Part III — Chapter 9
Thermodynamics & Conservation of Energy
The laws that govern heat, work, and the arrow of time
9.1 Carnot and the Ideal Engine
Sadi Carnot (1796–1832) showed in 1824 that no heat engine can be more efficient than a reversible one operating between two temperatures. His work founded thermodynamics, though he died of cholera at 36.
9.2 The First and Second Laws
The First Law (conservation of energy) was established by Joule, Helmholtz, and Mayer in the 1840s. The Second Law — that entropy always increases in an isolated system — was formulated by Clausius and Thomson (Lord Kelvin).
9.3 Boltzmann and Statistical Mechanics
Ludwig Boltzmann (1844–1906) showed that the Second Law is statistical in nature: entropy measures the number of microscopic arrangements consistent with a macroscopic state. His equation S = k log W is carved on his tombstone.