The rise in temperature of bodies when they are heated is approximately proportional to the energy supplied. 
A commonly used unit to measure this energy (heat) is called the calorie: the heat necessary for a gram of water to increase its temperature by 1ºC.
Not all bodies heat up in the same way. Specific heat is the property of bodies which measures this difference and can be defined as the heat necessary for the unit mass of a body to increase its temperature by 1ºC. 
   

The heat lost or absorbed by a body can be measured by the expression:
Q = m·c·(Tf-To) where m is the mass of the body, c its specific heat, Tf its final temperature and To its initial temperature.
  

A calorie is equivalent to the transfer of  4.18 j of energy, which permits us to write all the former expressions in SI units. Thus, the specific heat of water is Ca = 1 cal/gºC = 4180 j/kgºC