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 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)

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 Ivy Tello
Vitamania was written, directed and produced by Sonya Pemberton

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.

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"

Here’s what happens when you just keep zooming in. Use code veritasium at https://incogni.com/veritasium to get an exclusive 60% off an annual Incogni plan.

A big thank you to Magnus Garbrecht from the University of Sydney for showing us around the lab and for his feedback on the script.

Special thanks to Quentin Ramasse for his expertise on the video.

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

▀▀▀
0:00 Why is it hard to see atoms?
2:12 How does an electron microscope work?
4:09 Transmission Electron Microscope (TEM)
5:11 Spherical Aberration
8:55 Field Ion Microscope
11:05 Scanning Transmission Electron Microscope (STEM)
13:24 Probe microscopes
14:02 An unlikely solution
18:08 Seeing atoms

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Join us on Patreon for early access videos, bonus content, and to support Veritasium! https://ve42.co/PatreonDE

Adam Foreman, Albert Wenger, Alexander Tamas, Anton Ragin, Autodidactic Studios, Bertrand Serlet, Blake Byers, Bruce, Dave Kircher, David Johnston, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, Greg Scopel, 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, 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


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References:
Busch, H. (1926). Berechnung der Bahn von Kathodenstrahlen im axialsymmetrischen elektromagnetischen Felde. Annalen Der Physik - https://ve42.co/Busch1926
Ruska, E. (1986). The development of the electron microscope and of electron microscopy. Nobel Lecture - https://ve42.co/Ruska1986
Scherzer, O. (1936) - https://ve42.co/Scherzer1936
Jensen, G. (2015). Part 1: EM Lenses. Caltech - https://ve42.co/Jensen2015
Field Ion Microscope via Wikipedia - https://ve42.co/FieldIon
Transmission Electron Microscope via Wikipedia - https://ve42.co/MicroscopeTEM
Albert V. Crewe biography via UChicagoNews Microscopy Society of America - https://ve42.co/CreweBio
McMullan, D. (1993). Scanning Electron Microscopy 1928 - 1965. Microscopy Society of America, Cincinnati - https://ve42.co/McMullan1993
Electric and Magnetic Field Lenses via MIT - https://ve42.co/LensesMIT
Haider, M. et al. (1998). Towards 0.1 nm resolution with the first spherically corrected transmission electron microscope. Journal of Electron Microscopy - https://ve42.co/Haider1998_1
Haider, M. et al. (1998). Electron microscopy image enhanced. Nature - https://ve42.co/Haider1998_2
Krivanek, O. et al. (2022). Aberration correction in the STEM. CRC Press EBooks - https://ve42.co/Krivanek2022
Crewe, A. V., et al. (1970). Visibility of Single Atoms. Science - https://ve42.co/Crewe1970
Secrets of Size: Atoms to Supergalaxies via the BBC - https://ve42.co/AtomsBBC
Pennycook, S. J. (2012). Seeing the atoms more clearly: STEM imaging from the Crewe era to today. Ultramicroscopy - https://ve42.co/Pennycook2012
Rose, H. H. (2009). Historical aspects of aberration correction. Journal of Electron Microscopy - https://ve42.co/Rose2009
Kavli Prize in Nanoscience via kavliprize.org - https://ve42.co/Kavli2020
Vogt, T. (2019) Aberration-Corrected Electron Microscopy - https://ve42.co/Vogt2019

Images & Video:
Available here - https://ve42.co/AtomsVisuals

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Directed by Gregor Čavlović, Derek Muller, and Tim Usborne
Written by Gregor Čavlović, Tim Usborne, Emily Zhang, and Casper Mebius
Edited by Trenton Oliver and Charlie Grayley
Animated by Mike Radjabov, Fabio Albertelli, Ivy Tello, Emma Wright, and Andrew Neet
Illustrated by Jakub Misiek and Maria Gusakovich
Filmed by Charles Clements
Additional research by Gabe Strong, Geeta Thakur, and Emili Gyles
Produced by Casper Mebius, Derek Muller, Emily Zhang, Gregor Čavlović, Rob Beasley Spence, Tori Brittain, Gabe Strong, Luke Lewis, and Matthew Cavanagh
Thumbnail contributions by Ben Powell, Ren Hurley, and Peter Sheppard
Additional video/photos supplied by Getty Images, Storyblocks
Music from Epidemic Sound

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 final flight
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, Ivy Tello, Mike Radjabov, Mohamed Alhaj, Emma Wright
Illustrations by Jakub Misiek, Emma Wright, Maria Gusakovich
Filmed by Derek Muller and Bernard Lau
Additional Research by Gabriel Strong, 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 Storyblocks
Music from Epidemic Sound and Jonny Hyman

To kickstart your business or online store with a free trial of Shopify, go to http://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

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Huge thanks to Carlo Rovelli: https://t.co/FF5ohRQB8R
And Geraint Lewis: https://www.geraintflewis.com/

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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 Maz - 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 - 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 and Han Evans

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

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. Massive thanks to Curtis Gilberts, and to Radiolab -- listen to their great episode on voting systems here https://radiolab.org/podcast/tweak-vote

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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

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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 Strong
Produced by Petr Lebedev, Derek Muller, Gabriel Strong, 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

#democracy #voting #mathematics

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

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

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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, 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

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References: https://ve42.co/GlassReferences

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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 Strong, Geeta Thakur
Produced by Petr Lebedev, Derek Muller, Rob Beasley Spence, Gabe Strong, 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

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.

