How a Pendulum Clock Works

Clocks are something we use every day. The technology is so old that we often take it for granted. But even though pendulum clocks were perfected over 300 years ago, the way they work is amazing.

Early inventors discovered that the time it took for a pendulum to swing back and forth was always the same as long as the pendulum stayed the same length and the pendulum kept swinging. The key to a pendulum clock is the escapement. The pendulum and the escapement work together to create the tic-tock sound you hear. The escapements connect to the gear trains that drive the hands, chimes and moon phase dial. Each gear train is attached to a pulley by a weight. Over time the weight drops very slowly and that turns the gears. To keep the pendulum swinging, the escapement gives the pendulum just enough extra energy to overcome friction on each swing. When the weights get close to the end of the chain, you have to wind the clock. Winding the clock pulls the weights back up to the top so the entire process can start over again.

So that's how a pendulum clock works...