How do you demonstrate floating magnets with liquid nitrogen?

Answer 1

You get a ceramic thats superconductive below 77K (liquid nitrogen temperature)(yttrium barium copper oxide is an example) and a small magnetic cube. When you have it at room temperature, nothing happens, the cube will just sit idly on top of the ceramic. When you put liquid N2 on the ceramic and place the cube on it, the cube will levitate an inch about, and you can spin it or move it anywhere on the surface of the ceramic.