The Discovery of Temperature
Although humans have always been aware of temperature differences, the first important method of classification was only introduced in 1714 (although not published until 1724) by the German scientist, Gabriel Fahrenheit. O degrees F was chosen as the temperature of a mixture giving the lowest artificially created temperature possible at the time, and 32 degrees F as the freezing point of water. 96 degrees F was chosen being the temperature of a human. From these fixed points the scale was extended below zero and above 96 degrees. This gave the boiling point of water on the Fahrenheit scale as 212 degrees F.

The Centigrade Scale is now Widely used
The Centigrade scale is now the recommended one to use. First published by the Swedish astronomer Anders Celsius in 1742, it is based on two fixed points - the freezing and boiling points of water. Freezing point is 0 degrees C and boiling point is 100 degrees C.

A quick, but not accurate, way of converting C to F.For temperatures above 0 degrees C double the Centigrade figure and add 30.

10 degrees C x 2 = 20 + 30 = 50 degrees F

To convert C to F the reverse applies. Deduct 30 and halve the result.