–610 (1994). https://doi.org/10.3758/BF03206956 Gregory RL. Looking through the Ames window. Perception. 2009;38(12):1739-40. doi: 10.1068/p3812ed. PMID: 20192124. Jahoda, G. (1966). Geometric illusions and environment: A study in Ghana. British Journal of Psychology, 57(1-2), 193–199. https://doi.org/10.1111/j.2044-8295.1966.tb01019.x V. Mary Stewart (1974) A Cross-Cultural Test of the “Carpentered World” Hypothesis Using The Ames Distorted Room Illusion, International Journal of Psychology, 9:2, 79-89, DOI: 10.1080/00207597408247094 Margaret Kathleen Cappone (1966) The Effect of Verbal Suggestion on the Reversal Rate of the Ames Trapezoid Illusion, The Journal of Psychology, 62:2, 211-219, DOI: 10.1080/00223980.1966.10543786 Researched and written by Petr Lebedev and Derek Muller Filmed by Derek Muller and Raquel Nuno Animations, VFX, and Music by Jonny Hyman Ames Room VFX and additional Ames Window animation by Nicolas Pratt Additional Music from https://epidemicsound.com "Life in Color" "Singularity" Large Ames window construction by GW Construction Video supplied by Getty Images

Stephen Hawking thought an asteroid impact posed the greatest threat to life on Earth. Thanks to Kiwico for sponsoring this video. For 50% off your first month of any crate, go to https://kiwico.com/veritasium50 For other potential world ending catastrophes, check out Domain of Science: https://ve42.co/DoS Special thanks to: Prof. Dave Jewitt from UCLA Earth, Planetary, and Space Sciences Prof. Mark Boslough from Sandia National Labs Scott Manley: https://www.youtube.com/user/szyzyg Ryan Wyatt at Morrison Planetarium Prof. Amy Mainzer Alexandr Ivanov for the opening shot of Chelyabinsk Meteor Maps of Asteroid Impacts —https://ve42.co/Map Opposition Effect — https://ve42.co/Belskaya2000 Belskaya, I. N., & Shevchenko, V. G. (2000). Opposition effect of asteroids. Icarus, 147(1), 94-105. Potentially Hazardous Asteroids — https://ve42.co/Perna2013 Perna, D., Barucci, M. A., & Fulchignoni, M. (2013). The near-Earth objects and their potential threat to our planet. The Astronomy and Astrophysics Review, 21(1), 65. Survey of Potentially Hazardous Asteroids — https://ve42.co/NEOSurvey Population Vulnerability — https://ve42.co/Rumpf2017 Rumpf, C. M., Lewis, H. G., & Atkinson, P. M. (2017). Population vulnerability models for asteroid impact risk assessment. Meteoritics & Planetary Science, 52(6), 1082-1102. Size distribution of NEOs — https://ve42.co/Trilling17 Trilling, D. E., Valdes, F., Allen, L., James, D., Fuentes, C., Herrera, D., ... & Rajagopal, J. (2017). The size distribution of near-earth objects larger than 10 m. The Astronomical Journal, 154(4), 170. 2020 NEOWISE Data Release — https://ve42.co/NEOWISE National Research Council Report— https://ve42.co/Defending Board, S. S., & National Research Council. (2010). Defending planet earth: Near-Earth-Object surveys and hazard mitigation strategies. National Academies Press. Tug Boat — https://ve42.co/Schweickart03 Schweickart, R. L., Lu, E. T., Hut, P., & Chapman, C. R. (2003). The asteroid tugboat. Scientific American, 289(5), 54-61. Gravity Tractor 1 — https://ve42.co/Lu05 Lu, E. T., & Love, S. G. (2005). Gravitational tractor for towing asteroids. Nature, 438(7065), 177-178. Laser Ablation — https://ve42.co/Thiry14 Thiry, N., & Vasile, M. (2014). Recent advances in laser ablation modelling for asteroid deflection methods. SPIE Optical Engineering+ Applications, 922608-922608. Yarakovsky Effect — https://ve42.co/Yara DART Mission — https://ve42.co/DART Nuclear 1 — https://ve42.co/Ahrens92 Ahrens, T. J., & Harris, A. W. (1992). Deflection and fragmentation of near-Earth asteroids. Nature, 360(6403), 429-433. Nuclear 2 — https://ve42.co/Bradley10 Bradley, P. A., Plesko, C. S., Clement, R. R., Conlon, L. M., Weaver, R. P., Guzik, J. A., ... & Huebner, W. F. (2010, January). Challenges of deflecting an asteroid or comet nucleus with a nuclear burst. In AIP Conference Proceedings (Vol. 1208, No. 1, pp. 430-437). American Institute of Physics. Researched and Written by Petr Lebedev, Jonny Hyman and Derek Muller 3D animations, VFX, SFX, Audio Mixing by Jonny Hyman 2D animation by Ivàn Tello Intro animation by Nicolas Pratt With Filming by Raquel Nuno Music from https://epidemicsound.com "Stellar Dance" "Orbit" "That Notebook" "What We Discovered" "Out of Poppies" "Handwriting" Images and video supplied by Getty Images

Physics students learn the speed of light, c, is the same for all inertial observers but no one has ever actually measured it in one direction. Thanks to Kiwico for sponsoring this video. For 50% off your first month of any crate, go to https://kiwico.com/veritasium50 Huge thanks to Destin from Smarter Every Day for always being open and willing to engage in new ideas. If you haven't subscribed already, what are you waiting for: https://ve42.co/SED For an overview of the one-way speed of light check out the wiki page: https://ve42.co/wiki1way The script was written in consultation with subject matter experts: Prof. Geraint Lewis, University of Sydney https://ve42.co/gfl Prof. Emeritus Allen Janis, University of Pittsburgh Prof. Clifford M. Will, University of Florida https://ve42.co/cmw The stuff that's correct is theirs. Any errors are mine. References: Einstein, A. (1905). On the electrodynamics of moving bodies. Annalen der physik, 17(10), 891-921. (English) https://ve42.co/E1905 (German) https://ve42.co/G1905 Greaves, E. D., Rodríguez, A. M., & Ruiz-Camacho, J. (2009). A one-way speed of light experiment. American Journal of Physics, 77(10), 894-896. https://ve42.co/Greaves09 Response to Greaves et al. paper — https://arxiv.org/abs/0911.3616 Finkelstein, J. (2009). One-way speed of light?. arXiv, arXiv-0911. The Philosophy of Space and Time - Reichenbach, H. (2012). Courier Corporation. Anderson, R., Vetharaniam, I., & Stedman, G. E. (1998). Conventionality of synchronisation, gauge dependence and test theories of relativity. Physics reports, 295(3-4), 93-180. https://ve42.co/Anderson98 A review article about simultaneity — Janis, Allen, "Conventionality of Simultaneity", The Stanford Encyclopedia of Philosophy (Fall 2018 Edition), Edward N. Zalta (ed.) https://ve42.co/janis Will, C. M. (1992). Clock synchronization and isotropy of the one-way speed of light. Physical Review D, 45(2), 403. https://ve42.co/Will92 Zhang, Y. Z. (1995). Test theories of special relativity. General Relativity and Gravitation, 27(5), 475-493. https://ve42.co/Zhang95 Mansouri, R., & Sexl, R. U. (1977). A test theory of special relativity: I. Simultaneity and clock synchronization. General relativity and Gravitation, 8(7), 497-513. https://ve42.co/Sexl Research and writing by Derek Muller and Petr Lebedev Animations by Ivàn Tello VFX, music, and space animations by Jonny Hyman Filmed by Raquel Nuno Special thanks for reviewing earlier drafts of this video to: Dominic Walliman, Domain of Science: https://ve42.co/DoS Henry Reich, Minutephysics: https://ve42.co/MP My Patreon supporters Additional music from https://epidemicsound.com "Observations 2"

As the universe expands, #expanding #space is said to "stretch" photons. But if it stretches photons, does it also stretch molecules, galaxies and you? A portion of this video was sponsored by Salesforce. Go to https://salesforce.com/veritasium to learn more. Special thanks to Geraint Lewis - this video was based on his paper "On the relativity of redshifts" https://arxiv.org/abs/1605.08634 Check out his YouTube channel: https://ve42.co/gfl and books: https://ve42.co/GFLbooks References: Expanding Space: the Root of all Evil? Matthew J. Francis, Luke A. Barnes, J. Berian James, Geraint F. Lewis https://arxiv.org/abs/0707.0380 Editing and VFX by Trenton Oliver Thumbnail by Ignat Berbeci Music from https://epidemicsound.com #SMB #smallbiz #startups #SalesforceEssentials

In 2015 astronomers successfully predicted the appearance of a supernova within a couple weeks. How did they do it? Win your Ultimate Tech Bundle by entering Fasthosts’ Techie Test here: https://fasthosts.com/veritasium This video was sponsored by Fasthosts. Special thanks to Geraint Lewis for consulting on gravitational lensing. Check out his YouTube channel: https://ve42.co/gfl and books: https://ve42.co/GFLbooks The supernova image in the thumbnail is from my documentary, Uranium: Twisting The Dragon's Tail. Check it out here: https://ve42.co/Upbs References: DEJA VU ALL OVER AGAIN: THE REAPPEARANCE OF SUPERNOVA REFSDAL P. L. Kelly et al. https://arxiv.org/abs/1512.04654 Predicted properties of multiple images of the strongly lensed supernova SN Refsdal Masamune Oguri. Monthly Notices of the Royal Astronomical Society: Letters, Volume 449, Issue 1, 01 May 2015, Pages L86–L89, https://arxiv.org/abs/1411.6443 Multiple Images of a Highly Magnified Supernova Formed by an Early-Type Cluster Galaxy Lens Patrick L. Kelly et al. https://arxiv.org/abs/1411.6009 "Refsdal" meets Popper: comparing predictions of the re-appearance of the multiply imaged supernova behind MACSJ1149.5+2223. T. Treu et al. https://arxiv.org/abs/1510.05750 Irwin I. Shapiro (1964). "Fourth Test of General Relativity". Physical Review Letters. 13 (26): 789–791. doi:10.1103/PhysRevLett.13.789 Irwin I. Shapiro; Gordon H. Pettengill; Michael E. Ash; Melvin L. Stone; et al. (1968). "Fourth Test of General Relativity: Preliminary Results". Physical Review Letters. 20 (22): 1265–1269. doi:10.1103/PhysRevLett.20.1265 Research & Writing by Stephanie Hamilton, Ralph Crewe, Petr Lebedev, Derek Muller, and Jonny Hyman Animations & VFX by Jonny Hyman & Ivàn Tello Thanks to Jaime Portsmouth for his gravitational lensing simulator and help enabling it to render simulations. Supernova simulations courtesy of Adam Burrows Numerous hubble images by Hubble Legacy Archive, NASA/ESA/STScI Numerous images by ESO / NASA

The General Theory of Relativity tells us gravity is not a force, gravitational fields don't exist. Objects tend to move on straight paths through curved spacetime. Thanks to Caséta by Lutron for sponsoring this video. Find out more at: https://www.lutron.com/veritasium Huge thanks to Prof. Geraint Lewis for hours of consulting on this video so I could get these ideas straight in my own brain. Check out his YouTube channel: https://ve42.co/gfl or his books: https://ve42.co/GFLbooks Amazing VFX, compositing, and editing by Jonny Hyman 2D animations by Ivàn Tello Filmed by Steven Warren and Raquel Nuno Special thanks to Petr Lebedev for reviews and script consultation Music by Jonny Hyman and from Epidemic Sound https://epidemicsound.com Rocket made by Goodnight and Co. Screen images in rocket by Geoff Barrett Slow motion rocket exhaust footage from Joe Barnard at BPS.Space https://www.youtube.com/channel/UCILl8ozWuxnFYXIe2svjHhg

Simples rules of geometry meant that 5-fold symmetry was impossible as were crystals without a periodic structure. This turns out to be wrong. Thanks to LastPass for sponsoring a portion of this video. Click here to start using LastPass: https://ve42.co/LPs

Kodak detected the first atomic bomb before anyone else figured it out. Then they made a deal not to tell anyone. Thanks to HBO Max, and their new show raised by Wolves for sponsoring this video! https://rb.gy/alghwn References: Albuquerque Tribune Bulletin, July 16, 1945 – https://www.marshallfoundation.org/library/documents/albuquerque-tribune-bulletin-16-july-1945/ Webb, J. H. (1949). The fogging of photographic film by radioactive contaminants in cardboard packaging materials. Physical Review, 76(3), 375. Julian Webb at Oak Ridge – Snavely, B. B. (1989). Julian H. Webb. PhT, 42(7), 87.https://physicstoday.scitation.org/doi/pdf/10.1063/1.2811100 Radium in watch dials – https://www.epa.gov/radtown/radioactivity-antiques A 1958 video about how Kodak film is made, noting the careful monitoring of radioactive contaminants – https://www.youtube.com/watch?v=9qjBJOFImaU&t=597s&ab_channel=OwenMorgan Radioactive fallout in 1951 - https://www.nytimes.com/1951/02/03/archives/increased-radiation-found-in-east-laid-to-atom-tests-held-harmless.html?searchResultPosition=20 1998 senate hearing – https://www.govinfo.gov/content/pkg/CHRG-105shrg44045/html/CHRG-105shrg44045.htm Institute of Medicine and National Research Council. 1999. Exposure of the American People to Iodine-131 from Nevada Nuclear-Bomb Tests: Review of the National Cancer Institute Report and Public Health Implications. Washington, DC: The National Academies Press. https://doi.org/10.17226/6283. https://www.cancer.gov/about-cancer/causes-prevention/risk/radiation/i131-report-and-appendix Baby Teeth Survey – Reiss, L. Z. (1961). Strontium-90 absorption by deciduous teeth. Science, 134(3491), 1669-1673. Strontium 90 and Cancer rates – Gould, J. M., Sternglass, E. J., Sherman, J. D., Brown, J., McDonnell, W., & Mangano, J. J. (2000). Strontium-90 in deciduous teeth as a factor in early childhood cancer. International Journal of Health Services, 30(3), 515-539. Wine forensics – Hubert, P., Perrot, F., Gaye, J., Médina, B., & Pravikoff, M. S. (2009). Radioactivity measurements applied to the dating and authentication of old wines. Comptes Rendus Physique, 10(7), 622–629. doi:10.1016/j.crhy.2009.08.007 Strontium 90 in forensics – Maclaughlin-Black, S. M., Herd, R. J., Willson, K., Myers, M., & West, I. E. (1992). Strontium-90 as an indicator of time since death: a pilot investigation. Forensic science international, 57(1), 51-56. Research and Writing by Derek Muller, Petr Lebedev, and Jonny Hyman Filmed and edited by Derek Muller Animations by Iván Tello and Jonny Hyman Music by Jonny Hyman Additional Music from: Epidemic Sound https://epidemicsound.com "Seaweed" Kevin MacLeod https://incompetech.com "Lightless dawn" Craig Conrad https://www.craigconard.com/royaltyfree "ASTRAL"

In a competitive world, tiny advantages can make all the difference. Get 10% off Snatoms with code 'giveluck' in the US: https://ve42.co/USA or International: https://snatoms.com If you would like to receive Snatoms, submit the form here: https://ve42.co/getluck Snatoms are also available on Amazon Prime in the US but with no discount code: https://ve42.co/Asnatoms Huge thanks to Gene and Sam from Potato Jet for filming with me: https://ve42.co/potatojet This video was inspired by and draws examples from the book "Success and Luck: Good Fortune and the Myth of Meritocracy" by Robert H. Frank Special thanks to Patreon supporters (and to everyone who commented on an earlier version of this video): Marc Forand, Robert Dickerson, Christian Stauffer, LoadTooSlow, Vincent, Lyvann Ferrusca, DALE HORNE, Alfred Wallace, Kevin Beavers, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Michael Krugman, Ron Neal, Donal Botkin Animations by Iván Tello

People claim that 70-80% of household dust is dead skin, but is it true? Thanks to Google for sponsoring this video! Learn more about Search here: https://www.google.com/search/howsearchworks/ Special thanks to J.M.E.H van Bronswijk, author of 'House Dust Biology'. We exchanged emails to make sure I got my facts straight for this video. Below is an excerpt from her email to me, responding to my claims that start with a dash: - Around half of airborne dust particles under 100um are skin scales This is true for climates, regions and seasons where people live mostly indoors. The 1 to 2 g of skin scales shed each 24 hours will end up in places where people are present (and rub their skin or have textile moving over the skin). You can also look at it from a different angle: What else has the same size and could contribute? That will usually be pollen from outdoor sources, also depending on season, region and climate, as well as the ventilation regime of the building. However, taken as the median value over a whole year, I consider your statement correct for regions with a temperate climate. - 53% of dust particles vacuumed from a mattress were found to be skin scales It depends a little on the type of mattress. For polyether mattresses the amount may even be larger. For mattresses made of natural material it could be less since the mattress-material will also give off small particles. - larger particles consist mostly of fibers, eg. cotton, paper, wool, synthetics That's true .. including bread crumbs ..... 🙂 - skin scales seem to form a larger fraction of dust where we spend more time, e.g. in or near bed. ..... and on the couch used to view television or be active in gaming. It has to do with the constant production of skin scales over the 24 hours. - skin scales form a smaller fraction of dust if there are significant other sources, e.g. carpeting, dirt from outside etc. Yes, everyting you walk on with your shoes or that recieves dirt from the outside with other means, will have a lessr percentage of human skin scales. However, do not forget the skin scales of pets that will also be an active allergen for many people, and a food source for house dust mites. Information on dust particle size ©ISO. This material is adapted from ISO 7708:1995, with permission of the American National Standards Institute (ANSI) on behalf of the International Organization for Standardization. All rights reserved. Research and Writing by AJ Fillo and Derek Muller Editing, Music, Computer animations by Jonny Hyman Dust and character animation by Ivan Tello Filming by Raquel Nuno

Half of the ordinary baryonic matter has been tough to find but Fast Radio Bursts made it possible to detect the WHIM. Thanks to Kiwico for sponsoring this video! For 20% off go to https://kiwico.com/veritasium or use code VERITASIUM at checkout. Special thanks to Prof. Geraint Lewis https://ve42.co/gfl Nature paper: A census of baryons in the Universe from localized fast radio bursts https://ve42.co/whim Research and Writing by Max Levy, Derek Muller and Jonny Hyman Editing, Animations, Audio Mix & Mastering by Jonny Hyman Filmed by Raquel Nuno Thumbnail by Ignat Berbeci Music from Epidemic Sound https://epidemicsound.com

This was a pretty extraordinary experience - thanks to NASA for inviting me! The Atlas V 541 rocket took off carrying the Perseverance rover and Ingenuity the Mars helicopter at 7:50 am July 30, 2020. They should arrive in about seven months on February 18, 2021

Everyone loves laminar flow but turbulent flow is the real MVP. A portion of this video was sponsored by Cottonelle. Purchase Cottonelle Flushable Wipes and try them for yourself: https://bit.ly/2WJm9Hq Special thanks to: Prof. Beverley McKeon and team https://www.mckeon.caltech.edu Destin from Smarter Every Day https://www.youtube.com/smartereveryday I got into turbulent flow via chaos. The transition to turbulence sometimes involves a period doubling. Turbulence itself is chaotic motion, it is unpredictable and sensitively dependent on initial conditions. What surprised me is all the ways turbulent flow is useful to us. It is diffusive, meaning it causes mixing. This is useful in jet engines or rocket nozzles (which Destin studies) and is important to achieve in microfluidic devices, which are so small that turbulent flow is actually difficult to achieve. Turbulent flow can energize a boundary layer, which is important to maintain flow attachment over a wing, maintaining lift and delaying stall. Similarly a turbulent boundary layer over a golf ball reduces pressure drag allowing golf balls to fly further. This is the reason for the dimples on golf balls. Flow transitioning to turbulence in the wake of a bluff body can create periodic vortex shedding. This beautiful phenomenon can be seen in the von Kàrmàn vortex street in clouds viewed from space. Turbulence is everywhere, in the air currents in a room, in your aorta, in the breaths you exhale, in oil pipelines and water pipes, in the flow over cars and ships and planes. Animals have evolved for it (like dead fish swimming up stream) and we have engineered our environment, our planes and golf balls for it. Laminar flow may be nice to look at (which is why we use it in decorative fountains) but turbulent flow does the real lifting. Animations by: Jonny Hyman (Sun, Jupiter, Reynolds, airfoil, Earth time-lapse) Research and writing: AJ Fillo and Derek Muller. AJ also created the wind tunnel golf ball shots Filmed by: Daniel Bydlowski and Derek Muller Additional footage: Images of Jupiter courtesy of NASA Turbulence in air currents by the Physics Girl, Dan Walsh, and Grant Sanderson https://youtu.be/N7d_RWyOv20 https://youtu.be/_UoTTq651dE Music: illBird "Shaffuru" https://youtu.be/5rkt53fNMgc From EpidemicSound https://epidemicsound.com "Seaweed" "Colorful Animation 4" Kevin MacLeod https://incompetech.com "Sneaky Adventure"

The most elegant interpretation of quantum mechanics is the universe is constantly splitting A portion of this video was sponsored by Norton. Get up to 60% off the first year (annually billed) here: https://bit.ly/32SM0yd or use promo code VERITASIUM Special thanks to: Prof. Sean Carroll https://www.preposterousuniverse.com His book, a major source for this video is 'Something Deeply Hidden: Quantum Worlds and The Emergence of Spacetime' I learned quantum mechanics the traditional 'Copenhagen Interpretation' way. We can use the Schrödinger equation to solve for and evolve wave functions. Then we invoke wave-particle duality, in essence things we detect as particles can behave as waves when they aren't interacting with anything. But when there is a measurement, the wave function collapses leaving us with a definite particle detection. If we repeat the experiment many times, we find the statistics of these results mirror the amplitude of the wave function squared. Hence the Born rule came into being, saying the wave function should be interpreted statistically, that our universe at the most fundamental scale is probabilistic rather than deterministic. This did not sit well with scientists like Einstein and Schrödinger who believed there must be more going on, perhaps 'hidden variables'. In the 1950's Hugh Everett proposed the Many Worlds interpretation of quantum mechanics. It is so logical in hindsight but with a bias towards the classical world, experiments and measurements to guide their thinking, it's understandable why the founders of quantum theory didn't come up with it. Rather than proposing different dynamics for measurement, Everett suggests that measurement is something that happens naturally in the course of quantum particles interacting with each other. The conclusion is inescapable. There is nothing special about measurement, it is just the observer becoming entangled with a wave function in a superposition. Since one observer can experience only their own branch, it appears as if the other possibilities have disappeared but in reality there is no reason why they could not still exist and just fail to interact with the other branches. This is caused by environmental decoherence. Schrodinger's cat animation by Iván Tello Wave functions, double slit and entanglement animation by Jonny Hyman Filming of opening sequence by Casey Rentz Special thanks to Mithuna Y, Raquel Nuno and Dianna Cowern for feedback on the script Music from https://epidemicsound.com "Experimental 1" "Serene Story 2" "Seaweed" "Colorful Animation 4"

The logistic map connects fluid convection, neuron firing, the Mandelbrot set and so much more. Fasthosts Techie Test competition is now closed! Learn more about Fasthosts here: https://www.fasthosts.co.uk/veritasium Code for interactives is available below... Animations, coding, interactives in this video by Jonny Hyman 🙌 Try the code yourself: https://github.com/jonnyhyman/Chaos References: James Gleick, Chaos Steven Strogatz, Nonlinear Dynamics and Chaos May, R. Simple mathematical models with very complicated dynamics. Nature 261, 459–467 (1976). https://doi.org/10.1038/261459a0 Robert Shaw, The Dripping Faucet as a Model Chaotic System https://archive.org/details/ShawRobertDrippingFaucetAsAModelChaoticSystem1984_201811/mode/2up Crevier DW, Meister M. Synchronous period-doubling in flicker vision of salamander and man. J Neurophysiol. 1998 Apr;79(4):1869-78. Bing Jia, Huaguang Gu, Li Li, Xiaoyan Zhao. Dynamics of period-doubling bifurcation to chaos in the spontaneous neural firing patterns Cogn Neurodyn (2012) 6:89–106 DOI 10.1007/s11571-011-9184-7 A Garfinkel, ML Spano, WL Ditto, JN Weiss. Controlling cardiac chaos Science 28 Aug 1992: Vol. 257, Issue 5074, pp. 1230-1235 DOI: 10.1126/science.1519060 R. M. May, D. M. G. Wishart, J. Bray and R. L. Smith Chaos and the Dynamics of Biological Populations Source: Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 413, No. 1844, Dynamical Chaos (Sep. 8, 1987), pp. 27-44 Chialvo, D., Gilmour Jr, R. & Jalife, J. Low dimensional chaos in cardiac tissue. Nature 343, 653–657 (1990). https://doi.org/10.1038/343653a0 Xujun Ye, Kenshi Sakai. A new modified resource budget model for nonlinear dynamics in citrus production. Chaos, Solitons and Fractals 87 (2016) 51–60 Libchaber, A. & Laroche, C. & Fauve, Stephan. (1982). Period doubling cascade in mercury, a quantitative measurement. http://dx.doi.org/10.1051/jphyslet:01982004307021100. 43. 10.1051/jphyslet:01982004307021100. Special thanks to Patreon Supporters: Alfred Wallace, Arjun Chakroborty, Bryan Baker, DALE HORNE, Donal Botkin, halyoav, James Knight, Jasper Xin, Joar Wandborg, Lee Redden, Lyvann Ferrusca, Michael Krugman, Pindex, Ron Neal, Sam Lutfi, Tige Thorman, Vincent Special thanks to: Henry Reich for feedback on earlier versions of this video Raquel Nuno for enduring many earlier iterations (including parts she filmed that were replaced) Dianna Cowern for title suggestions and saying earlier versions weren't good Heather Zinn Brooks for feedback on an earlier version. Music from: https://epidemicsound.com "What We Discovered" "A Sound Foundation 1" "Seaweed" "Colored Spirals 4" https://ve42.co/Artlist "Busy World" "Children of Mystery"

Common pitfalls of New Year's resolutions and how I plan to avoid them. Thanks Audible! Start listening with a 30-day trial and your first audiobook plus two Audible Originals free when you go to https://audible.com/veritasium or text veritasium to 500500. Thanks to Simone Giertz for sending me and Every Day Calendar! Get notified when they're available to order here: http://www.simonegiertz.com/every-day-calendar Special thanks to Patreon Supporters: Alfred Wallace, Arjun Chakroborty, Chuck Lauer Vose, Dale Horne, Jasper Xin, Joar Wandborg, Kevin Beavers, Leah Howard, Lyvann Ferrusca, Michael Krugman, Noel Braganza, Ron Neal, Tige Thorman

Scientists like Prof Sinclair have evidence of speeding up, slowing, and even reversing aging. Thanks to LastPass for sponsoring this video. Click here to start using LastPass: https://ve42.co/VeLP What causes aging? According to Professor David Sinclair, it is a loss of information in our epigenome, the system of proteins like histones and chemical markers like methylation that turn on and off genes. Epigenetics allow different cell types to perform their specific functions - they are what differentiate a brain cell from a skin cell. Our DNA is constantly getting broken, by cosmic rays, UV radiation, free radicals, x-rays and regular cell division etc. When our cells repair that damage, the epigenome is not perfectly reset. And hence over time, noise accumulates in our epigenome. Our cells no longer perform their functions well. To counter this decline, we can activate the body's own defenses against aging by stressing the body. Eat less, eat less protein, engage in intense exercise, experience uncomfortable cold. When the body senses existential threats it triggers longevity genes, which attempt to maintain the body to ensure its survival until good times return. This may be the evolutionary legacy of early bacteria, which established these two modes of living (repair and protect vs grow and reproduce). Scientists are uncovering ways to mimic stresses on the body without the discomfort of fasting. Molecules like NMN also trigger sirtuins to monitor and repair the epigenome. This may slow aging. Reversing aging requires an epigenetic reset, which may be possible using Yamanaka factors. These four factors can revert an adult cell into a pluripotent stem cell. Prof. Sinclair used three of the four factors to reverse aging in the retinal cells of old mice. He found they could see again after the treatment. Special thanks to: Professor David Sinclair, check out his book "Lifespan: Why We Age & Why We Don't Have To" Assistant Professor David Gold Noemie Sierra (for polyp images) Genepool Productions for telomere animations from Immortal: https://ve42.co/immortal Epigenetics animations (DNA, histones, methylation etc) courtesy of: http://wehi.tv Animation: Etsuko Uno Art and Technical Direction: Drew Berry Sound Design: Francois Tetaz & Emma Bortignon Scientific Consultation: Marnie Blewitt Courtesy of Walter and Eliza Hall Institute of Medical Research Filming, editing and animation by Jonny Hyman and Derek Muller Music from https://epidemicsound.com "Clearer Views" "Innovations" "A Sound Foundation" "Seaweed" Additional music by Kevin MacLeod from https://incompetech.com "Marty Gots a Plan"

Chaos theory means deterministic systems can be unpredictable. Thanks to LastPass for sponsoring this video. Click here to start using LastPass: https://ve42.co/VeLP Animations by Prof. Robert Ghrist: https://ve42.co/Ghrist Want to know more about chaos theory and non-linear dynamical systems? Check out: https://ve42.co/chaos-math Butterfly footage courtesy of Phil Torres and The Jungle Diaries: https://ve42.co/monarch Solar system, 3-body and printout animations by Jonny Hyman Some animations made with Universe Sandbox: https://universesandbox.com/ Special thanks to Prof. Mason Porter at UCLA who I interviewed for this video. I have long wanted to make a video about chaos, ever since reading James Gleick's fantastic book, Chaos. I hope this video gives an idea of phase space - a picture of dynamical systems in which each point completely represents the state of the system. For a pendulum, phase space is only 2-dimensional and you can get orbits (in the case of an undamped pendulum) or an inward spiral (in the case of a pendulum with friction). For the Lorenz equations we need three dimensions to show the phase space. The attractor you find for these equations is said to be strange and chaotic because there is no loop, only infinite curves that never intersect. This explains why the motion is so unpredictable - two different initial conditions that are very close together can end up arbitrarily far apart. Music from https://epidemicsound.com "The Longest Rest" "A Sound Foundation" "Seaweed"

Why does shaken soda explode? Does ice melt first in fresh or salt water? Thank you Squarespace for sponsoring this video. Go to https://squarespace.com to save 10% off your first purchase of a website or domain using code: VERITASIUM This video features experiments that have been shown to me by science teachers over the years. Does ice melt fast in salt water or fresh water was an experiment introduced to me at the Utah Science Teachers' conference. The ring of metal over a chain demo came from a teachers event in Florida. The idea shaking a carbonated drink increases pressure came from an email. Special thanks to Petr Lebedev for building the pressure gauge. Links to literature are below: Victims of the pop bottle, by Ted Willhoft. New Scientist, 21 August 1986 p.28 Carbonation speculation The Physics Teacher 30, 173 (1992); https://doi.org/10.1119/1.2343501 Agitation solution The Physics Teacher 30, 325 (1992); https://doi.org/10.1119/1.2343556 Filmed by Cristian Carretero, Jordan Schnabel, Jonny Hyman, and Raquel Nuno Music from https://epidemicsound.com "Seaweed" "Quietly Tense" "Mind Shift" "Observations"

Want to help plant 20M trees by 2020? Go to https://teamtrees.org #teamtrees Huge thanks to all the YouTubers who organized this. My apologies for the repost. These videos are from 2012 so my interest in trees goes back a long ways. I think these videos discuss two of the most interesting and amazing facts about our leafy friends: they are made mostly of CO2 (which comes from us breathing out amongst other sources) and they can transport water up a tube higher than any we can currently manufacture. So trees are out to get you. But we do much worse to them so we owe it to them to plant some more. 20 mil is a good start.

