Changes

==Etymology==

==Etymology==

[[Latin]] temperatura mixture, moderation, from temperatus,  past participle of temperare

[[Latin]] temperatura mixture, moderation, from temperatus,  past participle of temperare

*Date: [http://www.wikipedia.org/wiki/16th_Century 1533]

*Date: [https://www.wikipedia.org/wiki/16th_Century 1533]

==Definitions==

==Definitions==

*1 archaic a : complexion 1  

*1 archaic a : complexion 1  

:b : [[mood]] <testing the temperature of voters>

:b : [[mood]] <testing the temperature of voters>

==Description==

==Description==

'''Temperature''' is a thermodynamic [[quantity]] that is related to the [[average]] [[energy]] of [[motion]], or [http://en.wikipedia.org/wiki/Kinetic_energy kinetic energy], of [[particles]] in [[matter]].

'''Temperature''' is a thermodynamic [[quantity]] that is related to the [[average]] [[energy]] of [[motion]], or [https://en.wikipedia.org/wiki/Kinetic_energy kinetic energy], of [[particles]] in [[matter]].

Historically, two [[equivalent]] [[concepts]] of temperature have [[developed]], the thermodynamic description and a microscopic [[explanation]] based on [http://en.wikipedia.org/wiki/Statistical_physics statistical physics]. Since thermodynamics deals entirely with macroscopic measurements, the thermodynamic definition of temperature, first stated by [http://en.wikipedia.org/wiki/Lord_Kelvin Lord Kelvin], is stated entirely in empirical, measurable variables. [http://en.wikipedia.org/wiki/Statistical_physics Statistical physics] provides a deeper [[understanding]] of [http://en.wikipedia.org/wiki/Thermodynamics thermodynamics] by describing [[matter]] as a collection of a large number of particles, and derives thermodynamic (i.e. macroscopic) [[parameters]] as [[statistical]] [[averages]] of the microscopic parameters of the [[particles]].

Historically, two [[equivalent]] [[concepts]] of temperature have [[developed]], the thermodynamic description and a microscopic [[explanation]] based on [https://en.wikipedia.org/wiki/Statistical_physics statistical physics]. Since thermodynamics deals entirely with macroscopic measurements, the thermodynamic definition of temperature, first stated by [https://en.wikipedia.org/wiki/Lord_Kelvin Lord Kelvin], is stated entirely in empirical, measurable variables. [https://en.wikipedia.org/wiki/Statistical_physics Statistical physics] provides a deeper [[understanding]] of [https://en.wikipedia.org/wiki/Thermodynamics thermodynamics] by describing [[matter]] as a collection of a large number of particles, and derives thermodynamic (i.e. macroscopic) [[parameters]] as [[statistical]] [[averages]] of the microscopic parameters of the [[particles]].

In [http://en.wikipedia.org/wiki/Statistical_physics statistical physics], it is shown that the thermodynamic definition of temperature can be [[interpreted]] as a [[measure]] of the [[average]] [[energy]] in each [[degree]] of [[freedom]] of the [[particles]] in the [http://en.wikipedia.org/wiki/Thermodynamic_system thermodynamic system]. Because its temperature is seen as a [[statistical]] property, a [[system]] must contain a large number of ''particles'' for temperature to have a useful [[meaning]]. For a [[solid]], this [[energy]] is found primarily in the [[vibrations]] of its [[atoms]] about their [[equilibrium]] positions. In an [http://en.wikipedia.org/wiki/Ideal_gas ideal monatomic gas], energy is found in the translational [[motions]] of the [[particles]]; with [[molecular]] [[gas]]es, [[vibrational]] and rotational motions also provide thermodynamic [[degrees]] of [[freedom]].

In [https://en.wikipedia.org/wiki/Statistical_physics statistical physics], it is shown that the thermodynamic definition of temperature can be [[interpreted]] as a [[measure]] of the [[average]] [[energy]] in each [[degree]] of [[freedom]] of the [[particles]] in the [https://en.wikipedia.org/wiki/Thermodynamic_system thermodynamic system]. Because its temperature is seen as a [[statistical]] property, a [[system]] must contain a large number of ''particles'' for temperature to have a useful [[meaning]]. For a [[solid]], this [[energy]] is found primarily in the [[vibrations]] of its [[atoms]] about their [[equilibrium]] positions. In an [https://en.wikipedia.org/wiki/Ideal_gas ideal monatomic gas], energy is found in the translational [[motions]] of the [[particles]]; with [[molecular]] [[gas]]es, [[vibrational]] and rotational motions also provide thermodynamic [[degrees]] of [[freedom]].

