THERMOMETRY
There are two scales used in thermometry, the Fahrenheit and the Centigrade. The former is generally used. However, since many of the scientific calculations are made using the Centigrade scale it is wise for the nurse to understand how to translate one to the other.
Centigrade has 0° as the freezing point and 100° as the boiling point, while Fahrenheit has 32° as freezing point and 212° as boiling point. To change Fahrenheit to Centigrade it is necessary to subtract 32 from 212 in order to make the freezing points correspond. This would read 212 -32 = 180° F. = 100° C; hence a degree Centigrade represents 5/9 of a degree Fahrenheit.
To change Centigrade to Fahrenheit it is necessary to remember that every Fahrenheit degree is 9/5 times as large as the Centigrade and the addition of 32° must also be made. For example: Change 105° F. to Centigrade: 105°-32° × 5/9 = 41° C. Change 50° C. to Fahrenheit: 50° × 9/5 + 32° = 90° + 32° = 122° F.