Origami is inspiring a plethora of new engineering designs. Try yourself: https://ve42.co/Origami Thanks Audible! Start listening with a 30-day trial and your first audiobook, plus two Audible Originals free when you go to https://audible.com/veritasium or text veritasium to 500500 Huge thanks to: Dr. Robert Lang https://langorigami.com Prof. Larry Howell https://www.compliantmechanisms.byu.edu/ On first glance it's surprising that origami -- a centuries old art of folding paper to achieve particular aesthetics -- is applicable to engineering. But upon closer consideration there are a lot of reasons methods developed for paper folding are also applicable to engineering: origami allows you to take a flat sheet of material and convert it to almost any shape only by folding. Plus for large flat structures, origami provides a way of shrinking dimensions while ensuring simply deployment - this is particularly useful for solar arrays in space applications. Furthermore, motions designed to take advantage of the flexibility of paper can also be used to form compliant mechanisms for engineering like the kaleidocycle. Since the principles of origami are scalable, mechanisms can also be dramatically miniaturized. Some of the work shown is based upon work supported by the National Science Foundation and the Air Force Office of Scientific Research under Grant No. EFRI-ODISSEI-1240417. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Special thanks to Patreon supporters: Alfred Wallace, Arjun Chakroborty, Bryan Baker, Chris Vargas, Chuck Lauer Vose, DALE HORNE, Donal Botkin, halyoav, James Knight, Jasper Xin, Joar Wandborg, Kevin Beavers, kkm, Leah Howard, Lyvann Ferrusca, Michael Krugman, Noel Braganza, Pindex, Ron Neal, Sam Lutfi, Stan Presolski, Tige Thorman Edited by Jonny Hyman, Isaac Frame, and Derek Muller Music by Jonny Hyman

Spinning objects have strange instabilities known as The Dzhanibekov Effect or Tennis Racket Theorem - this video offers an intuitive explanation. Part of this video was sponsored by LastPass, click here to find out more: https://ve42.co/LP References: Prof. Terry Tao's Math Overflow Explanation: https://ve42.co/Tao The Twisting Tennis Racket Ashbaugh, M.S., Chicone, C.C. & Cushman, R.H. J Dyn Diff Equat (1991) 3: 67. https://doi.org/10.1007/BF01049489 Janibekov’s effect and the laws of mechanics Petrov, A.G. & Volodin, S.E. Dokl. Phys. (2013) 58: 349. https://doi.org/10.1134/S1028335813080041 Tumbling Asteroids Prave et al. https://doi.org/10.1016/j.icarus.2004.07.021 The Exact Computation of the Free Rigid Body Motion and Its Use in Splitting Methods SIAM J. Sci. Comput., 30(4), 2084–2112 E. Celledoni, F. Fassò, N. Säfström, and A. Zanna https://doi.org/10.1137/070704393 Animations by Iván Tello and Isaac Frame Special thanks to people who discussed this video with me: Astronaut Don Pettit Henry Reich of MinutePhysics Grant Sanderson of 3blue1brown Vert Dider (Russian YouTube channel) Below is a further discussion by Henry Reich that I think helps summarize why axes 1 and 3 are generally stable while axis 2 is not: In general, you might imagine that because the object can rotate in a bunch of different directions, the components of energy and momentum could be free to change while keeping the total momentum constant. However, in the case of axis 1, the kinetic energy is the highest possible for a given angular momentum, and in the case of axis 3, the kinetic energy is the lowest possible for a given angular momentum (which can be easily shown from conservation of energy and momentum equations, and is also fairly intuitive from the fact that kinetic energy is proportional to velocity squared, while momentum is proportional to velocity - so in the case of axis 1, the smaller masses will have to be spinning faster for a given momentum, and will thus have more energy, and vice versa for axis 3 where all the masses are spinning: the energy will be lowest). In fact, this is a strict inequality - if the energy is highest possible, there are no other possible combinations of momenta other than L2=L3=0, and vice versa for if the energy is the lowest possible. Because of this, in the case of axis 1 the energy is so high that there simply aren't any other possible combinations of angular momentum components L1, L2 and L3 - the object would have to lose energy in order to spin differently. And in the case of axis 3, the energy is so low that there likewise is no way for the object to be rotating other than purely around axis 3 - it would have to gain energy. However, there's no such constraint for axis 2, since the energy is somewhere in between the min and max possible. This, together with the centrifugal effects, means that the components of momentum DO change.

A planet has been predicted to orbit the sun with a period of 10,000 years, a mass 5x that of Earth on a highly elliptical and inclined orbit. What evidence supports the existence of such a strange object at the edge of our solar system? Huge thanks to: Prof. Konstantin Batygin, Caltech Prof. David Jewitt, UCLA I had heard about Planet 9 for a long time but I wondered what sort of evidence could support the bold claim: a planet at the very limits of our ability to detect one, so far out that its period is over 60 times that of Neptune. The planet 9 hypothesis helps explain clustering of orbits of distant Kuiper belt objects. It also explains how some of these objects have highly inclined orbits - up to 90 degrees relative to the plane of the solar system. Some are orbiting in reverse. Plus their orbits are removed from the orbit of Neptune, the logical option for a body that could have ejected them out so far. The fact that the perihelion is so far out suggests another source of gravity was essential for their peculiar orbits. Special Thanks to Patreon Supporters: Alfred Wallace, Arjun Chakroborty, Bryan Baker, Chris Vargas, Chuck Lauer Vose, DALE HORNE, Donal Botkin, Eric Velazquez, halyoav, James Knight, Jasper Xin, Joar Wandborg, Kevin Beavers, kkm, Leah Howard, Lyvann Ferrusca, Michael Krugman, Mohammed Al Sahaf, Noel Braganza, Pindex, Ron Neal, Sam Lutfi, Stan Presolski, Tige Thorman Music from http://epidemicsound.com "Observations - From Now On" "Magnified XY"

We put aerogel to the test vs 'not-a-flamethrower', a huge 2000°C flame to a large fiberglass blanket infused with silica aerogel - formerly the lightest solid (that title is now held by graphene aerogel). Special thanks to: Aerogel Technologies: https://ve42.co/aerogeltech Aspen Aerogels: https://ve42.co/aspen Ben: @BenScho999999 Dr. Stephen Steiner and the Aerogel Technologies team The footage of aerogel materials in cold environments was provided courtesy of Aspen Aerogels. Their product, cryogel, was shown to be flexible in liquid nitrogen while preventing cold burns to the hand. They are the manufacturer of the blanket used in the main portion of this video. This is the finale of my three-part series on aerogel. I'll put links to the other parts below: World's Lightest Solid: https://youtu.be/AeJ9q45PfD0 I Waterproofed Myself With Aerogel: https://youtu.be/GcdB5bFwio4 Huge thanks to Patreon supporters: Alfred Wallace, Arjun Chakroborty, Bryan Baker, Chris Vargas, Chuck Lauer Vose, Dale Horne, Donal Botkin, Eric Velazquez, halyoav, James Knight, Jasper Xin, Joar Wandborg, Kevin Beavers, kkm, Leah Howard, Lyvann Ferrusca, Michael Krugman, Mohammed Al Sahaf, Noel Braganza, Philipp Volgger, Pindex, Ron Neal, Sam Lutfi, Stan Presolski, Tige Thorman This is an educational video demonstrating scientific experiments performed by professionals. It should not be attempted by viewers. Music from Epidemic Sound: http://epidemicsound.com "Running Against the Clock" "Dangerous Forests"

I used a nitrogen membrane and Stirling cryocooler to liquefy nitrogen out of the air. For this video I partnered with Starbucks to celebrate their Nitro Cold Brew. Order one here: https://starbucks.app.link/derekmuller Making liquid nitrogen is hard - in fact up until 150 years ago scientists doubted whether it was even possible to liquefy nitrogen. In 1823, At the royal institution in London, Michael Faraday first produced liquid chlorine, kind of accidentally by putting it under high pressure. He similarly liquefied ammonia. Borrowing a mixture from Thilorier in France, a combination of dry ice, snow and ether, he reached a temperature of -110C. By 1845 he used this mixture plus a hand pump to pressurize gases to liquefy all the known gases except six, which included oxygen and nitrogen. These became known as the “permanent” gases. A French Physicist Aimé compressed oxygen and nitrogen in tanks and then lowered them into the ocean over 1.6km deep, where the pressure got up to 200 atmospheres. Still the gases didn’t liquefy. Only at the end of 1877 were the first droplets of liquid oxygen and liquid nitrogen produced, by Cailletet in France. He first tried oxygen by compressing it up to 300 atmospheres, cooled to -30C, but that wasn't even enough to liquefy oxygen. But when he suddenly released the pressure, the expanding gas cooled, he estimated to -200C and he saw a mist and then droplets slide down the walls of his vessel. It's amazing how far we've come in that now I can purchase a helium-based cryocooler. It compresses and expands the gas to absorb heat from the tip of the cold finger and eject it into the surroundings at ambient temperature.

The Mars Helicopter aims to make the first powered flight on another planet when it takes off on Mars as part of the Mars 2020 mission. I learned a lot getting to visit the drone right before it was mounted on the rover. How do you fly in 1% of Earth's atmosphere: Have large rotors (they are 1.2m in diameter) and spin them very fast, around 2500 RPM (5x the speed of a helicopter on Earth). Plus the aircraft has to be light: The Mars helicopter weighs in at 1.8kg or around the same as a laptop. Every piece had to be stripped down for weight. Instead of using aerogel for insulation, the craft makes use of CO2 gaps between components. Even aerogel was too heavy! One of the major challenges is surviving the Martian night: Temperatures plunge to -80C to -100C so two thirds of the craft's power is actually used to keep its electronics warm. Only one third is used for flying. The estimated flight time is 90 seconds. The craft can't be driven remotely, it will have to fly autonomously, using its own sensor suite to determine how to fly. The round trip 20 minute delay with Earth means steering the craft from mission control would be impossible. Huge Thanks to Patreon Supporters: Philipp Volgger, Chris Vargas, Ron Neal, Alfred Wallace, Colin Bellmore, Michael Krugman, James Knight, Donal Botkin, Sam Lutfi, Mohammed Al Sahaf, Kevin Beavers, Chuck Lauer Vose, Bryan Baker, James Wong, kkm, Manuel Zürcher, Tige Thorman, Jasper Xin, Leah Howard, Daniel Milum, Mathias Göransson, Stan Presolski, Lyvann Ferrusca, Arjun Chakroborty, June Kang, Listen Money Matters, Pindex, Joar Wandborg, DALE HORNE, Parker Linn, Roberto Rezende Jonny Hyman was a legend in editing, animation, filming, and sound design for this video.

Electric cars are now ready to take over thanks to advances in battery technology and their inherent benefits: torque, handling, maintenance. This video was sponsored by BMW: https://www.bmwusa.com/ Full disclosure: I drive an #electric #car. I think electric cars are the future, not mainly because they're better for the environment (which they are if you drive the car for any reasonable length of time) but because they are just better cars. The have better torque and acceleration, better handling, they're more efficient, quieter, they don't smell, they're cheaper to run and best of all you never have to visit a gas station - this appeals to me. I never have to worry about being low on gas because every morning my car is charged and ready to go - just like my phone and laptop. And if you're worried about range, don't. Almost all trips can already be done in an electric car with modest battery pack. And fast chargers along the way make it possible to do longer road trips if necessary. You have to make rest stops anyway, just time them with the charging. And consider that battery tech is getting dramatically cheaper, smaller, lighter. All these reasons are why I see the #future of cars as electric. Writing & Research Derek Muller Jonny Hyman Matthew Shribman https://ve42.co/sciencebath Editing, Animation, Audio, & Music: Jonny Hyman Camerawork: Raquel Nuno Jonny Hyman 1890s Music "National fantasie" by William Paris Chambers, archived in Library of Congress #BMWUSA #NEXTGen #BMWPartner #ad

Apollo astronauts trained in nuclear bomb craters at the Nevada National Security Site. But why?Thanks Audible! Start listening with a 30-day trial and your first audiobook plus two Audible Originals free when you go to http://audible.com/veritasium or text veritasium to 500500 I found this story fascinating because in a way a nuclear bomb crater is more like a meteorite impact site than an impact site itself. Consider: Barringer Crater was claimed to be a meteorite impact site but geologists dismissed it as a volcanic formation. It was only after studying nuclear bomb craters and the minerals found there that geologists concluded the energy and pressures that created Barringer Crater were too high to be from volcanic activity and therefore must have formed from a meteorite impact. Special Thanks to: Nevada National Security Site The National Atomic Testing Museum Jonny Hyman and Verse: https://youtu.be/7bUUGzi-AAY Active Galactic for footage of craters in Arizona: https://youtu.be/yhoooBpndog Special thanks to Patreon supporters: a human, Alfred Wallace, Arjun Chakroborty, Brent Stewart, Bryan Baker, Chris Vargas, Chuck Lauer Vose, Clip Tree, Coale Shifflett, Colin Bellmore, DALE HORNE, Daniel Milum, Donal Botkin, Eric Velazquez, Illya Nayshevsky, James Knight, James Wong, Jasper Xin, Joar Wandborg, Johnny, June Kang, Kevin Beavers, kkm, Leah Howard, Listen Money Matters, Lyvann Ferrusca, Manuel Zürcher, Mathias Göransson, Michael Bradley Wirz, Michael Krugman, Mohammed Al Sahaf, OddJosh, Philipp Volgger, Pindex, Roberto Rezende, Robin DeBank, Ron Neal, Sam Lutfi, Stan Presolski, Tige Thorman, Warrior8252 Filmed by Raquel Nuno Story and Editing by Derek Muller and Jonny Hyman Music and Animation by Jonny Hyman Produced by Casey Rentz

The Vikings suffered many hardships living in the north of Europe: long, cold winters and importantly a lack of sunlight. Luckily, they had cod. Check out Vitamania: https://ve42.co/cod When making a video about vitamins I thought the story would mainly be about supplement pills, whether we should or shouldn't take them and how they're made. But what I found out is vitamins have a remarkable story that affects many more aspects of our lives. For example the Vikings needed a source of vitamin D to last the dark winter months and for their children to develop strong, healthy bones, avoiding rickets. Special thanks to Patreon supporters: a human, Albert Jachowicz-Brzeziński, Alfred Wallace, Arjun Chakroborty, Brent Stewart, Chris Vargas, Chuck Lauer Vose, Clip Tree, Coale Shifflett, Colin Bellmore, DALE HORNE, Eric Velazquez, Fedor Indutny, Fran Rodriguez, James Wong, Jasper Xin, Joar Wandborg, Johnny, Jorge Angel Sandoval, June Kang, Kevin Beavers, Kishore Tipirneni, Levan Ferr, Listen Money Matters, Manuel Zürcher, Mark Bevilacqua, Mathias Göransson, Michael Bradley Wirz, Michael Krugman, Mohammed Al Sahaf, Nicholas Hastings, OddJosh, Patrick Čalija, Peter Tajti, Philipp Volgger, Roberto Rezende, Robin DeBank, Ron Neal, Stan Presolski, Swante Scholz, Tiago Bruno, Tige Thorman, Warrior8252 This video was filmed by Harry Panagiotidis Researched and written by Derek Muller and Jonny Hyman Editing, animation and music by Jonny Hyman Cod liver oil animation by Iván Tello Vitamania was written, directed and produced by Sonya Pemberton

Aerogel has extraordinary properties but it can be tough to work with. This video looks at modifying aerogels to take advantage of their unique characteristics. Subscribe to Veritasium: https://ve42.co/sub Huge thanks to Dr. Stephen Steiner and the crew at Aerogel Technologies. To find out more or buy your own aerogel sample, check out: http://www.aerogeltechnologies.com/ Thanks to Dr. Steven Jones and Dr. Mihail Petkov at NASA's Jet Propulsion Laboratory And thanks to FLIR for loaning us the awesome high definition thermal camera. The footage is amazing! https://www.flir.com Aerogel’s extraordinary properties are due in large part to its structure. Aerogel is a solid but on the nanoscale it has a mesh or sponge-like structure. The struts of this structure are nanoscale, as are the pores at around 20nm across. This makes silica aerogel incredibly light (it was once the lightest solid but has now been superseded by graphene aerogel), transparent and adsorbent. An ice-cube sized piece of aerogel has an internal surface area roughly equal to half a football field. Aerogel is used in high end museum cases to regulate humidity. Plus it helps maintain the vacuum on the Mars Insight seismometers - it adsorbs moisture and other outgassed volatiles that come from the spacecraft itself. Proposed uses include as a physical insecticide by ‘drying out insects’ reducing the need for chemical and toxic pesticides. Special thanks to all my Patreon supporters especially those who contributed feedback to an earlier draft of this video: a human, Albert Jachowicz-Brzeziński, Alfred Wallace, Arjun Chakroborty, Brent Stewart, Chris Vargas, Chuck Lauer Vose, Clip Tree, Coale Shifflett, Colin Bellmore, DALE HORNE, Eric Velazquez, Fedor Indutny, Fran Rodriguez, James Wong, Jasper Xin, Joar Wandborg, Johnny, Jorge Angel Sandoval, June Kang, Kevin Beavers, Kishore Tipirneni, Levan Ferr, Listen Money Matters, Manuel Zürcher, Mark Bevilacqua, Mathias Göransson, Michael Bradley Wirz, Michael Krugman, Mohammed Al Sahaf, Nicholas Hastings, OddJosh, Patrick Čalija, Peter Tajti, Philipp Volgger, Roberto Rezende, Robin DeBank, Ron Neal, Stan Presolski, Swante Scholz, Tiago Bruno, Tige Thorman, Warrior8252 Filmed by Paul Gramaglia Thumbnail by Ignat Berbeci Animations by Catherine Chooljian Music from https://epidemicsound.com “Tonic Zone” “Betelgeuse” “Insidious Mice” “Seaweed” “It’s not that serious” “Platin00m - Sum It” This is an educational, scientific video.

I bought 10,000 shade balls and tried to swim in them. They appear to act like a non-Newtonian fluid: rigid under high shear stress, but they flow like a liquid under low shear. Get a signed shade ball by supporting Veritasium: https://ve42.co/patreon Receiving a shade ball: 1. Support Veritasium on any Patreon tier and enter your address https://ve42.co/patreon 2. In about a month I will send out signed shade balls 3. I will cover all shipping costs but if things get really crazy I will prioritize existing Patreon supporters and higher tiers My sense was that swimming in shade balls would be difficult but still doable. This was roughly true for the single layer of shade balls. The shade balls slide past each other so they act like a liquid, albeit a viscous one owing to their significant inertia. It's much more intense exercise and it's also annoying to be bombarded with shade balls on all sides of your body, particularly your head. With multi-layer shade balls (as exists on much of LA reservoir) things get significantly more difficult. The balls bunch together and when you try to move through them quickly, they become more rigid, providing significant resistance to motion. This has the benefit that you can lie on them and as long as they stay trapped under you, you can float on them. But a little bit of motion causes them to move around and you sink through quickly. Huge thanks to: Jordan Schnabel and Cristian Carretero for filming and swimming and providing lifeguard services. Raquel Nuno for filming and putting up with me. Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme and everyone who provided feedback on an early draft of this video. Music from https://epidemicsound.com "Dubstep Mammoth 2" "Finally Here (Instrumental)" "The Last Arrival" "Sundown Love (Instrumental)"

Aerogels are the world's lightest (least dense) solids. They are also excellent thermal insulators and have been used in numerous Mars missions and the Stardust comet particle-return mission. The focus of this video is silica aerogels, though graphene aerogels are now technically the lightest. At one point Dr. Steven Jones literally held the Guinness World Record for making the lightest aerogel and therefore lightest solid. If you're interested in learning more about aerogels, let me know in the comments as there is a potential trilogy in the works... Huge thanks to Dr. Stephen Steiner and the crew at Aerogel Technologies. To find out more or buy your own aerogel sample, check out: http://www.aerogeltechnologies.com/ Thanks to Dr. Steven Jones and Dr. Mihail Petkov at NASA's Jet Propulsion Laboratory And thanks to FLIR for loaning us the awesome high definition thermal camera. The footage is amazing! https://www.flir.com Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme and everyone who provided feedback on an early draft of this video. Filming by Raquel Nuno Animations by Maria Raykova Drawings by Mariel Solsberg Music From http://epidemicsound.com "Seaweed" "Swagger Stagger"

My hypothesis is that the algorithm, rather than viewer preference, drives views on the site. As the algorithm shifts, various YouTubers experience burnout (as what used to work no longer works) and right now click-through rate is the key metric. So clickable titles and thumbnails are the only way to get a lot of impressions and hence views - they are the only way to go viral. This leads me to wonder which audiences will become most prevalent on the site and if there will even be a place for educational content. In the long-term, hopefully YouTube is able to measure satisfaction through surveys and other metrics to ensure an optimal experience for everyone on the site. Flipchart artwork by Maria Raykova Filmed by Raquel Nuno Thumbnail by Ignat Berbeci

I took a boat through 96 million black plastic balls on the Los Angeles reservoir to find out why they're there. The first time I heard about shade balls the claim was they reduce evaporation. But it turns out this isn't the reason they were introduced. Huge thanks to LADWP for arranging this special tour for me. Next time let's put the GoPro on the submersible! The balls are made of high density polyethylene (HDPE) which is less dense than water so they float on the surface of the reservoir even if they break apart. They are 10cm (4 inches) in diameter and contain about 210ml of water. So the main reason they are on the reservoir is to block sunlight from entering the water and triggering a chemical reaction that turns harmless bromide into carcinogenic bromate. This effect occurs with prolonged exposure to bromate so regulators insist that levels be kept below 10 microgram per liter on average over a 12 month period. Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme and everyone who provided feedback on an early draft of this video. Thanks to: Las Virgenes Reservoir for footage of initial shade ball dump Euro-Matic for bird into jet-engine footage Researched and Produced by Casey Rentz Animations by Maria Raykova Music from http://epidemicsound.com "Colorful Animation 4" "Seaweed" And from Kevin MacLeod "Marty Gots a Plan" This is an educational video about the science of water quality.

Tiny robots activated by magnetic fields may be used in future biomedical procedures. Start listening to Audible with a 30-day trial and your first audiobook, plus two Audible Originals free when you go to http://audible.com/veritasium or text veritasium to 500500 Huge thanks to: Dr. Eric Diller, Assistant Professor of Mechanical Engineering at the University of Toronto http://microrobotics.mie.utoronto.ca Research Referenced in this video: T. Xu, J. Zhang, M. Salehizadeh, O. Onaizah and E. Diller, Millimeter-scale flexible robots with programmable three-dimensional magnetization and motions. Science Robotics. 4, eaav4494 (2019). http://robotics.sciencemag.org/lookup/doi/10.1126/scirobotics.aav4494 H. Xie, M. Sun, X. Fan, Z. Lin, W. Chen, L. Wang, L. Dong, and Q. He, Reconfigurable magnetic microrobot swarm: Multimode transformation, locomotion, and manipulation. Science Robotics. 4, eaav8006 (2019). http://robotics.sciencemag.org/lookup/doi/10.1126/scirobotics.aav8006 G. Hwang, A. J. Paula, E. E. Hunter, Y. Liu, A. Babeer, B. Karabucak, K Stebe, V. Kumar, E. Steager, and H. Koo, Catalytic antimicrobial robots for biofilm eradication. Science Robotics. 4, eeaw2388 (2019). http://robotics.sciencemag.org/lookup/doi/10.1126/scirobotics.aaw2388 Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme Music by Kevin MacLeod http://incompetech.com "Marty Gots a Plan" "March of the Spoons"

The story of three impressive high school science projects. Can you guess which student won $250,000 in the #RegeneronSTS? Applications open June 1: http://bit.ly/2HkLXT1 This video was sponsored by Regeneron. The Science Talent Search was founded and produced by the Society for Science and the Public. Huge thanks to the students: Ronak Roy, Ana Humphrey, and Anjali Chadha. It was great getting to meet all of you and learn about your original scientific research. Special thanks to Assistant Professor Konstantin Batygin for discussing Ana's research and Planet 9 with me. More is coming on the Planet 9 front. Ronak came up with a new design for the phoropter, the device used to determine eye-glass prescriptions. It's basically been unchanged for 200 years. Using a liquid lens, he miniaturized the device and wrote an algorithm to determine your prescription. Ana used math and physics to search for hidden exoplanets. There are a number of reasons why the transit method and Kepler telescope may have missed them: they're too small, too inclined, or take too long to orbit and so were not seen. By considering which planetary systems have additional space for more planets, Ana came up with 560 locations where we may look again for planets in future. Anjali developed an internet enabled device for measuring arsenic concentrations in drinking water. The device performs several chemical reactions to release the arsenic into a measurable state. It then reacts the arsenic with a test strip to produce a color output. This color is sampled by a camera and processed to determine the concentration of arsenic in the water sample. This has significant potential applications around the world helping reduce exposure to arsenic and potentially other contaminants. Filming by Raquel Nuno

The Event Horizon Telescope Collaboration observed the supermassive black hole at the center of M87, finding the dark central shadow in accordance with General Relativity, further demonstrating the power of this 100 year-old theory. To understand more about why the shadows look the way they do, check out: https://www.youtube.com/watch?v=zUyH3XhpLTo I will continue updating this description with more links. Event Horizon Telescope collaboration: https://ve42.co/EHT Animations and simulations with English text: L. R. Weih & L. Rezzolla (Goethe University Frankfurt) https://youtu.be/jvftAadCFRI Video of observation of M87 courtesy of: C. M. Fromm, Y. Mizuno & L. Rezzolla (Goethe University Frankfurt) https://youtu.be/meOKmzhTcIY Video of observation of SgrA* courtesy of C. M. Fromm, Y. Mizuno & L. Rezzolla (Goethe University Frankfurt) Z. Younsi (University College London) https://youtu.be/VnsZj9RvhFU Video of telescopes in the array 2017: C. M. Fromm & L. Rezzolla (Goethe University Frankfurt) https://youtu.be/Ame7fzBuFnk Animations and simulations (no text): L. R. Weih & L. Rezzolla (Goethe University Frankfurt) https://youtu.be/XmvpKFSvB7A Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme Scale animation by Maria Raykova

We have just seen the first image of a black hole, the supermassive black hole in the galaxy M87 with a mass 6.5 billion times that of our sun. But what is that image really showing us? This is an awesome paper on the topic by J.P. Luminet: Image of a spherical black hole with thin accretion disk Astronomy and Astrophysics, vol. 75, no. 1-2, May 1979, p. 228-235 https://ve42.co/luminet Using my every day intuition I wondered: will we see the "shadow" of the black hole even if we're looking edge on at the accretion disk? The answer is yes because the black hole warps space-time, so even if we wouldn't normally be able to see the back of the accretion disk, we can in this case because its light is bent up and over the black hole. Similarly we can see light from the bottom of the back of the accretion disk because it's bent under the bottom of the black hole. Plus there are additional images from light that does a half turn around the black hole leading to the inner rings. What about the black hole "shadow" itself? Well initially I thought it can't be an image of the event horizon because it's so much bigger (2.6 times bigger). But if you trace back the rays, you find that for every point in the shadow, there is a corresponding ray that traces back to the event horizon. So in fact from our one observing location, we see all sides of the event horizon simultaneously! In fact infinitely many of these images, accounting for the virtually infinite number of times a photon can orbit the black hole before falling in. The edge of the shadow is due to the photon sphere - the radius at which light goes around in closed orbits. If a light ray coming in at an oblique angle just skims the photon sphere and then travels on to our telescopes, that is the closest 'impact parameter' possible, and it occurs at sqrt(27)/2*r_s Huge thanks to: Prof. Geraint Lewis University of Sydney https://ve42.co/gfl Like him, I'm hoping (predicting?) we'll see some moving images of black holes tomorrow Prof. Rana Adhikari Caltech https://ve42.co/Rana Riccardo Antonelli - for excellent images of black holes, simulations and ray-tracing code, check out: https://ve42.co/rantonels The Event Horizon Telescope Collaboration Check out their resources and get your local link for the livestream here: https://ve42.co/EHT Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme Filming by Raquel Nuno Animation by Maria Raykova

I always wanted to know why film looked better than video. Moving electronic images have as long a history but were invented for a different purpose. This video was sponsored by B&H Photo: https://www.bhphotovideo.com Huge thanks to: Richard Diehl, Video Labguy https://www.youtube.com/user/videolabguy https://www.labguysworld.com Branch Education for awesome animations https://ve42.co/BranchEd Minutephysics for mechanical TV animations https://www.youtube.com/minutephysics Mark Schubin Engineer and explainer, SMPTE Life Fellow https://www.smpte.org This is a video I've long wanted to make, about what makes video look like video and, up until 10 years ago or so, not as appealing as film. I grew up with the two technologies (film and video) in parallel and to me they always seemed like two ways of achieving the same ends: recording and replaying moving images. But their histories are quite distinct. Film was always a way to capture moving images for later replaying. Video started out as a way to transfer images from one place to another instantaneously. This dates back to the first fax machine, mechanical TV, live broadcast tv and ultimately videotapes. This history focuses on the early decades of video and not the more recent switches to chip cameras and solid state storage. Maybe that's a story for another day. Additional resources and references: The Dawn of Tape: Transmission Device as Preservation Medium https://ve42.co/dawnoftape What Sparked Video Research in 1877? The Overlooked Role of the Siemens Artificial Eye https://ve42.co/sparkvideo Video Preservation Website: http://videopreservation.conservation-us.org Image Orthicon Tube: http://interiorcommunicationselectrician.tpub.com/14120/141200335.htm Film vs Digital https://stephenfollows.com/film-vs-digital/ Eyes of a Generation: http://eyesofageneration.com Television in the US: http://www3.northern.edu/wild/th100/tv.htm http://www.classictvinfo.com Music from https://www.epidemicsound.com "Seaweed" "Capture a Picture 1" "Colorful Animation 4"

Research has found some human brains can pick up on rotations of geomagnetic-strength fields as evidenced by drops in alpha wave power following stimulus. For more, see https://ve42.co/magneto Huge thanks to: Prof. Shinsuke Shimojo, Connie Wang, and Isaac Hilburn, plus Prof. Joe Kirschvink. Their lab: https://ve42.co/maglab Special thanks to Patreon supporters: Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd Additional filming by Whitney Clavin

Compliant mechanisms have lots of advantages over traditional devices. SimpliSafe is awesome security. It's really effective, easy to use, and the price is great. Check out SimpliSafe here: https://simplisafe.com/veritasium I visited the Compliant Mechanisms Research group at Brigham Young University and spoke to Professor Larry Howell: https://www.compliantmechanisms.byu.edu At the above link, you can download 3D-print files to make some of the objects in the video, plus learn more about compliant mechanisms. What I learned about compliant mechanisms I summarize in the 8 P's of compliant mechanisms: 1. Part count (reduced by having flexible parts instead of springs, hinges) 2. Productions processes (many, new, different enabled by compliant designs) 3. Price (reduced by fewer parts and different production processes) 4. Precise Motion (no backlash, less wear, friction) 5. Performance (no outgassing, doesn't require lubricant) 6. Proportions (reduced through different production processes) 7. Portability (lightweight due to simpler, reduced part count designs) 8. Predictability (devices are reliable over a long period of time) Special thanks to Patreon supporters: Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd Animation by Alan Chamberlain

Is it possible to reconstruct sound from high-speed video images? Part of this video was sponsored by LastPass: http://bit.ly/2SmRQkk Special thanks to Dr. Abe Davis for revisiting his research with me: http://abedavis.com This video was based on research by Dr. Abe Davis and colleagues. I found out about this work years ago and was fascinated by the way he was able to capture vibration information in image-only video. I always imagined the motions of objects would be visible as when recording a tuning fork in slow motion - so deriving sound from high speed images seemed a feasible task. But the reality is much more difficult. Sound vibrations only cause objects to wiggle by about a micrometer. This is much smaller than a pixel, so the algorithm must understand the characteristics of the image. A move in one direction should cause some pixels to lighten slightly, while others darken - and this behavior is correlated along the edges of the image. So noise can be reduced because it's random over the image and there are enough places to sample that you can get it to cancel out. Something I'm wondering now is - would it be possible to capture sound in a single image? I'm thinking it would have to be an image of a large object or space because the wavelengths of typical sounds are quite long. Maybe a high frequency sound could be imaged in a suitable medium... Animations by Alan Chamberlain Music from http://epidemicsound.com "Seaweed"

A bisected grape in the microwave makes plasma. But how does it work? A grape is the right size and refractive index to trap microwaves inside it. When you place two (or two halves) close together the fields interact with each other creating a maximum of electromagnetic energy where they touch. This creates heating, sparks, and plasma, which is further fed with energy directly by the microwaves. Huge thanks to Hamza Khattak, Prof. Pablo Bianucci and Prof. Aaron Slepkov (unavailable for the call) for chatting to me and helping me understand the physics of this cool phenomenon. Linking plasma formation in grapes to microwave resonances of aqueous dimers https://www.pnas.org/cgi/doi/10.1073/pnas.1818350116 Special thanks to Patreon supporters: Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd Thanks also to Steve Bosi, my original plasma collaborator. Animations by Alan Chamberlain Music from http://epidemicsound.com "Seaweed"

Do negative air ions improve mood, anxiety, depression, alertness? Part of this video was sponsored by LastPass, click here to find out more: http://bit.ly/2RZZTZk Special thanks to Prof. Jack Beauchamp and Dr. Nathan Dalleska from Caltech for all their help running these experiments and discussing the research. For more, check out the links below: http://www.cce.caltech.edu/people/jesse-l-jack-beauchamp http://beckmaninstitute.caltech.edu/eac.shtml If you want to dig into the research on negative ions yourself, I suggest starting with the review studies: Air ions and mood outcomes: a review and meta-analysis. Perez V, Alexander DD, Bailey WH. BMC Psychiatry. 2013 Jan 15;13:29. https://www.ncbi.nlm.nih.gov/pubmed/23320516 Air ions and respiratory function outcomes: a comprehensive review Dominik D Alexander, William H Bailey, Vanessa Perez, Meghan E Mitchell, and Steave Su J Negat Results Biomed. 2013; 12: 14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848581/ Exposure of laboratory animals to small air ions: a systematic review of biological and behavioral studies. Bailey WH, Williams AL, Leonhard MJ. Biomed Eng Online. 2018 Jun 5; 17(1):72. https://www.ncbi.nlm.nih.gov/pubmed/29866122 Thumbnail photography by Raquel Nuno VFX by Alan Chamberlain Sound recording by Whitney Clavin Motion Graphics by Charlie Kilman Music from Epidemic Sound: http://epidemicsound.com "Capture a Picture 1" and "Seaweed"

Droplets levitate on a bath of liquid nitrogen and are spontaneously self-propelled. Thanks Audible! Start a 30-day trial and your first audiobook is free. Go to https://audible.com/VERITASIUM or text VERITASIUM to 500500. Special thanks to Dr. Anaïs Gauthier Physics of Fluids: https://pof.tnw.utwente.nl/ Self-propulsion of inverse Leidenfrost drops on a cryogenic bath Anaïs Gauthier, Christian Diddens, Rémi Proville, Detlef Lohse, and Devaraj van der Meer PNAS January 22, 2019 116 (4) 1174-1179; published ahead of print January 22, 2019 https://www.pnas.org/content/116/4/1174 For a detailed description of the setup: http://www.lps.ens.fr/~adda/papiers/Langmuir2016.pdf And self-propulsion is also seen: http://www.lps.ens.fr/~adda/papiers/InvLeidenfrost.avi Other recent (hot) Leidenfrost experiments that might be interesting: * Leidenfrost wheels: https://www.youtube.com/watch?v=glRGl-eYuXo * Leidenfrost maze: https://www.youtube.com/watch?v=vPZ7sx3EwUY * Leidenfrost explosions: https://www.youtube.com/watch?v=z0sp3AjgUy4 Special thanks to Patreon supporters: Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd Thanks to Prof. Kevin McKeegan at UCLA for the liquid nitrogen Filming by Raquel Nuno Additional animations by Alan Chamberlain

A pulsing black hole in the centre of a distant galaxy sheds light on black hole and galaxy formation. How fast are black holes rotating and how does that rotation change over its life-span? Huge thanks to Prof. Geraint Lewis and study author Dr. Dheeraj Pasham. A loud quasi-periodic oscillation after a star is disrupted by a massive black hole https://ve42.co/pasham Special thanks to Patreon supporters: Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd Music from http://epidemicsound.com "Colorful animation 4" "serene story 2" "To the stars 01" "Black Vortex Animations by Alan Chamberlain and courtesy of NASA

A launch mishap led to the best experimental confirmation of gravitational redshift. Get a free audiobook with a 30-day trial of Audible: http://audible.com/VERITASIUM or text VERITASIUM to 500500 Huge thanks to Dr. Pacome Delva: https://ve42.co/pacome Dr. Sven Herrmann: https://ve42.co/sven Gravitational Redshift Test Using Eccentric Galileo Satellites: https://ve42.co/GRtest Disclaimer: It is arguable what is THE best test of general relativity because there are different ways to test the theory. This is the best confirmation of gravitational redshift, which is one of the three original tests proposed by Einstein. Special thanks to Patreon supporters: Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd Animations and editing by Alan Chamberlain Music from http://epidemicsound.com "Subtle Substitutes 2" "A sound Foundation 1" "Cell Research 1" "Particle Attraction 1"

Scientists have combined ultrasound, viruses and synthetic drugs to control regions of the brain. Check out Skillshare: https://skl.sh/veritasium (first 500 get 2 months free) Special thanks to Prof. Mikhail Shapiro and Dr. Jerzy Szablowski: http://shapirolab.caltech.edu Human brains are complicated - the most complicated thing in the known universe, many people say. So far we understand little - just that certain regions of the brain appear to be involved in certain activities and certain disorders. In extreme cases this has led to the practice of removing sections of the brain, or using electrodes or optical fibers to control activation rates. What is unique about this approach is it offers a way to turn on and off specific brain regions without invasive surgery. It has promise because it combines existing technologies: micro-bubbles, ultrasound, synthetic viruses, and synthetic drugs to achieve this goal. Special thanks to Patreon supporters: Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd Animations and editing by Alan Chamberlain Music from http://epidemicsound.com "Experimental1"

Mars InSight will be the first to detect seismic activity on Mars’ surface, first to measure rate of heat transmitted from interior, first to dig nearly 5m down, first to measure magnetic fields on Mars’ surface, and first to use a robotic arm to place instruments on the surface of Mars (assuming it lands of course…) If you want to watch the InSight landing “live” (with 4-minute speed of light time delay), go to: https://ve42.co/insight Special thanks to Patreon supporters: Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd Animations courtesy of NASA Script and Filming with Raquel Nuno Editing and graphics by Ignat Berbeci

The kilogram, mole, kelvin, and ampere will be redefined by physical constants. For a limited time, get 3 months of Audible for just $6.95 a month: http://audible.com/VERITASIUM or text VERITASIUM to 500500 Will this be the last video I make about SI units? Quite possibly. There's something about being so precise and defining the systems within which science works. When we can more accurately and routinely measure a kilogram, a mole, a kelvin and an ampere, then we can make better observations, we can better detect anomalies and improve our theories. That is why this is so important to me. Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Ron Neal, Nathan Hansen, James M Nicholson, Terrance Shepherd, Stan Presolski Special thanks to NIST: http://nist.gov Additional graphics by Ignat Berbeci Music from http://epidemicsound.com "Experimental1"

A trip to #Mars involves radiation, muscle and bone loss, intermediate axis theorem and liquids. Check out Mars on National Geographic, Monday Nov 12 at 9/8c #sponsored When I got offered the chance to fly in another #zeroG plane, I jumped at the chance. Do you know how hard it is when you are thrust into low-gravity, like the 37% of Earth's gravity of Mars, and you have to remember what you were going to say in a 30 second window as blood floods your head? It's pretty hard. It would be even harder to actually travel to Mars. It would take about 8 months in microgravity during which time your muscles and bones would weaken substantially, even if you exercise for hours a day like the astronauts on the space station. And your heart is a muscle too so it weakens as well. Before I contemplated these rates of muscle and bone loss, I thought the major challenge with a round trip journey to Mars would be the logistics of spacecraft and having enough fuel to get back. But with the weakening of the human body, it's an open question whether anyone would really want to come back. Filmed by Steve Boxall Music from Epidemic Sound: http://epidemicsound.com

This fungus lives on your scalp and may affect the genes you express. Check out Head & Shoulders research on getting rid of dandruff: https://ve42.co/HS Animation by Pindex: https://ve42.co/pindex When I started this project, I wasn't sure what caused dandruff and I also didn't think much science would go into making a shampoo like Head & Shoulders. So what I learned really surprised me: There are hundreds of scientists working on this shampoo. They run crazy-sounding experiments like hanging hair near Tokyo highways to understand how real-world environments deposit dirt on hair. They use sophisticated scientific techniques like electron microscopes, nuclear magnetic resonance and gene sequencing to study dandruff on the molecular level. In fact they sequenced the entire genome of Malassezia globosa in 2002, one year after the human genome project. Their findings are published in international refereed journals. What they have found is that the Malassezia fungi create free fatty acids as byproducts of their digestion, which for some people create irritation and lead to hyper-proliferation of skin cells, flaking, histamines, inflammatory cytokines, and blood proteins reaching the surface of the skin. These findings indicate the unhealthiness of dandruff scalp and suggest a possible remedy - controlling the metabolism of the Malassezia fungi. This is achieved using different active ingredients in different products and different parts of the world, including zinc pyrithione, selenium sulfide, and piroctone olamine. With the reduction of irritants, the scalp actually expresses different genes, producing a signature more similar to a non-dandruff baseline scalp. Music from Epidemic Sound: http://epidemicsound.com Music also by Kevin MacLeod: http://incompetech.com

Boredom makes you more creative, altruistic, introspective, and helps with autobiographical planning. This video was sponsored by LastPass: http://bit.ly/2wAsdUu I feel like this video might come across as condescending but the person I'm really talking to is myself. Despite the fact that I know how useful it can be to be bored, I still find myself trying to fill every last moment with stimulus. Boredom is unpleasant - the open, unstructured thinking that can take place can also feel pointless. But now I'm made this video to remind myself how important boredom is so hopefully I'll make more time to be bored. More resources: The boredom leads people to shock themselves study: Just Think: The challenges of the disengaged mind https://wjh-www.harvard.edu/~dtg/WILSON%20ET%20AL%202014.pdf Boredom leads people to consider their future and set goals study: Back to the future: Autobiographical planning and the functionality of mind-wandering https://www.sciencedirect.com/science/article/pii/S1053810011001978 On boredom and altruism: https://pdfs.semanticscholar.org/ca72/0f959d3c9c31187ac30b28ecfec430bc98cc.pdf Does boredom make us more creative? https://www.tandfonline.com/doi/abs/10.1080/10400419.2014.901073 Amazing filming by Raquel Nuno Music from http://epidemicsound.com "I Think I Was There" "Critical Thinking 2" "Wide Open" "Seaweed" "A Sound Foundation 1" Music also by Kevin MacLeod http://incompetech.com "Fig Leaf Rag"

Or almost any garage - it's particularly good with fixed code gates and garages. Samy proposes other weaknesses with rolling codes. This video was sponsored by LastPass: http://bit.ly/2oscAe9 I don't condone malicious hacking of gates, garages or other property. The point of this video was to discuss how it could be done using fairly basic technology like this toy that was originally intended as an instant messaging device. I learned a lot in making this video about how codes are sent and received, how they are encrypted or not encrypted. I found out how hard it is to execute in practice something which in principle doesn't seem that difficult. Special thanks to Samy! His original videos on using the IM ME to open radio frequency garages and gates can be found here: https://www.youtube.com/user/s4myk He's got a really cool channel so be sure to subscribe if you're interested in this stuff. Music from http://epidemicsound.com "Critical thinking 2" "I think I was there" "Magnified X 3" And music by Kevin MacLeod http://incompetech.com "Marty Gots a Plan"

UV at ground level is non-ionizing but it damages DNA and causes photoaging - how? Also, it turns out glass doesn't block all UV (specifically UVA passes through). This is something I learned filming with the UV camera inside. Special thanks to Dr. Hayley Golbach, @hayleysgold on twitter https://twitter.com/hayleysgold Ultraviolet light causes damage to DNA, leads to cancer and photoaging: age spots and wrinkles. I was curious about this because UV is technically non-ionizing. A photon of UV doesn't have enough energy to strip an electron off atoms or molecules. However it does have enough energy to trigger photo-chemical reactions. For example, it causes pyrimidine dimers - the unauthorized covalent bonding of adjacent thymine or cytosine bases in our DNA. If these spots are not properly repaired, they may lead to mutations and cancer. Photoaging is typically the result of degradation of collagen and elastin fibers - scaffolding that supports the skin. This leads to wrinkles and saggy-looking skin. Huge thanks to Patreon supporters: Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Yildiz Kabaran, Terrance Snow, Stan Presolski, James M Nicholson, KIMoFy Support Veritasium on Patreon: http://ve42.co/patreon Music from Epidemic Sound http://epidemicsound.com "Serene Story 2"

The nutrient content of food is declining. Is it because of soil depletion, selective breeding, or... something else? Watch my new documentary, VITAMANIA: http://ve42.co/vita I came across this story as I was making the film Vitamania. When you ask sellers of vitamins why you should take vitamin supplements even if you eat a healthy diet, they will say because our food doesn't contain all the nutrients it once did. This is supposedly due to soil depletion, cold storage, food ripening off the vine, and global transport of out-of-season foods. And to an extent this is true. Foods contain the greatest amount of nutrients if they are eaten soon after they are harvested. An unexpected source of nutrient decline is the increasing amount of carbon dioxide in the atmosphere. It causes plants to grow faster and bulk up on carbs but at the expense of other nutrients, so in percentage terms the amount of nutrients are actually declining. For now this decline is modest so supplementing with vitamin pills is probably unnecessary for most people with a healthy diet but it may be a concern in future. Thanks to Kate Pappas & Chris Kamen for writing, producing and filming this video with me Edited by Lucy McCallum Sound mix by Wayne Hyett Fact Checking by Calvin Lee and Claire Smith Thanks to the Collingwood Children’s Farm and Glenn Fitzgerald from the University of Melbourne & Agriculture Victoria Further Reading: https://www.sciencedirect.com/science/article/pii/S0889157516302113 https://www.ncbi.nlm.nih.gov/pubmed/15637215/?ncbi_mmode=std http://soils.wisc.edu/facstaff/barak/poster_gallery/minneapolis2000a/ https://www.politico.com/agenda/story/2017/09/13/food-nutrients-carbon-dioxide-000511 http://www.abc.net.au/news/2018-05-24/scientists-warning-rice-may-become-less-nutritious/9792822

Vitamins are 13 molecules essential for life that our bodies can't make themselves. Watch Vitamania here: https://ve42.co/vita Now available worldwide, except France and Germany where it will be broadcast on ARTE soon. Subscribe on the Vitamania website for updates. Use #vitamania to join the conversation on Twitter and Facebook. Vitamania is a Genepool Productions feature documentary for SBS Australia, CuriosityStream, and ARTE France. Principal production investment from Screen Australia, in association with Film Victoria.

UV cameras expose a hidden world and reveal the incompleteness of our perception The Physics Girl looks at sunscreen: https://youtu.be/GRD-xvlhGMc How to make sunscreen from scratch: https://youtu.be/lMXAY5F28L0 In summary, ultraviolet light interacts differently with matter for a number of reasons: 1. Some pigments selectively absorb UV so they may appear white in the visible but dark in the UV. The pigments usually dissipate the UV energy as heat, though the breaking of bonds can also occur. 2. Fluorescent molecules absorb UV light and re-radiate that energy as visible light. This makes them look dark in the UV but glowing under black light. 3. Ultraviolet light scatters more than visible light because the wavelength is shorter and Raleigh scattering is proportional to the reciprocal of wavelength to the power of four. Special thanks to HHMI BioInteractive for their awesome animations of melanocytes and how the melanin in melanosomes protect your DNA. To see the full video explaining how we get our skin color, check out: https://www.youtube.com/watch?v=VC0TL_lYLm8 Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Yildiz Kabaran, Terrance Snow, Stan Presolski References: Overview of main UV effects: Visualizing Rayleigh Scattering through UV Photography https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-14-00260.1 Arctic animals are photographed in the UV to increase visibility and get an accurate count: Lavigne, D. (1976). Counting Harp Seals with ultra-violet photography. Polar Record, 18(114), 269-277. doi:10.1017/S0032247400000310 Absorption spectrum of melanin: http://www.cl.cam.ac.uk/~jgd1000/melanin.html "The spectroscopy of human melanin pigmentation," by N. Kollias. In: Melanin: Its Role in Human Photoprotection, pp. 31 - 38. Valdenmar Publishing Co. (1995). "Optical properties of human sclera, and their consequences for transscleral laser applications," by A. Vogel, C. Dlugos, and R. Nuffer, Lasers in Surgery and Medicine 11(4), pp. 331 - 340 (1991). "The incidence and time-course of latanoprost-induced iridial pigmentation as a function of eye color," by P. Wistrand, J. Stjernschantz, and K. Olsson, Survey of Ophthalmology 41(S2), pp. S129 - S138 (1997). Music by Epidemic Sound: https://www.epidemicsound.com "Spring Moods 5"

An experiment on how turbulent convection in Earth's core makes a magnetic field Get a free audiobook with a free 30 day trial at http://www.audible.com/Veritasium or text Veritasium to 500-500 Huge thanks to Prof. Dan Lathrop and team: http://ve42.co/Lathrop Companion video to explain Earth's magnetic fields in more detail: https://youtu.be/lWHxmJf6U3M Australians! I'm on my way. I'll be doing live shows in Perth, Sydney and Melbourne. Details and tickets here: http://ve42.co/tour Find out more about the film Vitamania: http://ve42.co/VITA Special thanks to Brady Haran and Periodic Videos for sodium vs water footage. Original clip is here: https://www.youtube.com/watch?v=mzEOL-N2cbw Special thanks to Patreon supporters: Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Yildiz Kabaran, Terrance Snow, Stan Presolski I learned a lot in making this video and the one on my second channel with Prof. Jon Arnou. I changed a lot of my preconceptions, specifically I thought: 1. That the Earth's magnetic field was a passive thing - it shouldn't need a continuous input of energy to maintain itself (that seemed reasonable to me because the magnetic field has been around for a long time and it seems mostly stable). But as it turns out, the Earth is a giant electromagnet, and so of course those currents dissipate their energy as they encounter resistance in the liquid metal through which they flow. So the energy to continuously create these currents comes from the kinetic energy of the liquid metal flows in the Earth's outer core. 2. If it's convection, I'm thinking hot things rising, cooler things falling. But apparently the main effect driving convection is the compositional differences at the boundary with the Earth's inner core. This is because of the differential freezing at the boundary. Things like iron freeze into the inner core, while elements like sulfur do not. Hence the pockets of lighter material which then rise outwards. 3. I didn't get why the fluid motion was necessary for the generation of the magnetic field. I mean if it's a conducting liquid, it can conduct currents whether it moves or not. But the key is that the liquid metal can 'trap' magnetic fields. I imagine this like how iron channels magnetic fields. Then once these fields are channeled, they can be pulled and stretched, making more magnetic field. 4. Fluids operate very differently in rotating frames of reference. This is something I didn't intuitively grasp. But, as fluids move from the inner core outwards, those particles are moving much more slowly in the direction of rotation than the matter that has been there for a long time, which means the convection currents get deflected and form helices. Music by Kevin MacLeod http://incompetech.com Brandenburg Concerto No4

The truth, with photons. I hope I've articulated everything clearly in this video. If not, I'll clarify in comments. Thanks to everyone who appears in this video and thanks to everyone who watches this video! Veritasium is of course a combination of the latin 'veritas' meaning truth, and the common element ending 'ium'. I guess this is my version of the 'draw my life' craze that rolled through YouTube many years ago. Except I wanted to tell my story with the actual moments, the photons, the stored magnetic states. There's something about that which is so important to me (because I think the alternative involves fooling yourself) which is why I'm so fascinated by film and video. One of my inspirations for the name Veritasium came from the end of the poem Ode on a Grecian Urn by John Keats, in which he writes: "Beauty is truth, truth beauty,—that is all Ye know on earth, and all ye need to know." Special thanks to Patreon supporters: Tony Fadell, Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Yildiz Kabaran, Terrance Snow, Stan Presolski Music from http://epidemicsound.com Magnified X1 - Gunnar Johnsen Fluorescent Lights - Martin Gauffin Dissolving Patterns - Ebb & Flod Luna - Ebb & Flod Additional music by Kevin MacLeod: http://incompetech.com Sneaky Snitch

Without neutrons, harnessing nuclear energy would be impossible. Try Audible free for 30 days: http://audible.com/veritasium I have a new documentary coming out in a few months - sign up here to be notified and see a sneak preview: http://vitamaniathemovie.com Special thanks to Patreon supporters: Tony Fadell, Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Yildiz Kabaran, Terrance Snow A few years ago I made a documentary about uranium, radioactivity and radiation. I always thought of the characters in our story as the scientists and maybe the uranium nucleus itself. It was only through making the documentary that I realized the real hero of the story is the neutron. Without a neutral nuclear particle, it would be virtually impossible to release the energy from the nucleus. But with it, and the idea of a chain reaction, nuclear energy went from science fiction to reality. That is something I had not grasped as clearly before and it motivated me to make this video. Filmed by Raquel Nuno.

Will artificial intelligence weapons cause World War III? https://www.youtube.com/watch?v=qiJTq11kqdw This animated clip is from my friends at http://ve42.co/pindex2 New series! http://vrv.co/paradigms I'm not sure how alarmed to be about artificial intelligence. Personally I think it's really hard to predict when we'll create a machine that essentially has consciousness. That's because we don't know what consciousness is, how it works, what's required to create it etc. So It might be technologically around the corner or a hundred years away. What I do think is more predictable is the development of autonomous weapons that use AI to be the most effective killing machines of all time. That is scary. As outline by people like Musk and Hawking, this threat is clear and present so we should address it. I would like to see us agree as a species not to develop these sorts of weapons because if any one state does develop them, they would be very hard to stop.

Mosquitoes are attracted to me and it's likely due to my genes. This video is sponsored by 23andMe https://23andme.com/veritasium Huge thanks to Prof. Immo Hansen and team: http://ve42.co/hansen References: Genome Wide Association Study for self-reported mosquito attractiveness: http://ve42.co/MossieGWAS The twin study showing correlated attractiveness is stronger for identical twins: http://ve42.co/MossieTwins Some things we know make mosquitoes more attracted to you: Exercising, higher metabolism, higher body temperature, more body odor, being pregnant, type O blood, infrequent bathing, lactic acid, ammonia, acetone. There are a number of folk remedies people believe protect them from mosquito bites like drinking alcohol, eating garlic, or taking vitamin B. These do not appear to provide any benefit in lab studies and in fact drinking alcohol is associated with increased mosquito activity because it causes blood vessels near the surface of the skin to dilate. And apparently some of your attractiveness to mosquitos is simply genetic. This may be mediated through your immune system, which is what a lot of the genes identified were associated with. Molecular models are microSnatoms: http://snatoms.com Filming in New Mexico by Raquel Nuno Animations by Jacqui Robertson The opinions and conclusions drawn in this video are those of Veritasium and not 23andMe.

Increasing entropy is NOT the only process that's asymmetric in time. Check out the book: http://WeHaveNoIdea.com This video was co-written by Daniel Whiteson and Jorge Cham You can also check out PhD Comics: http://phdcomics.com Special thanks to Patreon supporters: Tony Fadell, Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Joshua Abenir Support Veritasium on Patreon: http://ve42.co/patreon Original paper on parity violation by the weak force by Lee and Yang: http://www.physics.utah.edu/~belz/phys5110/PhysRev.104.254.pdf More on B-meson oscillations and time reversal violation: Physics World Article: http://ve42.co/TimeReversal Original paper: https://arxiv.org/pdf/1410.1742.pdf https://en.wikipedia.org/wiki/B_meson Physics consultant: Prof. Stephen Bartlett Studio filming by Raquel Nuno

I got to drive the world's first car (replica), patented by Benz in 1886 Check out the series on new safety features: http://ve42.co/MB This video is sponsored by Mercedes-Benz, who invited me to come to Stuttgart to see their latest cars, crash test facilities and experience the innovations they are working on. Physics is something that is directly applicable to car safety. Cars go fast, but they also sometimes collide with obstacles, which brings them to a sudden stop, subjecting the car and occupants to very high accelerations, which can cause injury or death. So the major idea to improve car safety is to reduce these accelerations and there are a number of ways to do this: Passive safety: Seat belts: keep passengers in the vehicle, preventing them from continuing with constant velocity, flying through the windshield and suffering a worse deceleration when they make contact with the road. Crumple zones: increase the distance over which deceleration occurs, thereby reducing peak magnitude of deceleration. Air bags: increase the distance over which the head decelerates, again reducing peak magnitude of deceleration of the head. Active Safety: Anti-lock braking system: rather than 'locking' the wheels as can happen if you slam on the brakes with a traditional braking system leading to the tires skidding across the road, ABS attempts to control the amount of braking so that the tires always roll with static friction in contact with the road. This increases the backward frictional force that can be applied to the tires, again increasing the distance over which deceleration occurs, and it gives the driver an opportunity to steer to avoid the collision (hence why it's referred to as an active safety system). Special thanks to Mercedes for having me visit facilities in Stuttgart. I had a lot of fun making these videos so please do check out the series on Mercedes Benz's channel: http://ve42.co/MB Filmed by Simon Schneider Edited by Hoplite Creative and Trevor Carlee

These are the molecular machines inside your body that make cell division possible. Animation by Drew Berry at the Walter and Eliza Hall Institute of Medical Research. http://wehi.tv Special thanks to Patreon supporters: Joshua Abenir, Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen Support Veritasium on Patreon: http://ve42.co/patreon Every day in an adult human roughly 50-70 billion of your cells die. They may be damaged, stressed, or just plain old - this is normal, in fact it’s called programmed cell death. To make up for that loss, right now, inside your body, billions of cells are dividing, creating new cells. And cell division, also called mitosis, requires an army of tiny molecular machines.DNA is a good place to start - the double helix molecule that we always talk about. This is a scientifically accurate depiction of DNA. If you unwind the two strands you can see that each has a sugar phosphate backbone connected to the sequence of nucleic acid base pairs, known by the letters A,T,G, and C. Now the strands run in opposite directions, which is important when you go to copy DNA. Copying DNA is one of the first steps in cell division. Here the two strands of DNA are being unwound and separated by the tiny blue molecular machine called helicase. It literally spins as fast as a jet engine! The strand of DNA on the right has its complimentary strand assembled continuously but the other strand is more complicated because it runs in the opposite direction. So it must be looped out with its compliment strand assembled in reverse, section by section. At the end of this process you have two identical DNA molecules, each one a few centimeters long but just a couple nanometers wide. To prevent the DNA from becoming a tangled mess, it is wrapped around proteins called a histones, forming a nucleosome. These nucleosomes are bundled together into a fiber known as chromatin, which is further looped and coiled to form a chromosome, one of the largest molecular structures in your body. You can actually see chromosomes under a microscope in dividing cells - only then do they take on their characteristic shape. The process of dividing the cell takes around an hour in mammals. This footage is from a time lapse. You can see how the chromosomes line up on the equator of the cell. When everything is right they are pulled apart into the two new daughter cells, each one containing an identical copy of DNA. As simple as it looks, this process is incredibly complicated and requires even more fascinating molecular machines to accomplish it. Let’s look at a single chromosome. One chromosome consists of two sausage-shaped chromatids - containing the identical copies of DNA made earlier. Each chromatid is attached to microtubule fibers, which guide and help align them in the correct position. The microtubules are connected to the chromatid at the kinetochore, here colored red. The kinetochore consists of hundreds of proteins working together to achieve multiple objectives - it’s one of the most sophisticated molecular mechanisms inside your body. The kinetochore is central to the successful separation of the chromatids. It creates a dynamic connection between the chromosome and the microtubules. For a reason no one’s yet been able to figure out, the microtubules are constantly being built at one end and deconstructed at the other. While the chromosome is still getting ready, the kinetochore sends out a chemical stop signal to the rest of the cell, shown here by the red molecules, basically saying this chromosome is not yet ready to divide The kinetochore also mechanically senses tension. When the tension is just right and the position and attachment are correct all the proteins get ready, shown here by turning green. At this point the stop signal broadcasting system is not switched off. Instead it is literally carried away from the kinetochore down the microtubules by a dynein motor. This is really what it looks like. It has long ‘legs’ so it can avoid obstacles and step over the kinesins, molecular motors walking the other direction. Studio filming by Raquel Nuno

The merging of two neutron stars was detected by gravitational waves and then by telescopes in all parts of the electromagnetic spectrum. This is a historic detection as it demonstrates: - the first gravitational waves detected from inspiraling neutron stars - the first joint observation by gravitational wave and electromagnetic wave astronomy - identification of a gamma ray burst in conjunction with merging neutron stars - how gravitational waves and gamma rays can be used together to locate their source All evidence so far indicates that the data support General Relativity. Special thanks to Patreon supporters: Tony Fadell, Donal Botkin, Curational, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Corvi Support Veritasium on Patreon: http://ve42.co/patreon Graphics from: Jets and Debris from a Neutron Star Collision This animation captures phenomena observed over the course of nine days following the neutron star merger known as GW170817. They include gravitational waves (pale arcs); a near-light-speed jet that produced gamma rays (magenta); expanding debris from a "kilonova" that produced ultraviolet (violet), optical and infrared (blue-white to red) emission; and, once the jet directed toward us expanded into our view from Earth, X-rays (blue). Credit: NASA's Goddard Space Flight Center/CI Lab Virgo Helps Localize Gravitational-Wave Signals Sky localizations of gravitational-wave signals detected by LIGO beginning in 2015 (GW150914, LVT151012, GW151226, GW170104), and, more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo came online in August 2017, scientists were better able to localize the gravitational-wave signals. The background is an optical image of the Milky Way. The localizations of GW150914, LVT151012, and GW170104 wrap around the celestial sphere, so the sky map is shown with a translucent dome. Credit: LIGO/Virgo/NASA/Leo Singer (Milky Way image: Axel Mellinger) Variety of Gravitational Waves and a Chirp The signal measured by LIGO and Virgo from the neutron star merger GW170817 is compared here to previously detected binary black hole mergers. All signals are shown starting at 30 Hertz, and the progression of GW170817 is shown in real time, accompanied by its conversion to audio heard at the end of the movie. GW170817 was observable for more than 30 times longer than any previous gravitational-wave signal. Credit: LIGO/University of Oregon/Ben Farr LIGO is funded by the NSF, and operated by Caltech and MIT, which conceived of LIGO and led the Initial and Advanced LIGO projects. Financial support for the Advanced LIGO project was led by the NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council) making significant commitments and contributions to the project. More than 1,200 scientists and some 100 institutions from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration and the Australian collaboration OzGrav. Additional partners are listed at http://ligo.org/partners.php The Virgo collaboration consists of more than 280 physicists and engineers belonging to 20 different European research groups: six from Centre National de la Recherche Scientifique (CNRS) in France; eight from the Istituto Nazionale di Fisica Nucleare (INFN) in Italy; two in the Netherlands with Nikhef; the MTA Wigner RCP in Hungary; the POLGRAW group in Poland; Spain with the University of Valencia; and the European Gravitational Observatory, EGO, the laboratory hosting the Virgo detector near Pisa in Italy, funded by CNRS, INFN, and Nikhef.

