Euler’s (pronounced “oilers”) Disk is a scientific educational toy. It demonstrates the dynamics of a spinning and rolling disk on a flat or slightly concave surface, using a carefully calibrated disk that spins for a much longer time than ordinary disks (such as spinning a coin on a tabletop). It’s also fascinating to watch.
As the angle between the disk and the surface it spins on decreases, the speed of the spin increases until it comes to an abrupt stop. The spin is so fast that it almost appears to hover before it stops. (Fun trivia: the sound of Euler’s Disk was used to create the torpedo soun d effects in the film Pearl Harbor.)
The physics of it all is complicated — click HERE for the Wikipedia explanation. But the sight is intriguing, and if you want your own, we sell them in the Casper Planetarium gift shop. Check out the video below: