https://www.youtube.com/watch?v=3V1rrVPWUOE
Invented by Joseph Bendik, a graduate of the University of California at Berkeley who worked at Hughes Aircraft, Euler's disc is thus named in homage to Leonhard Euler (1707 - 1783). Indeed, the description of the movement of this scientific toy is based on Euler's equations. It is in fact an improvement in the rotation of a coin. The weight, diameter and geometry of the edge of the disc lead to a large increase in the duration of the rotation, almost 3 minutes with the commercial model used here. A prototype made it possible to exceed 4 minutes. Besides the increase in the speed of rotation and the frequency of the vibration generated by the disc, it is the sudden end of the movement which is the most remarkable phenomenon of this experience. So watch this video to the end. Your patience will be rewarded ... The toy is sold for around $ 30 in the United States by Joseph Bendik.