How Schlieren imaging works in color, black and white and slow-mo. Get a free audiobook with a 30 day free trial at http://www.audible.com/veritasium Special thanks to Patreon supporters: Tony Fadell, Donal Botkin, Curational, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Corvi Support Veritasium on Patreon: http://ve42.co/patreon Filming by Raquel Nuno Sound Effects by A Shell in the Pit

The total solar eclipse from Madras, Oregon on August 21, 2017. As the moon passed in front of the sun turning day to night and revealing the sun's corona, apparently all I could think to say was 'Oh my goodness!' Special thanks to Patreon Supporters: Nathan Hansen, Donal Botkin, Ron Neal, Zach Mueller, Jeff Straathof, Curational, Tony Fadell Everyone says not to photograph your first solar eclipse and I think they might be right. I was focused on getting the exposure right for Bailey's beads and the diamond ring, plus making sure to get the corona and solar flares. This was a bit stressful but I'm delighted with the results. This video originally included more info but since I'm uploading from Madras where the internet is sluggish, I cut out three minutes so the upload would happen before I had to leave for my flight. Special thanks also to Dr. Teagan Wall for sharing this experience with me and Raquel Nuno for inspiring me to come to Oregon. Music from http://epidemicsound.com "Spinning Earth 2" and Kevin MacLeod http://incompetech.com "Big Mojo"

In 2018 the kg will be defined by Planck's constant, not a hunk of metal. Try a free book from Audible for 30 days http://ve42.co/audible Special thanks to the staff at NIST who made this possible: Darine Haddad, Jon Pratt, Stephan Schlamminger, and Ben Stein. Additional footage and animations by Sean Kelley, Jennifer Lauren Lee, and Frank Seifert. I have been obsessed with measurement for a long time and I'm not sure quite how it happened. The world's roundest object played a role in this. I guess I'm just fascinated by how difficult it is to pin down a quantity like a kilogram. A physical object seemed like a good idea until the mass of the international prototype kilogram wasn't as constant as expected. These methods of the Kibble balance and silicon sphere have shown better precision than 20 parts per billion, making them superior to the old method. The agreement between Avogadro approaches Special thanks to Patreon Supporters: Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen Support Veritasium on Patreon: http://ve42.co/patreon Interferometer video by TSG Physics: https://www.youtube.com/watch?v=j-u3IEgcTiQ Music from http://epidemicsound.com "ExperiMental1" by Gunnar Johnsén Studio filming by Raquel Nuno

On a stream of water you can levitate light balls of all sizes and even disks and cylinders. The mechanism is not the Bernoulli effect... Want to make this at home? https://youtu.be/BppcHF2EdAY My friend Blake from InnoVinci emailed me with a cool idea for a video and footage of levitating balls in water streams. Initially it was tough to explain the physics of what was going on. The standard Bernoulli effect relies on the object being completely immersed in the upward-flowing fluid. But in this case the water seems to form a single stream around the object and it's deflected away and down from the stream. By Newton's third law, the force on the water by the ball is equal and opposite to the force of the water back on the ball, pushing it up into the stream. There is a stable equilibrium position because if the ball moves into the stream, it "cuts off" the water going over the ball so it drifts out. If it drifts out too far, then lots of water passes over the ball, pushing it back into the stream. Special thanks to Patreon Supporters: Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen Support Veritasium on Patreon: http://ve42.co/patreon Filmed by Raquel Nuno Slow motion by Hollywood Special Ops http://hollywoodspecialops.com Music from Epidemic Sound http://epidemicsound.com "Colored Spirals 3" "Magnified X 3" "In Orbit 2" "ExperiMental 1"

This is what the world would look like if you could see invisible air currents, temperature gradients, and differences in pressure or composition of the air. Support Veritasium on Patreon: http://ve42.co/patreon Special thanks to Patreon Supporters: Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen I first saw a Schlieren imaging setup around ten years ago in Melbourne. I was immediately fascinated by the way I could see the warm air coming off my hand. I hadn't expected the currents to be moving that fast or to be so visible. This was a tricky setup to get right because alignment is very important and here I'm just working with what I had lying around the house mostly (plus the mirror). For the best Schlieren photography, making sure the mirror is stable is essential. I want to improve my setup so the mirror doesn't wobble back and forth too much creating the pulsing light and dark sections of this video. The relationship between index of refraction of air and temperature, pressure, humidity and wavelength is complicated. This website will calculate it for you: http://emtoolbox.nist.gov/Wavelength/Ciddor.asp Slow motion by Hollywood Special Ops: http://www.hollywoodspecialops.com Sound Effects by A Shell in the Pit: http://www.ashellinthepit.com Filmed by Raquel Nuno Special thanks to Blake Nichols for assistance

Grant Thompson - the King of Random - teaches me how to start a fire with a Sandwich bag. And we tried to melt glass in my backyard: https://goo.gl/zb0uE0 Check out his channel: http://ve42.co/KoR The intensity of sunlight on Earth is about 1300 Watts per square meter. When you focus the sun's rays using a magnifying glass (or in this case sphere of water) you can increase the intensity roughly ten thousand fold. This increases the temperature of wood to its autoignition point starting the reaction with oxygen in the atmosphere. By protecting the hot embers and adding more energy and fuel, you can get these hot coals to start a roaring fire. Special thanks to Patreon Supporters: Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen Support Veritasium on Patreon: http://ve42.co/patreon

Scientists have JUST published this new observation. On January 4th, 2017 they detected the merger of two black holes 3 billion light-years away. This marks the furthest detection they've been able to make and increases confidence that these events will be seen with increasing frequency as the LIGO interferometers become more sensitive to low amplitude gravitational waves (as sources of noise are eliminated). Special thanks to: Prof. Rana Adhikari Prof. David Reitze Resources by: Binary Neutron Star merger: Relastro @ ITP - Goethe University, Frankfurt https://www.youtube.com/watch?v=nOTXC4FG9gU Numerical simulation of black hole merger: S. Ossokine/A. Buonanno/T. Dietrich (MPI for Gravitational Physics)/R. Haas (NCSA)/SXS project Artist's impression of merger and chart: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet) Simulation of black hole merger: SXS Collaboration Special thanks to Patreon Supporters: Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen Support Veritasium on Patreon: http://ve42.co/patreon Sound Recording by Raquel Nuno

How do you measure big forces accurately? By calibrating your force transducer on the world's biggest weight - 1,000,000 pounds of force. This machine ensures planes don't break apart, jets provide required thrust, and rockets make it to their destination. Thanks to the people at NIST for showing me around: Rick Seifarth and Ben Stein. Animations here are by Sean Kelley and additional footage by Jennifer Lauren Lee. Special thanks to Patreon Supporters: Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen Support Veritasium on Patreon: http://ve42.co/patreon Before visiting NIST in Washington DC I had no idea machines like this existed. Surely there's an accurate way to measure forces without creating such a huge known force?! Nope. This appears to be the best way, with a stack of 20 x 50,000 lb masses creating a maximum force of 4.45 MN or 1,000,000 pounds of force. I also wouldn't have thought about all the corrections that need applying - for example buoyancy subtracts about 125 pounds from the weight of the stack. Plus the local gravitational field strength must be taken into account. And, the gravitational field varies below grade. All of this must be taken into account in order to limit uncertainty to just five parts per million (.0005%) Music from The Epidemic Sound http://epidemicsound.com "Serene Story 2"

In 2020, NASA will send a new rover to the Martian surface with one of its objectives to search for evidence of ancient life on the planet. I made this clip as a correspondent for Bill Nye Saves the World on Netflix. Touring the Jet Propulsion Lab (JPL) in Pasadena was an awesome experience. I didn't think we were going to get into the control room but we got lucky. Some of the greatest moments in the history of space exploration have taken place there. They have a giant vacuum chamber where they can take the rover down to the atmospheric pressure on Mars (roughly .01x Earth's atmosphere) and test all of the devices to make sure there are no electrical discharges due to the reduced pressure. I also enjoyed seeing how the rocks will be cored and stored in tubes and deposited on the Martian surface awaiting pickup by the following mission. Images courtesy of NASA. Filmed by Raquel Nuno from 3:30 onwards. Music: http://epidemicsound.com "Serene Story 2"

The US signed the metre convention and bases all customary units on SI standards. As an aside, the Utah constitution from 1895 required the metric system to be taught in schools. This requirement was repealed in 1987. ¯\_(ツ)_/¯ Huge thanks to NIST, Ben Stein and Patrick Abbott. https://www.nist.gov/ https://www.nist.gov/pml/weights-and-measures/si-units-mass Special thanks to Patreon Supporters: Tony Fadell, Donal Botkin, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen Back in 1875 The US signed the Metre Convention, which basically committed the country to use the metric system. In return, French scientists sent two platinum-iridium cylinders that weigh 1kg to the US in 1889 (known by their designations K4 and K20 from a set of 40 identical objects that were produced and sent around the world). So even though everything you see and buy in the US is usually reported in pounds, all weights are traceable back to the K20 kilogram (by applying a conversion factor to get to pounds). When I was in DC a few weeks ago, I visited the National Institute of Standards and Technology (NIST) and got up close with K20, which is still kept there and used to calibrate all mass standards in this country. I thought it was pretty cool. Edited by Bill Connor

In a zero-g plane I experimented with flames and slinkies with surprising results. Check out e-penser's video: http://ve42.co/EPzeroG Check out Physicsgirl's video: http://ve42.co/PGzeroG Thanks to Novespace: http://ve42.co/novespace Special thanks to Patreon Supporters: Tony Fadell, Donal Botkin, Nick Luchsinger, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen The zero-g plane allows for a lot of experiments to be conducted without the expense of getting equipment into orbit. Apparently 80% of microgravity research can be performed in a zero-gravity plane, which is much cheaper than going to space. The flame from the lighter seemed much lazier in zero-g because without weight there is no buoyant force and therefore no convection. This makes the process of combustion more challenging because it's difficult for oxygen to reach the fuel. Music from the Epidemic Sound: http://ve42.co/epidemic "Serene Story 2" "In Orbit 2"

I have the photic sneeze reflex so I sneeze when I look at bright light. Check out 23andMe: http://ve42.co/23andme *So technically the single nucleotide swap (C instead of T) is not actually in a gene per se but in an intergenic region on chromosome 2. It's also not clear exactly how this affects physiology or causes the sun sneeze but there is correlative evidence that every copy of this single nucleotide polymorphism (SNP) is associated with a 1.3x increase in likelihood of having the photic sneeze reflex. I have wanted to make a video about sun-sneezing for a long time. It is something I've experienced my whole life. When I go from a dark room indoors into full sunlight I invariably sneeze. I thought everyone did it. So my original question was why do people sneeze when they see bright light? That led me to consider what possible evolutionary advantages there could be to sneezing in sunlight. The obvious advantage to me is that sunlight kills pathogens of which there may be many in your snot or mucus. So sneezing in sunshine is a much better idea than sneezing inside a dark, damp cave where you may be living. For more info, check out: Web-Based, Participant-Driven Studies Yield Novel Genetic Associations for Common Traits http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1000993 Filmed by Raquel Nuno

The solution to 4 rotation-related riddles, including the mystery cylinder, bike pedal pulling puzzle, track problem, and train part going backwards. Thank you to everyone who responded, liked, shared, or made a video response. Please fill out this short survey for research: http://ve42.co/Rresearch Special thanks to: Mathematician George Hart: http://georgehart.com/ For allowing me to use excerpts from his pedal pulling puzzle solution: http://ve42.co/ppp Petr Lebedev for combing through thousands of comments and providing the stats I gave in this video. Video responses I used in this video (or watched): everWonder? https://www.youtube.com/watch?v=5Ub2Cuclh1M A Random Nerdy Channel https://www.youtube.com/watch?v=I9RB9TrZGps The Physics DoJo https://www.youtube.com/watch?v=Pns0LCGLu9k Oblivious Jim https://www.youtube.com/watch?v=12WZIMEPi1A Armchair Explorers https://www.youtube.com/watch?v=S1yX_LTqtms MrEngineeringGuy https://www.youtube.com/watch?v=DRF82Rx9_YI Professor Cubers https://www.youtube.com/watch?v=qOd5orH-jfM Scoop Science https://www.youtube.com/watch?v=uzLO6GqmfhI A few notes on the puzzle: 1. A half-full container of honey does pretty well in reproducing the behaviour of the mystery cylinder. I wonder if the motion is a little smoother or more periodic with the ping-pong balls because they move as organized objects - also the delays between motion seemed to be longer with them than without ping pong balls. 2. For the average speed track problem, every time I said velocity I meant speed. Sorry to the pedants out there who are perhaps looking for some trick answer due to displacement being zero when you run around a track. 3. Although a lot of people identified it was something about a train's wheels that move backwards, fewer identified that specifically it was the part of the flange below the rail. Some simply said the bottom half of the wheel. 4. The bicycle question is perhaps the most complex of these riddles. If you tried it with a bike you likely found that it went backwards. But what happens if you sit on the bike and only push backwards on the bottom pedal. The answer might surprise you so give it a shot!

Can you solve these four rotation-related riddles? Support Veritasium on Patreon: http://ve42.co/patreon Test yourself playlist: http://ve42.co/testurself Huge thanks to Patreon supporters: Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen I came across these four physics puzzles over the years in discussions with Neil deGrasse Tyson (riddle 4: which part(s) of a moving train are going backwards with respect to the ground?), Simon Pampena (riddle 2: run around a track twice, the first time slowly, the second time much faster so that the average for the two laps is twice the speed of the first lap). Someone tweeted me a video of the mystery cylinder rolling down the ramp in riddle 1 (sorry I'm not sure who it was). Riddle three about a bicycle going forward or backward when it's bottom peddle is pulled back was brought to me by a number of people and I appreciate all of their help! Filmed by Raquel Nuno. Thanks to everyone at the Palais de la Decouverte! I've had this footage for five years and am only finally releasing it now. I wanted to talk about the way grass grows on a spinning turntable but I couldn't locate the footage...

Bayes' theorem explained with examples and implications for life. Check out Audible: http://ve42.co/audible Support Veritasium on Patreon: http://ve42.co/patreon I didn't say it explicitly in the video, but in my view the Bayesian trap is interpreting events that happen repeatedly as events that happen inevitably. They may be inevitable OR they may simply be the outcome of a series of steps, which likely depend on our behaviour. Yet our expectation of a certain outcome often leads us to behave just as we always have which only ensures that outcome. To escape the Bayesian trap, we must be willing to experiment. Special thanks to Patreon supporters: Tony Fadell, Jeff Straathof, Donal Botkin, Zach Mueller, Ron Neal, Nathan Hansen, Saeed Alghamdi Useful references: The Signal and the Noise, Nate Silver The Theory That Would Not Die: How Bayes’ Rule Cracked the Enigma Code, Hunted Down Russian Submarines, and Emerged Triumphant from Two Centuries of Controversy, by Sharon Bertsch McGrayne Bayes' theorem or rule (there are many different versions of the same concept) has fascinated me for a long time due to its uses both in mathematics and statistics, and to solve real world problems. Bayesian inference has been used to crack the Enigma Code and to filter spam email. Bayes has also been used to locate the wreckage from plane crashes deep beneath the sea. Music from http://epidemicsound.com "Flourishing Views 3"

The definitive answer about the direction water swirls in two hemispheres Sync the videos yourself: http://toiletswirl.com For the record Destin and I repeated the experiment 3-4 times each in each hemisphere and got the same results every time. The idea that water going down a drain or flushed down a toilet swirls in opposite directions in the Northern and Southern Hemispheres has a long history. But few have ever done the experiment. Destin from Smarter Every Day and I performed identical experiments in the Northern and Southern hemispheres. What we found is the direction of water swirl in a toilet, sink, or bathtub is determined by other sources of angular momentum. However if the body of water is big enough, e.g. a kiddy pool, and left still for long enough (at least 24 hours), then the Coriolis effect is observable with water swirling counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere. Veritasium on Instagram: http://instagram.com/veritasium Patreon Support Link: http://www.patreon.com/veritasium Twitter: http://twitter.com/veritasium http://www.facebook.com/veritasium Smarter Every Day Instagram: http://instagram.com/smartereveryday Patreon Support Link: http://www.patreon.com/smartereveryday Twitter: http://twitter.com/smartereveryday www.facebook.com/SmarterEveryDay Gordon McGladdery did all of the sound design for the video. We used two songs from other artists (licensed of course). Derek split the first one up so it fades from video to video, and Gordon split the instruments up on the second one. There are violins on one video and percussion on the other for example. It's really neat. The neat earth animation at the beginning and the synchronizing timer was made by http://eisenfeuer.com/. He also made still images of the earth from the top and the bottom. Thanks to Vanessa for filming in Sydney: http://youtube.com/braincraftvideo MORE INFO: There was a study performed at MIT years ago (http://web.mit.edu/hml/ncfmf/09VOR.pdf) that explained the physics involved. We repeated some of these demonstrations, but on opposite sides of the globe…and in a way that can be easily understood. This site is a great resource on the Coriolis effect and ways people have gotten it wrong: http://www.ems.psu.edu/~fraser/Bad/Ba...

How the brain works, how we learn, and why we sometimes make stupid mistakes. Submit ideas: http://ve42.co/GotIdeas Apply to work with me: http://ve42.co/JoinUs Thanks to Patreon supporters: Nathan Hansen, Donal Botkin, Tony Fadell, Zach Mueller, Ron Neal Support Veritasium on Patreon: http://bit.ly/VePatreon This video was inspired by the book Thinking Fast and Slow by Daniel Kahneman Harpist: Lara Somogyi http://ve42.co/Lara Animator: Jesse Agar http://ve42.co/ThisPlace Filmed by Raquel Nuno Music by Kevin MacLeod, http://incompetech.com "Sneaky Adventure" "Harlequin"

NEW CHANNEL! http://youtube.com/sciencium For a long time we thought the Moon was completely dry, but it turns out there are actually three sources of lunar water. Thanks to Google Making and Science for supporting the new channel! http://youtube.com/makingscience Thanks to Patreon supporters: Nathan Hansen, Donal Botkin, Tony Fadell, Zach Mueller, Ron Neal Support Veritasium on Patreon: http://bit.ly/VePatreon References: Great history of water on the moon: https://arxiv.org/pdf/1205.5597.pdf Filmed by Raquel Nuno Music from http://epidemicsound.com "Serene Story 2"

Spinning magnets near copper sheets create levitation! Try Audible free for 30 days: http://bit.ly/AudibleVe Special thanks to Hyperloop One for showing me around. Thanks to Patreon supporters: Nathan Hansen, Donal Botkin, Tony Fadell, Saeed Alghamdi, Zach Mueller, Ron Neal, Perry cl, Bryan Baker Support Veritasium on Patreon: http://bit.ly/VePatreon Filmed by Raquel Nuno, Edited by Trevor Carlee Obviously this "quadcopter" is a demonstration device, showing how moving magnets over a conducting surface can generate levitation. It has not been optimized to minimize losses or be an efficient mode of transport. I still think it's pretty cool. I'm used to seeing light things levitated by induced currents but not a 100+ lb machine. For more on Hyperloop One: https://hyperloop-one.com/

We talk about all the potentially challenging situations autonomous cars could get into but not about how human drivers are not very good. Tens of thousands die on the roads every year in collisions, most of which could be prevented by autonomous vehicles. Sponsored by BMW I wanted to make a video about autonomous cars for some time but I hadn't had the opportunity. The self-driving technology is already at a state where it can save lives if only it were more widely implemented. Links to original clips: TED-Ed https://www.youtube.com/watch?v=ixIoDYVfKA0 BBC Newsnight: https://www.youtube.com/watch?v=FypPSJfCRFk Music from http://www.epidemicsound.com "Ambient Electronic Groove," "Pet Animals 2," "The Long Ride." Filmed by Raquel Nuno Edited by Trevor Carlee

A head-vaporizing laser with a perfect wavelength detecting sub-proton space-time ripples. Huge thanks to Prof Rana Adhikari and LIGO: http://ligo.org Here's how he felt when he learned about the first ever detection: https://youtu.be/ViMnGgn87dg Thanks to Patreon supporters: Nathan Hansen, Donal Botkin, Tony Fadell, Saeed Alghamdi, Zach Mueller, Ron Neal Support Veritasium on Patreon: http://bit.ly/VePatreon A lot of videos have covered the general overview of the discovery of gravitational waves, what they are, the history of the search, when they were found but I wanted to delve into the absurd science that made the detection possible. When scientists want one megawatt of laser power, it's not just for fun (though I'm sure it's that too), it's because the fluctuations in the number of photons is proportional to their square root, making more powerful beams less noisy (as a fraction of their total). The smoothest mirrors were created not for aesthetic joy but because when you're trying to measure wiggles that are a fraction the width of a proton, a rough mirror surface simply won't do. Filmed by Daniel Joseph Files Music by Kevin MacLeod, http://www.incompetech.com "Black Vortex" (appropriately named) Music licensed from Epidemic Sound http://epidemicsound.com "Observations 2" (also appropriately named)

Why we can't seem to agree on what's true when it's easier than ever to check. Videos like this are usually on 2Veritasium: http://bit.ly/2Veritasium Support Veritasium on Patreon: http://bit.ly/VePatreon This video was filmed at a meetup in Stockholm, Sweden on Dec. 9, 2016. Huge thanks to everyone who attended - I had a great time. Sorry to those of you I missed, especially Lund and Gothenburg. Thanks to Patreon supporters (but this is a non-paid post): Meshal Alshammari, Nathan Hansen, Bryan Baker, Donal Botkin, Tony Fadell, Saeed Alghamdi, Ron Neal

Used in everything from bullet-proof vests to the walls of the Pentagon, polyurea's strength comes from its long-chain molecules. Check out How Ridiculous: http://bit.ly/VeHowRidiculous Snatoms magnetic molecules: http://bit.ly/VeSnatoms Veritasium on Patreon: http://bit.ly/VePatreon Special thanks to South Bay Line-X: http://southbaylinex.com/ Thanks to Patreon supporters: Nathan Hansen, Bryan Baker, Donal Botkin, Tony Fadell, Saeed Alghamdi Filmed by Prashanth Venkataramanujam SFX by A Shell in the Pit

The crazy story of the arbitrary temperature scale used in a tiny minority of countries. Check out Audible: http://bit.ly/AudibleVe Snatoms are available again! http://www.snatoms.com Support Veritasium on Patreon: http://bit.ly/VePatreon Celsius didn't invent Celsius: http://bit.ly/VeCelsius Video animated by Marcello Ascani: http://bit.ly/VeMarcello Thanks to Patreon supporters: Nathan Hansen, Bryan Baker, Donal Botkin, Tony Fadell, Saeed Alghamdi Music by Kevin MacLeod: http://incompetech.com "Modern Piano Zeta - Improbable" "Ice Demon" "Divertimento K131" "Sneaky Adventure" "Sheep May Safely Graze" "Professor and the Plant" References: A History of the Thermometer and its uses in Meteorology by W. E. Knowles Middleton Absolute Zero and the Conquest of Cold by Tom Shachtman The Science of Measurement, A Historical Survey by Herbert Arthur Klein Lehrbuch der Chemie by Jöns Jakob Berzelius Script: As an Australian-Canadian the Fahrenheit temperature scale always seemsed a bit arbitrary. I mean why does water freeze at 32 degrees? And what exactly does zero represent? According to many sources the Fahrenheit scale was defined by setting zero degrees equal to the temperature of an ice, salt, and water mixture and 100 degrees being roughly equal to human body temperature. But that isn’t true. The real story is much more interesting, and scientific... August 14th 1701 was almost certainly the worst day in the life of fifteen year-old Daniel Gabriel Fahrenheit. On that day both of his parents died suddenly from mushroom poisoning. He was sent from Poland, where he lived, to Amsterdam to become an apprentice bookkeeper. But Fahrenheit couldn’t stand his apprenticeship and ran away so many times his employers put out a warrant for his arrest. Traveling from city to city around Europe, he became fascinated with scientific instruments and in particular thermometers. In 1708, possibly seeking help with the warrant, Fahrenheit met with the mayor of Copenhagen, who happened to be the famous astronomer Ole Romer. Romer is known for observing the eclipses of Jupiter’s moons and realizing that variations in the timing of those eclipses was caused by the time it took light to reach Earth. In other words, he found a way to accurately measure the finite speed of light. But more pertinent to this story, in 1702 Romer was housebound after breaking his leg. To pass the time he devised a new temperature scale with the freezing point of water at 7.5 degrees and body temperature at 22.5 degrees. This might seem odd until you consider that Romer wanted the boiling point of water to be 60 degrees (as an astronomer, he had experience dividing things by 60). If you take this scale, divide it in half, in half again, and in half once more, you find the freezing point of water 1/8th up the scale, and human body temperature 3/8th up the scale. So at their meeting in 1708, Fahrenheit learned of Romer’s temperature scale and adopted it as his own, adjusting it slightly because he found it “inconvenient and inelegant on account of the fractional numbers”. So he scaled them up to 8 and 24. That is the original Fahrenheit scale. He produced thermometers for some time using this scale. But then, at some later time Fahrenheit multiplied all numbers on his scale by four, setting freezing point to the now familiar 32 and body temperature to 96. It’s unclear exactly why he did this. He may just have wanted finer precision in his measurements but I think there was a better reason. You see, Fahrenheit was an excellent instrument maker. His thermometers agreed with each other precisely, at a time when that was unheard of. He pioneered the use of mercury as a measuring liquid, which has the benefit of a much higher boiling point than the alcohol used in most other thermometers at the time. For these accomplishments, he was inducted into the British Royal Society. And we know he read the works of Newton, Boyle, and Hooke, in which he would have come across the idea that a one degree increase in temperature should correspond to a specific fractional increase in the volume of the measuring liquid. And today a one degree Fahrenheit increase in temperature increases the volume of mercury by exactly one part in 10,000. Is this just a coincidence? We’ll probably never know for sure because as an instrument maker Fahrenheit was secretive about his methods. But I think the data strongly suggests this was the case. So what exactly did zero represent on the scales of Fahrenheit and Romer? By many accounts it’s the temperature of a salt, ice and water mixture. But there are different descriptions of these mixtures and none of them actually produces the temperature they’re supposed to. More likely I think they picked the coldest temperature in winter, set that as zero and later used ice and brine to calibrate new thermometers. Now his scale is only used regularly in the Cayman Islands, Bahamas, Belize, oh and the United States of America.

