Glossary / Coefficient of thermal expansion

Coefficient of thermal expansion

The coefficient of thermal expansion refers to how an object's size is affected by changes in temperature. Specifically, it measures the fractional change in size per degree change in temperature at a constant pressure. Several types of coefficients have been developed: volumetric, area and linear. Which one is used depends on the particular application and whic dimensions are considered important. For solids, one might be concerned with the change along a length or over some area.