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Conversion Between Fahrenheit and Celsius Scales

The metric system measures temperature in degrees Celsius rather than degrees Fahrenheit. In the histology laboratory, almost all temperature readings are taken using the Celsius scale, which is divided into 100 parts. (The Fahrenheit scale is divided into 180 parts.) Conversion may be necessary from one scale to the other in the histology laboratory.
Converting Fahrenheit to Celsius
Taking into account that a Fahrenheit degree is 5/9th of a Celsius degree because of the difference in scales AND that 0º on the Celsius scale = 32º on the Fahrenheit scale, the following formula is derived to convert a Fahrenheit temperature to a Celsius temperature:
°C = 5/9 X (°F – 32) OR °C = (°F – 32) X 0.555
Example 1
The histology laboratory is very warm today at 83 °F, a temperature that is not optimal for the automated equipment. How does this temperature equate to the Celsius scale?
°C = 5/9 X (83° F – 32)
°C = 5/9 X 51
°C = 28.3

Converting Celsius to Fahrenheit
This formula can be used to convert a Celsius temperature to a Fahrenheit temperature:
°F = 9/5 X °C + 32 OR °F = [1.8 X °C] + 32
Example 2
A histotechnician notes his flotation water bath temperature registering at only 30 °C. What temperature does that equate to in degrees Fahrenheit?
°F = 9/5 X 30° C + 32
°F = 54 + 32
°F = 86
TIP! Remember, 0° C = 32° F and 100° C = 212° F. A Fahrenheit temperature will always be the higher reading.