Physicist — Ludwig Boltzmann (Vienna, 1844 – Duino, 1906) was an Austrian physicist, one of the founders of statistical mechanics. Trained at the University of Vienna, he taught at Graz, Munich, Leipzig and Vienna. His crucial contribution was explaining the laws of thermodynamics from the collective behaviour of an enormous number of atoms and molecules: macroscopic quantities such as temperature and pressure emerge as statistical averages of microscopic motion. In particular he showed that entropy measures the number of microscopic configurations compatible with a macroscopic state, thereby giving a probabilistic interpretation of the second law of thermodynamics. His ideas, opposed during his lifetime by those who denied the existence of atoms, were confirmed a few years after his death and today underpin modern physics.
Trivia
On his tomb in Vienna’s central cemetery is carved the formula S = k log W, summarising his statistical interpretation of entropy; Boltzmann, worn down by criticism and depression, took his own life in 1906.
Theories and contributions
- Entropy formula — Relates entropy to the number of microstates W accessible to the system: , where is the Boltzmann constant.
- Boltzmann distribution — Gives the probability that a particle occupies a state of energy at temperature : .
- H-theorem and equation — Describes the statistical evolution of a gas and shows how, on average, entropy grows until equilibrium, explaining irreversibility.
Featured in chapters
Linked atoms
16 linked atoms.
00 Grandezze fisiche, stime, equilibrio
00a Come usare il libro
06 Centro di massa
08b Termologia
09 Teoria cinetica dei gas
- History: from the philosophical atom to the physical atom
- Internal energy of an ideal gas
- The distribution of speeds
- The three characteristic speeds
- Atoms: from philosophical hypothesis to experimental evidence
11 Entropia
- Boltzmann’s formula
- Clausius, Boltzmann and the fate of the universe
- The arrow of time: why the past differs from the future