Ever seen a magnet levitate above bismuth? It shouldn’t happen—but it does, thanks to a mind-bending mix of quantum mechanics and relativity. In this video from The Action Lab, host James Orgill dive into the world of diamagnetism—the surprising force that makes everyday materials, including water, weakly repel magnets.

Bismuth, despite having unpaired electrons that should make it attracted to magnets, is actually the most diamagnetic naturally occurring element. Why? Einstein’s special relativity comes into play—when bismuth’s outer electrons move at 10% the speed of light, their increased mass alters the way they interact with magnetic fields. The result? A levitating magnet, held up by the strange forces of physics.

This is science at its most mesmerizing! Watch below!