Bimetal See Saw

This little see saw rocks to and fro, as long as the little candle remains alight. The mechanism is based on a bimetallic spring. A bimetallic strip consists of two different metals joined together. Because the metals expand different amounts when heated, the strip will bend one way when heated, and then bend back again when it cools. Simple temperature sensors can be built using bimetallic strips.

This little craft toy, which is made in Germany, consists of a little see saw which is powered by a small candle. Initially the bimetallic spring or coil is in the candle flame, and becomes heated. This causes it to twist, and the wire rod with the wooden weight at the end moves to the right, and the see saw rocks to the other position. The bimetal spring is no longer in the candle flame, and it starts to cool down. It now twists the other way, and the wire rod now moves to the left. his causes the see saw to rock the other way. Now the bimetal spring is back in the flame, and the whole process starts over again.