Chapter 21, Problem 15A

Why does a bimetallic strip curve when it is heated (or cooled)?

To determine

To explain: The reason for a bimetallic strip curve when it is heated (or cooled).

Explanation of Solution

Introduction:

When two dissimilar metallic strips are bonded together in one side, the resulting arrangement is known as bimetallic strip. Generally steel or stainless steel that has high thermal expansion is coupled with an alloy that has low thermal expansion, to prepare a bimetallic strip. Other combinations used in bimetallic strip are steel and copper, steel and brass.

When the bimetallic strip is heated, the metal which has high thermal expansion expands more than metal that having low thermal expansion. As a result one strip becomes longer than the other strip. Since the two metallic strips are bonded together, the bimetallic strip curves to provide accommodations to the subsequent change in the length of its two strips.