Measurement of heat energy

Measurement of heat energy

                      Measurement of heat energy was a very difficult process in early days. The addition of heat energy raises the temperature. Hence the rise of temperature of water was used by the scientists to define heat energy. The amount of heat energy required to raise the temperature of one gram of water through 1°C is called one calorie.

              However, the unit of heat energy calorie was found to be very small. Thus a bigger unit kilo calorie is in use.

            The amount of heat energy required to raise the temperature of one kilogram (1000g) of water through 1°C is called kilocalorie. 

 1 kilo calorie = 1000 calorie

This means that when 1 kilo calorie of heat is supplied to 1 kilogram of water, its temperature will raise by 1°C The modern and generally accepted unit of heat energy is joule.

1 calorie          = 4.2 joule

1 kilo calorie   = 4200 joule.