# Question #b9216

Heat energy at the microscopic level is just the kinetic energy of the atoms ot molecules of which a substance is composed. The point then is that the total kinetic energy is the sum of translational (i.e. just the usual $\frac{1}{2} m {v}^{2}$), rotational and vibrational energies. These last come into play at different temperatures (in different substances and may in some case not be presnt at all) so that heat capacity actually even varies with temperature.