Heat

heat is the energy transfer from one object to another because of difference in temperature.

calorie ( not Calorie )( cal ) : amount of heat necessary to raise 1g of water by 1 degrees celsius ( from 14.5 - 15.5 degrees Celsius ), because the difference, although less than 1% from 0-100 degrees Celsius, still exists ).

Mechanical Equivalent of Heat:

$$4.186 \text{J} = 1 \text{cal}$$