Hover over the menu bar to pick a physics animation.
This animation will show how a pendulum clock works. The clock is composed of a pendulum suspended at a point above what is called an escapement wheel. Attached to and rotating back and forth with the pendulum is a rocker arm that will control the rotation of the escapement wheel. When the rocker arm is tilted to the left, the wheel moves anglularly by one tooth. When the rocker arm is tilted to the right, the wheel stops moving anglularly.
So if the wheel has n teeth, the wheel moves a full rotation after n pendulum swings. Let's assume that a full pendulum cycle takes 1 second. Then if the wheel has 60 teeth, then it could be attached to the second hand of a clock. In order to turn this into a more useful clock, one must engage the wheel motion into a gear train of the correct ratio. For example, if the pendulum swing period is one second, then one would use a gear ratio of 60 to 1 in order to drive the minute hand of a clock. Obviously using another gear ratio of 60 to 1 would drive the hour hand of the clock. For the physics of the period of the pendulum see Clock Physics For a more elaborate illustration see Escapement