What are the various temperature scales used and how do you convert from one to the other?


by Evan Stewart


Posted on March 10, 2010 at 5:51 PM

Updated Wednesday, Mar 10 at 5:58 PM

45In meteorology, three different temperature scales are used: Fahrenheit, Celsius, and Kelvin.

German-born scientist Gabriel Daniel Fahrenheit developed the Fahrenheit Scale. He introduced his scale and new mercury thermometer in 1714 in Holland. Zero Fahrenheit was the coldest temperature Fahrenheit could create with a mixture of ice and salt. On the Fahrenheit Scale, water freezes at 32 and boils at 212.

Swedish astronomer Anders Celsius introduced his scale in 1742. He used 0 as the freezing point of water, and 100 as the boiling point. 

For many years, the Celsius scale was also called the Centigrade because the Greek prefix "centi-" means one-hundredth, and each degree Celsius is one-hundredth of the way between the freezing and boiling points of water.

The third scale we use is the Kelvin Scale. British scientist William Thomson, Lord Kelvin did research on heat in the 1800s. Theoretically, the coldest temperature possible is -273.15 Celsius. This temperature is called absolute zero because at this temperature scientists believe that molecular motion stops. The Kelvin Scale uses this number as zero.

Conversion Formulas

From Fahrenheit to Celsius
C = 5/9 x (F - 32)

From Celsius to Fahrenheit
F = (9/5 x C) + 32

From Celsius to Kelvin
K = C + 273.15