Temperature is a [http://en.wikipedia.org/wiki/Physical_property physical] property that underlies the common notions of hot and cold. Something that feels hotter generally has a higher temperature, though temperature is not a direct [[measurement]] of [[heat]]. Temperature is one of the principal [[parameters]] of thermodynamics. If no net [[heat]] [[flow]] occurs between two objects, the objects have the same temperature; otherwise, heat flows from the object with the higher temperature to the object with the lower one. This is a consequence of the [http://en.wikipedia.org/wiki/Laws_of_thermodynamics laws of thermodynamics].

Temperature is a [https://en.wikipedia.org/wiki/Physical_property physical] property that underlies the common notions of hot and cold. Something that feels hotter generally has a higher temperature, though temperature is not a direct [[measurement]] of [[heat]]. Temperature is one of the principal [[parameters]] of thermodynamics. If no net [[heat]] [[flow]] occurs between two objects, the objects have the same temperature; otherwise, heat flows from the object with the higher temperature to the object with the lower one. This is a consequence of the [https://en.wikipedia.org/wiki/Laws_of_thermodynamics laws of thermodynamics].

Temperature is [[measured]] with [http://en.wikipedia.org/wiki/Thermometers thermometers] that may be calibrated to a variety of [http://en.wikipedia.org/wiki/Temperature_conversion_formulas temperature scales]. In most of the world (except for Belize, Myanmar, Liberia and the United States), the [http://en.wikipedia.org/wiki/Celsius Celsius] scale is used for most temperature measuring [[purposes]]. The entire scientific world (these countries included) measures temperature using the Celsius scale and thermodynamic temperature using the [http://en.wikipedia.org/wiki/Kelvin Kelvin] scale, which is just the Celsius scale shifted downwards so that 0 K[1]= −273.15 °C, or [http://en.wikipedia.org/wiki/Absolute_zero absolute zero]. Many engineering fields in the U.S., notably high-tech and US federal specifications (civil and military), also use the Kelvin and Celsius scales. Other engineering fields in the U.S. also rely upon the [http://en.wikipedia.org/wiki/Rankine_scale Rankine scale] (a shifted Fahrenheit scale) when working in thermodynamic-related [[disciplines]] such as [http://en.wikipedia.org/wiki/Combustion combustion].[http://en.wikipedia.org/wiki/Temperature]

Temperature is [[measured]] with [https://en.wikipedia.org/wiki/Thermometers thermometers] that may be calibrated to a variety of [https://en.wikipedia.org/wiki/Temperature_conversion_formulas temperature scales]. In most of the world (except for Belize, Myanmar, Liberia and the United States), the [https://en.wikipedia.org/wiki/Celsius Celsius] scale is used for most temperature measuring [[purposes]]. The entire scientific world (these countries included) measures temperature using the Celsius scale and thermodynamic temperature using the [https://en.wikipedia.org/wiki/Kelvin Kelvin] scale, which is just the Celsius scale shifted downwards so that 0 K[1]= −273.15 °C, or [https://en.wikipedia.org/wiki/Absolute_zero absolute zero]. Many engineering fields in the U.S., notably high-tech and US federal specifications (civil and military), also use the Kelvin and Celsius scales. Other engineering fields in the U.S. also rely upon the [https://en.wikipedia.org/wiki/Rankine_scale Rankine scale] (a shifted Fahrenheit scale) when working in thermodynamic-related [[disciplines]] such as [https://en.wikipedia.org/wiki/Combustion combustion].[https://en.wikipedia.org/wiki/Temperature]

For a [[system]] in thermal equilibrium at a constant [[volume]], temperature is thermodynamically defined in terms of its [[energy]] (E) and [http://en.wikipedia.org/wiki/Entropy entropy] (S) as:

For a [[system]] in thermal equilibrium at a constant [[volume]], temperature is thermodynamically defined in terms of its [[energy]] (E) and [https://en.wikipedia.org/wiki/Entropy entropy] (S) as:

[[File:Temperature.jpg]]

[[File:Temperature.jpg]]