Cuando se comprime el aire rápidamente, puede alcanzar temperaturas altas. En esta demostración, enseñamos como el algodón puede llegar al punto de auto-ignición por una compresión rápida de aire en la jeringa de fuego.

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Dirección y edición- Enrique Morán
Traducción- Diego Magaña

Doblaje por:
Diego Magaña - Derek Muller
Enrique Morán- Nigel

Veritasium fue fundado por Derek Muller- https://www.youtube.com/channe....l/UCHnyfMqiRRG1u-2Ms

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

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

How much would it take for you to risk $10?
Check out Audible: http://bit.ly/AudibleVe
Can you solve this? http://bit.ly/248Ve
Regression to the mean: http://bit.ly/VeRTTM

Help translate Veritasium videos into other languages: http://veritasium.subtitl.us

Psychological literature shows that we are more sensitive to small losses and than small gains, with most people valuing a loss around 1.5-2.5 times as much as a gain. This means that we often turn down reasonable opportunities for fear of the loss. However over the course of our lives we will be exposed to many risks and opportunities and this invariably means that taking every small reasonable bet will leave us better off than saying no to all of them.

NOTE: The video is not saying to accept every bet, only those with reasonable odds (preferably in your favour), and those which if you lose would not cause significant financial or other damage. In those cases it is wise to be loss averse!

Filmed by Adrian Tan

Thanks to Physics Girl for suggestions on previous versions of this video. https://www.youtube.com/physicswoman

Why does time appear to speed up as we get older? Can we slow it down?
Thanks to the National Geographic Channel for sponsoring this video!
The new season of Brain Games starts Sunday, February 14th at 9/8c - http://po.st/90S7Ow

Brain Games is an Emmy-nominated TV series that explores the inner workings of the human mind through experiments and interactive games. Did you know it's estimated that you have more than a dozen senses in addition to the standard five? One of those is a sense of time or chronoception. Tune in to the new season of Brain Games to learn about all of your senses, and more, starting Sunday, February 14 at 9/8c

References:

Ageing and duration judgement:
http://bit.ly/1TRN0cr

Nerve conduction velocity slowing with age:
http://bit.ly/23Wq6oE

Experiments with rats suggest time perception is distributed across brain:
http://bit.ly/1T6IjdO

Time perception with repeated stimuli:
http://bit.ly/1TRNbo5

Energy usage in brain with age:
http://bit.ly/1nXliOU

Time perception in moments of fear / danger:
http://bit.ly/1RoK7Ps
http://1.usa.gov/1TRNa3w
http://bit.ly/1Q8tDvW

Attention’s relation to time perception and recollection of perceived time:
http://bit.ly/20odeD8
http://bit.ly/1TRNfEf

The merging of two neutron stars was detected by gravitational waves and then by telescopes in all parts of the electromagnetic spectrum. This is a historic detection as it demonstrates:
- the first gravitational waves detected from inspiraling neutron stars
- the first joint observation by gravitational wave and electromagnetic wave astronomy
- identification of a gamma ray burst in conjunction with merging neutron stars
- how gravitational waves and gamma rays can be used together to locate their source

All evidence so far indicates that the data support General Relativity.

Special thanks to Patreon supporters:
Tony Fadell, Donal Botkin, Curational, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Corvi

Support Veritasium on Patreon: http://ve42.co/patreon

Graphics from:
Jets and Debris from a Neutron Star Collision
This animation captures phenomena observed over the course of nine days following the neutron star merger known as GW170817. They include gravitational waves (pale arcs); a near-light-speed jet that produced gamma rays (magenta); expanding debris from a "kilonova" that produced ultraviolet (violet), optical and infrared (blue-white to red) emission; and, once the jet directed toward us expanded into our view from Earth, X-rays (blue).
Credit: NASA's Goddard Space Flight Center/CI Lab

Virgo Helps Localize Gravitational-Wave Signals
Sky localizations of gravitational-wave signals detected by LIGO beginning in 2015 (GW150914, LVT151012, GW151226, GW170104), and, more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo came online in August 2017, scientists were better able to localize the gravitational-wave signals. The background is an optical image of the Milky Way. The localizations of GW150914, LVT151012, and GW170104 wrap around the celestial sphere, so the sky map is shown with a translucent dome.
Credit: LIGO/Virgo/NASA/Leo Singer (Milky Way image: Axel Mellinger)

Variety of Gravitational Waves and a Chirp
The signal measured by LIGO and Virgo from the neutron star merger GW170817 is compared here to previously detected binary black hole mergers. All signals are shown starting at 30 Hertz, and the progression of GW170817 is shown in real time, accompanied by its conversion to audio heard at the end of the movie. GW170817 was observable for more than 30 times longer than any previous gravitational-wave signal.
Credit: LIGO/University of Oregon/Ben Farr

LIGO is funded by the NSF, and operated by Caltech and MIT, which conceived of LIGO and led the Initial and Advanced LIGO projects. Financial support for the Advanced LIGO project was led by the NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council) making significant commitments and contributions to the project.

