Explain an experiment to show that different metals expand by a different amount.
For this simple experiment, a composite bimetallic strip is taken consisting of two flat bars of different metals (A.B.) revetted or welded together. When heated the straight bar is found to bend as shown in fig (b). Metal A expands more than metal B, but as they are joined together, they can not expand independently, the strip bends with the more expanding metal bar (A) on the convex side. This experiment proves that different metals expand by different amounts.