Why does the Fahrenheit scale use 32 degrees as a freezing point?

Asked by: Maria Ciaramitaro

Answer

Daniel Fahrenheit did not use the freezing point of water as a basis for developing his scale. He called the temperature of an ice/salt/water mixture 'zero degrees', as this was the lowest temperature he could conveniently attain in his lab. He called his own body temperature '96 degrees', and then divided the scale into single degrees between 0 and 96. On this scale, the freezing point of pure water happens to occur at 32 (and the boiling point at 212). The Celsius scale has more convenient values for these phase transition points (0 and 100 degrees) because Anders Celsius DID use water as a basis for his scale.
Answered by: Jonathan Heath