Coefficient of Thermal Expansion: What does it mean?

In layman’s terms, the coefficient of thermal expansion, or also known as CTE, describes how a change in temperature affects the size of an object. CTE is also often defined as the fractional increase in length per unit rise in temperature. It measures the fractional change in size per degree change in temperature at a constant pressure. With varying temperatures, objects either expand or contract. Thermal expansion relates to the volume, length and area of the object on hand.  

To correctly measure the coefficient of thermal expansion, displacement and temperature must be calculated during the thermal cycle. To measure CTE, one can use dilatometry, interferometry, and thermomechanical analysis. Dilatometry involves heating a material in a furnace and displacing the ends which are studied by push rods. Interferometry utilizes optical interference technology with displacing the ends of the material measured in the number of wavelengths of light.  With Thermomechanical analysis, measurements are made with a thermomechanical analyzer. This analyzer includes a material observation holder and a probe that records deviations in length to a transducer that translates movements of the probe into an electrical signal. Necessary materials for this technique include a furnace, an element that can detect changes in temperature, and calipers.