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Oh Rayleigh?!
So the sky is blue because short wavelengths of light coming from the Sun (blue, etc.) are scattered more than long ones (yellow, red, etc.), reflecting the short wavelength light into our eyes instead of it passing through the atmosphere as part of white light. Sunsets are red for the opposite reason … but yeah, why isn’t it violet?
Violet has an even shorter wavelength than blue light. So does indigo, whatever that is. There’s a good logical case for a purple sky, right?
Want to know the answer? Why the sky isn’t violet?
Do ya?
The truth is that the sky is both violet and blue. But the color receptors in our eyes don’t see violet very well, so we get the (incorrect) impression that the sky is just blue. Some birds actually see well into the violet and ultraviolet, so the sky must look trippy as hell to them.
(via xkcd)
(via project-argus)
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Ever wonder how Einstein proved E=mc²? This is how.
Via Minutephysics:
Google+ - http://bit.ly/qzEwc6
Facebook - http://facebook.com/minutephysics
Twitter - @minutephysicsDamn. Now that’s cool.
Damn. I feel like I should have known that already.
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If this video doesn’t make your jaw drop … you don’t have a jaw.
Behold: Quantum Levitation!
I have to admit, I was flabbergasted by this one. I mean, that means of motion is just so unnatural that it seems fake. But it isn’t fake. So how does it work?
Physics!
What you start with is an inert disc, in this case a crystal sapphire wafer. That wafer is then coated with a superconductor called yttrium barium copper oxide. When superconductors get very cold (like liquid nitrogen cold) they conduct electricity with no loss of energy, which normal conducting materials like copper can’t do.
Superconductors hate magnetic fields (when cold enough), and normally would just repel the magnetic force and float in a wobbly fashion. But because the superconductor is so thin in this case, tiny imperfections allow some magnetic forces through. These little magnetic channels are called flux tubes:
The flux tubes cause the magnetic field to be “locked” in all three dimensions, which is why the disk remains in whatever position it starts in, levitating around the magnets.
Of course, I am a biologist, not a physicist. For more, check out here or here.
Supercold, superconducting hoverboards … HERE WE COME!
(by ASTCvideos)
Holy schnikeys.
(via jtotheizzoe)
