Can we change the volume of the body without changing the number of molecules?

The volume of the body, without changing the number of molecules, can be increased by increasing the temperature under the condition of constant pressure. A quantitative change in the volume of a body can be determined using the coefficient of thermal expansion (volumetric or linear), but it should be borne in mind that some materials have a negative coefficient of thermal expansion (when heated, they shrink), and some at certain temperatures have a coefficient of thermal expansion that is practically zero.