Thermodynamics
Theory · 1824 to 1870s, France, Germany, and Britain · Physics, stage 2: Map the theories
Thermodynamics describes heat, work, and temperature without any commitment about what matter is made of. It began with an engineering question: Sadi Carnot asked in 1824 how much work a steam engine could possibly extract from a given amount of heat, and found a limit that no design can beat. Clausius and Kelvin turned that result into two general laws, the first stating that energy is conserved when heat is counted as a form of it, the second that entropy never decreases in an isolated system. Because thermodynamics assumes nothing about atoms, its conclusions survived every later revolution in physics intact, and they still constrain black holes and information processing.
What it claims
- Energy is conserved once heat is counted as a form of energy.
- The entropy of an isolated system never decreases.
- No engine can convert heat entirely into work; the maximum efficiency depends only on the two temperatures involved.
- Temperature and pressure are only defined for systems at or near equilibrium.
Key ideas
People
Sources
- Thermodynamics English Wikipedia
- Second law of thermodynamics English Wikipedia
- Thermodynamic Asymmetry in Time Stanford Encyclopedia of Philosophy
