The word signifies flow of heat.Thermo means heat and dynamics, means flow. We know that energy can neither be created nor destroyed. Here we deal with the interconversion of one kind of energy into another without actually creating or destroying the energy.We know that energy is the capacity to do work. It can exist in many forms like electrical thermal chemical and gravitational etc. Transformation of energy from one form to another and the prediction of the feasibility of a process is the realm of thermodynamics.