The study of the relations between heat, work, temperature, and energy is known as thermodynamics. These laws of thermodynamics describe how the energy in a system changes and whether the system can perform useful work on its surroundings. The four laws of thermodynamics define the fundamental physical quantities that characterize thermodynamic systems at thermal equilibrium. The laws describe how these quantities behave under various circumstances and forbid certain phenomena. There are four laws of thermodynamics.
- Zeroth law of thermodynamics: The zeroth law of thermodynamics states that if two thermodynamic systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.
- First law of thermodynamics: The first law of thermodynamics states that heat can neither be created nor destroyed, it can only be converted from one form to another.
- Second law of thermodynamics: The second law of thermodynamics states that any spontaneously occurring process will always lead to an escalation in the entropy (S) of the universe.
- Third law of thermodynamics: The third law of thermodynamics states that the entropy of a perfect crystal at a temperature of zero Kelvin (absolute zero) is equal to zero.