This pendulum swings independently of the motion of its rotating base. Pull the brass ball at the pendulum's end to one of the black lines on the white ring and let it go. With the pendulum vibrating, slowly and smoothly rotate the base with the wooden handle. Notice that the path of the ball remains constant between the same two points while the white ring rotates around it. This exhibit is modeled after a giant pendulum, called a Foucault pendulum, which swings independent of the earth's rotation. While the giant pendulum appears to rotate relative to the earth, it is actually the earth which rotates beneath the pendulum.