How Does a Pendulum Clock Keep Time?
Quick Answer
A pendulum clock keeps time because a pendulum of fixed length swings at a very regular rate, and an escapement counts each swing to move the hands.
The Full Story
Galileo observed that a pendulum's swing takes nearly the same time regardless of how wide the swing is, provided it is small. The period depends mainly on the pendulum's length: a pendulum about 99.4 centimetres long takes one second per swing. In 1656 Dutch scientist Christiaan Huygens built the first pendulum clock, improving accuracy from about 15 minutes a day to around 15 seconds. An escapement mechanism releases the gear train one tooth at a time with each swing and gives the pendulum a small push to keep it going. Clockmakers adjust timekeeping by moving a weight to change the effective length.
Key Facts
YouTube Angle
Suggested video title for this topic:
"The swinging weight that made time accurate."