Thermal energy

Thermal energy — the energy form connected with the movement of atoms, molecules or other particles of which the body consists. In fact, thermal energy is a total kinetic energy of structural elements of substance (whether it be atoms, molecules or charged particles). Thermal energy of system plus potential energy of interatomic interactions is called internal energy of system.

Thermal energy can be emitted thanks to chemical reactions (burning), to nuclear reactions (nuclear fission, nuclear synthesis), mechanical interactions (friction). Warmth can be transmitted between bodies through heat conductivity, convection or radiation.