The Momentum Machine demonstrates the concept of "angular momentum." The visitor stands on a circular platform that can freely rotate. With a slight push, the visitor can twirl around. It is immediately noticeable that the straighter one stands, bringing body parts closer to the axis of rotation, the faster one spins. Although "linear momentum" depends only on the mass of an object and its velocity, the angular momentum also depends on how far the mass is from the axis of rotation.