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

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!

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 Ivy 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

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

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

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The wager agreement: https://ve42.co/wager

Prof. Kusenko's slides: https://ve42.co/Kusenko

My rebuttal: https://ve42.co/rebuttal
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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

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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

Ruina corrects errors in the above paper: http://ruina.tam.cornell.edu/r....esearch/topics/misce

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.

The Manim Community Developers. (2021). Manim – Mathematical Animation Framework (Version v0.13.1) [Computer software]. https://www.manim.community/

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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

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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

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

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References:
Libbrecht, K. G. (2019). A Quantitative Physical Model of the Snow Crystal Morphology Diagram. arXiv preprint arXiv:1910.09067. -- https://ve42.co/Libbrecht2019

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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 Ivy Tello and Trenton Oliver
Additional video supplied by Getty Images
Music from Epidemic Sound
Produced by Derek Muller, Petr Lebedev and Emily Zhang

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.

The beautiful math behind six degrees of separation. Sponsored by Incogni - use code veritasium at https://incogni.com/veritasium to get an exclusive 60% off.

If you’re looking for a molecular modelling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV

Sign up to the Veritasium newsletter for weekly science updates - https://ve42.co/Newsletter

To play around with the simulations in the video, you can follow these links:
Disease spreading - https://www.veritasium.com/simulation2
Preferential attachment - https://ve42.co/barabasiAlbertSim


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A huge thank you to:
Duncan Watts, for creating the small-world model that inspired this video and expanding on his further work; Steve Strogatz, for telling the story with such clarity & humour; Albert-László Barabási, for revealing the the inevitability and impact of hubs; Mark Buchanan, for his insightful takeaways that pulled it all together.

Check out Duncan Watts’ books here - https://www.amazon.com/Six-Deg....rees-Science-Connect
Check out Mark Buchanan’s book here - https://ve42.co/bookNexusWorlds

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Chapters:
0:00 What is six degrees of separation?
4:23 Network Shortcuts
7:11 The Strength of Weak Ties
8:20 Proving it’s a small world
10:39 How quickly can disease spread?
12:36 Strogatz goes viral
16:59 What is a network hub?
18:23 Preferential Attachment
23:38 The Prisoner’s Dilemma
28:22 Your behavior can change the world’s


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References can be found here - https://ve42.co/networksRefs

Image and video references can be found here - https://ve42.co/networksVisuals

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Special thanks to our Patreon supporters:
Alex Porter, Alexander Tamas, Anton Ragin, Anupam Banerjee, Gnare, Ibby Hadeed, Jon Jamison, Juan Benet, Lee Redden, Meekay, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Ubiquity Ventures, Adam Foreman, Albert Wenger, armedtoe, Balkrishna Heroor, Bertrand Serlet, Blake Byers, Bruce, Dave Kircher, David Johnston, David Tseng, Evgeny Skvortsov, Garrett Mueller, gpoly, Jeromy Johnson, KeyWestr, Kyi, Marinus Kuivenhoven, Matthias Wrobel, meg noah, Michael Bush, Michael Krugman, Robert Oliveira, Tj Steyn & wolfee

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Writers: James Moore, Casper Mebius & Derek Muller
Producer & Director: James Moore
Editors: Peter Nelson & Jack Saxon
Camera Operators: Derek Muller & Casper Mebius
Animators: Andrew Neet, Emma Wright, Fabio Albertelli & Ivy Tello
Illustrators: Jakub Misiek
Assistant Editor: James Stuart
Researchers: Callum Cuttle, Aakash Singh Bagga & Gabe Strong
Simulations: Callum Cuttle, Gabe Strong & Ivy Tello
Sound Designers: Pavle Peric & James Stuart
Thumbnail Designers: Abdallah Rabah, Ren Hurley & Ben Powell
Production Team: Josh Pitt, Nicola Griffiths & Rob Beasley Spence
Executive Producers: Derek Muller & Casper Mebius
Additional video/photos supplied by Getty Images, Storyblocks
Music from Epidemic Sound

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.

How an SAT question became a mathematical paradox.

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/

The Perseverance Rover and helicopter Ingenuity have landed safely on Mars. A few years back I got to visit NASA JPL to interview the scientists to find out their goals for the mission. 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"

How do you make infinite choices? 👉 To try everything Brilliant has to offer for free for a full 30 days, visit http://brilliant.org/veritasium. You’ll also get 20% off an annual premium subscription.

Try Snatoms! A molecular modelling kit I invented where the atoms snap together.
https://ve42.co/SnatomsV

Sign up to the Veritasium newsletter for weekly science updates - https://ve42.co/Newsletter

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A huge thank you to Dr Asaf Karagila, Prof. Alex Kontorovich, Prof. Joel David Hamkins, Prof. Andrew Marks, Prof. Gabriel Goldberg and Prof. Elliot Glazer for their invaluable expertise and contributions to this video.

Head over and sign up to our Patreon for some exclusive behind the scenes footage, showing how the animations and illustrations for this video were made - https://www.patreon.com/posts/patreon-behind-126443880?utm_medium=clipboard_copy&utm_source=copyLink&utm_campaign=postshare_creator&utm_content=join_link

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0:00 What comes after one?
2:42 Some infinities are bigger than others
6:17 The Well Ordering Principle
10:32 Zermelo And The Axiom Of Choice
17:22 Why is the axiom of choice controversial?
23:16 The Banach–Tarski Paradox
27:53 Obviously True, Obviously False
29:58 Your Proof Your Choice

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References:

Up and Atom - https://www.youtube.com/watch?v=X56zst79Xjg
Minutephysics - https://www.youtube.com/watch?v=A-QoutHCu4o
PBS Infinite Series - https://www.youtube.com/watch?v=hcRZadc5KpI&t=125s
Vsauce - https://www.youtube.com/watch?v=s86-Z-CbaHA&t=474s
Ernst Zermelo via Wikipedia - https://ve42.co/zermeloBio
Axiom of choice via Wikipedia - https://ve42.co/choiceAxiom
Georg Cantor via Wikipedia - https://ve42.co/cantorMath
Gregory H. Moore (2013). Consequences of the Axiom of Choice. Dover Publications - https://ve42.co/choiceBook
Georg Cantor (1874). On a property of the class of all real algebraic numbers. Journal für die Reine und Angewandte Mathematik - https://ve42.co/MeyerCantor1874
Heinz-Dieter Ebbinghaus (Dec 2012). Zermelo and the Heidelberg Congress 1904. Historia Mathematica - https://ve42.co/SciDirect1904
Herbert B. Enderton (1977). Elements of Set Theory. - https://ve42.co/SciDirectGCH

Additional References - https://ve42.co/AoCAdRefs

Images & Video:

Foundations of a general theory of sets by Georg Cantor via ViaLibri - https://ve42.co/grundlagen
Alfred Tarski by George Bergman via Wikimedia Commons - https://ve42.co/tarski
Alfred Tarski Offprint Group by Alfred Tarski via Bonhams - https://ve42.co/tarskipaper
La mission strasbourgeoise de Maurice Fréchet by Laurent Mazliak via Images des mathematiques - https://ve42.co/frechet
Kurt Gödel by Alfred Eisenstaedt via New Yorker - https://ve42.co/godel
Leopold Kronecker by Granger via Fine Art America - https://ve42.co/kronecker
Lashi Bandara (2006). Zermelo-Frankel Set Theory and Well Orderings. ResearchGate - https://ve42.co/zermelofrankel
Heidelberg, Germany 1936 by Wagner & Debes via Ward Maps - https://ve42.co/heidelberg
Pythagoras by J. Augustus Knapp via the marginalian - https://ve42.co/pythag
Paul Cohen by C. J. Mozzochi via C. J. Mozzochi - https://ve42.co/paulcohen
Instituto de Matemática Pura e Aplicada. Lecture 01: Introduction: a non-measurable set via Youtube - https://www.youtube.com/watch?v=llnNaRzuvd4&t=834s
Simons Foundation. Fields Medal: James Maynard. Youtube https://www.youtube.com/watch?v=un-z8kgOrV0&t=8s

