Tech

A gyroscopic exercise tool is a device used to exercise the wrist as part of physical therapy or in order to build hand and finger strength. It can also be used as a clever demonstration of some aspects of rotational dynamics. The device consists of a tennis ball-sized plastic or metal shell around a free-spinning mass, which can be started with a short rip string or by a snap of the thumb. Once the gyroscope inside is going fast enough, a person holding the device can accelerate the spinning mass to high revolution rates by moving the wrist in a circular motion.