Definition

• Celsius is a temperature scale in which 0 degrees is the freezing point of water and 100 degrees is the boiling point of water, under normal atmospheric conditions. The difference between freezing and boiling is thus divided into 100 degrees.
  
  

History

• The Celsius scale was created in 1742 by the Swedish astronomer Anders Celsius. However, the scale was originally called Centigrade, and was not renamed Celsius until 1948. Some sources still use the term Centigrade.
  
  

Conversion

• To convert Celsius temperatures to Fahrenheit, multiply the Celsius temperature by 1.8 and add 32 degrees.
  
  To convert Fahrenheit to Celsius, take the temperature in Fahrenheit, subtract 32, and divide by 1.8.
  
  

Fun Fact

• When Anders Celsius devised his scale in 1742, he actually created it in reverse---the freezing point of water was was 100 degrees, and the boiling point 0 degrees.
  
  

Comparison with Fahrenheit

• By contrast, in the Fahrenheit scale, 32 degrees is the freezing point of water and 212 degrees is the boiling point of water. The difference between freezing and boiling is thus divided into 180 degrees.