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Special thanks to our Patreon supporters:
Adam Foreman, Albert Wenger, Alex Porter, Alexander Tamas, Anton Ragin, Autodidactic Studios, Balkrishna Heroor, Bertrand Serlet, Blake Byers, Bruce, Dave Kircher, David Johnston, David Tseng, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, Greg Scopel, HydrochloRick, Jon Jamison, Juan Benet, Keith England, 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, wolfee


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Directed by Kaela Albert
Written by Kaela Albert and Emily Zhang
Edited by Jack Saxon and Luke Molloy
Assistant Edited by James Stuart
Animated by Fabio Albertelli, Andrew Neet, Alex Zepharin, Mike Radjabov, Emma Wright and Ivy Tello
Illustrations by Jakub Misiek, Maria Gusakovich, Cainejan Esperanza, Tommy A. Steven and Emma Wright
Additional research by Emilia Gyles, Gabe Bean, Geeta Thakur and Vincent Cheng
Produced by Kaela Albert, Casper Mebius, Derek Muller, Emily Zhang, Zoe Heron, Rob Beasley Spence, and Tori Brittain
Additional Editing by Luke Molloy and James Stuart

Thumbnail contributions by Ben Powell, Peter Sheppard and Ren Hurley

Additional video/photos supplied by Getty Images and Storyblocks
Music from Epidemic Sound

You probably don’t understand how a rainbow really works. Get a little smarter every day with Brilliant. Visit https://brilliant.org/veritasium to get 20% off your annual premium subscription.

Special thanks to Mats Vermeeren.

00:00 Most people don't understand rainbows
01:08 Light refraction explained
08:20 How does a rainbow form?
13:10 Circular rainbows
15:14 Why are rainbows curved?
17:30 Why can’t you see a rainbow with sunglasses?
18:43 Why is it brighter underneath a rainbow?
20:44 Different types of rainbow
23:46 Invention of the cloud chamber

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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, Farbod Mansorian, 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, Richard Sundvall, Sam Lutfi, Spilmann Reed, 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

CORRECTION: We mistakenly used picture of the portrait artist Henry Tanworth Wells at 23:54. It should be a picture of CTR Wilson. Sorry! Thanks, @manicpixiedreambuoy, for pointing it out.

CORRECTION: The animation at 18:06 shows only the parallel polarization being transmitted, when in reality both parallel and perpendicular polarization light gets transmitted. Perpendicularly polarized light doesn't exhibit a Brester's angle so there's always both reflection and transmission when going from a high index of refraction material to a low index of refraction material.

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References: https://ve42.co/RefsRainbows

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Directed by Pablo Rovetto and Derek Muller
Written by Pablo Rovetto and Derek Muller
Edited by Nick Lear and Trenton
Animated by Mike Radjabov, Ivy Tello, David Szakaly, Emma Wright and Fabio Albertelli
Filmed by Derek Muller
Additional research by Gabe Strong and Geeta Thakur
Produced by Pablo Rovetto, Derek Muller, Emily Zhang, Rob Beasley Spence 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 surprising genius of Strandbeests. Fight the data brokers with Incogni. Head over to https://incogni.com/veritasium to get 60% off your annual subscription.

