This is awesome.

“What you start with is an inert [i.e. chemically inactive] 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.”

Via io9