More than 1,200 scientists and some 100 institutions from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration and the Australian collaboration OzGrav. Additional partners are listed at http://ligo.org/partners.php

The Virgo collaboration consists of more than 280 physicists and engineers belonging to 20 different European research groups: six from Centre National de la Recherche Scientifique (CNRS) in France; eight from the Istituto Nazionale di Fisica Nucleare (INFN) in Italy; two in the Netherlands with Nikhef; the MTA Wigner RCP in Hungary; the POLGRAW group in Poland; Spain with the University of Valencia; and the European Gravitational Observatory, EGO, the laboratory hosting the Virgo detector near Pisa in Italy, funded by CNRS, INFN, and Nikhef.

Why do spikes form on ice cubes? Without them the world would be vastly different.
Awesome Jingle by Accent: http://bit.ly/AccentVe
Thanks to Prof. Stephen Morris from UofT: http://bit.ly/1GFANBE

Filmed in part by Martin Marek in Olomouc, Czech Republic

Time lapse of a growing ice spike by Lesley Hill, Russ Sampson and Edward Lozowski, with technical help by Kenny Lozowski.

Ice spike image by Dan and Lynn Wolaver: http://wolaver.org/log/09.11.29.htm

Concerned ice spike video by rocknut420: https://www.youtube.com/watch?v=GwM0we_t94c

Earth footage courtesy of NASA: https://www.youtube.com/watch?v=G4BPOEmugtM

Ice vase image by PgunnG: http://www.reddit.com/r/pics/c....omments/1voeqk/so_i_

Second ice vase image by A K Haart: http://akhaart.blogspot.com/20....15_01_01_archive.htm

For a report on ABC's Catalyst program (http://www.abc.net.au/catalyst/), I visited the Large Hadron Collider in Switzerland to find out what is being done now that the Higgs Boson has been discovered.

Although its mass has been measured around 125-126 GeV most of the other properties of the particle remain unknown. Its spin appears to be 0 or 2 but more results are required to nail this down. If it is the standard model Higgs, the spin should be 0, resulting in a fairly symmetric distribution of decay products in the detectors.

We may know this year if it's not the standard model Higgs - this would be the case if it doesn't decay into specific particles with the expected frequency. However if it is the standard model Higgs, it may take many more years to be certain. The large hadron collider will be shut down in 2013 for upgrades so that higher energies up to 14 TeV can be tested. Right now the LHC is operating at 8 TeV. The next announcement is expected in December.

Do negative air ions improve mood, anxiety, depression, alertness?
Part of this video was sponsored by LastPass, click here to find out more: http://bit.ly/2RZZTZk

Special thanks to Prof. Jack Beauchamp and Dr. Nathan Dalleska from Caltech for all their help running these experiments and discussing the research. For more, check out the links below:
http://www.cce.caltech.edu/peo....ple/jesse-l-jack-bea
http://beckmaninstitute.caltech.edu/eac.shtml

If you want to dig into the research on negative ions yourself, I suggest starting with the review studies:

Air ions and mood outcomes: a review and meta-analysis.
Perez V, Alexander DD, Bailey WH.
BMC Psychiatry. 2013 Jan 15;13:29.
https://www.ncbi.nlm.nih.gov/pubmed/23320516

Air ions and respiratory function outcomes: a comprehensive review
Dominik D Alexander, William H Bailey, Vanessa Perez, Meghan E Mitchell, and Steave Su
J Negat Results Biomed. 2013; 12: 14.
https://www.ncbi.nlm.nih.gov/p....mc/articles/PMC38485

Exposure of laboratory animals to small air ions: a systematic review of biological and behavioral studies.
Bailey WH, Williams AL, Leonhard MJ.
Biomed Eng Online. 2018 Jun 5; 17(1):72.
https://www.ncbi.nlm.nih.gov/pubmed/29866122

Thumbnail photography by Raquel Nuno

VFX by Alan Chamberlain

Sound recording by Whitney Clavin

Motion Graphics by Charlie Kilman

Music from Epidemic Sound: http://epidemicsound.com "Capture a Picture 1" and "Seaweed"

