Fahrenheit and Celsius Scales

Temperature

thermometer showing Farenheit and Celsius
Laurel Cook

Air temperature is measured by a mercury thermometer, which uses the principle of contraction and expansion. When the temperature rises, the mercury expands and rises in the thermometer tube. Cold weather makes the mercury contract and fall.

The Fahrenheit scale is used in the U.S. On this scale, 32° is the freezing point of water, 212° the boiling point.

The center of the sun is thought to be 40 million degrees Celsius.

The Celsius, or centigrade, scale is used by the World Meteorological Organization and most countries in the world. On this scale, 0° is freezing, 100° is boiling.


Fahrenheit and Celsius (Centigrade) Scales

°Celsius °Fahrenheit °Celsius °Fahrenheit
–250 –418 30 86
–200 –328 35 95
–150 –238 40 104
–100 –148 45 113
–50 –58 50 122
–40 –40 55 131
–30 –22 60 140
–20 –4 65 149
–10 14 70 158
0 32 75 167
5 41 80 176
10 50 85 185
15 59 90 194
20 68 95 203
25 77 100 212

Zero on the Fahrenheit scale represents the temperature produced by the mixing of equal weights of snow and common salt.

  °Fahrenheit °Celsius
Boiling point of water  212°  100°
Freezing point of water  32°   0°
Absolute zero –459.6° –273.1°

Absolute zero is believed to be the lowest possible temperature, the point at which all molecular motion would cease.

To convert Fahrenheit to Celsius (Centigrade), subtract 32 and multiply by 5/9.

To convert Celsius (Centigrade) to Fahrenheit, multiply by 9/5 and add 32.


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