Eddy Currents

The rods are made of plastic, stainless steel, bronze, brass, aluminium and copper, so the copper has a conductivity billions of times better than the plastic. So you get much larger currents induced in the rods, which of course produce a magnetic field and hold up the magnet, slowing its drop.


Jumping wire

This is a very standard piece of physics (Biot-Savart law) which Dave had always assumed was important but not strong enough to simply experience yourself. On the offchance while in the lab with some magnets he had a go, and it works rather beautifully. Turn on the current one way and the wire jumps to the left and then back again with the opposite current.