The potential energy of a compression spring is a type of elastic potential energy, and when the spring is compressed, the interatomic potential energy is stored as the elastic potential energy of the system. When the iron compression spring is dissolved by the acid, the stored elastic potential energy is converted into the kinetic energy of the atoms, resulting in a slight increase in the temperature of the solution. In this case, energy is conserved, and the elastic potential energy possessed by the compression spring will exist as some other form of energy.

Unlike the gravitational potential energy, the elastic potential energy is not necessarily proportional to the length of the spring being compressed. In fact, for the same spring, the greater the shape variable, the greater the elastic potential energy. The expression for the elastic potential energy is usually set to zero when the spring is at its original length. Therefore, when discussing the potential energy of the compression spring, we must take into account the nonlinear characteristics of the spring material, that is, the elastic force changes with the change of the shape variable.