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

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

This fungus lives on your scalp and may affect the genes you express.
Check out Head & Shoulders research on getting rid of dandruff: https://ve42.co/HS

Animation by Pindex: https://ve42.co/pindex

When I started this project, I wasn't sure what caused dandruff and I also didn't think much science would go into making a shampoo like Head & Shoulders. So what I learned really surprised me:

There are hundreds of scientists working on this shampoo. They run crazy-sounding experiments like hanging hair near Tokyo highways to understand how real-world environments deposit dirt on hair. They use sophisticated scientific techniques like electron microscopes, nuclear magnetic resonance and gene sequencing to study dandruff on the molecular level.

In fact they sequenced the entire genome of Malassezia globosa in 2002, one year after the human genome project. Their findings are published in international refereed journals. What they have found is that the Malassezia fungi create free fatty acids as byproducts of their digestion, which for some people create irritation and lead to hyper-proliferation of skin cells, flaking, histamines, inflammatory cytokines, and blood proteins reaching the surface of the skin. These findings indicate the unhealthiness of dandruff scalp and suggest a possible remedy - controlling the metabolism of the Malassezia fungi. This is achieved using different active ingredients in different products and different parts of the world, including zinc pyrithione, selenium sulfide, and piroctone olamine. With the reduction of irritants, the scalp actually expresses different genes, producing a signature more similar to a non-dandruff baseline scalp.

Music from Epidemic Sound: http://epidemicsound.com
Music also by Kevin MacLeod: http://incompetech.com

Veritasium second channel: http://bit.ly/2Veritasium
Rodney Fox Shark Attack Story: http://bit.ly/1frAwlI
Check out Audible: http://bit.ly/AudibleVe

For this video I went off the coast of South Australia to an island frequented by great white sharks. Here they hunt seals and fish. I've never been scuba diving before but I got into a cage and filmed the sharks under water. It was an incredible experience. Then we came back on the surface to tag the sharks.

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

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

We put aerogel to the test vs 'not-a-flamethrower', a huge 2000°C flame to a large fiberglass blanket infused with silica aerogel - formerly the lightest solid (that title is now held by graphene aerogel).

Special thanks to:
Aerogel Technologies: https://ve42.co/aerogeltech
Aspen Aerogels: https://ve42.co/aspen
Ben: @BenScho999999
Dr. Stephen Steiner and the Aerogel Technologies team

The footage of aerogel materials in cold environments was provided courtesy of Aspen Aerogels. Their product, cryogel, was shown to be flexible in liquid nitrogen while preventing cold burns to the hand. They are the manufacturer of the blanket used in the main portion of this video.

This is the finale of my three-part series on aerogel. I'll put links to the other parts below:
World's Lightest Solid: https://youtu.be/AeJ9q45PfD0
I Waterproofed Myself With Aerogel: https://youtu.be/GcdB5bFwio4

Huge thanks to Patreon supporters:
Alfred Wallace, Arjun Chakroborty, Bryan Baker, Chris Vargas, Chuck Lauer Vose, Dale Horne, Donal Botkin, Eric Velazquez, halyoav, James Knight, Jasper Xin, Joar Wandborg, Kevin Beavers, kkm, Leah Howard, Lyvann Ferrusca, Michael Krugman, Mohammed Al Sahaf, Noel Braganza, Philipp Volgger, Pindex, Ron Neal, Sam Lutfi, Stan Presolski, Tige Thorman

This is an educational video demonstrating scientific experiments performed by professionals. It should not be attempted by viewers.

Music from Epidemic Sound: http://epidemicsound.com "Running Against the Clock" "Dangerous Forests"

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

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Everyone has played with a mixture of corn starch and water (or at least I hope they have). This was one of my favorite experiments as a kid. Your hand slides into the slime easily when moving slowly but the mixture behaves as a solid if you hit it quickly. That is what is meant by 'non-Newtonian' - the fluid's properties change depending on its relative motion. These properties can be exploited to dramatic effect as has been shown on speaker cones before. Here I wanted to understand what is going on, what frequencies and amplitudes work best so I used a slow-mo camera.

Thanks to everyone at the YouTube Space LA for helping me film this. I couldn't have done it without you.

Music licensed from http://www.cuesongs.com
Love Lost (Instrumental) by Temper Trap
A Life in the Day by Ghost of Otis
Fortune's Fool Instrumental by Hiatus & Shura
The Man by Audio Android

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

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