Before going any further, I really should say thanks to William J. Beaty, a research engineer in the Chemistry department at the University of Washington, who e-mailed me a few days ago with a link to his page of odd physics videos, which I have been systematically mining for content ever since!

This latest gem shows a piece of high temperature superconductor floating around a closed track made of rare-earth magnets. YouTuber majos explains:

High-temperature superconductor (Yttrium barium copper oxide) floating in the magnetic field of Neodymium magnets. This phenomenon is called the Meißner-Ochsenfeld-Effect and was discovered in 1933. The superconductor has to be cooled with liquid nitrogen which has a temperature of 77 K or −196 °C. If it is placed in a strong magnetic field it remains in its position. It also works if you turn the track upside down.