Silicone oil droplets provide a physical realization of pilot wave theories. Check out Smarter Every Day: http://bit.ly/VeSmarter Support Veritasium on Patreon: http://bit.ly/VePatreon Huge thanks to: Dr. Stephane Perrard, Dr Matthieu Labousse, Pr Emmanuel Fort, Pr Yves Couder and their group site http://dualwalkers.com/ Prof. John Bush: http://math.mit.edu/~bush/ Dr. Daniel Harris Prof. Stephen Bartlett Looking Glass Universe: http://bit.ly/LGUVe Workgroup Bohemian Mechanics: http://www.mathematik.uni-muenchen.de/~bohmmech/ Filmed by Raquel Nuno Thanks to Patreon supporters: Nathan Hansen, Bryan Baker, Donal Botkin, Tony Fadell, Saeed Alghamdi Thanks to Google Making and Science for helping me pursue my #sciencegoals. If you want to try this experiment, instructions are here: link.springer.com/article/10.1007/s12650-016-0383-5 The standard theory of quantum mechanics leaves a bit to be desired. As Richard Feynman put it, "I think I can safely say that no one understands quantum mechanics." This is because observations of experiments have led us to a theory that contradicts common sense. The wave function contains all the information that is knowable about a particle, yet it can only be used to calculate probabilities of where a particle will likely turn up. It can't give us an actual account of where the particle went or where it will be at some later time. Some have suggested that this theory is incomplete. Maybe something is going on beneath the radar of standard quantum theory and somehow producing the appearance of randomness and uncertainty without actually being random or uncertain. Theories of this sort are called hidden variable theories because they propose entities that aren't observable. One such theory is pilot wave theory, first proposed by de Broglie, but later developed by Bohm. The idea here is that a particle oscillates, creating a wave. It then interacts with the wave and this complex interaction determines its motion. Experiments using silicone oil droplets on a vibrating bath provide a remarkable physical realization of pilot wave theories. They give us a physical picture of what the quantum world might look like if this is what's going on - and this theory is still deterministic. The particle is never in two places at once and there is no randomness. Edited by Robert Dahlem Sound design by A Shell in the Pit

In space, metals can weld together without heat or melting. Check out Audible: http://bit.ly/AudibleVe Support Veritasium on Patreon: http://bit.ly/VePatreon Written by Joh Howes and Derek Muller Yes, it's pronounced Gemini (ee not eye) because that's the way everyone pronounced this mission. Thanks to Patreon supporters: Bryan Baker, Donal Botkin, Tony Fadell, Saeed Alghamdi References: Gemini IV transcripts: http://www.jsc.nasa.gov/history/mission_trans/gemini4.htm Gemini IV recordings: https://archive.org/details/Gemini4 (relevant clip is 1297 at about 2:00) ESA cold welding recommendations: esmat.esa.int/Publications/Published_papers/STM-279.pdf Cold welding gold nanowire: http://www.nature.com/nnano/journal/v5/n3/full/nnano.2010.4.html Music by Kevin MacLeod "Intrepid" http://www.incompetech.com

All the large-scale structure in the universe may owe its existence to nothing. Sponsored by the Dyson 360 Eye Robot #ad: http://bit.ly/2cGqBRV Support Veritasium on Patreon: http://bit.ly/VePatreon Thanks to Patreon supporters: Bryan Baker, Donal Botkin, Tony Fadell, Saeed Alghamdi Let's see how clearly I can explain this. We think of empty space as, well... empty, the epitome of nothingness. But as our understanding of physics has evolved we have realized that it's not truly empty. Space is filled with fields. There is a field for every subatomic particle. One for electrons, up quarks, down quarks, neutrinos and so on. In empty space these fields are basically zero, flat, nil. But it's impossible to make them perfectly zero so there are always some quantum fluctuations in the fields, even in a perfect vacuum. These are sometimes called virtual particles but they should really just be thought of as little disturbances in the field. Vacuum fluctuation play a role mediating the interactions of subatomic particles but they don't really have an impact on the large-scale structure of the universe, EXCEPT during inflation, right after the big bang when the universe increased in size 10^26 times. Due to this rapid expansion, those tiny fluctuations were blown up to the scale of the observable universe. And we know this by looking at the cosmic microwave background radiation where we can see slightly hotter and cooler parts of the early universe that correspond to density fluctuations. And it is these density fluctuations that allowed matter to clump together into large structures like the gigantic gas clouds that would go on to contain stars and planets. In case the video isn't clear, this is what I've been trying to say. Animations by Gustavo Rosa This video was sponsored in part by Dyson #ad

The best and worst predictions in science are both based on the same underlying physics Check out the Great Courses Plus: http://ow.ly/cePe303oKDM Support Veritasium on Patreon: http://bit.ly/VePatreon Special thanks to: Prof. Sean Carroll Prof. Brian Schmidt Prof. Stephen Bartlett Prof. Geraint Lewis More on this topic: http://wke.lt/w/s/XDkwi Patreon supporters: Bryan Baker, Donal Botkin, Tony Fadell, Jason Buster, Saeed Alghamdi, Nathan Hansen Virtual particles are a way of talking about fields and their interactions as though particles are doing all the work. This is why there is some controversy around using the term 'virtual particles'. Some people think the term is useful, especially since in calculating with Feynman diagrams you draw all the particle interactions that are possible (and then do the calculations to get the right answer). While others feel this terminology is misleading because virtual particles don't behave like real particles and can't be observed.

Mounting evidence suggests a lot of published research is false. Check out Audible: http://bit.ly/AudibleVe Support Veritasium on Patreon: http://bit.ly/VePatreon Patreon supporters: Bryan Baker, Donal Botkin, Tony Fadell, Jason Buster, Saeed Alghamdi More information on this topic: http://wke.lt/w/s/z0wmO The Preregistration Challenge: https://cos.io/prereg/ Resources used in the making of this video: Why Most Published Research Findings Are False: http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0020124 Trouble at the Lab: http://www.economist.com/news/briefing/21588057-scientists-think-science-self-correcting-alarming-degree-it-not-trouble Science isn't broken: http://fivethirtyeight.com/features/science-isnt-broken/#part1 Visual effects by Gustavo Rosa

If you repeat something enough times, it comes to feel good and true. Support Veritasium on Patreon: http://bit.ly/VePatreon Science with Hot Wheels! My vids for kids: http://bit.ly/VeHotWheels More info on cognitive ease: http://bit.ly/29OMGas This episode was inspired by the book Thinking Fast and Slow by Daniel Kahneman. This video was edited by Daniel Joseph Files, with music from Kevin MacLeod at http://incompetech.com "Marty Gots a Plan" "Sing Along With Jim" and "Full On". Veritasium is supported on Patreon by: Jason Buster, Saeed Alghamdi, Tony Fadell, Donal Botkin, Bryan Baker, & Imthetroublesolver 8)

How can you Yo-Yo without the string attached? Check out Audible: http://bit.ly/AudibleVe For more Ben Conde: http://bit.ly/VeBenConde For Beyond Slow Motion: http://bit.ly/VeBeyondSlowMo For more on yo-yos check out: http://bit.ly/290wR3a How to yo-yo without a string attached... So many crazy tricks and the science that makes it possible. Edited and animated by Daniel Joseph Files

Celsius never devised nor used the scale that now bears his name. Veritasium is now on Patreon: http://patreon.com/veritasium Special thanks to Michael Stevens of Vsauce! http://youtube.com/vsauce1 More info about Celsius and temperature scales: http://wke.lt/w/s/2I6Nu References for this video: A History of the Thermometer and its uses in Meteorology by W. E. Knowles Middleton Absolute Zero and the Conquest of Cold by Tom Shachtman The Science of Measurement, A Historical Survey by Herbert Arthur Klein Lehrbuch der Chemie by Jöns Jakob Berzelius Special Thanks to the Uppsala University Museum I filmed this in Uppsala in the summer of 2012! So I've been thinking about this idea for a very long time. I'm glad to finally have it out there in the world.

A rare look inside the Svalbard Global Seed Vault which is closed ~350 days a year Check out Audible: http://bit.ly/AudibleVe More info on the seed vault: http://wke.lt/w/s/EKFlK My trip to Norway was funded by Screen Australia, Film Victoria and Genepool Productions as part of a new project. More information soon. Special thanks to Bente Naeverdal and the Crop Trust: https://www.croptrust.org

Longyearbyen on Svalbard is the northernmost settlement with over 1000 residents My trip to Norway was funded by Screen Australia, Film Victoria and Genepool Productions as part of a new project. More information soon. More info on Svalbard: http://wke.lt/w/s/yiYNC Music licensed from www.cuesongs.com "After Catalunya" Spotify page: https://play.spotify.com/artist/2JnQ2AxkaRjlGCNmfkHiJd iTunes: https://itunes.apple.com/gb/artist/emphemetry/id414183064 Captions: Come take a walk with me around Longyearbyen, the largest town on the Norwegian islands of Svalbard. Parts of it look familiar, but make no mistake, this place is different. At 78 degrees North, it lies just 800 miles or 1300 kilometres from the North Pole. And with over 2,000 permanent inhabitants it is the Northernmost real town on Earth. There are only 50km of road, including the small streets between houses, so people get around the island mainly on snowmobile. In fact there are more registered snowmobiles than residents. Anyone leaving town is required to travel with a gun and someone who knows how to use it because the islands are also home to polar bears. The average daytime high is below freezing for all but four months of the year, and from the end of October to mid-February the sun doesn’t rise at all. This is the long polar night. Living here is tough. This past December an avalanche in town destroyed 10 homes, which used to be here, killing two people. So how did this cold, remote, ice-covered archipelago come to be inhabited? The hills around town are rich in coal deposits that have been mined for over 100 years. The coal was transported to the port via a series of aerial tramways some of which remain today, though they are no longer operational. Coal is a reminder that Svalbard was not always an Arctic ice world. 360 million years ago it was actually in the tropics North of the equator. A swampy area, it was covered with the precursors to modern ferns, which were much larger than they are today, reaching 10-30 metres in height. This vegetation was then covered in mud and sand and submerged under the sea. Over time it turned into the coal deposits that in the 20th century brought miners from Norway, Russia, and the US. Most of the coal mines have now closed and the economy is gradually shifting towards tourism, education and research. Tourists take trips on snowmobiles and dog sleds. There is a university centre in Svalbard, which offers semester courses in biology, physics and geology. And up on the side of a mountain is the Svalbard Global seed vault… but that’s a story for another time. The locals tell me that interest in the region from different nations is increasing. As the globe warms and Arctic ice shrinks, trade routes are opening up across the North. And Svalbard is strategically placed between North America, Asia and Europe. One day in the future Svalbard may no longer be as cold or remote as it once was. But for now it is a reminder of how through our ingenuity people can live in the most inhospitable of places. Shot with a DJI Phantom 4 drone

We also made a video about laser cooling! http://bit.ly/PhysGirl Check out Audible: http://bit.ly/AudibleVe Check out Beyond Slow Motion: http://bit.ly/VeBeyondSlowMo More on this topic: http://wke.lt/w/s/ef3eV Special thanks to Laser Away in Santa Monica for helping make this happen - your staff was awesome! http://bit.ly/VeLaserAway Research and filming by Raquel Nuno and Aaron White.

A story is worth a thousand data points. My second channel: http://bit.ly/2veritasium More info on this topic: http://wke.lt/w/s/TzNC0

Why do droplets of food coloring attract, repel, and chase each other? Snatoms molecular models: http://igg.me/at/snatoms More about this topic: http://wke.lt/w/s/VRjRQ Original paper on droplets: http://stanford.edu/~manup/docs/Cira_DancingDroplets.pdf Marangoni Flow: http://web.mit.edu/2.21/www/Lec-notes/Surfacetension/Lecture4.pdf Surface Energy: https://itf.fys.kuleuven.be/~joi/papers/Wetting%20and%20spreading.pdf Filming and master pipetting by Raquel Nuno Research and writing by Aaron White

What is the specious present? And how do our brains perceive time? Get a 30-day free trial on Audible: http://bit.ly/AudibleVe More info about this topic: http://wke.lt/w/s/z8TeR

Why does time appear to speed up as we get older? Can we slow it down? Thanks to the National Geographic Channel for sponsoring this video! The new season of Brain Games starts Sunday, February 14th at 9/8c - http://po.st/90S7Ow Brain Games is an Emmy-nominated TV series that explores the inner workings of the human mind through experiments and interactive games. Did you know it's estimated that you have more than a dozen senses in addition to the standard five? One of those is a sense of time or chronoception. Tune in to the new season of Brain Games to learn about all of your senses, and more, starting Sunday, February 14 at 9/8c References: Ageing and duration judgement: http://bit.ly/1TRN0cr Nerve conduction velocity slowing with age: http://bit.ly/23Wq6oE Experiments with rats suggest time perception is distributed across brain: http://bit.ly/1T6IjdO Time perception with repeated stimuli: http://bit.ly/1TRNbo5 Energy usage in brain with age: http://bit.ly/1nXliOU Time perception in moments of fear / danger: http://bit.ly/1RoK7Ps http://1.usa.gov/1TRNa3w http://bit.ly/1Q8tDvW Attention’s relation to time perception and recollection of perceived time: http://bit.ly/20odeD8 http://bit.ly/1TRNfEf

Cell biology gives clues to why we age and lobsters don't. I made another video! The future of energy: http://bit.ly/1MAiJKm Check out Breakthrough, Sundays at 9/8c on Nat Geo with GE #ad Animations are from Emmy-winning film 'Immortal', reproduced here courtesy of December Media and Genepool Productions (previously Pemberton Films) Check out Immortal here: http://bit.ly/VeImmortal Find out more about telomeres and telomerase here: http://bit.ly/WakeTelomeres Special thanks to Dr. Fiona Ginty, Principal Scientist in the Life Sciences and Molecular Diagnostics Group at GE. Her research focuses on imaging different proteins within the cell. It's both a very powerful technique and it's beautiful. Filmed by Raquel Nuno and Vasilios Sfinarolakis Aging makeup by Heather Grippaldi: http://bit.ly/1Xebikh Music by Kevin MacLeod, www.incompetech.com "Past the Edge" and "Lightless Dawn"

I've created an educational product to help people learn chemistry! You can buy it here: http://www.snatoms.com

Why is there a bright spot behind spherical objects? Be the first to find out about new projects: http://www.veritasium.com Filmed by Nathan Watkins and Raquel Nuno, animation by Meg Rosenburg. Music by Kevin MacLeod, http://www.incompetech.com 'Scissors' 'Mirage' ' Marty Gots a Plan'. Special thanks to Laura Vican for helping with the experiment. References: http://www.princeton.edu/~rvdb/images/Questar/PoissonSpot.html Why Toast Lands Jelly-side Down: Zen and the Art of Physics Demonstrations By Robert Ehrlich

Stained glass is thicker at the bottom - so is it a liquid? Earth's mantle enables plate tectonics, so is it a liquid? Check out Audible: http://bit.ly/AudibleVe Sign up for the mailing list: http://www.veritasium.com Pitch drop experiment: http://www.thetenthwatch.com Thanks to Meg Rosenburg for scripting and animation, Raquel Nuno for filming and Aaron White for script consultation.

Are all people on Earth really connected through just six steps? There's much more science in this than I initially expected. It turns out ordered networks with a small degree of randomness become small-work networks. This is why your acquaintances turn out to be more important in job searches and finding new opportunities than close friends. DON'T SEND ME AN EMAIL anymore... 1. Do not send it directly to me unless you know me. 2. Send the email to someone you have met IN PERSON and know on a first name basis AND THEY KNOW YOU. 3. Make the subject line 'Six Degrees of Veritasium' 4. Explain that you're trying to get this email to me and ask them to forward it on to me (only if they know me IRL) or someone they know who might know me. 5. If your email reaches me by Sept. 1, 2015 I will email you back and ask for your address so I can send you a postcard. Animations in this video by The Lyosacks: https://www.youtube.com/user/TheLyosacks There are some great books on this topic: Duncan Watts, Six Degrees: The Science of a Connected Age Albert-Laszlo Barabasi, Linkds: How Everything is Connected to Everything Else And here are articles I referred to: Milgram's small world experiment: http://www.uvm.edu/~pdodds/files/papers/others/1969/travers1969.pdf http://snap.stanford.edu/class/cs224w-readings/milgram67smallworld.pdf Granovetter, Strength of Weak Ties: https://sociology.stanford.edu/sites/default/files/publications/the_strength_of_weak_ties_and_exch_w-gans.pdf

I am working on some big new projects I'm excited to share with you! So this video is a little different from most of the others. The channel is an element of truth, after all, not an element of science. This is my truth. It may not be everyone's but that's ok too. Clips included were from: Chernobyl and Pripyat - drone shots from shooting Uranium Obsidian dome, California Panum Crater El Capitan The Pyramids of Giza Toronto buildings The Holocaust Memorial in Berlin Abu Simbel temple at Aswan, Egypt Sydney Harbour Milky way time-lapse from the badlands of South Australia Sunset over Warrnambool, Victoria Big Bang animation courtesy of NASA Sunrise over Bondi Water off New Caledonia Great white sharks in the Neptune Islands, South Australia Crosswalk at Town Hall Sydney EDUtubers at the YouTube EDU summit in San Francisco Concert in Sydney Jetpacking in Western Sydney Vi's triangles at Perimeter Institute, Waterloo Canada Aurora Borealis north of Fairbanks Alaska Sagrada Familia, Barcelona, Spain Hiking with MinutePhysics in Washington State Music Licensed from cuesongs.com "The Secret Tower" by Nicholas O

When evolution favours a stable ratio of traits rather than one dominant trait. Check out Audible: http://bit.ly/AudibleVe Animation by The Lyosacks: https://www.youtube.com/TheLyosacks Hosting Neil Degrasse Tyson, info and tickets: http://bit.ly/NDTandVe Aug. 22 in Sydney Aug. 23 in Canberra Special thanks to Richard Dawkins Filmed at Academia Film Olomouc with help from Martyn Marek Music by Kevin MacLeod www.incompetech.com 'Marty Gots a Plan' 'Sing Along with Jim'

What was the procedure to launch a nuclear missile? Uranium premieres: July 28 & 29 on PBS at 10pm ET/ 9pm Central France and Germany: July 31 at 10pm on ZDF/arte Norway: August 5 & 6 at 21:30 on NRK2 Australia: August 9, 16, 23 at 8:30pm on SBS Sweden: TBD Middle East: TBD For more information on other screenings go to https://www.facebook.com/uraniumtwistingthedragon www.genepoolproductions.com A big thank you to The Titan Missile Museum, Yvonne and Chuck. http://www.titanmissilemuseum.org/ Space footage courtesy of NASA

How far would a basketball with backspin go? Rotor wing experimental aircraft: https://youtu.be/Ra8y6gGotwY E-ship 1: https://youtu.be/qJ7haGqXs_E Corner kick by Kyle: https://youtu.be/YIPO3W081Hw How Ridiculous World Record Basket: https://youtu.be/H9SF2YIKRY8

The Salton Sea is the largest body of water in California, home to the second most diverse group of birds in America and it exists by accident. Another great video on the Salton Sea: https://youtu.be/otIU6Py4K_A I used archive from this video. Music by Kevin MacLeod, www.incompetech.com ‘Mirage’, ‘Hyperfun’, ‘Marty Gots a Plan’, ‘Past the Edge’

This is what a nuclear disaster area looks like. Check out Audible: http://bit.ly/AudibleVe Broadcast locations and times: North America: PBS, July 28 & 29 @ 10pm ET / 9pm Central Europe: ZDF/arte, July 31 @ 10pm Australia: SBS, August 6, 13, 20 @ 8:30pm EST Not broadcast in your country? Contact your local broadcaster and/or email www.genepoolproductions.com Music by Kevin Macleod http://incompetech.com 'Come Play With Me' & 'Lost Frontier'

Uranium is a unique element, used in research, medicine, space travel, and of course weapons. Not broadcast in your country? Contact your local broadcaster and/or email www.genepoolproductions.com Documentary Dates: US: PBS, July 28 & 29 @ 10pm ET / 9pm Central France & Germany: ZDF/arte July 31 @ 10pm Australia: SBS, August 6, 13, 20 @ 8:30pm EST If you're wondering where the title comes from... “A number of ingenious experiments were devised to test the speed of the fission reaction, and the limit was pushed. But even so, I thought it would be very nice to go one step nearer to a real atomic explosion. Dick Feynman, who was present, started to chuckle and to say that this is just like tickling the tail of a sleeping dragon.” Professor Otto R Frisch, January 1969 Physicist, the Manhattan Project.

SYNCHRONIZE WITH DESTIN’S VIDEO: http://bit.ly/NorthernSwirl Both videos on one page (for desktop): http://bit.ly/ToiletSwirl Subscribe to Smarter Every Day: http://bit.ly/SubscribeSED Click to tweet: http://bit.ly/ToiletSwirlTWT Some notes: We each repeated the experiment 3 times, and got the same results every time. For those of you who might be skeptical, great! A right circular prismatic kiddie pool is only $10 and you can do the experiment for yourself at your latitude. There's really no reason you shouldn't do it for yourself. Veritasium on Instagram: http://instagram.com/veritasium Patreon Support Link: http://www.patreon.com/veritasium Twitter: http://twitter.com/veritasium http://www.facebook.com/veritasium Smarter Every Day Instagram: http://instagram.com/smartereveryday Patreon Support Link: http://www.patreon.com/smartereveryday Twitter: http://twitter.com/smartereveryday www.facebook.com/SmarterEveryDay Gordon McGladdery did all of the sound design for the video. We used two songs from other artists (licensed of course). Derek split the first one up so it fades from video to video, and Gordon split the instruments up on the second one. There are violins on one video and percussion on the other for example. It's really neat. The neat earth animation at the beginning and the synchronizing timer was made by http://eisenfeuer.com/. He also made still images of the earth from the top and the bottom. Thanks to Vanessa for filming in Sydney: http://youtube.com/braincraftvideo MORE INFO: There was a study performed at MIT years ago (http://web.mit.edu/hml/ncfmf/09VOR.pdf) that explained the physics involved. We repeated some of these demonstrations, but on opposite sides of the globe…and in a way that can be easily understood. This site is a great resource on the Coriolis effect and ways people have gotten it wrong: http://www.ems.psu.edu/~fraser/Bad/Ba...

Why do spikes form on ice cubes? Without them the world would be vastly different. Awesome Jingle by Accent: http://bit.ly/AccentVe Thanks to Prof. Stephen Morris from UofT: http://bit.ly/1GFANBE Filmed in part by Martin Marek in Olomouc, Czech Republic Time lapse of a growing ice spike by Lesley Hill, Russ Sampson and Edward Lozowski, with technical help by Kenny Lozowski. Ice spike image by Dan and Lynn Wolaver: http://wolaver.org/log/09.11.29.htm Concerned ice spike video by rocknut420: https://www.youtube.com/watch?v=GwM0we_t94c Earth footage courtesy of NASA: https://www.youtube.com/watch?v=G4BPOEmugtM Ice vase image by PgunnG: http://www.reddit.com/r/pics/comments/1voeqk/so_i_walked_outside_this_morning_and_found_this/ Second ice vase image by A K Haart: http://akhaart.blogspot.com/2015_01_01_archive.html

Watch this first! https://www.youtube.com/watch?v=QD3hbVG1yxM Follow on Twitter: https://twitter.com/veritasium Follow on Facebook: https://www.facebook.com/veritasium Special thanks to the Department of Earth, Planetary and Space Sciences, especially Gary for helping source the equipment and Raquel for filming.

Learned helplessness can prevent people from achieving their goals, something I've experienced first hand. Check out Audible: http://bit.ly/AudibleVe More walk and talk videos: http://bit.ly/2Veritasium

This is the solution to: http://youtu.be/QD3hbVG1yxM Watch this first!

Acrylic Ball: http://bit.ly/BBBacrylic Ping-Pong Ball: http://bit.ly/BBBpingpong Balanced: http://bit.ly/BBBbalanced This problem has made the rounds on the internet but I felt it deserved a treatment like this. Special thanks to Gary and the Department of Earth, Planetary and Space Sciences at UCLA, to the students for participating, to Ivy for helping me coordinate everything and to Raquel for filming. Music by Kevin MacLeod, http://incompetech.com "Monkeys, Spinning Monkeys"

Do we need more diversity in online video? NOTE: the free one-year membership offer has now expired. You can receive a free month trial at: http://vessel.com/science Watch the MinutePhysics announcement: http://bit.ly/1GbKtTi Thanks to Whole Foods UCLA for allowing us to film their potatoes and Zach T for filming.

New research shows chameleons actively tune nano-crystals to change their color. For a 10-day free trial, check out http://lynda.com/veritasium Chameleon research in Nature Communications: http://bit.ly/1FacHO2 "Photonic Crystals Cause Active Colour Change in Chameleons" This research was carried out by Jérémie Teyssier, Suzanne V. Saenko, Dirk van der Marel & Michel C. Milinkovitch at the University of Geneva Department of Quantum Matter Physics and the Laboratory of Artificial and Natural Evolution (LANE) Original videos of chameleons are here: https://www.youtube.com/watch?v=YIRiCwHlUd8 https://www.youtube.com/watch?v=XdQvtP8EKrM https://www.youtube.com/watch?v=YSH7EmXFMac https://www.youtube.com/watch?v=egwueh6wj1E Additional details available at: http://www.lanevol.org/LANE/chameleon_colour_change.html For correspondence: Michel C. Milinkovitch, Laboratory of Artificial & Natural Evolution (LANE), Dept. of Genetics & Evolution, University of Geneva, Switzerland. The melanin spreading out video is courtesy of Richard Wheeler: https://www.youtube.com/watch?v=hL0USeWjTHQ http://www.richardwheeler.net Special thanks to: Harry, Jo, Daniella and Raquel for helping me produce and film this video - it looks great thanks to you!

Students at UCF are designing an inexpensive 3D printed arm for kids. To find out more and to get involved, check out: http://office.tumblr.com Big thanks to Microsoft and the Collective Project for introducing me to Albert and his amazing team. They are continuing to help people around the world one hand at a time and they could use your help. Learn more and see how you can get involved by checking out The Collective Project on Tumblr, follow @MSONeNote on Twitter or head over to http://Onenote.com/collectiveproject

What it's like to see the Earth from orbit. Special thanks to Col. Chris Hadfield for chatting with me. http://chrishadfield.ca/ Space imagery courtesy of NASA and the ESA http://eol.jsc.nasa.gov/ http://www.esa.int/spaceinvideos/Videos Music by Kevin MacLeod "New Frontier" http://incompetech.com And "Eureka" by Huma-Huma

Inspired by this article by Prof. Emily Oster: http://bit.ly/Cellcancer Check out Audible: http://bit.ly/AudibleVe Featuring Physics Girl: http://bit.ly/PhysGirl Special thanks to Chris Gale and Physics Girl for filming this video. Music by: Amarante Music "One Last Time": http://bit.ly/VeAmarante Kevin McLeod, Incompetech.com "Harlequin"

Does quantum entanglement make faster-than-light communication possible? What is NOT random? http://bit.ly/NOTrandoVe First, I know this video is not easy to understand. Thank you for taking the time to attempt to understand it. I've been working on this for over six months over which time my understanding has improved. Quantum entanglement and spooky action at a distance are still debated by professors of quantum physics (I know because I discussed this topic with two of them). Does hidden information (called hidden variables by physicists) exist? If it does, the experiment violating Bell inequalities indicates that hidden variables must update faster than light - they would be considered 'non-local'. On the other hand if you don't consider the spins before you make the measurement then you could simply say hidden variables don't exist and whenever you measure spins in the same direction you always get opposite results, which makes sense since angular momentum must be conserved in the universe. Everyone agrees that quantum entanglement does not allow information to be transmitted faster that light. There is no action either detector operator could take to signal the other one - regardless of the choice of measurement direction, the measured spins are random with 50/50 probability of up/down. Special thanks to: Prof. Stephen Bartlett, University of Sydney: http://bit.ly/1xSosoJ Prof. John Preskill, Caltech: http://bit.ly/1y8mJut Looking Glass Universe: http://bit.ly/17zZH7l Physics Girl: http://bit.ly/PhysGirl MinutePhysics: http://bit.ly/MinPhys Community Channel: http://bit.ly/CommChannel Nigel, Helen, Luke, and Simon for comments on earlier drafts of this video. Filmed in part by Scott Lewis: http://google.com/+scottlewis Music by Amarante "One Last Time": http://bit.ly/VeAmarante

How much would it take for you to risk $10? Check out Audible: http://bit.ly/AudibleVe Can you solve this? http://bit.ly/248Ve Regression to the mean: http://bit.ly/VeRTTM Help translate Veritasium videos into other languages: http://veritasium.subtitl.us Psychological literature shows that we are more sensitive to small losses and than small gains, with most people valuing a loss around 1.5-2.5 times as much as a gain. This means that we often turn down reasonable opportunities for fear of the loss. However over the course of our lives we will be exposed to many risks and opportunities and this invariably means that taking every small reasonable bet will leave us better off than saying no to all of them. NOTE: The video is not saying to accept every bet, only those with reasonable odds (preferably in your favour), and those which if you lose would not cause significant financial or other damage. In those cases it is wise to be loss averse! Filmed by Adrian Tan Thanks to Physics Girl for suggestions on previous versions of this video. https://www.youtube.com/physicswoman

Who on Earth is exposed to the most ionizing radiation? Check out Audible: http://bit.ly/AudibleVe I'm filming a documentary for TV about how Uranium and radioactivity have shaped the modern world. It will be broadcast in mid-2015, details to come. The filming took me to the most radioactive places on Earth (and some places, which surprisingly aren't as radioactive as you'd think). Chernobyl and Fukushima were incredible to see as they present post-apocalyptic landscapes. I also visited nuclear power plants, research reactors, Marie Curie's institute, Einstein's apartment, nuclear medicine areas of hospitals, uranium mines, nuclear bomb sites, and interviewed numerous experts. Notes about measuring radiation: Sieverts are a measure of 'effective dose' - that means they measure the biological impact of the energy transferred to tissues from radiation. Obviously I owe a debt to the fantastic chart made by xkcd, which inspired my visual approach to this video. https://xkcd.com/radiation/ DOSES MAY VARY The level of radiation varies widely around the world depending mainly on altitude and geology (excluding nuclear accidents). Estimates of particular doses also vary. All numbers reported in this video should be taken as order of magnitude only. The most contentious claim may be that smokers receive the highest dose of ionizing radiation. This is not a whole body dose, but a dose to the lungs as specified in the video. References are here: http://en.wikipedia.org/wiki/Health_effects_of_tobacco http://www.rmeswi.com/36.html Special thanks to: Physics Girl: https://www.youtube.com/physicswoman MinutePhysics: https://www.youtube.com/minutephysics Natalie Tran: https://www.youtube.com/communitychannel Bionerd23: https://www.youtube.com/bionerd23 Nigel and Helen for feedback on earlier drafts of this video. Music is "Stale Mate"

