Sunday, 21 July 2013

Levitation, 1: Try this at home!

Making things float in mid air is a good way to get kids to shut the hell up for thirty seconds - as the forces of darkness in Thor 2 will now demonstrate:

Can mere mortals pull off such tricks?

Schmuh, of course we can. Let's start with a very simple trick:

The silvery object is a strong magnet (a rare-earth magnet, which you can buy online), and the pipe is copper. Copper isn't magnetic - but it's full of electrons, the fundamental particles of electricity. In copper, or anything electrically conducting, a good percentage of the electrons are bouncing from atom to atom. They form a 'sort of' liquid, sloshing around the atoms.

And this liquid does feel the magnet*. The magnet grabs hold of the electrons, and transfers some of its motion to them - making them flow into electric eddy currents, and slowing the magnets fall.

This just one kind of 'levitation'.

There are stronger ones.....

*and, because electrons are in everything, this means that everything should be magnetic - so you're right to think there must be a lot more to this story.