Physics:Degree (temperature)

From HandWiki
Short description: Term used in defining several scales of temperature

The term degree is used in several scales of temperature, with the notable exception of kelvin, primary unit of temperature for engineering and the physical sciences. The degree symbol ° is usually used, followed by the initial letter of the unit; for example, "°C" for degree(Souvik) Celsius. A degree can be defined as a set change in temperature measured against a given scale; for example, one degree Celsius is one-hundredth of the temperature change between the point at which water starts to change state from solid to liquid state and the point at which it starts to change from its liquid to gaseous state.

Scales of temperature measured in degrees

Common scales of temperature measured in degrees:

Unlike the degree Fahrenheit and degree Celsius, the kelvin is no longer referred to or written as a degree (but was before 1967[1][2][3]). The kelvin is the primary unit of temperature measurement in the physical sciences, but is often used in conjunction with the degree Celsius, which has the same magnitude.

Other scales of temperature:

Kelvin

Main page: Kelvin

The "degree Kelvin" (°K) is a former name and symbol for the SI unit of temperature on the thermodynamic (absolute) temperature scale.[1] Since 1967, it has been known simply as the kelvin, with symbol K (without a degree symbol).[2][3][4] Degree absolute (°A) is obsolete terminology, often referring specifically to the kelvin but sometimes the degree Rankine as well.

Comparisons

  • Boiling point of water: 100.0 °C / 212.0 °F
  • Melting point of ice: 0.0 °C / 32.0 °F
  • Typical human body temperature: 37.0 °C / 98.6 °F
  • Room temperature: 20–25 °C / 68–77 °F[5]

Temperature conversions

<timeline> ImageSize = width:905 height:50 PlotArea = left:80 right:15 bottom:20 top:5 AlignBars = justify Colors =

 id:black  value:black
 id:white  value:white
 id:lightline  value:rgb(0.8,0.8,0.8)

Period = from:223 till:383 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:10 start:230 ScaleMinor = unit:year increment:1 start:223

PlotData=

 align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5)

LineData=

 at:start      color:green layer:front
 at:end        color:green layer:front
 at:233.15 color:lightline layer:back
 at:253.15 color:lightline layer:back
 at:273.15 color:lightline layer:back
 at:293.15 color:lightline layer:back
 at:313.15 color:red layer:back
 at:333.15 color:lightline layer:back
 at:353.15 color:lightline layer:back
 at:373.15 color:lightline layer:back

TextData =

  fontsize:10
  textcolor:blue
  pos:(0,13)
  text: Kelvin K

</timeline>
<timeline> ImageSize = width:905 height:50 PlotArea = left:80 right:15 bottom:20 top:5 AlignBars = justify Colors =

 id:black  value:black
 id:white  value:white
 id:lightline  value:rgb(0.8,0.8,0.8)

Period = from:-50 till:110 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:10 start:-50 ScaleMinor = unit:year increment:1 start:-50

PlotData=

 align:center textcolor:black fontsize:8 mark:(line,black) width:5 shift:(0,-5)

LineData=

 at:start      color:green layer:front
 at:end        color:green layer:front
 at:-40 color:lightline layer:back
 at:-20 color:lightline layer:back
 at:0 color:lightline layer:back
 at:20 color:lightline layer:back
 at:40 color:red layer:back
 at:60 color:lightline layer:back
 at:80 color:lightline layer:back
 at:100 color:lightline layer:back

TextData =

  fontsize:10
  textcolor:blue
  pos:(0,13)
  text: Celsius °C

</timeline>
<timeline> ImageSize = width:905 height:50 PlotArea = left:80 right:15 bottom:20 top:5 AlignBars = justify Colors =

 id:black  value:black
 id:white  value:white
 id:lightline  value:rgb(0.8,0.8,0.8)

Period = from:-58 till:230 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:10 start:-50 ScaleMinor = unit:year increment:1 start:-58 PlotData=

 align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5)

LineData=

 at:start      color:green layer:front
 at:end        color:green layer:front
 at:-40 color:lightline layer:back
 at:-4 color:lightline layer:back
 at:32 color:lightline layer:back
 at:68 color:lightline layer:back
 at:104 color:red layer:back
 at:140 color:lightline layer:back
 at:176 color:lightline layer:back
 at:212 color:lightline layer:back

TextData =

  fontsize:10
  textcolor:blue
  pos:(0,13)
  text:Fahrenheit °F

</timeline>
<timeline> ImageSize = width:905 height:50 PlotArea = left:80 right:15 bottom:20 top:5 AlignBars = justify Colors =

 id:black  value:black
 id:white  value:white
 id:lightline  value:rgb(0.8,0.8,0.8)

