Spinning objects have strange instabilities known as The Dzhanibekov Effect or Tennis Racket Theorem - this video offers an intuitive explanation.
Part of this video was sponsored by LastPass, click here to find out more: https://ve42.co/LP

References:
Prof. Terry Tao's Math Overflow Explanation: https://ve42.co/Tao

The Twisting Tennis Racket
Ashbaugh, M.S., Chicone, C.C. & Cushman, R.H. J Dyn Diff Equat (1991) 3: 67. https://doi.org/10.1007/BF01049489

Janibekov’s effect and the laws of mechanics
Petrov, A.G. & Volodin, S.E. Dokl. Phys. (2013) 58: 349. https://doi.org/10.1134/S1028335813080041

Tumbling Asteroids
Prave et al. https://doi.org/10.1016/j.icarus.2004.07.021

The Exact Computation of the Free Rigid Body Motion and Its Use in Splitting Methods
SIAM J. Sci. Comput., 30(4), 2084–2112
E. Celledoni, F. Fassò, N. Säfström, and A. Zanna
https://doi.org/10.1137/070704393

Animations by Iván Tello and Isaac Frame

Special thanks to people who discussed this video with me:
Astronaut Don Pettit
Henry Reich of MinutePhysics
Grant Sanderson of 3blue1brown
Vert Dider (Russian YouTube channel)

Below is a further discussion by Henry Reich that I think helps summarize why axes 1 and 3 are generally stable while axis 2 is not:

In general, you might imagine that because the object can rotate in a bunch of different directions, the components of energy and momentum could be free to change while keeping the total momentum constant.

However, in the case of axis 1, the kinetic energy is the highest possible for a given angular momentum, and in the case of axis 3, the kinetic energy is the lowest possible for a given angular momentum (which can be easily shown from conservation of energy and momentum equations, and is also fairly intuitive from the fact that kinetic energy is proportional to velocity squared, while momentum is proportional to velocity - so in the case of axis 1, the smaller masses will have to be spinning faster for a given momentum, and will thus have more energy, and vice versa for axis 3 where all the masses are spinning: the energy will be lowest). In fact, this is a strict inequality - if the energy is highest possible, there are no other possible combinations of momenta other than L2=L3=0, and vice versa for if the energy is the lowest possible.

Because of this, in the case of axis 1 the energy is so high that there simply aren't any other possible combinations of angular momentum components L1, L2 and L3 - the object would have to lose energy in order to spin differently. And in the case of axis 3, the energy is so low that there likewise is no way for the object to be rotating other than purely around axis 3 - it would have to gain energy. However, there's no such constraint for axis 2, since the energy is somewhere in between the min and max possible. This, together with the centrifugal effects, means that the components of momentum DO change.

UV cameras expose a hidden world and reveal the incompleteness of our perception
The Physics Girl looks at sunscreen: https://youtu.be/GRD-xvlhGMc
How to make sunscreen from scratch: https://youtu.be/lMXAY5F28L0

In summary, ultraviolet light interacts differently with matter for a number of reasons:
1. Some pigments selectively absorb UV so they may appear white in the visible but dark in the UV. The pigments usually dissipate the UV energy as heat, though the breaking of bonds can also occur.
2. Fluorescent molecules absorb UV light and re-radiate that energy as visible light. This makes them look dark in the UV but glowing under black light.
3. Ultraviolet light scatters more than visible light because the wavelength is shorter and Raleigh scattering is proportional to the reciprocal of wavelength to the power of four.

Special thanks to HHMI BioInteractive for their awesome animations of melanocytes and how the melanin in melanosomes protect your DNA. To see the full video explaining how we get our skin color, check out: https://www.youtube.com/watch?v=VC0TL_lYLm8

Special thanks to Patreon supporters:
Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Yildiz Kabaran, Terrance Snow, Stan Presolski

References:

Overview of main UV effects:
Visualizing Rayleigh Scattering through UV Photography
https://journals.ametsoc.org/d....oi/pdf/10.1175/BAMS-

Arctic animals are photographed in the UV to increase visibility and get an accurate count:
Lavigne, D. (1976). Counting Harp Seals with ultra-violet photography. Polar Record, 18(114), 269-277. doi:10.1017/S0032247400000310

Absorption spectrum of melanin: http://www.cl.cam.ac.uk/~jgd1000/melanin.html

"The spectroscopy of human melanin pigmentation," by N. Kollias. In: Melanin: Its Role in Human Photoprotection, pp. 31 - 38. Valdenmar Publishing Co. (1995).

