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'

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 Ivy 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"

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

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/~b....elz/phys5110/PhysRev

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

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.

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.

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.

Thanks to https://www.chess24.com/ and Chessable for the clip of Magnus.

▀▀▀
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

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"

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/in....stant-stone-just-add
https://rootsofprogress.org/cement-redux

Cement Chemistry and Sustainable Cementitious Materials
https://www.youtube.com/@cemen....tchemistryandsustain

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

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.

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 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 Jones, Torrell Henderson and Nate Roth for being great instructors. iFly run STEM education trips, where you can experience terminal velocity first hand – https://www.iflyworld.com/prog....rams/stem-field-trip

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
Phantom slow motion camera & lenses provided by Panny Hire L.A
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
Thumbnail by Ignat Berbeci
Produced by Derek Muller, Petr Lebedev, and Emily Zhang

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

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

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/plosm....edicine/article?id=1

Trouble at the Lab:
http://www.economist.com/news/....briefing/21588057-sc

Science isn't broken:
http://fivethirtyeight.com/fea....tures/science-isnt-b

Visual effects by Gustavo Rosa

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/doc....s/Cira_DancingDrople
Marangoni Flow: http://web.mit.edu/2.21/www/Le....c-notes/Surfacetensi
Surface Energy: https://itf.fys.kuleuven.be/~j....oi/papers/Wetting%20

Filming and master pipetting by Raquel Nuno
Research and writing by Aaron White

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/Lu....tron-Caseta-Wireless
https://www.homedepot.com/p/Lu....tron-Caseta-Wireless
https://www.homedepot.com/p/Lu....tron-Caseta-Wireless
https://www.homedepot.com/p/Lu....tron-Caseta-Wireless
https://www.homedepot.com/p/Lu....tron-Caseta-Wireless
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/Lu....tron-Caseta-Wireless
https://www.homedepot.com/p/Lu....tron-Single-Pole-Cas
https://www.homedepot.com/p/Lu....tron-Caseta-Wireless -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
Thumbnail by Ignat Berbeci
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


▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
Executive Producer: Derek Muller
Writer: Derek Muller
Animators: Ivy Tello, Another Angle 3D Visuals
SFX: Shaun Clifford
Camerapeople: Derek Muller, Raquel Nuno, Shirley Dutoit, Emily Zhang
Editor: Derek Muller
Producers: Derek Muller, Casey Rentz, Petr Lebedev, Emily Zhang
Additional video supplied by Getty Images
Music from Epidemic Sound https://epidemicsound.com
▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

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.

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