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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

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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

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Animation by JD Pounds and Jonny Hyman
Thumbnail by Ivy 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
Sound Design by Jonny Hyman

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Are you smart enough to solve this Google interview question? Use code veritasium at https://incogni.com/veritasium to get an exclusive 60% off an annual Incogni plan.

A massive thank you to Dan Goldman, Jeff Aguilar, Daniel Soto and Georgia Tech’s Complex Rheology And Biomechanics Lab
We’re incredibly grateful to Carl Zimmer, Gayle McDowell, and Geoffrey West

Correction: Dan Goldman is a Professor of Physics not Biomechanics.

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

▀▀▀
0:00 Hard Google Interview Question
2:34 How do Geckos stick to walls?
5:58 Do physicists know the answer?
7:01 The Square-Cube Law
9:10 Tiny Superheroes
10:23 Simulating the problem
13:36 Adding Air Resistance
15:14 The End?
16:16 What would happen if you were shrunk?
17:39 What interviewers actually look for

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

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References:
William Poundstone (Jan 2012). Are You Smart Enough to Work at Google?. - https://ve42.co/smartenough
Giovanni Alfonso Borelli. Translated by Paul Maquet (1989). On the Movement of Animals. - https://ve42.co/borellianimals
In Head-Hunting, Big Data May Not Be Such a Big Deal. (Jun 2013) via New York Times - https://ve42.co/headhuntbigdata
Drag Forces. via Lumen Learning - https://ve42.co/dragforces
R. McN. Alexander (Feb 1995). Leg design and jumping technique for humans, other vertebrates and insects. The Royal Society Publishing - https://ve42.co/legdesignjump
Sharon B. Emerson (Sep 1978). Allometry and Jumping in Frogs: Helping the Twain to Meet. JSTOR - https://ve42.co/allometryfrogs
Jay J. Meyers, Anthony Herrel & James Birch (Jan 2002). Scaling of Morphology, Bite Force and Feeding Kinematics in an Iguanian and a Scleroglossan Lizard. Anthony Herrel - https://ve42.co/scalinglizard
Kirby TJ, McBride JM, Haines TL, Dayne AM. (Aug 2011). Relative Net Vertical Impulse Determines Jumping Performance. Journal of Applied Biomechanics - https://ve42.co/jumpperformance
Rasmussen Mette H. et al (Jul 2022). Evidence that gecko setae are coated with an ordered nanometre-thin lipid film. The Royal Society Publishing - https://ve42.co/geckosetae
Body Orientation During a Skydive. via Libre Texts Physics - https://ve42.co/skydivephysics

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Images & Video:
Here’s how many Google interviews it takes to hire a Googler. (Apr 2019) via CNBC Make It - https://ve42.co/googleinterviews
Google received 3.3 million job applications in 2019. (Jan 2020) via Axios - https://ve42.co/googleapplications
Here’s why you only have a 0.2% chance of getting hired at Google. (Oct 2014) via Quartz - https://ve42.co/hiredgoogle
Dear Reddit, my friend was asked this RIDICULOUS question in a job interview, what’s the best possible answer?. (2011) via Reddit - https://ve42.co/redditblender
Mark Rober. (May 2020) Backyard Squirrel Maze 1.0- Ninja Warrior Course https://www.youtube.com/watch?v=hFZFjoX2cGg
Cambridge University. (Feb 2010) Cambridge Ideas - Sticky Feet https://www.youtube.com/watch?v=hd5upt3IrWM
IV C. (Oct 2023)Incredible Shrinking Man (1957) Jack Arnold. The spider scene. El increíble hombre menguante. Araña https://www.youtube.com/watch?v=wJiJsbBBHpE&t=7s
Russ Amy. (Apr 2018) Honey I Shrunk the Kids 1989 1080p BluRay X264 AMIABLE mkv https://www.youtube.com/watch?v=byxGZ8cD7rk
R Sisters Gaming. (Feb 2022) It Takes Two - Destroyed by the Blender https://www.youtube.com/watch?v=QqrPufq2jP8
ClipsyBox. (May 2017) Hulk vs. Ant-Man - Coca-Cola: Coke Mini https://www.youtube.com/watch?v=sMkGwCw7iv8
El Gato. (June 2021) Squirrel has 44" vertical jump straight up to bird feeder! jumping https://www.youtube.com/watch?v=ethwLHw46JM
A-purpose . (Apr 2024). Who can jump bigger part #2 via Youtube - https://www.youtube.com/shorts/mJhf7wYNkYA

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Special thanks to our Patreon supporters:

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

▀▀▀
Directed by Henry van Dyck
Written by Henry van Dyck
Edited by Peter Nelson and Nick Lear
Assistant Edited by James Stuart
Animated by Fabio Albertelli, Andrew Neet, Jakub Misiek and Emma Wright
Filmed by Henry van Dyck and Lukas Guderjahn
Additional Research by Emilia Gyles and Geeta Thakur
Produced by Derek Muller, Henry van Dyck, Zoe Heron, Rob Beasley Spence and Tori Brittain
Thumbnail contributions by Ben Powell, Ren Hurley and Henry van Dyck
Additional video/photos supplied by Getty Images and Storyblocks
Music from Epidemic Sound and Jonny Hyman

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.

