Thermodynamics
Thermodynamics is a branch of physics which deals with the energy and work of a system.Thermodynamics is the study of macroscopic systems for which thermal effects are important. These systems are normally assumed to be at equilibrium, or at least, close to equilibrium. Systems at equilibrium are easier to study, both experimentally and theoretically, because their physical properties do not change with time. The framework of thermodynamics applies equally well to all such macroscopic systems; it is a powerful and very general framework.
An example of a thermodynamic system is a ?uid (a gas or a liquid) con?ned to a beaker of a certain volume, subjected to a certain pressure at a certain temperature. Another example is a solid subjected to external stresses, at a given temperature. Any macroscopic system for which temperature is an important parameter is an example of a thermodynamic system. An example of a macroscopic system which is not a thermodynamic system is the solar system, inasmuch as only the planetary motion around the Sun is concerned. Here, temperature plays no role, although it is a very important quantity in solar physics; our Sun is by itself a thermodynamic system.
Thermodynamics can be defined as the study of energy, energy transformations and its relation to matter. The analysis of thermal systems is achieved through the application of the governing conservation equations, namely Conservation of Mass, Conservation of Energy (1st law of thermodynamics), the 2nd law of thermodynamics and the property relations. Energy can be viewed as the ability to cause changes.
Laws of Thermodynamics
Zeroth law of thermodynamics: If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.
First law of thermodynamics: one of the most fundamental laws of nature is the conservation of energy principle. It simply states that during an interaction, energy can change from one form to another but the total amount of energy remains constant.
Second law of thermodynamics: energy has quality as well as quantity, and actual processes occur in the direction of decreasing quality of energy.
Third law of thermodynamics – As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.