Hot

metal warms.

Warmth (also amount of heat) is physical dimension, a process variable. It can be described both microscopically by the kinetic theory, and macroscopically by thermodynamics.

Warmth in thermodynamics is over a system border away transported thermal energy. Warmth appears as process variable only with being present a temperature gradient . Generally linguistic usage is confounded the term warmth however frequently with the thermal energy.

physical dimension

warmth is like workto transportation procedures bind and therefore a process variable, contrary to a variable of state. Thermal energy is always transferred due to the second main clause of thermodynamics the system with the higher temperature toward the system with the smaller temperature.This applies so long a temperature difference between two thermally feed back control systems exists, these thus yet in the thermal equilibrium is not.

The transferred warmth Q is usually with a change of temperature [itex] \ mathrm {D} T< /math> connected:

[itex] \ mathrm {D} Q = C_V \; \ mathrm {D} T \! [/itex]

Here C V is the thermal capacity with constant volume V. However also systems, with which a heat supply leads to the phase conversion and not to the rise in temperature, exist for example when the evaporation liquids. Also the heat supply (partial) can in Work (symbol W) to be converted.

As thermodynamic size the warmth is clearly defined over the first main clause:

[itex] \ mathrm {D} U = \ delta Q + \ delta W \! [/itex]

Heat supply increases thus (just like work) the internal energy U of a system. ThoseDetails of the physical procedures, which lead to the transport of thermal energy, are however not exactly fixed thereby.

In the theory of the heat transfer the heat flow is defined after Jean Baptiste Joseph Fourier with the help of a temperature gradient.

With the heat emission and/or. - admissionthe mass of the body has a directly proportional influence, so that the warmth with [itex] Q = C cdot \ m \; \ mathrm {D} T< /math> (m: Mass in kg, Q: Warmth in kJ, C: Thermal capacity, T: Temperature differencein Kelvin or degrees Celsius ) to be computed must.