# [SCI] Classical Thermodynamics
⏎
**Classical Thermodynamics** is the science of heat, work, and energy transformations, developed between 1820 and 1870 by Carnot, Clausius, Kelvin, and Gibbs.
⏎
## Overview
⏎
Sadi Carnot (1824) proved the existence of a maximum efficiency for heat engines — the Carnot limit — depending only on the temperatures of the hot and cold reservoirs. Rudolf Clausius (1850) reformulated this as two laws: energy is conserved (first law); the entropy of an isolated system never decreases (second law). William Thomson (Lord Kelvin) established the absolute temperature scale. Josiah Willard Gibbs synthesised thermodynamics into its modern form (chemical potential, phase equilibria, free energy).
⏎
Thermodynamics was the first deep theory of industrially relevant physics, born partly from the need to understand and improve steam engines already in use.
⏎
## Key Figures & Recognition
⏎
- **Sadi Carnot** (1796–1832): *Réflexions sur la puissance motrice du feu*, 1824.
- **Rudolf Clausius** (1822–1888): Named entropy; stated the Second Law. No Nobel (predates prize).
- **Lord Kelvin** (1824–1907): Absolute temperature scale, energy conservation.
- **J. W. Gibbs** (1839–1903): *On the Equilibrium of Heterogeneous Substances*, 1876–78.
⏎
## Seminal Papers
⏎
- Carnot, S. *Réflexions sur la puissance motrice du feu*. 1824.
- Clausius, R. "Über die bewegende Kraft der Wärme." *Ann. Phys.* 79 (1850).
- Gibbs, J.W. "On the Equilibrium of Heterogeneous Substances." *Trans. Conn. Acad.* 1876–78.
⏎
# Parents
⏎
* [SCI] Newtonian Mechanics⏎