Many technologies have promised to revolutionize education, but so far none has. With that in mind, what could revolutionize education? These ideas have been percolating since I wrote my PhD in physics education: http://www.physics.usyd.edu.au/super/theses/PhD(Muller).pdf I have also discussed this topic with CGP Grey, whose view of the future of education differs significantly from mine: https://www.youtube.com/watch?v=7vsCAM17O-M I think it is instructive that each new technology has appeared to be so transformative. You can imagine, for example, that motion pictures must have seemed like a revolutionary learning technology. After all they did revolutionize entertainment, yet failed to make significant inroads into the classroom. TV and video seem like a cheaper, scaled back film, but they too failed to live up to expectations. Now there is a glut of information and video on the internet so should we expect it to revolutionize education? My view is that it won't, for two reasons: 1. Technology is not inherently superior, animations over static graphics, videoed presentations over live lectures etc. and 2. Learning is inherently a social activity, motivated and encouraged by interactions with others. Filmed and edited by Pierce Cook Supported by Screen Australia's Skip Ahead program. Music By Kevin MacLeod, www.incompetech.com "The Builder" and by Amarante Music: http://www.amarantemusic.com

Key aspects of pyramid construction from quarry to completion. Check out Audible: http://bit.ly/AudibleVe Live show in Alabama: http://bit.ly/VeRAOI The most common misconception about the pyramids is that they were built by slaves. Recent archeological evidence suggests they were instead constructed by paid workers. Some may have performed this work as a form of tax payment for several months of the year. Skilled engineers would have planned and orchestrated the building. An estimated 10,000-20,000 people would have been working on a pyramid at any one point in time. They were well fed and provided with shelter near the pyramids. Plus their burial sites close by indicate they were respected and were not slaves. Much of the limestone was quarried from the Giza plateau itself, meaning the stones did not need to be transported far. The granite casing of Menkaure's pyramid, on the other hand, was transported from Aswan, around 600 miles, or 1000 km up the Nile. Editing assistance by Dustin Chow Music by Kevin MacLeod, Incompetech.com "Desert City" and "Ibn Al-Noor"

The physics behind Kelvin's Thunderstorm explained. No, it is not a practical way of generating electricity, which is why we use turbines at hydro stations. This video goes into more detail about the phenomenon demonstrated in this Hunger Games collab video: http://youtu.be/Rwa26CXG1fc

Panem finds power in the radiance of the sun, and the water which rains down upon us! District 5’s Chief Energy Researcher Derek Muller takes CapitolTV on a tour of our nation's cutting edge renewable technologies, and demonstrates one of the largest ‘Kelvin’s Thunderstorm’ experiments ever built to date… all for a brighter and more efficient Panem. Sanctioned by the Capitol Ministry of Information, DISTRICT VOICES was made with friends from Google - http://artcopycode.com/campaign/lionsgate For more of Panem’s finest programming, and to register for updates, visit http://CapitolTV.pn #CapitolTV - #DistrictVoices The Hunger Games: Mockingjay Part 1 – In theaters November 21 http://TheHungerGamesExplorer.com #Mockingjay

Learn how you can help reduce global warming → https://globalwarmingeffect.org Common misconceptions about climate change. Check out Audible: http://bit.ly/AudibleVe References below: For CO2, sea levels, Arctic sea ice, Antarctic and Greenland land ice: http://climate.nasa.gov Satellite data shows that ground-based stations underestimate recent warming: Cowtan and Way, 2014 http://onlinelibrary.wiley.com/doi/10.1002/qj.2297/full For papers published on climate change during the 1970's, see Peterson, 2008 http://ams.confex.com/ams/pdfpapers/131047.pdf For solar and temperature data see NASA GISS, PMOD: http://www.acrim.com/tsi%20monitoring.htm Krivova et al. 2007: http://www2.mps.mpg.de/projects/sun-climate/data.html CO2 ratio of Carbon-13:Carbon-12 decreasing. IPCC AR4: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-3.html CO2 emitted by volcanoes vs by humans: Gerlach, 2011 www.agu.org/pubs/pdf/2011eo240001.pdf Gerlach Mauna Loa CO2 data: http://www.esrl.noaa.gov/gmd/ccgg/trends/ Rising atmospheric water vapour: Santer, 2007 http://www.pnas.org/cgi/reprint/0702872104v1.pdf A doubling of CO2 will likely lead to a 3C increase in global temperatures according to many independent pieces of evidence: Knutti & Hegerl, 2008 http://www.iac.ethz.ch/people/knuttir/papers/knutti08natgeo.pdf Great resource on Milankovitch cycles: http://www.sciencecourseware.org/eec/GlobalWarming/Tutorials/Milankovitch/ CO2 lags temperature rise in the southern hemisphere but leads the global average temperature rise, Shakun et al. 2012 http://www.nature.com/nature/journal/v484/n7392/abs/nature10915.html Music by Kevin McLeod, http://incompetech.com Songs: Hidden Agenda, Sneaky Snitch, Harlequin

Have your voice heard at the UN Climate Summit in NYC, September 23: http://bit.ly/WhyNotVe Interview filming by Chris Cassella: http://bit.ly/ScienceAlertVe

Explanations for http://youtu.be/1Xp_imnO6WE Follow me on twitter: http://bit.ly/VeTwitter or Instagram: http://bit.ly/VeInsta or Facebook: http://bit.ly/FBVeritasium For more on deflecting polar streams with electric fields, see: http://pubs.acs.org/doi/abs/10.1021/ed077p1520 I'm in Hobart for a live show on Friday at UTAS followed by gigs in Sydney and Canberra next weekend.

Five cool physics tricks, but how do they work? Explanations: http://youtu.be/jIMihpDmBpY Check out Audible.com: http://bit.ly/AudibleVe Leave your ideas in the comments below or subscribe for the answers next week. Chris Hadfield in AUS: http://sciencealert.com.au/spaceoddity/ All tickets now sold out. The Cane Balance: Slide your fingers in from the ends of a horizontal cane to find its centre of mass. Shot and Edited by Pierce Cook at the YouTube Space LA. Music by Amarante: http://bit.ly/VeAmarante

Is the future of the universe already determined? Vsauce tackles "What is Random?": https://youtu.be/9rIy0xY99a0 Special Thanks to: Prof Stephen Bartlett, Prof Phil Moriarty, Prof Andrea Morello, Prof Tim Bedding, Prof Michio Kaku, A/Prof Alex Argyros, Henry Reich, Vanessa Hill, Dianna Cowern, George Ruiz and Mystery Cat. Views expressed in this video are not necessarily those of the amazing experts listed above but their advice was invaluable in making this video. Quantum simulation by PhET: https://phet.colorado.edu/en/simulation/quantum-tunneling Music by Jake Chudnow: https://soundcloud.com/jakechudnow Amarante Music: https://soundcloud.com/amarantemusic DNA animations by http://www.wehi.tv Space animations by NASA Topic inspired by The Information - a history, a theory, a flood by James Gleick Filmed on location at the University of Sydney, Washington DC and LA

How much information is there in Spanish vs English, you vs the world? Check out Audible: http://bit.ly/AudibleVe Huge thanks to all the amazing people who made this possible: Christina Ochoa - Spanish https://twitter.com/christina_ochoa Vanessa Hill - Filming https://www.youtube.com/braincraftvideo Henry Reich - Filming, cameo http://youtube.com/minutephysics Cara Santa Maria - Set design http://carasantamaria.com Michael Stevens - cameo http://youtube.com/vsauce Crystal Dilworth - consultation https://twitter.com/PolycrystalhD Thanks also to MinutePhysics for wardrobe and lending the use of the amazing "Things to do when it's really cold outside" video: https://www.youtube.com/watch?v=j3Gs6tyiNX4 More on this theme to come in the main collaboration with Vsauce.

Epigenetics means women have different active x-chromosomes in different cells. Animation courtesy of http://wehi.tv Music by Amarante: http://bit.ly/VeAmarante Animation: Etsuko Uno Art and Technical Direction: Drew Berry Sound Design: Francois Tetaz & Emma Bortignon Scientific Consultation: Marnie Blewitt Courtesy of Walter and Eliza Hall Institute of Medical Research: http://wehi.tv When a female embryo is four days old it consists of just 100 cells. At this point the x-chromosome from Mom and the one from Dad are both active. But in order for proper development to occur, one of the x chromosomes must be switched off. Through a tiny molecular battle within each cell, one of the x-chromosomes wins and remains active while the loser is deactivated. This is done by wrapping the DNA tighter around proteins, modifying histone tails, and DNA methylation - molecular markers to indicate this DNA should not be read. What's surprising is that it's pretty random which x chromosome wins - sometimes it's Mom's and sometimes it's Dad's. So when a female is just 100 cells big, her cells have a mix of active x-chromosomes, some from Mom and some from Dad.

Can we see things travelling faster than light? Check out Audible: http://bit.ly/AudibleVe Music by Amarante "One Last Thing" http://bit.ly/VeAmarante Awesome animations by http://youtube.com/minutephysics Thanks to Prof. Geraint Lewis for input on earlier drafts of this video. The expanding universe is a complicated place. During inflation the universe expanded faster than light, but that's something that actually happens all the time, it's happening right now. This doesn't violate Einstein's theory of relativity since nothing is moving through space faster than light, it's just that space itself is expanding such that far away objects are receding rapidly from each other. Common sense would dictate that objects moving away from us faster than light should be invisible, but they aren't. This is because light can travel from regions of space which are superluminal relative to us into regions that are subluminal. So our observable universe is bigger than our Hubble sphere - it's limited by the particle horizon, the distance light could travel to us since the beginning of time as we know it.

Can you predict what happens to the golf ball? Stays where it is: http://bit.ly/buoyStay Goes down: http://bit.ly/buoyGoDown Goes up: http://bit.ly/buoyGoUp In this experiment we see that a golf ball is denser than detergent (it is also denser than pure water incidentally, which is why water hazards are so effective at ruining a golfer's day on the course). But, a golf ball is less dense than a saturated salt solution. Now the question is: if you pour the detergent on top of the golf ball in the salt solution, what will happen to the golf ball? Special thanks to Duane Merrell for the idea, which I saw demonstrated at BYU back in February. Thanks to Emil Malmsten for excellent filming, and his Stockholm colleagues who were game to have a chat to me about this experiment.

Standing waves of fire! Check out Audible: http://bit.ly/AudibleVe Fysikshow: http://bit.ly/Fysikshow - I'm hosting Michio Kaku in Melbourne ONLY: http://bit.ly/VeKakuTickets Rubens' Tube is an awesome demo and here we take it to the next level with a two-dimensional 'Pyro Board'. This shows unique standing wave patters of sound in the box. The pressure variations due to the sound waves affect the flow rate of flammable gas from the holes in the Pyro Board and therefore affect the height and colour of flames. This is interesting for visualizing standing wave patterns and simply awesome to watch when put to music. Thank you to Sune Nielsen and everyone at Aarhus for sharing this demonstration with me! And thanks for having me at your conference. Music by Kevin MacLeod, www.Incompetech.com "Ice Flow"

A forest is like a meadow on useless stilts. Most amazing thing about trees: http://bit.ly/TFilQ8 Meetup in Stockholm Sunday, Apr 6 Cafe String We often imagine that unregulated competition produces optimal outcomes, behaviours, efficiencies, but trees and baggage carousels are two examples where the stable solution is worse for everyone than another strategy. This I find surprising and interesting - that evolution doesn't come to the best solution, it comes to the most stable one. The Forest of Friendship was a concept I first came across in Richard Dawkin's book "The Greatest Show on Earth." One point I'd like to clarify is that being taller comes with a cost - having a longer trunk requires costly expenditure of energy. However, in a forest of uniformly short trees, being a little taller conveys an advantage. That is until all the other trees catch up, at which time the extra height no longer provides a benefit. So over time as the whole forest rises up the conditions are getting worse for each tree, but they are powerless to stop the evolutionary arms race. Huge thank you to Brady Haran for filming (and summarizing the main points at the end of the film). He is the amazing creator of: Numberphile: http://youtube.com/numberphile Sixty Symbols http://youtube.com/sixtysymbols Periodic Videos http://youtube.com/periodicvideos And many more...

Baby photos of our universe show huge early growth spurt! Check out Audible: http://bit.ly/AudibleVe Regression to the Mean: http://bit.ly/1lgZQAQ Some clarifications: - The lengthening of wavelengths is not strictly due to stretching by the expanding universe but by the way the photons were emitted and absorbed in different frames of reference. - The effects of gravitational waves have been observed in the decaying orbital periods of some binary star systems, however detectors built to measure gravitational waves stretching and squeezing matter on Earth have not as yet detected them. - In the video I sometimes use the term Big Bang to refer to the beginning of time as we know it. The Big Bang actually refers to the whole process from the formation of our universe, through inflation, to the expanding mass of plasma in the early universe (not just the first instant). - Quantum gravity is by no means established by this observation but it is suggestive that General Relativity and Quantum Mechanics are working together here. Thank you to Professor Geraint Lewis and Henry Reich for comments on earlier drafts of this video (even if I haven't accepted all of your corrections).

It's a little shaky but if you average out the oscillations I think the result is clear. Again, huge thank you's to A/Prof Emeritus Rod Cross, Helen Georgiou, Alex Yeung, and Chris Stewart, Tom Gordon, the University of Sydney Mechanical Engineering shop, Duncan and co. Ralph and the School of Physics.

Explanation of gyro precession: http://bit.ly/U4e8HQ More: http://bit.ly/GyroMORE Less Than: http://bit.ly/GyroLESS Equal To: http://bit.ly/GyroEQUAL Huge thanks to A/Prof Emeritus Rod Cross, Helen Georgiou for filming, Alex Yeung, and Chris Stewart, the University of Sydney Mechanical Engineering shop, Duncan and co. Ralph and the School of Physics. In this video I attempt to lift a 19kg (42 lbs) wheel over my head one-handed while it's spinning at a few thousand RPM. This replicates an earlier experiment by Professor Eric Laithwaite. He claimed the wheel was 'light as a feather' and could not be explained by Newton's Laws. I wanted to find out for myself what I really felt like. Music By Kevin MacLeod www.Incompetech.com "Tempting Secrets"

Can you figure out the rule? Did you see the exponents pattern? http://youtu.be/AVB8vRC6HIY Why do you make people look stupid? http://bit.ly/12Fmlpl How do you investigate hypotheses? Do you seek to confirm your theory - looking for white swans? Or do you try to find black swans? I was startled at how hard it was for people to investigate number sets that didn't follow their hypotheses, even when their method wasn't getting them anywhere. In the video I say "when people came to Australia..." by which I meant, "when Europeans who believed all swans were white came to Australia..." I did not mean any offence to Indigenous Australians who were already in Australia at that time. Please accept my apologies for the poor phrasing if you were offended by it. This video was inspired by The Black Swan by Nassim Taleb and filmed by my mum. Thanks mum! Partly my motivation came from responses to my Facebook videos - social media marketers saying 'Facebook ads have worked for me so there can't be fake likes.' Just because you have only seen white swans, doesn't mean there are no black ones. And in fact marketers are only looking for white swans. They think it was invalid of me to make the fake Virtual Cat page: 'well of course if it's a low quality page you're going to get low quality likes.' But my point is this is black swan bait, something they would never make because their theory is confident in the exclusive existence of white swans.

*Watch with headphones on! Is 45 minutes really the longest anyone can stay in a perfectly silent, pitch-black room? Support Veritasium on Patreon http://bit.ly/VePatreon Check out Audible: http://bit.ly/AudibleVe Want to watch the whole hour of silence? http://youtu.be/jr1UMFC9DV0 Many stories have circulated claiming the longest anyone has stayed in an ultra-quiet anechoic chamber is 45 minutes, the reason being any longer would drive you insane. To me this sounded like unsubstantiated rubbish, like the claim the Great Wall is the only manmade structure visible from space. So I put my own psyche on the line, subjecting myself to over an hour of the most intense quiet on Earth. No, this was not THE quietest room on Earth (-9dB) but it is one of the quietest, and the truth is once you put a person inside, they are by far the loudest thing in there so the sound rating of the room is irrelevant. I was not surprised to find that I could stay in there for as long as I liked and feel perfectly fine. What was surprising is that my heartbeat was audible. You can hear it on the sound recording. Now I wasn't consciously aware of the sound of my heart while in the room, but I was more aware of the feeling of it beating. Huge thank you to everyone at BYU: Duane Merrell, Spencer Perry, Cameron Vongsawad, Jazz Myers, Ann Clawson, and Robert Willes.

Evidence Facebook's revenue is based on fake likes. My first vid on the problem with Facebook: http://bit.ly/1dXudqY I know first-hand that Facebook's advertising model is deeply flawed. When I paid to promote my page I gained 80,000 followers in developing countries who didn't care about Veritasium (but I wasn't aware of this at the time). They drove my reach and engagement numbers down, basically rendering the page useless. I am not the only one who has experienced this. Rory Cellan-Jones had the same luck with Virtual Bagel: http://www.bbc.co.uk/news/technology-18819338 The US Department of State spent $630,000 to acquire 2 million page likes and then realized only 2% were engaged. http://wapo.st/1glcyZo I thought I would demonstrate that the same thing is still happening now by creating Virtual Cat (http://www.facebook.com/MyVirtualCat). I was surprised to discover something worse - false likes are coming from everywhere, including Canada, the US, the UK, and Australia. So even those carefully targeting their campaigns are likely being duped into spending real money on fake followers. Then when they try to reach their followers they have to pay again. And it's possible to be a victim of fake likes without even advertising. Pages that end up on Facebook's "International Suggested Pages" are also easy targets for click-farms seeking to diversify their likes. http://tnw.co/NsflrC Thanks to Henry, Grey, and Nessy for feedback on earlier drafts of this video.

Physics of contraptions meant to go faster than light. Audible: http://bit.ly/AudibleVe My video about the problem with Facebook: http://bit.ly/PwFB Special thanks to MinutePhysics for visual effects and Prof. Geraint Lewis for revisions to earlier drafts of this video.

Veritasium second channel: http://bit.ly/2Veritasium Rodney Fox Shark Attack Story: http://bit.ly/1frAwlI Check out Audible: http://bit.ly/AudibleVe For this video I went off the coast of South Australia to an island frequented by great white sharks. Here they hunt seals and fish. I've never been scuba diving before but I got into a cage and filmed the sharks under water. It was an incredible experience. Then we came back on the surface to tag the sharks.

SEE THE SETUP FIRST: http://bit.ly/bulletblock Click here for the explanation: http://bit.ly/1dHPk2K Spinning Tube: http://bit.ly/Va43Z6 Spinning Disk: http://bit.ly/14MSKsT Chain Drop: http://bit.ly/1713VQO Spool: http://bit.ly/14wkxfn Special Thanks to: Henry (MinutePhysics): http://www.youtube.com/minutephysics Destin (Smarter Every Day): http://www.youtube.com/smartereveryday Greg and Mitch (ASAP Science): http://youtube.com/asapscience Elise Andrew (I F***ing Love Science): http://youtube.com/iflscience Thanks to everyone at RIT and Dickinson College who helped with the making of this video: Rochester Institute of Technology Robert Teese, Katelyn Wilkerson, Andrew Gillie, Andrew Stidwill Dickinson College This experiment was the brainchild of David Jackson based on a demo at Princeton. Priscilla Laws, Catrina Hamilton-Drager, Maxine Willis High-speed camera support: Charles Zwemer and Bria Antoine Music Licensed from CueSongs.com: The Temper Trap "Love Lost" Lights Motion "Epilogue"

Is punishment or reward more effective as feedback? Do new medical treatments really work? What about streaks in sport? Without considering regression to the mean, we are prone to making significant errors. Check out Audible.com: http://bit.ly/ZJ5Q6z Filmed at Perimeter Institute: http://pitp.ca Is punishment or reward more effective for helping people learn. A lot of people would say different incentives motivate different people, or in different circumstances, but in psychology there is a sizable body of evidence that in order to learn skills, positive feedback is more effective. This fining has been verified not just with humans, but also with other species. It was strange then that after Daniel Kahneman discussed this research with Israeli fighter pilot instructors that he was met with resistance. They found the opposite was true: when they reprimanded a cadet for performing poorly, he invariably improved, but if they praised a cadet for an excellent performance, the next attempt was not as good. In order to solve this apparent contradiction we first need to understand regression to the mean. Teacher study: http://bit.ly/1h8puVT Rugby player study: http://bit.ly/1aNSrBI

Thank you to Rodney Fox for sharing his story. He was attacked by a shark 50 years ago - Dec. 8 1963. If you're interested in his book or in going shark cage diving in South Australia, check out: http://bit.ly/rodneyfox

Remarkably little is known about great white sharks, but they are similar to humans in a lot of ways - they give birth to live young, maintain a higher body temperature than their surroundings and they are apex predators. There are also many misconceptions about these sharks: people think they don't get cancer and that they reside mainly in shallow waters near beaches. In this video I summarize some of the most interesting things I learned about sharks on my cage diving adventure. Special thanks to Rodney Fox Shark Expeditions for making this trip possible: http://bit.ly/rodneyfox Thanks also to Tourism South Australia for facilitating the trip: http://bit.ly/1aq9MgV Chris Cassella or C² as he is known after this trip was a shark spotter extraordinaire. He also took some of the best shark footage in this video. It was his idea to go on this expedition, which was definitely a once in a lifetime experience, so I am in his debt. Chris, I look forward to going on more great adventures with you. Check out Chris's facebook page ScienceAlert http://on.fb.me/18nhyLp

MinutePhysics on permanent magnets: https://www.youtube.com/watch?v=hFAOXdXZ5TM Subscribe to Veritasium: http://bit.ly/SuBVe Support Veritasium- get a t-shirt: http://dft.ba/-vetshirt Subscribe to MinutePhysics: http://bit.ly/1eVPynh Magnetism seems like a pretty magical phenomenon. Rocks that attract or repel each other at a distance - that's really cool - and electric current in a wire interacts in the same way. What's even more amazing is how it works. We normally think of special relativity as having little bearing on our lives because everything happens at such low speeds that relativistic effects are negligible. But when you consider the large number of charges in a wire and the strength of the electric interaction, you can see that electromagnets function thanks to the special relativistic effect of length contraction. In a frame of reference moving with the charges, there is an electric field that creates a force on the charges. But in the lab frame, there is no electric field so it must be a magnetic field creating the force. Hence we see that a magnetic field is what an electric field becomes when an electrically charged object starts moving. I was inspired to make this video by Prof. Eric Mazur http://mazur.harvard.edu/emdetails.php Huge thank you to Ralph at the School of Physics, University of Sydney for helping us out with all this magnetic gear. Thanks also to geology for loaning the rocks. This video was filmed in the studio at the University of New South Wales - thanks to all the staff there for their time and support. Music: Firefly in a Fairytale, Nathaniel Schroeder, and Love Lost (Instrumental) by Temper Trap licensed from CueSongs.com

Watch the bullet block experiment first: http://bit.ly/bulletblock Click for a free audiobook from Audible: http://bit.ly/ZJ5Q6z An interactive vignette of the bullet block http://ivv.rit.edu/bby/ Can you figure out the spinning disk? http://bit.ly/spinningdisk Thank you all for the awesome video responses and comments!! Simulation: http://bit.ly/19SCVnl Web comic: http://bit.ly/17o8HrR Wired Blog: http://bit.ly/17o9Dwu Science Blogs: http://bit.ly/17o9au3 Scientific American: http://bit.ly/19SDoWC Le's Blog: http://bit.ly/18q1m8a Video responses from which I borrowed: https://www.youtube.com/watch?v=hup-l4_Qt_U https://www.youtube.com/watch?v=uwZ1Mhy0BS0 https://www.youtube.com/watch?v=SgylTbknFdM Thanks to everyone at RIT and Dickinson College who helped with the making of this video: Rochester Institute of Technology Robert Teese, Katelyn Wilkerson, Andrew Gillie, Andrew Stidwill Dickinson College This experiment was the brainchild of David Jackson based on a demo at Princeton. Priscilla Laws, Catrina Hamilton-Drager, Maxine Willis High-speed camera support: Charles Zwemer and Bria Antoine Music: Temper Trap "Love Lost (Instrumental)" and Lights & Motion "Epilogue" licensed from CueSongs.com

Higher: http://bit.ly/blockhigher Same height: http://bit.ly/SameHeight Lower: http://bit.ly/BlockLower Special Thanks to: Henry (MinutePhysics): http://www.youtube.com/minutephysics Destin (Smarter Every Day): http://www.youtube.com/smartereveryday Greg and Mitch (ASAP Science): http://youtube.com/asapscience Elise Andrew (I F***ing Love Science): http://youtube.com/iflscience Thanks to everyone at RIT and Dickinson College who helped with the making of this video: Rochester Institute of Technology Robert Teese, Katelyn Wilkerson, Andrew Gillie, Andrew Stidwill Dickinson College This experiment was the brainchild of David Jackson based on a demo at Princeton. Priscilla Laws, Catrina Hamilton-Drager, Maxine Willis High-speed camera support: Charles Zwemer and Bria Antoine

Subscribe to Veritasium - it's free! http://bit.ly/YSWpWm Support Veritasium - get a t-shirt: http://dft.ba/-vetshirt Happy Geek Week! http://bit.ly/16wdDuk Everyone has played with a mixture of corn starch and water (or at least I hope they have). This was one of my favorite experiments as a kid. Your hand slides into the slime easily when moving slowly but the mixture behaves as a solid if you hit it quickly. That is what is meant by 'non-Newtonian' - the fluid's properties change depending on its relative motion. These properties can be exploited to dramatic effect as has been shown on speaker cones before. Here I wanted to understand what is going on, what frequencies and amplitudes work best so I used a slow-mo camera. Thanks to everyone at the YouTube Space LA for helping me film this. I couldn't have done it without you. Music licensed from http://www.cuesongs.com Love Lost (Instrumental) by Temper Trap A Life in the Day by Ghost of Otis Fortune's Fool Instrumental by Hiatus & Shura The Man by Audio Android

How does a transistor work? https://www.youtube.com/watch?v=IcrBqCFLHIY Silicon-28 sphere: http://bit.ly/10J1G2o This episode supported by audible.com: http://bit.ly/ZJ5Q6z We have looked at how a transistor works, the fundamental unit of classical computers, and how a quantum computer works in theory, taking advantage of quantum superposition to hold exponentially more information than classical computers. Now we look at the practical side of making a quantum bit, or qubit. How do you put it in a state where it is stable? How do you read and write information on it? These processes are described for a solid state qubit - a phosphorous atom in a silicon crystal substrate. Both the electron and the nucleus of the phosphorous atom can be used as qubits. Thanks to A/Prof. Andrea Morello: http://bit.ly/17wZ7lt Thanks to Henry Reich (MinutePhysics) for pushing me to make the explanations and visualizations clearer.

How does a transistor work? Our lives depend on this device. Support Veritasium on Patreon: http://bit.ly/VePatreon Subscribe to Veritasium - it's FREE! http://bit.ly/YSWpWm When I mentioned to people that I was doing a video on transistors, they would say "as in a transistor radio?" Yes! That's exactly what I mean, but it goes so much deeper than that. After the transistor was invented in 1947 one of the first available consumer technologies it was applied to was radios, so they could be made portable and higher quality. Hence the line in 'Brown-eyed Girl' - "going down to the old mine with a transistor radio." But more important to our lives today, the transistor made possible the microcomputer revolution, and hence the Internet, and also TVs, mobile phones, fancy washing machines, dishwashers, calculators, satellites, projectors etc. etc. A transistor is based on semiconductor material, usually silicon, which is 'doped' with impurities to carefully change its electrical properties. These n and p-type semiconductors are then put together in different configurations to achieve a desired electrical result. And in the case of the transistor, this is to make a tiny electrical switch. These switches are then connected together to perform computations, store information, and basically make everything electrical work intelligently. Special thanks to PhD Comics for awesome animations: http://bit.ly/16ZXcVY And thanks to Henry Reich and Vanessa Hill for reviews of earlier drafts of this video. Music: Kevin MacLeod (incompetech.com) Decisions

Veritasium t-shirts! http://dft.ba/-vetshirt Supported by Audible: http://bit.ly/ZJ5Q6z Can we really touch things? Well if by touch we mean exchange a force-carrying particle with, then yes. The photon is the force-carrier of the electromagnetic interaction. But if the photon is also a particle of light then why aren't magnets glowing? Because the photons are virtual particles, which means they can't be directly detected (without changing the outcome we are trying to measure. Who would win in a chin-up competition between me and MinutePhysics? What is going to be the most exciting area of scientific discovery in the next few decades? Where can you get a Veritasium t-shirt? http://dft.ba/-vetshirt Huge thanks to Brady, CGP Grey, and Henry for their cameos. Thank you to PhET for the Bohr model simulation: http://phet.colorado.edu/

For more on spin, check out: http://youtu.be/v1_-LsQLwkA This video was supported by TechNYou: http://bit.ly/19bBX5G A quantum computer works in a totally different way from a classical computer. Quantum bits or 'qubits' can exist in a superposition state of both zero and one simultaneously. This means that a set of two qubits can be in a superposition of four states, which therefore require four numbers to uniquely identify the state. So the amount of information stored in N qubits is two to the power of N classical bits. Thank you to Andrea Morello and UNSW. For more info, check out: http://bit.ly/17wZ7lt

Subscribe to Veritasium - it's FREE! http://bit.ly/YSWpWm Check out other unanswered science questions: http://youtu.be/UFydagCS9fg The universe is huge. That means two things: 1. there is probably life elsewhere, 2. It is likely too far away to have reached us. Fast, Furious & Funny - http://www.youtube.com/fastfuriousand... (http://www.youtube.com/watch?v=YWxub2...) The Brain Scoop - http://www.youtube.com/thebrainscoop (http://youtu.be/mNuu0y6ZmAs) ASAPScience - http://www.youtube.com/AsapSCIENCE (http://www.youtube.com/watch?v=wgxJhp...) The Royal Institute of Great Britain - http://www.youtube.com/TheRoyalInstit... (http://www.youtube.com/watch?v=gm02Oi...) PBS Idea Channel - http://www.youtube.com/pbsideachannel (http://www.youtube.com/watch?v=TbNymw...) The Spangler Effect - http://www.youtube.com/TheSpanglerEffect (http://www.youtube.com/watch?v=4fQ4uB...) Minute Physics - http://www.youtube.com/minutephysics (http://www.youtube.com/watch?v=2yHDeK...) Head Squeeze - http://www.youtube.com/HeadsqueezeTV (http://www.youtube.com/watch?v=UPBJX1...) Vsauce - http://www.youtube.com/Vsauce (http://www.youtube.com/watch?v=L45Q1_...) Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space. ~Douglas Adams Thanks to Dr. Simon O'Toole for talking exoplanets with me! We also discussed the Drake equation but there wasn't really room for it. Camera by Charles Clement Music by Kevin McLeod (incompetech.com) Mirage, Scissors

I actually have many, many more questions and answers so if you want to see them, like this video and let me know in the comments and I will edit them. Thank you for your support! I wouldn't have gotten this far without you.