"Optical properties of human sclera, and their consequences for transscleral laser applications," by A. Vogel, C. Dlugos, and R. Nuffer, Lasers in Surgery and Medicine 11(4), pp. 331 - 340 (1991).

"The incidence and time-course of latanoprost-induced iridial pigmentation as a function of eye color," by P. Wistrand, J. Stjernschantz, and K. Olsson, Survey of Ophthalmology 41(S2), pp. S129 - S138 (1997).

Music by Epidemic Sound: https://www.epidemicsound.com "Spring Moods 5"

Without neutrons, harnessing nuclear energy would be impossible.
Try Audible free for 30 days: http://audible.com/veritasium

I have a new documentary coming out in a few months - sign up here to be notified and see a sneak preview: http://vitamaniathemovie.com

Special thanks to Patreon supporters:
Tony Fadell, Donal Botkin, Michael Krugman, Jeff Straathof, Zach Mueller, Ron Neal, Nathan Hansen, Yildiz Kabaran,
Terrance Snow

A few years ago I made a documentary about uranium, radioactivity and radiation. I always thought of the characters in our story as the scientists and maybe the uranium nucleus itself. It was only through making the documentary that I realized the real hero of the story is the neutron. Without a neutral nuclear particle, it would be virtually impossible to release the energy from the nucleus. But with it, and the idea of a chain reaction, nuclear energy went from science fiction to reality. That is something I had not grasped as clearly before and it motivated me to make this video.

Filmed by Raquel Nuno.

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

What happens when a super long slinky is dropped?

1, 2, 3 A song about 'lectricity
because it powers our lives
makes it possible for us to thrive

because it powers our lives
makes it possible for us to thrive

Oh, 4, 5, 6, volts of potential difference
makes electrons go round
if the circuit is complete and sound

Circuit's closed
Voltage There
Current Flows
Power Everywhere

We use AC,
in factories
and homes because we can transform it
High voltage
transmits with lower loss
but low voltage is best for safety
I said what is electricity?

Well, so 1,2,3 a song about 'lectricty
because it powers our lives
makes it possible for us to thrive

because it powers our lives
makes it possible for us to thrive

Oh, 4,5,6 volts of potential difference
makes electrons go round if the circuit is complete and sound

Heat makes steam
turns turbines
and a magnet in
coils of wires

We use AC,
in factories
and homes because we can transform it
High voltage
transmits with lower loss
but low voltage is best for safety
I said what is electricity?

Oh yeah, Oh yeah, C'mon!
How'd it be
no energy
of the electrical persuasion
I know we'd
have no computers
no internet or mobile phones yeah
Powers the world
Makes the world
We need electricity yeah

I bought 10,000 shade balls and tried to swim in them. They appear to act like a non-Newtonian fluid: rigid under high shear stress, but they flow like a liquid under low shear.
Get a signed shade ball by supporting Veritasium: https://ve42.co/patreon

Receiving a shade ball:
1. Support Veritasium on any Patreon tier and enter your address https://ve42.co/patreon
2. In about a month I will send out signed shade balls
3. I will cover all shipping costs but if things get really crazy I will prioritize existing Patreon supporters and higher tiers

My sense was that swimming in shade balls would be difficult but still doable. This was roughly true for the single layer of shade balls. The shade balls slide past each other so they act like a liquid, albeit a viscous one owing to their significant inertia. It's much more intense exercise and it's also annoying to be bombarded with shade balls on all sides of your body, particularly your head. With multi-layer shade balls (as exists on much of LA reservoir) things get significantly more difficult. The balls bunch together and when you try to move through them quickly, they become more rigid, providing significant resistance to motion. This has the benefit that you can lie on them and as long as they stay trapped under you, you can float on them. But a little bit of motion causes them to move around and you sink through quickly.

