Comprises 2x different cycloid tracks plus 1x inclined plane [approx.] 310 x 345mm mounted side-by-side. A simple chiming device at the bottom of each ramp audibly announces the arrival of two steel balls when each one is rolled down its own track. Apparatus demonstrates that the straight line path from top to bottom of a ramp is not always the quickest. It is the cycloidal path in a gravitational field which has a fixed time of descent regardless of path length – known as a tautochronous property. Visually easy to understand that if the ball rolls down its specific track, it will take the same time regardless of where the two balls start.