Bimetallic strip

A bimetallic strip is a piece of metal made up of two different metals that are glued or welded together. The metals have different rates of expansion when warm, so when the strip is heated, one side of the strip expands more than the other side. This causes the strip to bend or curl. Bimetallic strips can be used in a variety of things, such as thermostats, toys and measuring instruments. In a thermostat, the bimetallic strip can open or close a switch when the temperature changes.