Huge thanks to:
Jordan Schnabel and Cristian Carretero for filming and swimming and providing lifeguard services.
Raquel Nuno for filming and putting up with me.

Special thanks to Patreon supporters:
Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme and everyone who provided feedback on an early draft of this video.

Music from https://epidemicsound.com "Dubstep Mammoth 2" "Finally Here (Instrumental)" "The Last Arrival" "Sundown Love (Instrumental)"

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

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

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

Latest Upload - First SpaceX Space Tourists
https://www.youtube.com/watch?v=1xWbCcaJnIQ

Earth from space seen from the International Space Station
Thanks for joining to share these wonderful views of our home -
please like and share this video.
Watch our latest upload here: https://www.youtube.com/watch?v=qDboL6K9kAU

This ISS live stream of planet earth from space is courtesy of Nasa Earth Viewing Cameras aboard the international space station.
The station is crewed by #NASA astronauts as well as Russian Cosmonauts and a mixture of Japanese, Canadian and European astronauts as well.

The Expedition 62 Crew is: Christina Koch, Andrew Morgan, Oleg Skripochka

#nasalive #earth #earthfromspace
THIS WILL SHOW LIVE and PRE-RECORDED FOOTAGE -
As the Space Station passes into a period of night every 45 mins video is unavailable - during this time, and other breaks in transmission, recorded footage is shown .
When back in daylight the live stream of earth will recommence

If you are here to talk about a flat earth then please don't bother. You can stay and watch our beautiful globe earth as it spins in space , but please don't share your nonsense beliefs in our chat.

Got a question about this feed? Read our FAQ's
https://spacevideosfaq.tumblr.com/
We encourage people to join in our live chat but ask that you are respectful of others. Rude and inappropriate comments will not be tolerated. We ask that you chat in English so everyone can participate together and also to enable us to identify any inappropriate comments.

#livechat #space #spacetalk #isslive #livestream

Watch the earth roll by courtesy of the NASA Live cameras
International Space Station Live Feed: Thanks to NASA for this
http://www.nasa.gov The ISS passes into the dark side of the earth for roughly half of each of its 90 minute orbits. During this time no video is available. We would recommend that you check out some recorded footage while you wait - click the link above.

Subscribe For More Videos Like This: http://www.youtube.com/user/ou....ramazingspace?sub_co
See my latest videos : https://www.youtube.com/user/o....uramazingspace/video

Bringing you the BEST Space and Astronomy videos online. Showcasing videos and images from the likes of NASA,ESA,Hubble etc.

Join me on Facebook: https://www.facebook.com/spaceisamazing
Twitter: https://twitter.com/AmazingSpace2

Music by Keving Macleod
http://incompetech.com/music/royalty-free/

Formula One World Champion visited NASA's Johnson Space Center in Houston on his day off to live a boyhood dream ahead of the United States Grand Prix. Narrated by Will Buxton. Edited by http://www.apex.one

???

LEVANTO MIS MANOS

• SAMUEL HERNÁNDEZ •

LETRA

Levanto mis manos,
aunque no tenga fuerzas.

Levanto mis manos,
aunque tenga mil problemas.

CORO
Cuando levanto mis manos,
comienzo a sentir,
una unción que me hace cantar.

Cuando levanto mis manos,
comienzo a sentir el fuego.

Cuando levanto mis manos mis cargas se van,
nuevas fuerzas tú me das,
todo esto es posible,
todo esto es posible,
cuando levanto mis manos.

SE REPITE TODO

Cuando levanto mis manos,
comienzo a sentir,
una unción que me hace cantar.

Cuando levanto mis manos,
comienzo a sentir el fuego.

Cuando levanto mis manos mis cargas se van,
nuevas fuerzas tú me das,
X2 // todo esto es posible,
todo esto es posible,
cuando levanto mis manos. //

BELLAS IMAGENES Y BELLA CANCION

Concierto de Samuel Hernandez
En Puerto Rico

musica cristiana