The degree celsius (°C) is a unit of temperature named for the Swedish astronomer, Anders Celsius (1701-1744), who first proposed it in 1742. With respect to the Celsius temperature scale, the freezing point of water is 0 degrees, and the boiling point is 100 degrees. Hence a degree celsius has the same size as a Kelvin; 0.00°C equals 273.15K, and 100.00°C equals 373.15K.
Anders Celsius originally proposed that the freezing point should be 100 degrees and that the boiling point should be 0 degrees however this was reversed, possibly at the instigation of Carl von Linné, otherwise known as Linnaeus, or possibly at the instigation of Daniel Ekström, the manufacturer of most of the thermometers used by Celsius.
Since a degree is defined as one hundredth of the difference between the two reference points the original term for this system was "centigrade" (100th part). To convert celsius to Fahrenheit: multiply the celsius temperature by 1.8 and add 32 degrees.
- F = 1.8 C + 32
To convert Fahrenheit to celsius: subtract 32 degrees from the Fahrenheit temperature and divide the quantity by 1.8.
- C = (F - 32) / 1.8.
The Celsius scale is used in most of the world for day-to-day purposes.