classical thermodynamics

Thermodynamics is the branch of physics that studies the relationship between heat, work, temperature, and energy. It explores how energy is transferred and transformed from one form to another. A fundamental concept is that heat is a form of energy directly related to mechanical work.1

Key principles include:
* Zeroth Law: Establishes the concept of thermal equilibrium and temperature.1
* First Law: States that energy cannot be created or destroyed, only converted from one form to another (conservation of energy). The change in a system's internal energy equals heat added minus work done by the system.123
* Second Law: Dictates that heat does not spontaneously flow from colder to hotter regions and that not all heat can be converted into work. This law introduces entropy, a measure of disorder, which tends to increase in closed systems.4526
* Third Law: States that the entropy of a system approaches a constant value as its temperature approaches absolute zero, implying absolute zero is unattainable.2

These laws are crucial for understanding energy transformations in all physical and biological systems.1