DefinitionsThermal energy is the portion of the internal energy that is responsible for a system's temperature. Microscopically, the thermal energy is identified with mechanical kinetic energy of the constituent particles or other forms of kinetic energy

DefinitionsThermal energy is the portion of the internal energy that is responsible for a system's temperature. Microscopically, the thermal energy is identified with mechanical kinetic energy of the constituent particles or other forms of kinetic energy associated with quantum-mechanical microstates. The distinguishing difference between the terms kinetic energy and thermal energy is that thermal energy is the mean energy of disordered, i.e., random, motion of the particles or the oscillations in the system. The conversion of energy of ordered motion to thermal energy results from collisions.[2]

All kinetic energy is partitioned into the degrees of freedom of the system. The average energy of a single particle with f quadratic degrees of freedom in a thermal bath of temperature T is a statistical mean energy given by the equipartition theorem as

» DefinitionsThermal energy is the portion of the internal energy that is responsible for a system's temperature. Microscopically, the thermal energy is identified with mechanical kinetic energy of the constituent particles or other forms of kinetic energy
» The term thermal energy is also often used as a property of single particles to designate the kinetic energy of the particles. An example is the description of thermal neutrons having a certain thermal energy, which means that the kinetic energy of the pa
» The term thermal energy is also often used as a property of single particles to designate the kinetic energy of the particles. An example is the description of thermal neutrons having a certain thermal energy, which means that the kinetic energy of the pa
» where k is the Boltzmann constant. The total thermal energy of a sample of matter or a thermodynamic system is consequently the average sum of the kinetic energies of all particles in the system. Thus, for a system of N particles its thermal energy is[3]
» where k is the Boltzmann constant. The total thermal energy of a sample of matter or a thermodynamic system is consequently the average sum of the kinetic energies of all particles in the system. Thus, for a system of N particles its thermal energy is[3]