Galileo's Chandelier

galileo's chandelierBowling ball pendulum with burning candles stuck in holes, used as prop only.

What It Shows

Rumor has it that one day at the cathedral, Galileo watched the swinging of a chandelier after it had been displaced and lit. By using his own pulse as a timer, he noticed that the period of the swing remained constant despite the fact that its amplitude decreased. And thus was born an important discovery that was later used by Huygens in the invention of the astronomical and navigational clock.

How It Works

This demonstration is a bit of a joke on the theme. The "chandelier" is a bowling ball pendulum1 hung from the ceiling skyhook. Candles are stuck into the thumb and finger holes of the bowling ball. The candles are lit and the bowling ball is set into motion. How the rest goes is left to the imagination of the lecturer.

Setting It Up

A little bit of advanced notice is required on this one as it involves bringing the "Hi-Jacker" lift in and out of the lecture hall to attach the cable to the skyhook—this ought to be done first before any other demonstrations are set up.

1A 5-meter long, 3/16"-diameter stranded cable hangs from the ceiling skyhook. A large (3/8"-16) eye-bolt, threaded into a ten-pin bowling ball, serves as the suspension point.