Calorie

Calorie

The calorie is a pre-SI metric unit of energy. It was first defined by Nicolas Clément in 1824 as a unit of heat.

Definitions of a calorie fall into two classes:

• The small calorie or gram calorie (symbol: cal approximates the energy needed to increase the temperature of 1 gram of water by 1 °C. This is about 4.2 joules.
• The large calorie, kilogram calorie or food calorie (symbol: Cal) approximates the energy needed to increase the temperature of 1 kilogram of water by 1 °C. This is exactly 1000 small calories or about 4.2 kilojoules.  

 meter：kilojoule

 standard：Calorimeter