A massive thank you to Theo Jansen, to learn more about him and his Strandbeests check out: https://www.strandbeest.com/

A special thank you to Adam Savage, check out his channel Tested over at: https://www.youtube.com/tested

If you enjoyed the Strandbeest song at the end, you can hear the whole thing on our Patreon: https://www.patreon.com/posts/....by-popular-song-1174

Also on Patreon: an extended bonus interview with Adam Savage https://www.patreon.com/posts/117886682

0:00 Creation of the Beests
2:40 Learning to walk
6:50 Overcoming the sand
9:00 Surviving the storms
11:46 Building muscle
14:27 A developing brain
17:39 Fossils and decay
18:13 Strandbeests and climate change
19:16 Legacy
20:03 The Virus is Spreading

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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, Autodidactic Studios, Bertrand Serlet, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Farbod Mansorian, Garrett Mueller, Gnare, Greg Scopel, I. H., Juan Benet, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Spilmann Reed, TTST, Tj Steyn, Ubiquity Ventures, gpoly, 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

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References: https://ve42.co/Refstrandbeest

Video and Image Credits:
Global Temperature Anomalies from 1880 to 2022 by via nasa.gov - https://ve42.co/temp188022
Adam Savage’s TestedAdam Savage's One Day Builds: Pedal-Powered Strandbeest! via Youtube - https://ve42.co/pedalbeest
greenmanbucket1980: Walter Cronkite on Climate Change via Youtube - https://ve42.co/cronkitecc
ThamesTvClimate Change | Global Warming | Pollution | This Week | 1988 via Youtube - https://ve42.co/1988ccnews
AP ArchiveUSA: VICE PRESIDENT AL GORE'S WARNING ON GLOBAL CLIMATE via Youtube - https://ve42.co/goresalarm
ThamesTvClimate Change - Warming Warning - 1981 via Youtube - https://ve42.co/1981warning
CBS New YorkReport Warns Of Rising Sea Levels via Youtube - https://ve42.co/searise
ShatnerMethodEarly Warnings of Climate Change Catastrophe - 1982 - CBS Evening News via Youtube - https://ve42.co/1982cbccc
The Weather NetworkNetherlands: Wind storm almost topples truck, tears roof off building via Youtube - https://ve42.co/dutchstorm
NBC NewsDeadly Storm Makes Crossing The Street A Battle In The Netherlands | NBC News via Youtube - https://ve42.co/stormbattle
Marcel OzymantraA clip from The Simpsons Season 28 Episode 10 "The Nightmare After Krustmas" via Youtube - https://ve42.co/simpsonscc
EngineezyI Built A Mechanical Walking Robot (with GPS) via Youtube - https://ve42.co/mechwalker
BigWR_永恒跳动的火焰Epic ride | Walking robot creature Strandbeest via Youtube - https://ve42.co/epicbeest
JK BrickworksLEGO Steampunk Walking Ship (Strandbeest) via Youtube - https://ve42.co/legobeest
The QEpic Cycling | Truly Unique Bicycle that Walks via Youtube - https://ve42.co/bikewalks
James BrutonBalancing Strandbeest via Youtube - https://ve42.co/beestbalance
TED-EdClosing the Dutch Maeslantkering (flood defence) | Timelapse via Youtube - https://ve42.co/floodclose
Peter TheobaldCentaur frame using Strandbeest mechanism - walking test via Youtube - https://ve42.co/centaurbot
The QDIY Walking Robotic Creature Strandbeest via Youtube - https://ve42.co/diybeest
HiroLabo OECUQuadruped Passive Walker by Strandbeest / Theo Jansen / LEGO via Youtube - https://ve42.co/quadwalker
Gabriel LaflammeStrandbeest 3d printed via Youtube - https://ve42.co/3dbeest
BigWR_永恒跳动的火焰Epic ride | Walking robot creature Strandbeest via Youtube - https://ve42.co/beestride
EngineezyI Built A Mechanical Walking Robot (with GPS) via Youtube - https://ve42.co/gpswalker
JKBrickworksLEGO Steampunk Walking Ship (Strandbeest) via Youtube - https://ve42.co/legoship
ZenichiWorksThe Playa Crawler Construction via Youtube - https://ve42.co/playabot
Concept BytesI built a WALKING coffee table via Youtube - https://ve42.co/walkingtable

