This one’s from the e-vaults. I spent my first year of grad school making up undergraduate physics classes because I came in with a chemistry degree. One of those requirements was a laboratory class where we did things like measure the resistance of materials as a function of temperature. It wasn’t as dull as most of the labs because we got to play around with a Yttrium-Barium-Copper (YBC) superconductor. At liquid nitrogen temperatures-−321 °F–YBC was able to levitate a magnet. Fun! Below are two little videos of superconductor levitation:

The magnet spins above the superconductor, wrapped in masking tape and sitting in a well of liquid nitrogen. The wires are for measuring resistance and reading the temperature of the superconductor.