Degree (temperature)

The term degree is used in several scales of temperature. The symbol ° is usually used, followed by the initial letter of the unit, for example “°C” for degree(s) 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:

• Celsius (°C)
• Fahrenheit (°F)
• Rankine (°R or °Ra), which uses the Fahrenheit scale, adjusted so that 0 degrees Rankine is equal to absolute zero.

Unlike the degree Fahrenheit and degree Celsius, the kelvin is not referred to or written as a degree. 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:

• Delisle (°D)
• Newton (°N)
• Réaumur (°Ré)
• Rømer (°Rø)
• Wedgwood (°W)

Kelvin

(Measurement of temperature)

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 Since 1967 it has been known simply as the kelvin, with symbol K (without a degree symbol).[1] Degree absolute (°A) is obsolete terminology, often referring specifically to the kelvin but sometimes the degree Rankine as well.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

Temperature conversions

All three of the major units of temperature are linearly dependent, and so the conversion between any of them is relatively straightforward. For instance, any temperature ${\displaystyle c}$ measured in °C can be calculated from a corresponding value ${\displaystyle f}$ in degrees Fahrenheit or ${\displaystyle k}$ Kelvin, by

${\displaystyle {\begin{aligned}c\;=\;{\frac {5}{9}}(f-32)\;=\;k-273.15\end{aligned}}}$

The equations above may also be rearranged to solve for ${\displaystyle f}$ or ${\displaystyle k}$, to give

${\displaystyle {\begin{aligned}f\;&=\;{\frac {9}{5}}c+32\;=\;{\frac {9}{5}}(k-273.15)+32\\k\;&=\;c+273.15\;=\;{\frac {5}{9}}(f-32)+273.15\end{aligned}}}$

See also

• Comparison of temperature scales
• Degree sign
• International System of Units

References

1. "Unit of thermodynamic temperature (kelvin) (International System of Units brochure, Section 2.1.1.5)". International Bureau of Weights and Measures. Archived from the original on 2014-10-07.
2. "Metric system temperature (kelvin and degree Celsius)". Colorado State University - Lamar. Archived from the original on 2000-01-16. Retrieved 2009-02-10.