Changes

==Etymology==

==Etymology==

[https://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] heten, from [https://nordan.daynal.org/wiki/index.php?title=English#ca._600-1100.09THE_OLD_ENGLISH.2C_OR_ANGLO-SAXON_PERIOD Old English] hǣtan; akin to Old English hāt hot

[https://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] heten, from [https://nordan.daynal.org/wiki/index.php?title=English#ca._600-1100.09THE_OLD_ENGLISH.2C_OR_ANGLO-SAXON_PERIOD Old English] hǣtan; akin to Old English hāt hot

*Date: before [http://en.wikipedia.org/wiki/12th_Century 12th century]

*Date: before [https://en.wikipedia.org/wiki/12th_Century 12th century]

==Definitions==

==Definitions==

:intransitive verb  

:intransitive verb  

*2 : excite

*2 : excite

==Description==

==Description==

In [[physics]] and [http://en.wikipedia.org/wiki/Thermodynamics thermodynamics], '''heat''' is the [[process]] of [[energy]] transfer from one [[body]] or [[system]] due to thermal contact, which in turn is defined as an energy transfer to a body in any other way than due to [[work]] performed on the body.[1]

In [[physics]] and [https://en.wikipedia.org/wiki/Thermodynamics thermodynamics], '''heat''' is the [[process]] of [[energy]] transfer from one [[body]] or [[system]] due to thermal contact, which in turn is defined as an energy transfer to a body in any other way than due to [[work]] performed on the body.[1]

When an infinitesimal amount of heat δQ is transferred to a body in thermal equilibrium at [http://en.wikipedia.org/wiki/Thermodynamic_temperature absolute temperature] T in a reversible way, then it is given by the [[quantity]] TdS, where S is the [http://en.wikipedia.org/wiki/Entropy entropy] of the body.

When an infinitesimal amount of heat δQ is transferred to a body in thermal equilibrium at [https://en.wikipedia.org/wiki/Thermodynamic_temperature absolute temperature] T in a reversible way, then it is given by the [[quantity]] TdS, where S is the [https://en.wikipedia.org/wiki/Entropy entropy] of the body.

A related term is [http://en.wikipedia.org/wiki/Thermal_energy 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 [[Motion|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 also known as "Energy".

A related term is [https://en.wikipedia.org/wiki/Thermal_energy 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 [[Motion|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 also known as "Energy".

Energy transfer by heat can occur between objects by [http://en.wikipedia.org/wiki/Thermal_radiation radiation], [http://en.wikipedia.org/wiki/Heat_conduction conduction] and [http://en.wikipedia.org/wiki/Convection convection]. Temperature is used as a [[measure]] of the internal energy or [http://en.wikipedia.org/wiki/Enthalpy 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 [http://en.wikipedia.org/wiki/Zeroth_law_of_thermodynamics zeroth law of thermodynamics]). This transfer happens [[spontaneously]] only in the direction of the colder body (as per the [http://en.wikipedia.org/wiki/Second_law_of_thermodynamics 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]].[http://en.wikipedia.org/wiki/Heat]

Energy transfer by heat can occur between objects by [https://en.wikipedia.org/wiki/Thermal_radiation radiation], [https://en.wikipedia.org/wiki/Heat_conduction conduction] and [https://en.wikipedia.org/wiki/Convection convection]. Temperature is used as a [[measure]] of the internal energy or [https://en.wikipedia.org/wiki/Enthalpy 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 [https://en.wikipedia.org/wiki/Zeroth_law_of_thermodynamics zeroth law of thermodynamics]). This transfer happens [[spontaneously]] only in the direction of the colder body (as per the [https://en.wikipedia.org/wiki/Second_law_of_thermodynamics 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]].[https://en.wikipedia.org/wiki/Heat]

== External links ==

== External links ==

*[http://www.foxnews.com/story/0,2933,187464,00.html Plasma heat at 2 gigakelvins] - Article about extremely high temperature generated by scientists (Foxnews.com)

*[https://www.foxnews.com/story/0,2933,187464,00.html Plasma heat at 2 gigakelvins] - Article about extremely high temperature generated by scientists (Foxnews.com)

*[http://www.cheresources.com/convection.shtml Correlations for Convective Heat Transfer] - ChE Online Resources

*[https://www.cheresources.com/convection.shtml Correlations for Convective Heat Transfer] - ChE Online Resources

*[http://canadaconnects.ca/chemistry/10114/ An Introduction to the Quantitative Definition and Analysis of Heat written for High School Students]

*[https://canadaconnects.ca/chemistry/10114/ An Introduction to the Quantitative Definition and Analysis of Heat written for High School Students]

[[Category: Physics]]

[[Category: Physics]]