Build your own gumball machines and learn physics lessons in the process. A turn of a handle dispenses one gumball at a time out of the clear storage globe and down the track. Each segment of the track teaches a different lesson in physics: force, motion, momentum, gravity, energy, and more. The segments can be moved around to create an almost limitless number of different machines. Small supply of standard machine-size (5/8-inch) gumballs included.