Temperature

Temperature is a measure of the average energy of motion, or kinetic energy, of particles in matter. When particles of matter, whether in solids, liquids, gases, or elementary plasmas, move faster or have greater mass, they carry more kinetic energy, and the material appears warmer than a material with slower or less massive particles. Kinetic energy, a concept of mechanics, is the product of mass and the square of a particle's velocity. In the context of thermodynamics, it is also referred to as thermal energy and the transfer of thermal energy is commonly referred to as heat. Heat always flows from regions of higher temperature to regions of lower temperature.