Levitation 2: DON'T try this at home....

......Because this approach to the art of levitation involves liquid nitrogen. Liquid nitrogen has a temperature of -196 degrees Celsius, so it boils on contact with room temperatures. And, if it boils too quickly, it'll force all the oxygen out of a room. If that happens then your choke reflex won't go off, and your nose won't notice anything amiss: Air is more than three quarters nitrogen anyway.

So everyone in the room will just drop dead for no obvious reason*.

That said: Here's a magnet, levitating over a block of a material called YBCO (Yttrium Barium Copper Oxide). Literally no strings attached, the magnet is just floating there all by itself:



This trick works because the YBCO becomes a superconductor when dunked in liquid nitrogen and left to cool down. 'Superconductor' just means the YBCO conducts electricity with no resistance - but superconductors have another property: Magnetic fields cannot enter them**. So when you drop a magnet onto a superconductor what it lands on is it's magnetic field, and it appears to float.

If you've got the equipment, and the funding, you can get superconductors and magnets to do some even weirder stuff, like this:



Here there are two magnets floating above an YBCO plat, cooled with liquid oxygen this time. Liquid oxygen is paramagnetic - which means it's attracted to the magnets.

So the liquid oxygen drips upwards, onto the floating magnets - and gravity goes and has a little sulk in the corner..........

* One thing science teaches you is that almost everything you encounter during the course of your day can kill you, including things that are normally harmless.

** This isn't totally true: A magnetic field can penetrate a superconductor for a certain distance, called the London depth.