Thermodynamics is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. The term thermodynamics was coined by James Joule in 1858 to designate the science of relations between heat and power.
The starting point for most thermodynamic considerations are the laws of thermodynamics, which postulate that energy can be exchanged between physical systems as heat or work. They also postulate the existence of a quantity named entrope, which can be defined for any system.
In thermodynamics, there are four laws of very general validity, and as such they do not depend on the details of the interactions or the systems being studied. They are: zeroth law of thermodynamics, stating that thermodynamic equilibrium is an equivalence relation; first law of thermodynamics, about the conservation of energy; second law of thermodynamics, about entropy; third law of thermodynamics, about absolute zero temperature.
An important concept in thermodynamics is the system. A system is the region of the universe under study. A system is separated from the remainder of the universe by a boundary which may be imaginary or not, but which by convention delimits a finite volume. The possible exchanges of work, heat, or matter between the system and the surroundings take place across this boundary. There are five dominant classes of systems: Isolated Systems, Adiabatic Systems, Diathermic Systems, Closed Systems, Open Systems.
Thermodynamics describes how systems respond to changes in their surroundings.
This can be applied to a wide variety of topics in science and engineering, such as engines, phase transitions, chemical reactions, transport phenomena, and even black holes. The results of thermodynamics are essential for other fields of physics and for chemistry, engineering, cell biology and material science.