Thermal Statistical Mechanics: Microstates and Macrostates

This lecture introduces the fundamental postulate of statistical thermodynamics, stating that all microstates in an isolated system have equal probability. It explores the distribution of probabilities for macrostates, the number of configurations, and the concept of entropy. The Boltzmann entropy is discussed in relation to the number of configurations, and an experiment with mixing balls illustrates the concept of entropy increase. The lecture also covers the distribution of momentum and velocity in gases, emphasizing the Maxwell-Boltzmann distribution. Additionally, it delves into the kinetic theory of gases, focusing on average kinetic energy, gas behavior in a box, and the equipartition theorem for solids.