Pendulum Pace

A fake stone wall with a blue and white information panel on it, sits behind a brown exhibit table with a vertical pendulum siting on top.
A fake stone wall with a blue and white information panel on it, sits behind a brown exhibit table with a vertical pendulum siting on top.

Pendulums are used to keep time in certain clocks, based on their properties of length and patterns of swing.

How it works

Swing two pendulums from different heights and estimate which pendulum will reach the centre first.

Things to try or ask around the exhibit

Compare how many times the pendulum swings past the centre point in 10 seconds when you release it from the top of the curve, then from halfway up the curve.

Background

A pendulum's back-and-forth pace depends only on the pendulum's length and not on its starting position.

Pendulums swing faster through wider arcs and move slowly through narrow arcs, so that each swing is completed in a uniform time. This is why pendulums were used in early clocks to count seconds.

Finding the science in your world

Digital watches use quartz crystals to keep time. The crystal vibrates and sends out regular electric pulses. The watch's circuitry converts the pulses into seconds, minutes and hours.