Degree symbol facts for kids
°  

Degree symbol


The degree symbol (°) is a typographical symbol that is used, among other things, to represent degrees of arc (e.g. in geographic coordinate systems), hours (in the medical field), degrees of temperature, alcohol proof, or diminished quality in musical harmony. The symbol consists of a small raised circle, historically a zero glyph.
History
The first known recorded modern use of the degree symbol in mathematics is from 1657 where the usage seems to show that the symbol is a small raised zero, to match the prime symbol notation of sexagesimal subdivisions of degree such as minute ( ′ ), second ( ″ ), and third ( ‴ ), which originate as small raised Roman numerals.
Typography
In the case of degrees of angular arc, the degree symbol follows the number without any intervening space, e.g. 30°. The addition of minute and second of arc units follow the degree units, with intervening spaces between the units but no spaces between the numbers and arc symbols, e.g. 30° 12′ 5″.
In the case of degrees of temperature, three scientific and engineering standards bodies (the International Bureau of Weights and Measures, the International Organization for Standardization and the U.S. Government Printing Office) prescribe printing temperatures with a space between the number and the degree symbol, e.g. 10 °C. However, in many works with professional typesetting, including scientific works published by the University of Chicago Press or Oxford University Press, the degree symbol is printed with no spaces between the number, the symbol, and the Latin letters "C" or "F" representing Celsius or Fahrenheit, respectively, e.g. 10°C. This is also the practice of the University Corporation for Atmospheric Research, which operates the National Center for Atmospheric Research.
Though not recommended, use of the degree symbol without a following Latin letter is done so without a space between the number and symbol, e.g. 10°; this is considered more acceptable if the standard of temperature is not known, but it is recommended in this case that the full word be used rather than the symbol, e.g. 10 degrees. Use of the degree symbol to refer to temperatures measured in kelvins (symbol: K) was abolished in 1967 by the 13th General Conference on Weights and Measures (CGPM). Therefore, the triple point of water, for instance, is written simply as 273.16 K. The name of the SI unit of temperature is now "kelvin", in lower case, and no longer "degrees Kelvin".
In photography, the symbol is used to denote logarithmic film speed grades. In this usage, it follows the number without spacing as in 21° DIN, 5° ASA.