Perpetual motion is the motion which continues indefinitely without the need of any external source of energy. There has been constant pursuit about the existence of perpetual motion, however there are very strong disagreements popularly labeled as ‘impossible’ of the existence of such a motion by various scientists. The reason for the belief that perpetual motion is impossible is because of the fact that it violates the two most important laws of physics, the first law and the second law of thermodynamics. The reasons for the violation are given below in examples.
Example 1: The first law of thermodynamics states that the total energy of an isolated system is constant, since energy is neither created, not destroyed. However, energy can change from one form to another form of energy. The theory about perpetual motion of first kind is that it produces work without taking any external source of energy. This violates the first law of thermodynamics because of the fact that it is impossible to produce such work which once activated, can operate indefinitely without requiring any external energy.
Example 2: The second law of thermodynamics states that entropy of an isolated system generally tends to increase or if not stays the same due to its spontaneous attainment of thermodynamic equilibrium. The perpetual motion of second kind violates the second law of thermodynamics as even if it can convert thermal energy to mechanical energy, the concept states that there is spontaneous cooling without any transfer of heat, which is impossible according to the second law of thermodynamics.