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Directed by Casper Mebius
Written by Casper Mebius, Derek Muller and Petr Lebedev
Edited by Luke Molloy, Laura Mills, and Peter Nelson
Animated by Fabio Albertelli and Mike Radjabov
Illustrated by Jakub Misiek
Filmed by Casper Mebius, Rasoel Al Safar and Derek Muller
Additional research by Gabe Strong
Produced by Casper Mebius, Derek Muller, Leah Yost, Petr Lebedev, Rob Beasley Spence and Tori Brittain
Thumbnail contributions by Ben Powell, Ren Hurley and Peter Sheppard
Additional video/photos supplied by Getty Images, Storyblocks
Music from Epidemic Sound

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.

How Thermite turned the clickety-clack of railroads into seamless, silent tracks. Get an exclusive 15% discount on Saily data plans! Use code veritasium at checkout. Download Saily app or go to https://saily.com/veritasium
A massive thank you to everyone at Goldschmidt for making this possible. With special thanks to Dr. Axel Hoeschen, Christof Gassmann and Claudia Koch.

If you want to learn all the details about why we don’t need expansion joints anymore, check out Grady’s excellent video here: youtu.be/zqmOSMAtadc

If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically. https://snatoms.com/

Sign up to the Veritasium newsletter for weekly science updates - https://ve42.co/Newsletter

▀▀▀
00:00 The problem with continuous welded rail
03:33 How to weld two rails together
10:16 Why is rapidly cooled steel brittle?
11:40 Thermite reaction and a see-through mould
16:30 Clean up
19:11 Metallurgy
22:15 How strong is the weld?
24:26 Why don’t the rails buckle?

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References:
Practical Engineering. Why Railroads Don't Need Expansion Joints youtu.be/zqmOSMAtadc
Stress–strain curve In Wikipedia - https://ve42.co/stressstrain
The Efficient Engineer. Understanding Metals via Youtube https://youtu.be/PaGJwOPg2kU
moodlemech. Properties and Grain Structure via Youtube - youtu.be/uG35D_euM-0

Images & Video:
bhadeshi123. Martensitic transformation via Youtube youtu.be/OQ5lVjYssko
Stratford Works In Wikipedia - https://ve42.co/stratford
Electric Tram 1881 In Wikipedia - https://ve42.co/tram
Water Quenched Steel In Wikipedia - https://ve42.co/quench
Synagoge 1922 In Wikipedia - https://ve42.co/synagoge

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Special thanks to our Patreon supporters!
Join the community to help us keep our videos free, forever: https://ve42.co/PatreonDE

Alexander Tamas, Autodidactic Studios, Farbod Mansorian, Gnare, Juan Benet, Lee Redden, Meekay, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Sam Lutfi, Ubiquity Ventures, Adam Foreman, Albert Wenger, Anton Ragin, Bertrand Serlet, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, gpoly, Greg Scopel, I. H., KeyWestr, Kyi, Marinus Kuivenhoven, Matthias Wrobel, meg noah, Michael Krugman, Spilmann Reed, Tj Steyn, TTST, wolfee.

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Directed by Derek Muller and Casper Mebius
Written by Derek Muller and Casper Mebius
Edited by Trenton Oliver
Animated by Mike Radjabov, Rokas Vikšraitis and Fabio Albertelli
Filmed by Derek Muller, David Bochmann, Casper Mebius, Luise Dietert, Henning Fischer and Harald Schweiger
Additional research by Geeta Thakur
Produced by Derek Muller, Casper Mebius, Gregor Čavlović, Geeta Thakur, Rob Beasley Spence, Emily Lazard and Tori Brittain
Thumbnail contributions by Peter Sheppard and Ren Hurley
Additional video/photos supplied by Getty Images and Story Blocks
Music from Epidemic Sound

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

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

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 follow their social media @skydive_perris and 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.

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References:
The Exam — https://ve42.co/AAPT2014Exam
The Solution — https://ve42.co/AAPT2014Solutions

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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

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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

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