Rankine scale

The Rankine scale is a temperature scale that, like the Kelvin scale, has its zero value at absolute temperature zero, but in contrast to this it uses the scale distance of the Fahrenheit scale . It is named after the Scottish engineer and physicist William John Macquorn Rankine , who proposed it in 1859 (see also the Rankine-Hugoniot equation ). It was mainly used in Anglophone countries.

The distance of one degree Rankine ( unit symbol : ° Ra or, to a limited extent , ° R) is the same as the difference of one degree Fahrenheit , but the absolute zero point is 0 degrees Rankine or −459.67 degrees Fahrenheit. Rankine is not an SI unit .

Temperature differences with the scale distance of the Fahrenheit scale can also be specified in ° Ra, since their numerical value does not change with differences: ${\displaystyle {\frac {\Delta \,T}{\,^{\circ }\mathrm {Ra} }}={\frac {\Delta \,\vartheta }{\,^{\circ }\mathrm {F} }}}$

Comparison with other scales

conversion

Temperatures in degrees Rankine can be converted exactly using a numerical equation as follows:

Degree Celsius :		${\displaystyle \left\{t\right\}_{\mathrm {^{\circ }C} }=\left\{t\right\}_{\mathrm {^{\circ }Ra} }\cdot {\tfrac {5}{9}}-273{,}15}$		${\displaystyle \left\{t\right\}_{\mathrm {^{\circ }Ra} }=\left\{t\right\}_{\mathrm {^{\circ }C} }\cdot 1,8+491{,}67}$
Fahrenheit degree :		${\displaystyle \left\{t\right\}_{\mathrm {^{\circ }F} }=\left\{t\right\}_{\mathrm {^{\circ }Ra} }-459{,}67}$		${\displaystyle \left\{t\right\}_{\mathrm {^{\circ }Ra} }=\left\{t\right\}_{\mathrm {^{\circ }F} }+459{,}67}$
Kelvin :		${\displaystyle \left\{T\right\}_{\mathrm {K} }=\left\{t\right\}_{\mathrm {^{\circ }Ra} }\cdot {\tfrac {5}{9}}}$		${\displaystyle \left\{t\right\}_{\mathrm {^{\circ }Ra} }=\left\{T\right\}_{\mathrm {K} }\cdot {\tfrac {9}{5}}}$

Fixed points

Fixed points of common temperature scales

	Kelvin	° Celsius	° Fahrenheit	° Rankine	° Réaumur
Boiling point of water at normal pressure	373.150K	100,000 ° C	212,000 ° F	671.670 ° Ra	80,000 ° Ré
" Human body temperature " according to Fahrenheit	308.70 5  K	35, 555  ° C	96,000 ° F	555.670 ° Ra	28, 444  ° Ré
Triple point of water	273.160K	0.010 ° C	32.018 ° F	491.688 ° Ra	0.008 ° Ré
Freezing point of water at normal pressure	273.150K	0.000 ° C	32,000 ° F	491.670 ° Ra	0.000 ° Ré
Cold mixture of water, ice and NH 4 Cl	255.37 2  K	−17, 777  ° C	0.000 ° F	459.670 ° Ra	−14, 222  ° Ré
absolute zero	0 K	−273.150 ° C	−459.670 ° F	0 ° Ra	−218.520 ° Ré

The fixed points with which the scales were originally defined are highlighted in color and converted exactly into the other scales. Today they have lost their role as fixed points and are only approximate. Only the absolute zero point still has exactly the specified values.