The Higgs Boson is awesome but it's NOT responsible for most of your mass! Thanks to audible.com for supporting this episode: http://bit.ly/ZJ5Q6z The Higgs mechanism is meant to account for the mass of everything, right? Well no, only the fundamental particles, which means that electrons derive their mass entirely from the Higgs interaction but protons and neutrons, made of quarks, do not. In fact the quark masses are so small that they only make up about 1% of the mass of the proton (and a similar fraction of the neutron). The rest of the mass comes from the energy in the gluon field. Gluons are massless, but there is so much energy in the field that by E=mc^2 there is a significant amount of mass there. This is where most of your mass comes from and the mass of virtually everything around you. Thanks to Professor Derek Leinweber for his great images, animations and explanations. Check out his site to find out more: http://bit.ly/ZZTKFP

An atom is mostly empty space, but empty space is mostly not empty. The reason it looks empty is because electrons and photons don't interact with the stuff that is there, quark and gluon field fluctuations. It actually takes energy to clear out space and make a true 'empty' vacuum. This seems incredibly counter-intuitive but we can make an analogy to a permanent magnet. When at low energies, like at room temperature, there is a magnetic field around the magnet due to the alignment of all the magnetic moments of the atoms. But if you add some energy to it by heating it, the particles gain thermal energy, which above the Curie temperature makes their magnetic moments randomly oriented and hence destroying the magnetic field. So in this case energy is needed to clear out the field, just as in the quantum vacuum. Special thanks to Professor Derek Leinweber, find out more about his research here: http://bit.ly/ZZTKFP

Check out 2Veritasium! http://dft.ba/-ve2 MinutePhysics has a great video on Milkman, vomiting levitator: http://dft.ba/-vomphysics Jetpacking was awesome fun! Despite the fat lip I had a great time. I think knowing a bit about physics actually helps fly the jetpack. It works on the same principle as a rocket (Newton's 3rd law) but unlike the shuttle, you don't carry your own propellant with you. Instead, water is pumped out of the lake by the jetski at up to 60 litres a second. It is then fired out of the nozzles at around 15 m/s creating 1800 N of force, the equivalent of about 150 fire extinguishers. On me this can produce acceleration of about 1.5g's. Music by Kevin McLeod (http://incompetech.com) Silly Fun, Also Sprach Zarathustra Supported by Science Alert: http://on.fb.me/14ehuxA Slow motion filming by Questacon: http://bit.ly/ZoWFGR

Negative Pressure Exists! http://bit.ly/TFilQ8 Vsauce's Space Straw: http://bit.ly/XubIm3 Smarter Every Day's Prince Rupert's Drop: http://bit.ly/10VQBGW ViHart's Optimal Potatoes: http://bit.ly/14egJoe Thanks to Questacon for filming! Check out their slow-mo playlist: http://bit.ly/ZoWFGR Science Alert brings science to your news feed: http://on.fb.me/14ehuxA Music by Kevin Mcleod (http://incompetech.com): Pale Rider & The Cannery

The world's roundest object helps solve the longest running problem in measurement -- how to define the kilogram. Support Veritasium on Patreon: http://bit.ly/VePatreon A kilogram isn't what it used to be. Literally. The original name for it was the 'grave', proposed in 1793 but it fell victim to the French Revolution like its creator, Lavoisier. So begins the tale of the most unusual SI unit. The kilogram is the only base unit with a prefix in its name, and the only one still defined by a physical artifact, the international prototype kilogram or IPK. But the problem with this definition has long been apparent. The IPK doesn't seem to maintain its mass compared to 40 similar cylinders minted at the same time. The goal is therefore to eliminate the kilogram's dependence on a physical object. Two main approaches are being considered to achieve this end: the Avogadro Project and the Watt Balance. The Avogadro project aims to redefine Avogadro's constant (currently defined by the kilogram -- the number of atoms in 12 g of carbon-12) and reverse the relationship so that the kilogram is precisely specified by Avogadro's constant. This method required creating the most perfect sphere on Earth. It is made out of a single crystal of silicon 28 atoms. By carefully measuring the diameter, the volume can be precisely specified. Since the atom spacing of silicon is well known, the number of atoms in a sphere can be accurately calculated. This allows for a very precise determination of Avogadro's constant. Special thanks to Katie Green, Dr. David Farrant, the CSIRO, and the National Measurment Institute for their help. Thanks also to Nessy Hill for filming and reviewing earlier drafts of this video. There is debate as to whether this is truly the roundest object ever created. The Gravity Probe-B rotors are also spherical with very low tolerances such that they may in fact be rounder. Music by Kevin McLeod (incompetech.com) Decision, Danse Macabre, Scissors

What happens when single photons of light pass through a double slit and are detected by a photomultiplier tube? In 1801 Thomas Young seemed to settle a long-running debate about the nature of light with his double slit experiment. He demonstrated that light passing through two slits creates patterns like water waves, with the implication that it must be a wave phenomenon. However, experimental results in the early 1900s found that light energy is not smoothly distributed as in a classical wave, rather it comes in discrete packets, called quanta and later photons. These are indivisible particles of light. So what would happen if individual photons passed through a double slit? Would they make a pattern like waves or like particles?

Check out the original double slit experiment: https://www.youtube.com/watch?v=Iuv6hY6zsd0 - oh, and for the sun to be seen as single photons, you would have to be ~1000 light years away, so well past Pluto. For clarification on this video, please see: https://www.youtube.com/watch?v=OW7tfrTh66c What would you see if you were drifting through space, looking back at the sun? Well its light intensity would decrease as the inverse square of distance from the sun. And you would imagine the intensity would decrease smoothly, asymptotically approaching zero. But this is not what happens. If you had sensitive enough eyes, like frogs' eyes, you would find that at some point the sun would start to flicker. You would see flashes of light separated by complete darkness. And as you drift further from the sun, what's strange is that these flashes do not decrease in brightness, but they do become less frequent. That's because light comes in lumps, called quanta or photons, which are indivisible. So if you try to spread light out very thinly, you reach a point where there are only single bits of light reaching an observer's eye at any given time. I should acknowledge the book "The Fabric of Reality" by David Deutsch, which contains a similar story about a frog and a torch. It inspired me to make this film. Thanks also to MinutePhysics for reviewing earlier drafts and suggesting I make it more ridiculous.

Light is so common that we rarely think about what it really is. But just over two hundred years ago, a groundbreaking experiment answered the question that had occupied physicists for centuries. Is light made up of waves or particles? The experiment was conducted by Thomas Young and is known as Young's Double Slit Experiment. This famous experiment is actually a simplification of a series of experiments on light conducted by Young. In a completely darkened room, Young allowed a thin beam of sunlight to pass through an aperture on his window and onto two narrow, closely spaced openings (the double slit). This sunlight then cast a shadow onto the wall behind the apparatus. Young found that the light diffracted as it passed through the slits, and then interfered with itself, created a series of light and dark spots. Since the sunlight consists of all colours of the rainbow, these colours were also visible in the projected spots. Young concluded that light consist of waves and not particles since only waves were known to diffract and interfere in exactly the manner that light did in his experiment. The way I have always seen this experiment performed is with a laser and a manufactured double slit but since the experiment was conducted in 1801 I have always thought that it should be possible to recreate the experiment using sunlight and household materials. That is basically what I did here. I will show the interference pattern I observed with my homemade double slit on 2Veritasium but I chose to use a manufactured double slit here to ensure that the pattern was impressive for observers at the beach. Special thanks to Henry, Brady, and Rupert for their cameos, Glen for filming and Josh for helping create the apparatus. Thanks also to the Royal Society for allowing us to view the original manuscript of Young's lecture and the University of Sydney for lending the double slits. Music by Kevin Mcleod (incompetech.com) Danse Macabre, Scissors

Veritasium is a channel of science and engineering videos featuring experiments, expert interviews, cool demos, and discussions with the public about everything science. Clips featured in this video: Trees are Freaking Awesome - http://bit.ly/TFilQ8 Gyroscopic Precession - http://bit.ly/U4e8HQ Can We Go The Speed of Light? (Principle of Relativity) - http://bit.ly/X1BlXZ Where Does The Sun Get Its Energy? - http://bit.ly/125jbeM Where Do Trees Get Their Mass? - http://bit.ly/11AA817 What Is A Candle Flame Made Of? - http://bit.ly/Q3enCb Levitating Barbecue (Electromagnetic Induction) - http://bit.ly/SWgOWh Imploding Drum - http://bit.ly/125jG8B Microwave Grape Plasma - http://bit.ly/QkCwUt Spinning Tube Trick - http://bit.ly/Va43Z6 Spinning Disk Trick - http://bit.ly/14MSKsT Why Do You Make People Look Stupid? - http://bit.ly/12Fmlpl Awesome HD Slinky Slow-Mo - http://bit.ly/TRa4sE Subscribe to Veritasium - http://bit.ly/YSWpWm

As a Canadian-Australian, I have always wondered why it is that Australia has so many venomous animals that can kill you while Canada has virtually none. Subscribe to Veritasium - it's free! http://bit.ly/YSWpWm But it's not just Australia - it seems like all beautiful, warm places are cursed with venomous native species. So I set out to find the truth: why have all these venomous species evolved in the world's best holiday destinations? I asked chemists, visited the zoo, interviewed entomologists and snake experts. The answer I found was complicated: 1. The majority of venomous species are ectotherms, cold-blooded creatures whose internal temperatures are governed by their surroundings. 2. This means they have limited periods of activity - mainly while it's warm out, and can only exert short bursts of energy, so they are generally "sit and wait" predators. This may explain why they, more than mammals or birds, evolved venom. 3. It also explains why there are more of these species in warm climates. There are more of all species in warm climates, but this trend is especially pronounced for ectotherms. 4. So there are a greater number of venomous species in warm places, simply because there are more species in warm places. Cold climates still have venomous creatures, like the rattlesnakes of Canada and European vipers. 5. But history also has a role to play. In Australia, there were no snakes until 20 million years ago when a venomous sea snake from Asia encountered the land, sending venomous species to all corners of the continent. Later non-venomous arrivals have done well in the tropics but not as well in Australia's colder climates, so venomous types still dominate there. Hawaii has no venomous land snakes and nor does Jamaica. 6. The recent ice age also would have driven ectotherms from the northern parts of the Northern Hemisphere. This is why there are no snakes in Ireland, for example. Special thanks to Prof. Rick Shine, Prof. Dieter Hochuli, Prof. Roger Lowe, Prof. Martyn Poliakoff and Taronga Zoo, especially Joe Haddock and Dean Purcell. Cinematography by Charles Clement

Scientists are being inspired by nature to design the next generation of security devices. Arrays of nanoscale holes create beautiful reflected colours that are almost impossible to forge. This video was supported by TechNyou - check out their series on logical fallacies: http://bit.ly/WBsD31 Soon these nanoscale security devices could replace holograms. They are many times more reflective than holograms, and although the structures are smaller scale, they are lower aspect ratio and therefore easy to manufacture in bulk. The electron wiggle simulation is from PhET, the best physics simulations ever: http://phet.colorado.edu Special thanks to Thomas from Copenhagen who showed me around the city including the science museum where he assisted with the soap bubble demonstration. Clint Landrock is the Chief Technology Officer for Nanotech Securities: http://www.nanosecurity.ca Music is "Firefly in a Fairytale" by Gareth Coker

Heisenberg's uncertainty principle tells us that it is impossible to simultaneously measure the position and momentum of a particle with infinite precision. In our everyday lives we virtually never come up against this limit, hence why it seems peculiar. In this experiment a laser is shone through a narrow slit onto a screen. As the slit is made narrower, the spot on the screen also becomes narrower. But at a certain point, the spot starts becoming wider. This is because the photons of light have been so localised at the slit that their horizontal momentum must become less well defined in order to satisfy Heisenberg's uncertainty principle. I based this video on one by Prof. Walter Lewin of MIT: http://bit.ly/100Wk2K Henry (MinutePhysics) has previously made a video about Heisenberg's Uncertainty Principle where he treats it as less spooky and more a consequence of waves: http://bit.ly/TV3xO5 Sixty Symbols has a great video on Planck's constant: http://bit.ly/11upebY Thanks to the University of Sydney for hosting this experiment, especially to Tom and Ralph for their assistance getting it working. Music: Kevin McLeod (Incompetech.com) Mirage and Danse Macabre

I am nearing the end of a 6-week road trip filming for an Australian TV show called Catalyst (http://abc.net.au/catalyst). Along with co-presenters Anja and Simon, I have travelled from Perth towards our destination, Melbourne, picking up all the interesting science stories along the way. Since we have been working long days I haven't had time to make any new Veritasium material. Instead I thought I'd share some things I have done for this show in the past, including narrating short 'factoid' segments like this one. Hope everyone is having a great holiday season and I look forward to getting back to Veritasium stuff in a few weeks. Nuclear Fungus Producer: Nicky Ruscoe Researcher: Kiri Beilby Editor: Chris Spur Graphics: Rapt Animation P/L http://abc.net.au/catalyst

Innovative research conducted in Lausanne, Switzerland has shown that a combination of neurotransmitters and electrical stimulation can restore movement to the lower limbs of previously paralysed rats. But in order for this motion to be made voluntarily the rats must be motivated to walk. This motivation comes in the form of cheering, visual cues, and of course, chocolate. Why Trees Are Amazing: http://bit.ly/TFilQ8 Space Junk: http://bit.ly/XlLdjG Why Astronauts Are Weightless: http://bit.ly/SuF2p1 Higgs Boson Update: http://bit.ly/Vw1Sgu

Space junk is a real problem. NASA now tracks around 20,000 pieces of debris orbiting Earth, most of them larger than 10cm across. Since the average speed of a collision between orbiting objects is 10 km/s these pieces of trash can cause a lot of damage despite their small size. Scientists in Switzerland have a plan to clean up space junk - it involves creating a 'Janitor Satellite' that will seek out pieces of space junk to drag back into the atmosphere causing them to burn up. This video was created for the Aussie science show Catalyst on the ABC: http://www.abc.net.au/catalyst

Corn flour blown through a funnel produces an excellent fireball. This both looks cool and demonstrates some interesting science. In any chemical reaction, the reactants must mix with each other significantly in order to increase the rate of reaction. Here we demonstrate that corn flour on a spoon burns slowly, but blown from a funnel, the reaction is dramatic and violent. This is because the surface area where the reaction can occur is greatly increased. HD Slinky Slow-mo http://bit.ly/TRa4sE How to make solid nitrogen http://bit.ly/RqPw8l Levitating BBQ http://bit.ly/SWgOWh Electric Flame http://bit.ly/Q3enCb As always, if you are planning to recreate this experiment, make sure you have appropriate supervision and take necessary precautions.

Huge thanks to the Royal Institution, Professor Frank James, and Katie Atmore for filming. For the Sixty Symbols version of this experiment click http://bit.ly/RGfLY5 Michael Faraday created the first electric generator in 1831 using a coil of wire and a permanent magnet. When the magnet was moved relative to the coil, current was induced in the coil. A similar experiment can be performed with a copper tube and a magnet. Although copper is not magnetic, it is a conductor. As the magnet falls through the pipe, the magnetic field changes over different sections of the pipe. This induces swirling currents (called eddy currents), which create a magetic field that opposes the motion of the magnet. This means work must be done to move the magnet through the pipe. This work generates the electrical energy, which is then dissipated as thermal energy in the pipe. The same basic principle is used to generate electricity throughout the world: moving a magnet inside copper coils. Experiments A Cappella http://bit.ly/TtdflV Where Did The Earth Come From http://bit.ly/VQBzQJ The Coastline Paradox http://bit.ly/TIapxM Microwave Grape Plasma http://bit.ly/QkCwUt Music by Kevin McLeod (http://www.incompetech.com) Sneaky Snitch and Danse Macabre

Hope this was worth the wait! So many people helped with this video: Prof John Sperry, Hank Green, Henry Reich, CGP Grey, Prof Poliakoff, my mum filmed for me in beautiful Stanley Park and Jen S helped with the fourth version of the script. Prof John Sperry http://biologylabs.utah.edu/sperry/john.html Hank Green (SciShow) http://www.youtube.com/user/scishow Henry Reich (minutephysics) http://www.youtube.com/user/minutephysics CGP Grey http://www.youtube.com/user/cgpgrey Prof Poliakoff (Periodic Videos) http://www.youtube.com/user/periodicvideos Also thanks to the Palais de la Decouverte - they helped me with the whole vacuum pump setup in Paris. No, I could not actually suck water up 10m - I did about 4m, but the vacuum pump was easily able to do it and I saw spontaneous boiling on all of our various trials. Footage from this may end up on 2Veritasium. Trees create immense negative pressures of 10's of atmospheres by evaporating water from nanoscale pores, sucking water up 100m in a state where it should be boiling but can't because the perfect xylem tubes contain no air bubbles, just so that most of it can evaporate in the process of absorbing a couple molecules of carbon dioxide. Now I didn't mention the cohesion of water (that it sticks to itself well) but this is implicit in the description of negative pressure, strong surface tension etc.

For a report on ABC's Catalyst program (http://www.abc.net.au/catalyst/), I visited the Large Hadron Collider in Switzerland to find out what is being done now that the Higgs Boson has been discovered. Although its mass has been measured around 125-126 GeV most of the other properties of the particle remain unknown. Its spin appears to be 0 or 2 but more results are required to nail this down. If it is the standard model Higgs, the spin should be 0, resulting in a fairly symmetric distribution of decay products in the detectors. We may know this year if it's not the standard model Higgs - this would be the case if it doesn't decay into specific particles with the expected frequency. However if it is the standard model Higgs, it may take many more years to be certain. The large hadron collider will be shut down in 2013 for upgrades so that higher energies up to 14 TeV can be tested. Right now the LHC is operating at 8 TeV. The next announcement is expected in December.

At the Palais de la Decouverte in Paris, they showed me this experiment where a 1kg aluminium plate is levitated above a large coil of wire that is being supplied with 800A of alternating current at 900Hz. This is by far the best demonstration of electromagnetic induction I have ever seen. Back in London, I visited the magnetic lab of Michael Faraday in the basement of the Royal Institution. It was here that he did his groundbreaking work on induction. People had previously observed that current in a wire causes a compass needle to deflect, but more exciting was the prospect of using a magnetic field to generate current. Faraday created his famous induction ring by winding two coils of insulated wire onto an iron ring. When he connected a battery to one coil, a small pulse of current was induced in the other. When the battery was disconnected, current was induced in the other direction. This led Faraday to the conclusion that current was induced in the second coil only when the magnetic field through it was changing. And if they hadn't been wrapped on the same ring, Faraday may have noticed that the two coils repel each other when the current is induced due to the interaction of their magnetic fields. This is the same thing that is happening with the aluminium plate, except we're using alternating current to create a continually changing magnetic field. This induces an alternating current in the plate, producing an opposing magnetic field which levitates the disk.

Yes, I have made a similar vid before. This is the Australian TV version for the ABC show Catalyst http://www.abc.net.au/catalyst/ Misconceptions About Temperature https://www.youtube.com/watch?v=vqDbMEdLiCs The Mysterious Falling Slinky https://www.youtube.com/watch?v=mAA613hqqZ0 Why Are Astronauts Weightless? https://www.youtube.com/watch?v=iQOHRKKNNLQ And for those of you wanting a more General Relativity based explanation. Don't worry, it's coming.

What happens when you decrease the pressure around a liquid? It boils. Water boils at room temperature once the pressure is low enough. What is interesting is that this decreases the temperature of the liquid. The fastest molecules escape, leaving the slower ones behind. Using this trick with liquid nitrogen, it is possible to create solid nitrogen at a temperature of -210C. We then poured the solid and liquid nitrogen mixture onto a tray of water. The surface of the water became so cold that CO2 solidified out of the atmosphere on its surface. Then, since CO2 does not pass through the liquid phase at atmospheric pressure, it was propelled on the water surface by jets of gas as it sublimed. Huge thanks to the Palais de la Decouverte. Music by Kevin MacLeod of Incompetech.com (Mirage)

Microwave grape plasma: https://www.youtube.com/watch?v=RwTjsRt0Fzo Northern Lights: https://www.youtube.com/watch?v=knwiWm4DpvQ Nanodiamonds in candle flames: https://www.youtube.com/watch?v=KzOkuGQC3Rw Relight Candle Trick: https://www.youtube.com/watch?v=1tXPVTIisl0 Is a flame really a plasma? Well it depends on your definition of plasma, but there are certainly ions in a flame, formed as molecules collide with each other at high speed, sometimes knocking electrons off of their atoms. Special thanks to the Palais de la Decouverte for helping me perform this experiment. Using tens of thousands of volts on two metal plates, we created a strong electric field around the plasma. This pulled positive ions in one direction and negative ions in the other direction elongating the flame horizontally and causing it to flicker like a "papillon" (butterfly). Then we showed that much longer sparks can be made through the flame than through air since the ions increase the conductivity.

Answer video: https://www.youtube.com/watch?v=BickMFHAZR0 The longest vertical straw you can use is 10.3 m https://www.youtube.com/watch?v=HUmZrtiXDik This is because the weight of water in the straw must be supported by the pressure difference at its two ends. At the bottom, the pressure is atmospheric, and at the top, the lowest pressure you can create is a perfect vacuum (pressure = 0). Atmospheric pressure can support a water column about 10m high - BUT with 0 pressure at the top, the water would start boiling. This is called cavitation and it obviously can't be happening in trees. After I posted the straw video, I received a lot of questions about how trees could be taler than 10m. I assumed there was a simple answer because there are plenty of trees taller than that. But as I asked around and read articles about it, I couldn't really find an explanation I was happy with. Maybe there is not a continuous water column inside the tree, so each section only lifts water a little ways? This could be but it seems to require a series of pump mechanisms, and how would you join this pump sections together? Perhaps capillary action is holding the water up? But the xylem tubes in a tree seem too wide (~50 um) for this effect to be significant. Maybe osmotic pressure could push the water from below rather than sucking it up from above? But some trees live in mangroves, where there is much higher solute concentration in the sea water than in their roots, so osmosis would work the other way. Eventually I spoke to a plant biologist and sorted this all out, but I wanted to give you a little back to school challenge. How do you think this could work?

Made for ABC TV Catalyst http://www.abc.net.au/catalyst/ as an extended version of my Comparing Temperatures video: https://www.youtube.com/watch?v=hNGJ0WHXMyE

A boomerang can execute its unique roundtrip flight by making use of three fundamental physics principles: lift, relative velocity, and gyroscopic precession. numberphile http://bit.ly/numberphile efit30 http://bit.ly/O4CMme appchat http://bit.ly/NxAMlX erikaanear http://bit.ly/MdyUzQ whoisjimmy http://bit.ly/LtFzpW minutephysics http://bit.ly/Muh6CC 1veritasium http://bit.ly/MrupzL

The strange thing about high jump is that the technique changed dramatically after 1968, when Dick Fosbury used his trademark flop to win the gold medal at the Olympics in Mexico City. Previously the scissors and straddle had been the most common jumping technique, but after the introduction of safer landing matts, the new unorthodox Fosbury Flop became the jump of choice. There are good physical reasons for this - the style allows the jumper to pass over the bar while his or her centre of mass actually passes below the bar. Huge thanks to Elly (Appchat http://bit.ly/NxAMlX ) for filming, editing, and music! numberphile http://bit.ly/numberphile efit30 http://bit.ly/O4CMme appchat http://bit.ly/NxAMlX erikaanear http://bit.ly/MdyUzQ whoisjimmy http://bit.ly/LtFzpW minutephysics http://bit.ly/Muh6CC 1veritasium http://bit.ly/MrupzL

How lift actually works: https://www.youtube.com/watch?v=aFO4PBolwFg More with Canadian Olympian Hunter Lowden: https://www.youtube.com/watch?v=6YVOPUkbu6g How does a sailboat work? The standard idea is that the wind pushes the sails from behind, causing the boat to move forward. Although this technique is used at times, it is not the most efficient way to sail a boat (and it means the boat can never go faster than the wind). Lift is the key mechanism driving a boat forwards. As air flows over the sails, it moves faster over the outer side, creating lower pressure than on the inner side. This produces a force which is mostly to the side and a bit forwards. Lift on the centerboard pushes to the opposite side, cancelling the sideways force and adding a forward component of force to the boat. numberphile http://bit.ly/numberphile efit30 http://bit.ly/O4CMme appchat http://bit.ly/NxAMlX erikaanear http://bit.ly/MdyUzQ whoisjimmy http://bit.ly/LtFzpW minutephysics http://bit.ly/Muh6CC 1veritasium http://bit.ly/MrupzL

Lift is an important concept, not only in flying but also in sailing. This week I'm talking to Olympic Sailor, Hunter Lowden. But before I get to the physics of sailing I thought I would explain lift since it's generally poorly understood. minutephysics http://bit.ly/Muh6CC 1veritasium http://bit.ly/MrupzL efit30 http://bit.ly/O4CMme appchat http://bit.ly/NxAMlX erikaanear http://bit.ly/MdyUzQ whoisjimmy http://bit.ly/LtFzpW numberphile http://bit.ly/numberphile Music by Nathaniel Schroeder youtube: http://bit.ly/pakJLE myspace: http://mysp.ac/qtmZQj

I'm going to London! And I'm leading a team of YouTubers. For the next few weeks we will all be doing videos themed around the Olympics so I'm tackling the science of sport and science in and around London. The Team! HOWRIDICULOUS: http://bit.ly/LtFzpW APPCHAT: http://bit.ly/NxAMlX ERIKAANEAR: http://bit.ly/MdyUzQ MINUTEPHYSICS: http://bit.ly/Muh6CC EFIT30: http://bit.ly/O4CMme 2VERITASIUM http://youtube.com/2veritasium Music by Alankeys86 and Kevin McLeod (Incompetech.com) For the London 2012 Summer Olympics creators from all over the world are taking over YouTube with the most awesome Olympics videos ever. Go to YouTube.com/CreatorHub to see all the amazing gold medal videos.

Starring: Christie Wykes as Chlorine, Carbon, and Sodium Director of Photography: Sean McCallum Gravity (John Mayer Cover) https://www.youtube.com/watch?v=u7KpH9_I2Dw I'm Atoms (Jason Mraz Cover) https://www.youtube.com/watch?v=DBjZz0iQrzI Electricity (Jet Cover) https://www.youtube.com/watch?v=cY-kiddvAg0 Experiments A Cappella https://www.youtube.com/watch?v=lRbI_vPyOnc

To celebrate the announcement of the discovery of a particle consistent with the Higgs Boson at the LHC, I took to the streets with Vi Hart to give out free Higgs. Now giving out a subatomic particle, especially the Higgs, would have been incredibly difficult so instead we gave out hand-drawn cards of the Standard Model, our current best theory of all matter particles in the universe and their iteractions (now with Higgs!). We also offered a hug with an integer spin, usually 1 or 2 (and in rare cases 0). This is a way of showing others that you care about the Higgs Boson.

Back in 2012, we all met for the first time at BrainSTEM - a conference of science YouTubers, instigated by Henry of MinutePhysics (Thank You Henry!!!) bringing together the most awesome STEM personalities from around the world. People like Vsauce, John Green, Vihart, Destin from Smarter Every Day, CGP Grey, Brady Haran of Numberphile et al. I had an awesome three days hanging out with all the cool people in this video and hopefully this is only the start of many fruitful collaborations to come. Thanks everyone!!! Now this happens to be video 100 for me. It's not really about science, but I think it's pretty awesome because it features all of my YouTube heroes.

In April 2012, I was part of a team of scientists, teachers and students who travelled to Alaska to observe the Northern Lights or Aurora Borealis. Our mission was a unique one - to launch weather balloons up to 100,000 feet loaded with experiments, tracking devices and HD cameras. This is the result of our trip, produced for Catalyst on ABC1 http://www.abc.net.au/catalyst/

This is how a slinky falls in slow motion - it appears to defy gravity but the centre of mass is accelerating at 9.8m/s^2 meaning the top is accelerating faster than that and the bottom is not falling at all until the entire slinky collapses. Read a pre-print of the physics paper here: http://arxiv.org/abs/1208.4629 Music by Kevin McLeod http://incompetech.com Songs: Industrial Music Box, Heavy Interlude, Pale Rider, Decisions. Slow motion photography courtesy of Questacon http://questacon.edu.au The original goal of Veritasium was to show the beauty of science and I think the first minute and a half of this is the closest I've come. This is the last in a series of six videos about slinkies.

Smarter Every Day Collaboration video: http://youtu.be/riwc3UgPaHw The Veritasium treatment of the final transit of Venus this century. The weather behaved for some key moments allowing me to observe Venus passing across the disk of the sun. The transit of Venus is steeped in historical significance. Observations of the transit in 1769 led to the first really accurate calculation of the Earth-Sun distance (or one astronomical unit AU). Since Cook was in Tahiti he then mapped the East coast of Australia and parts of New Zealand.

ZoggFromBetelgeuse's solution: https://www.youtube.com/watch?v=pwl-rBVbWAY This is a preliminary solution to the spinning disk trick based on the commonly cited tippe top explanation. I have my doubts that it tells the whole story because the disk seems to tilt, so the argument about constant angular velocity is in doubt. I wonder if the weight of the disk plays a more important role in making it flip. Plus, I think the disk appears to roll without slipping while the lighter side is moving down. This violates one of the assumptions of the tippe top explanation. So why am I publishing this now? I feel bad it has been two weeks and I haven't posted the answer yet so let's consider this a starting point for a work in progress...

Some months a go I filmed a slinky falling in slow motion. Now I have interviewed the public about what they expect to happen for ABC TV's Catalyst program and this is the result.

NOTE: This video will appear in a playlist on Smarter Every Day hence the references to Veritasium. Destin does lots of cool science stuff - check out his channel if you haven't already http://www.youtube.com/destinws2 We have been collaborating on rotational motion, which is timely for some of the videos I've been doing lately. In this video I talk about gyroscopic precession - the "wobbling" of a spinning top around its axis. This is caused by the torque due to the object's weight. The big idea is that the torque vector increases angular momentum in the direction of torque. So if there is no angular momentum initially, it will cause the system to swing in such a direction that it is rotating with new angular momentum in the direction of the torque. However, if there was angular momentum to begin with, the torque will change the direction of that angular momentum by causing precession.

