Kelvin
- For other uses, see Kelvin (disambiguation).
| | ||
| Conversion from | to | Formula |
|---|---|---|
| kelvins | degrees Celsius | °C = K − 273.15 |
| degrees Celsius | kelvins | K = °C + 273.15 |
| kelvins | degrees Fahrenheit | °F = K × 1.8 − 459.67 |
| degrees Fahrenheit | kelvins | K = (°F + 459.67) / 1.8 |
| 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 | ||
A temperature given in kelvins, without further qualification, is measured with respect to Absolute zero, where molecular motion stops. It is also common to give a temperature relative to the reference temperature of 273.15 K, approximately the Melting point of water under ordinary conditions; this convention is the Celsius temperature scale.
The kelvin is named after the British physicist and engineer William Thomson, 1st Baron Kelvin; his barony was in turn named after the River Kelvin, which runs through the grounds of the University of Glasgow.
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 degrees Fahrenheit, or degrees Celsius. This is because the latter are adjectives, whereas kelvin is a Noun. It takes the normal plural form by adding an s in English: kelvins. When the kelvin was introduced in 1954 (10th 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.
Unicode includes the "kelvin sign" at U+212A (in your browser it looks like K). However, the "kelvin sign" is canonically decomposed into U+004B, thereby seen as a (preexisting) encoding mistake, and it is better to use U+004B (K) directly.
Conversion factors
Kelvins and Celsius
The Celsius temperature scale is now defined in terms of the kelvin, with 0 °C corresponding to 273.15 kelvins.- kelvins to degrees Celsius
- :
n C = K - 273.15 n
Temperature and energy
The factual accuracy of this article is disputedIn a thermodynamic system, the energy carried by the particles is proportional to the absolute temperature, where the constant of proportionality is the Boltzmann constant. As a result, it is possible to determine the temperature of particles with a certain energy; or to calculate the energy of particles at a certain temperature:
n ––––––––
E kin }
= 3
––
2• k B • T n
- electron volts to kelvins
n K = eV × 11,!605 n
- kelvins to electron volts
n eV = K
–––––––––
11,!605n
SI multiples
| Multiple | Name | Symbol | Multiple | Name | Symbol | |
|---|---|---|---|---|---|---|
| 100 | kelvin | K | ||||
| 101 | decakelvin | daK | 10–1 | decikelvin | dK | |
| 102 | hectokelvin | hK | 10–2 | centikelvin | cK | |
| 103 | kilokelvin | kK | 10–3 | millikelvin | mK | |
| 106 | megakelvin | MK | 10–6 | microkelvin | µK | |
| 109 | gigakelvin | GK | 10–9 | nanokelvin | nK | |
| 1012 | terakelvin | TK | 10–12 | picokelvin | pK | |
| 1015 | petakelvin | PK | 10–15 | femtokelvin | fK | |
| 1018 | exakelvin | EK | 10–18 | attokelvin | aK | |
| 1021 | zettakelvin | ZK | 10–21 | zeptokelvin | zK | |
| 1024 | yottakelvin | YK | 10–24 | yoctokelvin | yK |
See also
- ITS-90 International Temperature Scale
External link
- BIPM brochure on the kelvin
| | Celsius | Fahrenheit | Kelvin | |||
| Delisle | Leyden | Newton | Rankine | Réaumur | Rømer | |
| Conversion formulas | ||||||