Period = from:402 till:690 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:10 start:410 ScaleMinor = unit:year increment:1 start:402 PlotData=

 align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5)

LineData=

 at:start      color:green layer:front
 at:end        color:green layer:front
 at:419.7   color:lightline layer:back
 at:455.7   color:lightline layer:back
 at:491.7   color:lightline layer:back
 at:527.7   color:lightline layer:back
 at:563.7 color:red layer:back
 at:599.7 color:lightline layer:back
 at:635.7  color:lightline layer:back
 at:671.7 color:lightline layer:back

TextData =

  fontsize:10
  textcolor:blue
  pos:(0,13)
  text:Rankine °Ra

</timeline>
<timeline> ImageSize = width:905 height:50 PlotArea = left:80 right:15 bottom:20 top:5 AlignBars = justify Colors =

 id:black  value:black
 id:white  value:white
 id:lightline  value:rgb(0.8,0.8,0.8)

Period = from:-18.75 till:65.25 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:5 start:-15 ScaleMinor = unit:year increment:1 start:-18

PlotData=

 align:center textcolor:black fontsize:8 mark:(line,black) width:5 shift:(0,-5)

LineData=

 at:start      color:green layer:front
 at:end        color:green layer:front
 
 at:-13.5 color:lightline layer:back
 at:-3 color:lightline layer:back
 at:7.5 color:lightline layer:back
 at:18 color:lightline layer:back
 at:28.5 color:red layer:back
 at:39 color:lightline layer:back
 at:49.5 color:lightline layer:back
 at:60 color:lightline layer:back

TextData =

  fontsize:10
  textcolor:blue
  pos:(0,13)
  text:Rømer °Rø

</timeline>
<timeline> ImageSize = width:905 height:50 PlotArea = left:80 right:15 bottom:20 top:5 AlignBars = justify Colors =

 id:black  value:black
 id:white  value:white
 id:lightline  value:rgb(0.8,0.8,0.8)

Period = from:-16.5 till:36.3 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:5 start:-15 ScaleMinor = unit:year increment:1 start:-15

PlotData=

 align:center textcolor:black fontsize:8 mark:(line,black) width:5 shift:(0,-5)

LineData=

 at:start      color:green layer:front
 at:end        color:green layer:front
 
 at:-13.2 color:lightline layer:back
 at:-6.6 color:lightline layer:back
 at:0 color:lightline layer:back
 at:6.6 color:lightline layer:back
 at:13.2 color:red layer:back
 at:19.8 color:lightline layer:back
 at:26.4 color:lightline layer:back
 at:33 color:lightline layer:back

TextData =

  fontsize:10
  textcolor:blue
  pos:(0,13)
  text:Newton °N

</timeline>
<timeline> ImageSize = width:905 height:50 PlotArea = left:80 right:15 bottom:20 top:5 AlignBars = justify Colors =

 id:black  value:black
 id:white  value:white
 id:lightline  value:rgb(0.8,0.8,0.8)

Period = from:-15 till:225 DateFormat = yyyy TimeAxis = orientation:horizontal order:reverse format:yyyy ScaleMajor = unit:year increment:15 start:-15 ScaleMinor = unit:year increment:1 start:-15


LineData=

 at:start      color:green layer:front
 at:end        color:green layer:front
 
 at:0 color:lightline layer:back
 at:30 color:lightline layer:back
 at:60 color:lightline layer:back
 at:90 color:red layer:back
 at:120 color:lightline layer:back
 at:150 color:lightline layer:back
 at:180 color:lightline layer:back
 at:210 color:lightline layer:back

TextData =

  fontsize:10
  textcolor:blue
  pos:(0,13)
  text:Delisle °D 

</timeline>
<timeline> ImageSize = width:905 height:100 PlotArea = left:80 right:15 bottom:70 top:5 AlignBars = justify Colors =

 id:black  value:black
 id:white  value:white
 id:lightline  value:rgb(0.8,0.8,0.8)

Period = from:-40 till:88 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:10 start:-30 ScaleMinor = unit:year increment:1 start:-40 PlotData=

 align:center textcolor:black fontsize:8 mark:(line,black) width:25 shift:(0,-5)

LineData=

 at:start      color:green layer:front
 at:end        color:green layer:front
 at:-32 color:lightline layer:back
 at:-16 color:lightline layer:back
 at:0 color:lightline layer:back
 at:16 color:lightline layer:back
 at:32 color:red layer:back
 at:48 color:lightline layer:back
 at:64 color:lightline layer:back
 at:80 color:lightline layer:back