If you enjoyed this video and want to go deeper, you'll find extended interviews, deleted scenes, and some of our early thumbnail concepts over on Patreon https://www.patreon.com/posts/....patreon-what-1120393

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?

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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

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

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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

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

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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 Strong
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

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

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"

Even the GOAT Tom Brady can’t throw a perfect spiral. Here’s why. 🌏 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 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

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A huge thank you to Tom Brady for coming and throwing some footballs with us and letting us analyse his throw. You can check out his channel here: https://www.youtube.com/@tombrady

Also thank you to Kevin Bonner and the team at Shadow Lion for helping make this happen!

A big thanks to Daniel Hare and Wilson for all their help collecting and analyzing the data.

A massive thank you to Prof. Philip Ansell, David Attig, Matt Brotnow, Sam Hince and Derrick Wiberg at the University of Illinois at Urbana-Champaign for all their work testing out footballs in their wind tunnel (more of that to come in our second video).

We’d also like to shout out Stewart Bible, Ryan Sayko and the rest of the team at Resolved Analytics for all their work on the CFD models - https://www.resolvedanalytics.com/

Thank you to Mike Lopez and Tom Bliss from the Football Data and Analytics at the NFL for sharing data and insights from across NFL history.

We’re incredibly grateful to Prof. Richard Price and Major Brett Gibbons for their invaluable contributions to this video.

Thank you to Prof. Chad Orzel, Prof. John Eric Goff, Dr Ainissa Ramirez, Prof. Tony Schmitz & Jonathan Ferguson for all their help on the project.

Also thanks to Chris Anstis for his help as a stand-in QB!

▀▀▀
0:00 How Tom Brady Throws a Football
2:51 Why do you spin a football to throw it?
5:36 How does rifling affect a projectile?
9:09 The Turnover Paradox
11:15 How fast can Tom Brady throw?
14:31 Analysing Brady’s Throw
16:38 Gyroscopic Procession
19:47 It’s impossible to throw straight
23:17 Outdoor vs Dome Stadiums
24:31 Why Tom Brady is the GOAT

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

Images & Video:
Image and video references can be found here - https://ve42.co/BradyVisuals

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

▀▀▀


Producer & Director: Henry van Dyck
Writing: Henry van Dyck & Derek Muller
Editor: Trenton Oliver
Animators: Mike Radjabov & Fabio Albetelli
Illustrator: Jakub Misiek
Researchers: Emilia Gyles & Gabe Strong
Field Producer: Katy Savage
Camera Operators: John Nicholls, Trenton Oliver, Melkwych Pierre-Louis & Scott Wellington
Drone Operators: Nathan Taupez Scinto, Angelo Fiorini
Sound Recordist: Vlady Garcia
Production Assistant: Leah Jiji
Media Manager: Gabriel C. Rodriguez
Assistant Editor: James Stuart
Thumbnail Designers: Ren Hurley & Ben Powell
Production Team: Josh Pitt, Rob Beasley Spence, Tori Brittain & Barbara Abraul
Executive Producers: Derek Muller & Zoe Heron

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

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...

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.

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

Thanks to Ansys for help with the simulations: https://www.ansys.com/products..../electronics/ansys-h

Huge thanks to Richard Abbott from Caltech for all his modeling

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/channe....l/UCgZUVIEtBnnBpFWJu
Big Clive: https://www.youtube.com/c/Bigclive
Z Y: https://www.youtube.com/user/ZongyiYang
NYU Quantum Technology Lab
https://www.youtube.com/channe....l/UCk7io8SN3ZwKvkpnM
Dr. Ben Miles
https://www.youtube.com/channe....l/UCUeZBocfxALSUdOgN
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

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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

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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
Thumbnail by Ignat Berbeci
Produced by Derek Muller, Petr Lebedev, and Emily Zhang

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.

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/
https://www.ncbi.nlm.nih.gov/p....ubmed/15637215/?ncbi
http://soils.wisc.edu/facstaff..../barak/poster_galler
https://www.politico.com/agend....a/story/2017/09/13/f
http://www.abc.net.au/news/201....8-05-24/scientists-w

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

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.

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
Nicole Sharp from FYFD https://ve42.co/fyfd
Pavol Dobryakov turbulent simulations: https://paveldogreat.github.io..../WebGL-Fluid-Simulat

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"