Pendulum A pendulum is a suspended rod that can swing from a pivot, back and forth, under gravity. The mathematical formula for the period (T) of a simple pendulum swinging through a small arc is T = 2π × square root of (length/acceleration of gravity) , or T. In 1656, Christiaan Huygens used the pendulum to create what was then the world’s most accurate clock – a domestic clock that used a pendulum, a swinging weight, as its timekeeping element. In early pendulum clocks, the pendulum typically consisted of a heavy bob with a means of adjustment to slightly increase or decrease the effective length of the pendulum rod and a suspension means, such as a flat spring, that bends as the pendulum swings, with no sliding friction.
