Where αis called the coefficient of linear expansion for the material.
For materials that are not isotropic, such as an asymmetric crystal for example, α can have a
different value depending on the axis along which the expansion is measured. α can also vary somewhat
with temperature so that the degree of expansion depends not only on the magnitude of the temperature
change, but on the absolute temperature as well.
In this experiment, you will measure α for copper, aluminum, and steel. These metals are isotropic so that
α need only be measured along one dimension. Also, within the limits of this experiment, α does not vary
with temperature.