The laws of thermodynamics put a light on how the energy of the system is changing and whether the system is performing any work on its surroundings.
Zeroth law: This law states that two bodies having the same thermal equilibrium with the third body are also in equilibrium with each other
First Law: This law is also known as the Law of conservation of energy. It states that energy can neither be created nor destroyed but can be transformed or converted from one form to another. It says that the energy of a system is equal to the addition of an increase in thermal energy and work done on the system.
The Second Law: This law states that it is impossible to transfer the energy from a body at a lower temperature to higher temperature without using the additional energy. Broadly speaking, it means that the entropy of a system always tends to increase. E.g. the entropy of the universe never decreases and always tends to increase.
The Third Law: It states that the entropy of a system approach at zero when the temperature is zero. A perfect crystal which has only one state and minimum energy has zero entropy at absolute zero.