Kelvin: Difference between revisions

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|kelvins ||degrees Fahrenheit ||°F = K × 1.8 − 459.67
|kelvins ||degrees Fahrenheit ||°F = K × 1.8 − 459.67
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|-
|[[degrees Fahrenheit]] ||kelvins ||K = (°F + 459.67) / 1.8
|degrees Fahrenheit ||kelvins ||K = (°F + 459.67) / 1.8
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|-
|kelvins ||degrees Celsius ||°C = K − 273.15
|kelvins ||degrees Celsius ||°C = K − 273.15
|-
|-
|[[degrees Celsius]] ||kelvins ||K = °C  + 273.15
|degrees Celsius ||kelvins ||K = °C  + 273.15
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|-
| colspan=3 align=center | Note that for temperature intervals rather than temperature readings,<br> 1 K = 1 °C and 1 K = 1.8 °F<br><small>[[temperature conversion formulas|Additional conversion formulas]]<br>[http://www.chemie.fu-berlin.de/chemistry/general/units_en.html#temp Conversion calculator for units of temperature]</small>
| colspan=3 align=center | Note that for temperature intervals rather than temperature readings,<br> 1 K = 1 °C and 1 K = 1.8 °F<br><small>[[temperature conversion formulas|Additional conversion formulas]]<br>[http://www.chemie.fu-berlin.de/chemistry/general/units_en.html#temp Conversion calculator for units of temperature]</small>
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The kelvin is named after the British physicist and engineer William Thomson, 1st Baron Kelvin.
The kelvin is named after the British physicist and engineer William Thomson, 1st Baron Kelvin.


In Unicode, a legacy code for a kelvin symbol to accomodate some old code pages in certain Oriental languages exists; it is not recommended for use any more.  In all languages, the symbol should be the Roman letter Unicode &#75; for current usage.
In Unicode, a legacy code for a kelvin symbol to accommodate some old code pages in certain Oriental languages exists; it is not recommended for use any more.  In all languages, the symbol should be the Roman letter Unicode &#75; for current usage.


== Typographical conventions ==
== Typographical conventions ==

Revision as of 23:42, 28 August 2017

Kelvin temperature conversion formulas
Conversion from to Formula
kelvins degrees Fahrenheit °F = K × 1.8 − 459.67
degrees Fahrenheit kelvins K = (°F + 459.67) / 1.8
kelvins degrees Celsius °C = K − 273.15
degrees Celsius kelvins K = °C + 273.15
Note that for temperature intervals rather than temperature readings,
1 K = 1 °C and 1 K = 1.8 °F
Additional conversion formulas
Conversion calculator for units of temperature

The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. It is defined by two facts: zero kelvins is absolute zero (when molecular motion stops), and one kelvin is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. The Celsius temperature scale is now defined in terms of the kelvin, with 0 °C corresponding to 273.15 kelvins, approximately the melting point of water under ordinary conditions.

The kelvin is named after the British physicist and engineer William Thomson, 1st Baron Kelvin.

In Unicode, a legacy code for a kelvin symbol to accommodate some old code pages in certain Oriental languages exists; it is not recommended for use any more. In all languages, the symbol should be the Roman letter Unicode K for current usage.

Typographical conventions

The word kelvin as an SI unit is correctly written with a lowercase k (unless at the beginning of a sentence), and is never preceded by the words degree or degrees, or the symbol °, unlike Fahrenheit, or Celsius. This is because the latter are scales of measurement, whereas the kelvin is a unit of measurement. It takes the normal plural form by adding an s in English: kelvins. When the kelvin was introduced in 1954 (10th Conférence Générale des Poids et Mesures|General Conference on Weights and Measures (CGPM), Resolution 3, CR 79), it was the "degree Kelvin", and written °K; the "degree" was dropped in 1967 (13th CGPM, Resolution 3, CR 104).

Note that the symbol for the kelvin unit is always a capital K and never italicised. There is a space between the number and the K, as with all other SI units.