This lecture covers the kinetic theory of gases, including the derivation of the ideal gas law, the relationship between microscopic agitation, kinetic energy, and temperature, and the introduction of a new thermodynamic function. It also explores the measurement of velocity distribution in gases, the Boltzmann postulate, and the Maxwell-Boltzmann speed distribution. The lecture delves into one-dimensional and three-dimensional cases, discussing the probability density functions and the thermalization of velocities.