Degrees Fahrenheit is named after Daniel Gabriel Fahrenheit unit of temperature.
Fahrenheit developed his temperature scale after a visit to the Danish astronomer Ole Rømer in Copenhagen. Rømer was the first who developed a thermometer, which was calibrated using two fixed points. The Rømer scale the freezing point of water at 7.5 degrees, the boiling point at 60 degrees and the average body temperature of a human is 26.9 degrees.
Fahrenheit selected as the zero point of his temperature scale, the lowest temperature of the cold winter of 1708/1709 in his hometown of Gdansk. With a mixture of " ice, water and ammonium chloride or sea salt " ( cold mix ) he could then zero or first checkpoint restore ( -17.8 ° C). Fahrenheit would thereby avoid negative temperatures, as occurred in the Rømer scale already during normal daily use.
The second and third fixed point in 1714 he put the freezing point of pure water ( ice point ) at 32 ° F and the " body temperature of a healthy person " at 96 ° F fixed. The disadvantage of this scale was that especially the lower and upper fixed point by today's standards are not sufficiently accurate to reproduce. Therefore, a new definition was necessary.
To define a temperature scale you need for a just two different, but closely as possible reproducible temperatures, on the other hand, the arbitrary determination of the classification of the temperature difference in scale units and a scale zero point. As a new fixed points you chose the freezing point and the boiling point of water. In order to achieve the best possible agreement with the previous definition, one divided this interval into 180 divisions and retained for freezing the scale value of 32 ° F with. On this new scale is the normal temperature of a human body, 98.6 ° F ( 37 ° C) and not 96 ° F, as originally laid down by Fahrenheit.
The Fahrenheit scale has long been used in Europe until it was replaced by the Celsius scale. Nowadays it is used only in the United States and a few other English speaking countries.
Below are some conversion tables for different temperature values and units are given.