Ball and Ring Apparatus

Description

Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change
in temperature.
Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is
heated, the kinetic energy of its molecules increases. Thus, the molecules begin vibrating/moving more and usually
maintain a greater average separation. Materials which contract with increasing temperature are unusual; this effect
is limited in size, and only occurs within limited temperature ranges. The degree of expansion divided by the change
in temperature is called the material’s coefficient of thermal expansion and generally varies with temperature.