TextData =

  fontsize:10
  textcolor:blue
  pos:(0,60)
  text:Réaumur °Ré
  fontsize:12
  textcolor:red
  pos:(110,20)
  text:313.15 K   =   40 °C   =   104 °F   =   563.67 °Ra   =   28.5 °Rø   =    13.2 °N   =   90 °D   =   32 °Ré

</timeline> All three of the major temperature scales are related through a linear equation, and so the conversion between any of them is relatively straightforward. For instance, any Celsius temperature c °C can be calculated from a corresponding Fahrenheit temperature f °F or absolute temperature k K.

[math]\displaystyle{ \begin{align} c \;=\; \frac{5}{9}(f - 32) \;=\; k-273.15 \end{align} }[/math]

The equations above may also be rearranged to solve for [math]\displaystyle{ f }[/math] or [math]\displaystyle{ k }[/math], to give

[math]\displaystyle{ \begin{align} f \;&=\; \frac{9}{5}c + 32 \;=\; \frac{9}{5} (k-273.15) + 32\\ k \;&=\; c+273.15 \;=\; \frac{5}{9}(f - 32) + 273.15 \end{align} }[/math]

See also

References

  1. 1.0 1.1 "Nox, Dunkelleuchtdichte, Skot" (in de). Physikalisches Wörterbuch (1 ed.). Berlin / Göttingen / Heidelberg, Germany: Springer-Verlag OHG. 1952. pp. 125, 271, 389. doi:10.1007/978-3-662-12706-3. ISBN 978-3-662-12707-0. https://books.google.com/books?id=QaCFBwAAQBAJ&pg=RA1-PA125. Retrieved 2023-03-16. "Dunkelleuchtdichte. […] Unter Zugrundelegung dieser Empfindlichkeitskurve hat man 1940 in Deutschland die Dunkelleuchtdichte mit der Einheit Skot (sk) so festgesetzt, daß bei einem Licht der Farbtemperatur 2360 °K 1 sk = 10−3 asb gilt. 1948 ist von der Internationalen Beleuchtungskommission (IBK) die Bezugstemperatur auf 2046 °K, die Erstarrungstemperatur des Platins, festgesetzt worden. Die Bezeichnung Skot wurde von der IBK nicht übernommen, dafür soll "skotopisches Stilb" gesagt werden. Als höchstzulässiger Grenzwert für die Dunkelleuchtdichte ist in Deutschland 10 Skot festgesetzt worden, um eine Verwendung der Dunkelleuchtdichte im Gebiet des gemischten Zapfen- und Stäbchensehens zu vermeiden, da in diesem Bereich die photometrischen Maßgrößen wegen der allmählich gleitenden Augenempfindlichkeitskurve ihren Sinn verlieren. […] Skot, abgek[ürzt] sk, Einheit für die Dunkelleuchtdichte, welche für zahlenmäßige Angaben und zum Anschluß der Dunkelleuchtdichte an die normale Leuchtdichte 1940 von der German Lighting Society (de) geschaffen wurde. Für diesen Anschluß wurde die Strahlung des schwarzen Körpers bei T = 2360 °K, d.h. eine Strahlung der Farbtemperatur T1 = 2360 °K vereinbart. Eine Lichtquelle strahlt mit der Dunkelleuchtdichte 1 sk, wenn sie photometrisch gleich einer Strahlung der Farbtemperatur T2 = 2360 °K und der Leuchtdichte von 10−3 asb (Apostilb) ist. Bei der Farbtemperatur T1 = 2360 °K gilt also die Relation: 1 sk = 10−3 asb = 10−7/π sb." 
  2. 2.0 2.1 "Resolution 3 of the 13th CGPM (1967)". BIPM. 1967. https://www.bipm.org/en/committees/cg/cgpm/13-1967/resolution-3. 
  3. 3.0 3.1 "Resolution 3: SI unit of thermodynamic temperature (kelvin)". Resolutions of the 13th CGPM. Bureau International des Poids et Mesures. 1967. http://www.bipm.fr/en/CGPM/db/13/3/. 
  4. "Unit of thermodynamic temperature (kelvin) (International System of Units brochure, Section 2.1.1.5)". International Bureau of Weights and Measures. http://www.bipm.org/en/publications/si-brochure/kelvin.html. 
  5. "Metric system temperature (kelvin and degree Celsius)". Colorado State University - Lamar. http://lamar.colostate.edu/~hillger/temps.htm.