The Boltzmann Constant is a fundamental physical constant denoted by the symbol k or k_B . It relates the average kinetic energy of particles in a gas with the temperature of that gas. Specifically, it provides a bridge between macroscopic and microscopic physics, allowing scientists to understand how temperature affects the behavior of individual particles. Its value is approximately 1.38 \times 10^-23 \, \textJ/K (joules per kelvin). The constant is named after the Austrian physicist Ludwig Boltzmann, who made significant contributions to statistical mechanics. The Boltzmann Constant plays a crucial role in various fields, including thermodynamics and quantum mechanics.