Thermodynamics

Thermodynamics - Laws

The three laws of thermodynamics are:

• The first law of thermodynamics: When energy passes, as work, as heat, or with the matter, into or out of a system, the system’s internal energy changes in accord with the law of conservation of energy. Equivalently, perpetual motion machines of the first kind (machines that produce work with no energy input) are impossible.
• The second law of thermodynamics: In a natural thermodynamic process, the sum of the entropies of the interacting thermodynamic systems increases. Equivalently, perpetual motion machines of the second kind (machines that spontaneously convert thermal energy into mechanical work) are impossible
• The third law of thermodynamics: The entropy of a system approaches a constant value as the temperature approaches absolute zero. With the exception of non-crystalline solids (glasses), the entropy of a system at absolute zero is typically close to zero.

In addition, there is conventionally added a “zeroth law”, which defines thermal equilibrium:

• Zeroth law of thermodynamics: If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other. This law helps define the concept of temperature.

Thermodynamics - SubBranchs

Each branch uses a different fundamental model as a theoretical and/or experimental basis