termodynamik

Termodynamik, often referred to in English as thermodynamics, is the branch of physics that studies energy transfer and conversion in systems, with emphasis on heat, work, and how these processes influence the state of matter. It analyzes how macroscopic properties such as temperature, pressure, and volume change and relate to energy exchanges with the surroundings. A system exchanges heat and work with its surroundings, and its state is described by variables such as internal energy U, entropy S, temperature T, pressure P, and volume V.

The foundation of termodynamik rests on several key concepts and laws. The Zeroth Law defines temperature through thermal equilibrium. The First Law, or the law of energy conservation, states that the change in a system’s internal energy ΔU equals the heat added Q minus the work W done by the system on its surroundings: ΔU = Q − W. The Second Law introduces entropy S and states that the total entropy of an isolated system cannot decrease; it imposes a direction on natural processes and sets limits on efficiency of energy conversion. The Carnot principle, derived from the Second Law, establishes the maximum possible efficiency for a heat engine operating between two reservoirs. The Third Law asserts that as temperature approaches absolute zero, the entropy of a perfect crystal approaches a minimum value.

Thermodynamics encompasses classical, chemical, and statistical formulations. It uses thermodynamic potentials such as Gibbs free energy G, Helmholtz free energy F, enthalpy H, and internal energy U to analyze processes. Practical applications include engines, refrigerators, heat exchangers, phase transitions, and chemical reactions. The field also connects to the kinetic theory of gases and statistical mechanics, which provides a microscopic interpretation of macroscopic quantities.