Is it real? Is it magic? Is it a trick? CGI? Clever video editing?
It’s science! More videos and explanations after the jump.
The behaviour of the magnet is puzzling because people are used to magnets simply sticking (or not sticking) to things. If you threw a magnet inside a metal tube, wouldn’t it just stick inside it?
Not if the tube is made of copper, as those in the demonstrations. A copper fridge would not hold your magnets. As a side note, our everyday experience seems to suggest most metals are magnetic, while in fact most metals are not. One very common and useful metal is indeed magnetic, and that’s of course, iron, and that’s why most people think that magnets will stick to any metal. End of side note.
If the magnet will not stick to the copper tube, why does it fall as if influenced by some magical anti-gravitational force? That’s the fascinating phenomenon here.
Copper is not magnetic, but it’s a conductor. And changing magnetic fields on a conductor generate eddy currents, that is, a flow of electrons. And a flow of electrons will create induced magnetic fields, which in turn, will be exactly opposed to the change of the original magnetic field. That, ladies and gentlemen, is Lenz’s law.
In short, the magnet auto-induces the magnetic field that slows its fall.
This happens with any conductor, including aluminium, and any change in magnetic field, whether it’s due to the magnet or the conductor moving. So, if you let an aluminium block fall near the extremely strong magnetic field of an MRI, you get this cool demonstration:
Note that it’s an aluminium block, if it was iron or steel (that is, a magnetic metal or alloy), those people would probably not be alive today.
One final comment. I couldn’t help but comment that in the heyday of the contactee era, in the 1950s, and as epitomized by George Adamski, it was common to claim flying saucers were able to fly in the sky (and space!) by manipulating mind-bogglingly powerful magnetic fields.
Forget for a moment how all magnetic metals would be flying in the air straight to the flying saucer. Can you think of what Lenz’s law would do to such a craft? It would not be pretty. [via MundoGump]
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