Heat

n physics and thermodynamics, heat due to thermal contact, which in turn is defined as an energy transfer to a body in any other way than due to is the process of energy transfer from one body or systemwork performed on the body. ^[1]

A related term is thermal energy, loosely defined as the energy of a body that increases with its temperature. Heat is also loosely referred to as thermal energy, although many definitions require this thermal energy to actually be in the process of movement between one body and another to be technically called heat (otherwise, many sources prefer to continue to refer to the static quantity as "thermal energy"). Heat is a form of Energy, but energy is not necessarily

Heat from the Sun is the driving force of most life on Earth. The science of heat and its relation to work is thermodynamics. Heat flow can be created in many ways.

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Energy transfer by heat can occur between objects by radiation, conduction and convection. Temperature is used as a measure of the internal energy or enthalpy, that is the level of elementary motion giving rise to heat transfer. Energy can only be transferred by heat between objects - or areas within an object - with different temperatures (as given by the zeroth law of thermodynamics). This transfer happens spontaneously only in the direction of the colder body (as per the second law of thermodynamics). The transfer of energy by heat from one object to another object with an equal or higher temperature can happen only with the aid of a heat pump via mechanical work.