Objects hang heavy side down, but what happens when you spin an asymmetrically weighted disk - well the heavy part actually rises to the top. Why is this?

http://www.abc.net.au/catalyst/team/default.htm I have been working with Catalyst on ABC1 to bring some Veritasium to Australian TV. In this segment I ask why astronauts in the space station are weightless. The most common answer is because there is no gravity in space. But of course there is gravity in space, especially where the space station is located (only about 400km from Earth's surface). So astronauts still experience a gravitational pull - it's just that they and the space station are in free fall so they are accelerating together towards the Earth. The space station doesn't crash into the Earth because of its orbital velocity - it's going 28,000 km/h so as it falls, the Earth curves away from it.

The sun has been producing light for about five billion years but where does all its energy come from? The most common idea is that the sun is burning gas - like a giant fireball in the sky. If this were true, the sun would have gone out long ago. So how is the sun actually fuelling itself? It is converting its own mass into energy. By combining protons (the nucleus of hydrogen) into helium, it squeezes some mass into energy - 4.3 billion kg per second. It is Einstein's famous E=mc^2 which gives us the quantitative relationship between mass and energy, where c is the speed of light.

The aurora borealis or northern lights is one of the most spectacular natural displays on the planet. Theories about its origins have been debated for centuries and common misconceptions persist that the aurora is the sun's rays scattered off ice crystals in the high atmosphere. In truth, the light is created more than 100km above Earth's surface as high speed electrons and protons ejected from the sun in a solar flare or coronal mass ejection collide with air molecules in the upper atmosphere. The charged particles from the sun excite air molecules which then de-excite by emitting light. The display is most common around the north and south poles because the Earth's magnetic field deflects the solar wind from the equator to the poles. Here the magnetic field dips towards the Earth's surface, channeling the charged particles into the atmosphere. Music is by Kevin MacLeod http://incompetech.com, the song is called Mirage

More about the Alaska Trip: http://education.projectaether.org Channel 10 Breakfast: http://www.tenbreakfast.com.au (6-9am weekdays in Australia) March 26 segment on live TV talking about solar storms and my upcoming trip to the Great White North. As you watch this I will probably be on a plane high over the pacific. PS a student recently told me that my hair to beard ratio is a bit off and watching this clip I tend to agree. However, it is still -20 C at night in Alaska so I'll need all the insulation I can get.

Raw interviews: https://www.youtube.com/watch?v=8dcw98B2Nzg The question has arisen often enough that I thought I'd answer it. If you hold views that are consistent with the majority of the population, does that make you stupid? I don't think so. Science has uncovered a lot of counterintuitive things about the universe, so it's unsurprising that non-scientists hold beliefs inconsistent with science. But when we teach, we must take into account what the learners know, including their incorrect knowledge. That is the reason a lot of Veritasium videos start with the misconceptions. Want to read my PhD? You can download the full text here: http://www.physics.usyd.edu.au/pdfs/research/super/PhD(Muller).pdf

Complete unedited interviews: https://www.youtube.com/watch?v=8dcw98B2Nzg Trees can weigh hundreds or even thousands of tons, but where do they get this mass from? A few common answers are: the soil, water, and sunlight. But the truth is the vast majority of a dry tree's mass comes from the air - it originated as carbon dioxide

Right: https://www.youtube.com/watch?v=AS9OXzSRBMQ Left: https://www.youtube.com/watch?v=FWQ-HJ4oGKQ It Depends: https://www.youtube.com/watch?v=R3GHiMOHEy8 What happens when nylon rope is wound around a spool and pulled horizontally to the right? Will the spool go to the right, to the left, or does it depend on how the rope is pulled?

The solution to the question posed in the spinning tube trick video, that is - what would you see if looking at the spinning tube from below a glass table. The explanation of why only the X or O is visible will be the subject of the next video.

When a tube spins with an X and an O labelled at either end, why do we see only one letter during the rotation?

To see what this looks like from under a glass table, see https://www.youtube.com/watch?v=E9WUaBGH7_I

Are you heaviest at night before you go to bed and lightest in the morning? I tried to tease out the factors to figure out what really causes weight gain and loss during the day, and what causes daily weight fluctuations.

What is the longest drinking straw that you can actually drink out of? Well in this video, we put the theory to the test. We started off with a one metre long straw made out of drinking straws taped together. We moved on to two pieces of plastic tubing, each 6 metres in length with different diameters. Then we tried a 10.5 metre tube over a cliff's edge. The maximum we achieved was about 7 metres though theoretically up to 10.3 metres is possible if a perfect vacuum is created.

For more info, please see http://www.physics.usyd.edu.au/~cross In baseball and cricket the best pitchers and bowlers know how to make the ball move due to the effects of aerodynamics. If one side of the ball is rough, the ball swings towards that side because turbulent air 'clings' to that side of the ball and is deflected. Although baseballs and cricketballs appear symmetric, they can be made to fly through the air with a smooth or rough side by judicious angling of the seams combined with the axis of rotation.

I saw my first wild koalas while driving on the great ocean road. Generally their days are not very exciting. They spend most of their time sleeping and the rest of the time eating eucalyptus leaves. The eucalyptus leaves are tough to digest which explains their consumate napping. Plus they require bacteria in their gut to help them break down their food. This bacteria must be passed down from mother to child through the mother's poo. It's a tough start to life for koalas!

How long is the coastline of Australia? One estimate is that it's about 12,500 km long. However the CIA world factbook puts the figure at more than double this, at over 25,700 km. How can there exist such different estimates for the same length of coastline? Well this is called the coastline paradox. Your estimate of how long the coastline is depends on the length of your measuring stick - the shorter the measuring stick the more detail you can capture and therefore the longer the coastline will be.

How to light a candle without touching a flame to the wick. A common misconception is that a candle burns by burning the wick. What is actually burning is wax vapour which is drawn up through the wick. When you blow a candle out, wax vapour continues to rise off the candle so you can light this vapour which burns back down to the wick, relighting the candle.

My entry to the techNyou Science Ambassadors competition, visit www.facebook.com/talkingtechnology and www.youtube.com/technyouvids to find out more about these guys.

What causes the phases of the moon? The common incorrect answer is the shadow of the Earth. The phases of the moon are actually just a result of our perception of the moon's half-illuminated surface. When the moon does pass through Earth's shadow the result is a lunar eclipse. This can be spectacular as the moon turns a deep shade of red. Images courtesy of NASAimages.org and Geoff Wyatt, Senior Astronomy Educator Powerhouse Museum

A quote by Einstein: A human being is a part of the whole, called by us "Universe", a part limited in time and space. He experiences himself, his thoughts and feelings as something separated from the rest — a kind of optical delusion of his consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest to us. Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty. Nobody is able to achieve this completely, but the striving for such achievement is in itself a part of the liberation and a foundation for inner security.

Whenever an object spins through the air it experiences a 'Magnus Force' due to friction between the air and the object's surface. This force was originally identified while studying the trajectories of cannon balls (though earlier observations of this effect exist). The Magnus force is essential in most ball sports including golf, cricket, tennis, and baseball. At the end the ball demonstrations were conducted with a 100 mm diam polystyrene ball and the launcher was made by bending a long, thin, aluminum rod and bolting the ends to a block of wood as a handle. Music was provided by Kevin McLeod (incompetech.com) Scissors and a stock clip from FCP.

How should we depict an atom? Like a solar system with electrons orbiting the nucleus on hula hoop orbits? That idea is so last century! Bosi takes us into the quantum world, where an electron's position and velocity aren't well defined - all we can calculate are the probabilities e.g. of finding an electron at different points in space. When we do that, we find electrons do not neccessarily occupy circles or spheres in space. Rather their probability densities make all sorts of interesting shapes from the dumbell to the peanut with the donut around it.

Einstein's classic thought experiment involves sitting on a train travelling at the speed of light. If you hold a mirror in front of your face, will you see your reflection in a mirror? How could light from your face reach the mirror if the mirror is travelling away from you? But it would be a pretty spooky train if you couldn't see your reflection so Einstein felt this solution wasn't realistic. On the other hand if you could see your reflection, it would mean light was travelling at the speed of light inside the train. But that meant the same light observed from outside the train would be going twice the speed of light. This again seems inconsistent. So Einstein resolved that you must see your reflection but that light must travel at the same speed inside and outside the train. The only way this is possible is if space and time are perceived differently by observers inside and outside the train.

The Nobel Prize for physics in 2011 was awarded to Brian Schmidt, Adam Riess, and Saul Perlmutter for discovering that the universe is expanding at an accelerating rate. This finding was completely unexpected because it was thought that gravity should slow the expansion of the cosmos. The best current explanation of why the universe is accelerating is that there is some energy tied to empty space which pushes matter apart. This 'Dark Energy' makes up 73% of the universe but is very difficult to detect. Images courtesy of NASA/NASAimages.org and Maritza A. Lara-Lopez

The Nobel Prize for physics in 2011 was awarded to Brian Schmidt, Adam Riess, and Saul Perlmutter for discovering that the universe is expanding at an accelerating rate. This finding was completely unexpected because it was thought that gravity should slow the expansion of the cosmos. The best current explanation of why the universe is accelerating is that there is some energy tied to empty space which pushes matter apart. This 'Dark Energy' makes up 73% of the universe but is very difficult to detect. Hopefully a better understanding of it will lead to a unification of our theories of gravitation and quantum mechanics. Images courtesy of NASA - NASAimages.org

http://www.youtube.com/spacelab gives you an opportunity to design an experiment to be performed in space! If you're between the ages of 14-18, make a 2 minute youtube video proposing an experiment to be performed in zero g. Your video will be assessed by a panel of experts with the winner having their experiment performed in space and broadcast live to the world.

What happens when a super long slinky is dropped?

When a grape is cut nearly in half and placed in a microwave, plasma is produced. Please use caution if attempting this experiment: don't leave the microwave on for too long, make sure the area is well ventilated, and stand back. Remember the contents will be very hot afterwards.

The answer to the question - what happens to a tennis ball tied to the bottom of a slinky after the top of the slinky is let go? For a great explanation, check out Rhett Allain's analysis here: http://www.wired.com/wiredscience/2011/09/modeling-a-falling-slinky/

What happens when a slinky that has been extended under its own weight is released? How does it fall to the ground? Answer link: https://www.youtube.com/watch?v=eCMmmEEyOO0

Want more awesome HD slow-mo? https://www.youtube.com/watch?v=uiyMuHuCFo4 Slinky not long enough? Click here: https://www.youtube.com/watch?v=JsytnJ_pSf8 How does a slinky fall when extended by its own weight and then released? We discover the surprising answer using a slow motion camera that records 300 frames per second. Answer link: https://www.youtube.com/watch?v=oKb2tCtpvNU For a great explanation, check out Rhett Allain's analysis here: http://www.wired.com/wiredscience/2011/09/modeling-a-falling-slinky/

Everyone is familiar with liquid water, ice and water vapour, but what are the differences between these three states of matter? Solids, liquids and vapours of the same substance differ in the motion of the molecules and the distance between them. Animations courtesy of VisChem (Trade Mark), Copyright 1995, Roy Tasker. Thanks for all your help!

The atmosphere applies a pressure of about 100 000 N to every square metre on Earth's surface. We take this pressure for granted because we have the same amount of pressure pushing out. But what happens when the pressure of the atmosphere is applied to an object with no outward pressure? It implodes. In spectacular fashion.

Scientific research has shown that heterosexual males and females find members of the opposite sex more attractive when they wear the colour red. This is a subconscious preference that seems to have some evolutionary basis. We attempted to replicate these findings in Sydney but our methods were much less controlled and the results achieved were not statistically significant.

On a mobile device? Click here: https://www.youtube.com/watch?v=X-QFAB0gEtE for the answer Two 1.5kg masses are released simultaneously from the top of a 10m high wall. One is attached to a chain while the other is free. Which one will hit the ground first?

Which weight hits the ground first - the free weight or the weight attached to the chain?

Scientists have recently discovered nanodiamonds in the flames of ordinary candles. They are produced at a rate of about 1.5 million per second. Unfortunately they are also burned up at this rate and released into the atmosphere as carbon dioxide. Still this finding may prove useful in the ongoing search for economical ways to produce diamonds.

It's the most abundant liquid on the planet and by weight we are about 60% water. But do we know what it is made of?

2011 is the international year of Chemistry. But what do Australians know about it?

On mobile, click here for the answer: https://www.youtube.com/watch?v=qQCVnjGUv24 When ice is put under pressure, its melting point decreases. When that pressure is removed it goes back to being solid. This process is known as 'regelation'. In this experiment regelation of ice is attempted with copper wire and fishing line of the same diameter. Which will pass through the ice first?

What passes through a block of ice more quickly, copper wire or fishing line?

Australian Science week runs August 13-21. Check out scienceweek.gov.au for more details.

When pressure is applied to ice, its melting point is reduced so it turns to water. When the pressure is removed, however, it turns back into ice. This process is called 'regelation.' Big thanks to Art of Ice Sculptures www.icesculpture.com.au who donated the beautiful block of ice.

In Sydney, ice melts because it is warm out in the middle of the day (even in winter). This creates a layer of water on top that certainly makes it slippery. But should it be slippery at night or in a cold northern climate where the air temperature is below zero? Yes, because the pressure your skates apply to the ice actually lowers its melting point allowing you to glide along a thin layer of water. Animation in this video is courtesy of VisChem (TM), Copyright 1995, Roy Tasker For a more complete picture of the mechanisms involved in making ice slippery, check out this great article: http://lptms.u-psud.fr/membres/trizac/Ens/L3FIP/Ice.pdf

One of the most common physics misconceptions is that an unbalanced force causes constant motion. In truth, an unbalanced force leads to changes in motion - accelerations.

The Earth spins on its axis, completing a full revolution every day. By why does it do this? One of the most common misconceptions in physics is the belief that constant motion requires a constant force. So many people believe there must be some force in the Earth (e.g. gravity, centrifugal force) that keeps it spinning. In truth, no force is required because a fundamental property of mass is that it maintains its state of motion in the absence of external forces. This property is called inertia.

Everything is not as it first appears. This simple plastic ball looks purple until you swing it in a circle and reveal its true nature. Inside are three light emitting diodes (LEDs), which are red, green and blue. They turn on and off in sequence very quickly. When still, the ball appears purple because your eyes and brain don't 'refresh' quickly enough to perceive the changing colours. However, when swung in a circle, the ball changes colours at different locations so the colours don't merge with each other and the ball's true nature is revealed. Now let's not think too carefully about how this illusion is conveyed through video (because the camera doesn't refresh quickly enough to perceive the colours changing either - so you have no hope of seeing it on YouTube even frame by frame).

When air is compressed very quickly, it can reach high temperatures. In this demonstration we show how cotton wool can reach the point of auto-ignition by quick compression of air in the fire syringe.

When we touch something that is hot or cold, what are we actually sensing? Is it the temperature of the object, or the rate at which heat flows between the object and our hand?

When sunlight shines through a small hole, it casts a circular image on the wall regardless of the shape of the hole. The size of the hole also doesn't affect the size of the image. This counterintuitive demonstration shows that the hole is acting like a pinhole camera, producing an image of the sun on the wall. Therefore the size and shape of the hole have no effect on the size and shape of the image.

How do our eyes scan across a landscape? Contrary to popular belief, they don't scan smoothly across a scene, they observe a series of images. The eye is capable of panning smoothly however. If something moves in your field of view, your eyes track it smoothly. This has an important effect on our perception of motion. It makes it more difficult to see when objects are accelerating since the eye tracks all motion quite smoothly.

At the jumper's fastest point, the acceleration is by definition zero. That is because the jumper is going from speeding up to slowing down. At this instant then there is no change in the jumper's velocity. This is counter-intuitive for a lot of people because it's easy to confuse velocity with acceleration. Velocity is how fast something goes while acceleration is the rate at which velocity changes.

Congratulations, the acceleration of the bungy jump is greatest at the jumper's lowest point. This is because the bungy is now stretched to its maximum, meaning if applies a force up on the jumper more than twice his weight. This means he accelerates up at a greater rate than the acceleration down when he left the platform.

When is the acceleration (rate of speeding up or slowing down) greatest during a bungy jump?

When the rope becomes taut, the force on the jumper is mainly his weight downwards, plus a bit of air resistance up. Therefore his speed is increasing nearly as much as it did when he leapt off the platform. So this is not the greatest acceleration of the jump.

On the rebound, the acceleration varies. The jumper is accelerating up but as the bungy recoils, the jumper starts accelerating down again due to the pull of gravity. This does not mean that he's moving down, however, only that his velocity upwards is decreasing.

Right after leaving the platform, the only significant force acting on the bungy jumper is his weight. This causes him to speed up from rest. His speed increases every second by nearly 10 m/s. This is not the maximum acceleration experienced by a bungy jumper, however.

In Queenstown, New Zealand, I jumped off the Kawarau Bridge - the site of the first bungy jump. It was a thrilling experience, preceded by a terrifying, gut-wrenching half hour wait. All in all an awesome adventure, even if the woman fitting my harness didn't know the first thing about the acceleration of free-falling bodies.

Do we take the Earth for granted? It gives us life and sustains us in the manner we're accustomed to, but we don't know the first thing about it: like where did it come from? And how did it form? Most people recognize that the Earth has a big explosion in its history, which they refer to descriptively as the 'Big Bang.' But there are two very good reasons why the Big Bang is not directly responsible for forming the Earth: 1) It happened 13.7 billion years ago. That's more than 9 billion years before the Earth formed (what happened during that time?), and 2) After the Big Bang the universe consisted of only Hydrogen and Helium - not great raw material for building the Earth. The truth is the big bang formed stars, which exploded and then (perhaps) formed more stars, which exploded and then formed our solar system, including the Earth. The early stars performed the vital role of making the heavier elements of which Earth is composed and we are made.

The Earth is clearly old, but exactly how old was difficult to work out. People long believed the Earth had only existed for several thousand years. Then, in the 1800's, a study of geological features (including fjords) led scientists to the conclusion that the planet must be much older - at least millions of years old. Later, the discovery of radioactivity provided a mechanism by which the Earth's core could be continually heated. This meant it was much older than previous estimates of 20-40 million years based on the cooling rate of the Earth. Today through many different methods we have established that the Earth is roughly 4.54 billion years old!

1, 2, 3 A song about 'lectricity because it powers our lives makes it possible for us to thrive because it powers our lives makes it possible for us to thrive Oh, 4, 5, 6, volts of potential difference makes electrons go round if the circuit is complete and sound Circuit's closed Voltage There Current Flows Power Everywhere We use AC, in factories and homes because we can transform it High voltage transmits with lower loss but low voltage is best for safety I said what is electricity? Well, so 1,2,3 a song about 'lectricty because it powers our lives makes it possible for us to thrive because it powers our lives makes it possible for us to thrive Oh, 4,5,6 volts of potential difference makes electrons go round if the circuit is complete and sound Heat makes steam turns turbines and a magnet in coils of wires We use AC, in factories and homes because we can transform it High voltage transmits with lower loss but low voltage is best for safety I said what is electricity? Oh yeah, Oh yeah, C'mon! How'd it be no energy of the electrical persuasion I know we'd have no computers no internet or mobile phones yeah Powers the world Makes the world We need electricity yeah

An introduction to alpha, beta, and gamma radiation

Sound waves in a tube of gas create flames of different heights that dance to the music. A metal tube with holes in it is filled with gas. The gas is lit to create a row of tiny flames. A speaker at one end plays sound into the tube, which creates a standing wave of sound: areas where air molecules are vibrating rapidly separated by areas where the air is fairly still. This produces the different heights of flames and allows the wavelength of the sound wave to be estimated.

There seems to be confusion about what radiation is and where it comes from. Many people believe it is the radiation that comes directly from nuclear power plants that poses a threat to public safety. In fact it is the radioactive atoms, which can escape in the event of an explosion, that pose a safety risk. They can be scattered by the wind over hundreds of kilometres. Then they may be ingested or breathed in. If they release radiation at this point, it is damaging to the body's molecules and cells because the radiation is delivered directly to tissues.

On the surface of Earth all objects accelerate downwards at the same rate - at least, they're supposed to. But we all know dust, pieces of paper, and feathers fall slower. This is of course due to the influence of air resistance. In this experiment we use an evacuated cylinder to test whether a coin and feather really do accelerate at the same rate.

Countries are powered by a diverse range of energy sources, but in Australia electricity generation mainly has one source: fossil fuels. Coal, natural gas, and oil account for over 90% of the country's electricity. Hydro provides 7% with only 0.3% provided by wind and solar. Should Australia consider nuclear power? It is a complicated issue leaving many uncertain about its place in Australia's energy future.

What is radiation? Are all types harmful? What are the most common sources of damaging radiation? Most people view radiation as harmful and negative without understanding what makes it potentially damaging and which forms should be avoided. For example, many felt radiation from mobile phones probably caused cancer but few focused on the carcinogenic effects of UV rays.

Many videos on YouTube show water freezing almost instantaneously. This video shows you how to replicate the experiment and it explains how the phenomenon works. Molecular illustrations are courtesy of: PhET Interactive Simulations University of Colorado http://phet.colorado.edu.

Most people recognize that atoms are the fundamental building blocks of all matter around us. An atom itself is composed of protons, neutrons and electrons. The simplest atom is the hydrogen atom because it consists of only one proton and one electron. If a neutron is added to the nucleus, the atom is still hydrogen, just a more massive version. Atoms of the same element (i.e. those with the same number of protons) but different numbers of neutrons are called isotopes.

My PhD: http://www.physics.usyd.edu.au/super/theses/PhD(Muller).pdf It is a common view that "if only someone could break this down and explain it clearly enough, more students would understand." Khan Academy is a great example of this approach with its clear, concise videos on science. However it is debatable whether they really work. Research has shown that these types of videos may be positively received by students. They feel like they are learning and become more confident in their answers, but tests reveal they haven't learned anything. The apparent reason for the discrepancy is misconceptions. Students have existing ideas about scientific phenomena before viewing a video. If the video presents scientific concepts in a clear, well illustrated way, students believe they are learning but they do not engage with the media on a deep enough level to realize that what was is presented differs from their prior knowledge. There is hope, however. Presenting students' common misconceptions in a video alongside the scientific concepts has been shown to increase learning by increasing the amount of mental effort students expend while watching it.

A short a cappella tribute to experimentalists. It is sung while performing three simple experiments with household items: Mentos dropped in diet Coke, a tea bag emptied and burned, and a ping pong ball floating in the air stream of a hair dryer.

Newton's Three Laws of Motion are a landmark achievement in physics. They describe how all objects move. Unfortunately most people do not really understand Newton's Laws because they have pre-existing ideas about the way the world works. This film is about those pre-existing ideas. By recognizing what people are thinking, it becomes easier to describe the correct scientific concepts of Newton's Three Laws and how they differ from this 'intuitive physics'.

If you've seen footage from the International Space Station or any of the space shuttle missions, you know that astronauts float around as they orbit the Earth. Why is that? Is it because the gravitational force on them is zero in space? (Or nearly zero?) The truth is that the strength of the gravitational attraction is only slightly less than it is on Earth's surface. So how are they able to float? Well, they aren't floating - they're falling, along with the space station. They don't crash into the Earth because they have a huge orbital velocity. So as they accelerate towards the Earth, the Earth curves away beneath them and they never get any closer. Since the astronauts have the same acceleration as the space station, they feel weightless. It's like being in a free-falling elevator (without the disastrous landing). Director of Photography: Stefan Smith Camera Assistant: Raa Perajeev Boom Operator: Maha Sivalingam Production Coordinator: Adrian Tan Production Assistants: James Peniata, Pratheep Ramachandran

If you drop a heavy object and a light object simultaneously, which one will reach the ground first? A lot of people will say the heavy object, but what about those who know both will land at the same time? What do they think? Some believe both objects have the same gravitational pull on them and/or both fall to the ground with the same constant speed. Neither of these things is true, however. The force is greater on the heavy object and both objects accelerate at the same rate as they approach the earth, i.e. they both speed up but at the same rate.

A basketball and a 5kg medicine ball are dropped simultaneously. Which one hits the ground first? It seems obvious that the heavy one should accelerate at a greater rate and therefore land first because the force pulling it down is greater. But this is forgetting inertia - the tendency of mass to resist changes in motion. Therefore, although the force on the medicine ball is greater, it takes this larger force to accelerate the ball at the same rate as the basketball.

Newton's Law of Universal Gravitation can be summarized as "all mass attracts all other mass." But if this is true, why don't we notice the gravitational force of attraction between everyday objects? The reason is because the gravitational force is quite weak.

There is a gravitational force of attraction between the Earth and the moon, but is it mutual? That is, are the forces on the Earth and the moon equal? Most people would say no, the Earth exerts a greater force of attraction because it is larger and has more mass. This is a situation in which Newton's Third Law is relevant. Newton's Third Law says that for every force, there is an equal and opposite reaction force. So the force the Earth exerts on the moon must be exactly equal and opposite the force the moon exerts on the Earth. But how can that be - that the same size force keeps the moon orbiting, but barely affects the Earth? The answer is inertia - the tendency for all objects with mass to maintain their state of motion. Since the Earth has much more mass than the moon, it has greater inertia and therefore experiences much less acceleration for the same amount of force.

People have a lot of different ideas about what gravity is: a downward force that stops you from flying off into space, an attraction smaller objects experience towards larger objects, or a mutual attraction between all masses. It is the last of these ideas that best reflects a scientific conception of gravity.

It takes the moon about 27 days to orbit the Earth. What makes it go round? It is the gravitational attraction of the Earth on the moon. Due to the moon's velocity, the Earth keeps pulling the moon towards it without the moon actually getting closer to the Earth. This is similar to how satellites orbit the Earth.

What forces (i.e. pushes or pulls) are acting on you right now? Most people can identify the gravitational force down, but there must be something else otherwise you would accelerate down towards the center of the Earth. The other main force on you is called the normal force. It is a force perpendicular to the surface that supports you, like the ground or the seat of your chair. You compress this surface and it acts like a spring, pushing you up.

If the Earth were the size of a basketball and the moon a tennis ball, how far apart would they be? Diagrams that are not to scale make us think that they're closer than they really are.

Force is a central concept in physics. By analysing the forces on an object, its resulting motion can be determined. But what exactly is a force? The word force is used in everyday language in a variety of contexts, only some of which reflect the scientific definition of force. In this video, people at Victoria Park in Sydney are interviewed on their ideas of force and the forces that act on them.

A song about Gravity set to the tune of John Mayer's Gravity. Gravity is working with me And Gravity, keeps me on the ground All mass attracts all other mass a force proportional to mass one and two and inversely to the distance between them squared Oh, gravity is working with me and gravity, makes apples fall to ground Oh twice the mass has twice the pull but the force on each is still equal It keeps the moon and the satellites going round Oh twice the mass has twice the pull but the force on each is still equal It keeps the moon and the satellites going round Oh gravity, the force that makes weight on me Woah, gravity, now general relativity (how can that be?) The force between us all is The force between us all is The force between us all is Gravity between us all is Gravity between us all is Gravity between gravity between us all is

If you spin a raw egg and then stop it, it will start spinning again without you having to touch it. A boiled egg, on the other hand, stops and stays stopped. Why is this? Well a raw egg contains a yolk that moves inside the egg independently of the shell. If you stop the shell, the yolk inside continues to move due to its inertia and it therefore gets the egg spinning again.

There is a common perception that weight and mass are basically the same thing. This video aims to tease out the difference between mass and weight by asking people what makes a car difficult to push. The standard answer is that it is difficult to push because it's heavy. But heaviness is a measure of weight, the gravitational pull of the Earth attracting the car to Earth's center. When the car is pushed on a flat road, the force of gravity does not oppose the motion. Instead the resistance felt is an indication of the car's mass which determines its inertia. Inertia is the property of matter that means it tends to resist acceleration - the greater the mass, the less the acceleration for a given amount of force.

If the sun were entirely made of protons, how many would there be in the sun? How can this be worked out using the Google search field?

Well an atom's made of protons, neutrons, and electrons the first two in the nucleus, the third around it it's mostly empty space, but it feels solid in any case The elements are all the different types of atoms they differ by the number of protons in the middle. Hydrogen has only one, but Uranium has a ton It's just chemistry that you and me are made of these atoms Well atoms bond together to form molecules Most of what's surrounding me and you Water, sugar, things yet undreamed of of of of Look around you, see the combinations in a eucalypt tree Mendeleev's periodicity gives us sand and water and the air above ove ove ove ove It's just chemistry that you and me are made of these atoms: Hydrogen, Oxygen, Carbon, Nitrogen, make up the world's life forms Do do do you, do do do do but do you wonder how matter forms something strange when there's a chemical change? Where did these atoms come from? They were fused in stars Light elements combine releasing light from afar Fusion in the sun, creates Helium I guess what I be saying is you gotta use your reason To open up your mind and see the cause of the seasons -How do we know what's true? The scientific method shows you It's just chemistry that you and me are made of these atoms Atoms bond together to form molecules Most of what's surrounding me and you Water, sugar, sand and you'll find things undreamed of So Argon, Neon, Xenon There's no need to overstate 'Cause we are of course This, of this, of this, we're made: atoms

Scientists have to work with some very large and some very small numbers. To represent these numbers more easily, they use scientific notation. Scientific notation relies on powers of 10. This video gives examples of how to represent a large and small number and explains powers of ten.

In the mid 1800's scientists successfully passed an electric current through a vacuum in a glass tube. They saw a glow from the tube that seemed to emanate from the negatively charged plate called the cathode. Since scientists didn't know what the glow was they called it a cathode ray. There was debate over whether the cathode ray was a wave phenomenon like light or a stream of negatively charged particles. JJ Thomson effectively resolved the debate in 1897 by performing a clever experiment that determined the charge to mass ratio of the particles making up the cathode ray. He also showed that this same particle was in all different cathode materials so it must be a constituent common to all atoms. This changed our understanding of the atom from the previous billiard ball model to Thomson's plum pudding model of the atom.

JJ Thomson proposed the first model of the atom with subatomic structure. He had performed a series of experiments and was credited with the discovery of the first sub-atomic particle, the electron. He therefore proposed a new model of the atom called the plum pudding model. In this model, the plums represent negatively charged electrons which can be plucked out of the atom, leaving behind some positively charged pudding. In this film, cherry tart is used as a delicious substitute for plum pudding.

This is the first Veritasium science video. It addresses one of the most fundamental concepts in science: the idea that all things are made of atoms, tiny particles that are in perpetual motion. They attract each other when a little distance apart and repel when squeezed together.

There are a few persistent misconceptions about what causes the seasons. Most believe it is the distance between the Earth and sun which varies to give us seasonal temperature variations. However it is actually the directness of the sun's rays leading to more intense sunshine in summer and less in winter.

A recent survey of scientific literacy in Australia found 30% believe it takes one day for the Earth to go around the sun. This video provides qualitative evidence for the finding from Sydney's Eastern beaches.