Several tiny white spheres are placed inside a tall clear plastic tube. At the bottom of the tube is notched disk that, when rotated by the motor to which it is attached, stirs the spheres. Inside the plastic tube over the spheres is another disk that attaches by string over two pulleys to a counterweight. When the spheres are agitated by the notched disk they press upward causing the upper disk to rise. The faster the motor turns, the more the upper disk will rise.