20. Coriolis Force

A strap of spring steel is pivoted from the center of a platform on a rotating turntable. The strap has a nail in its end so that as it falls from a standing position, it impales itself on the periphery of the platform. When the turntable is not rotating, the strap falls normally to a marked position. But when the turntable is rotating, as the strap falls the turntable continues to rotate, and the Coriolis "force" causes the strap to impale itself somewhat behind the previous mark.