CALORIE

The calorie was first defined by Nicholas Clement in 1824 as a unit of heat energy and entered French and English dictionaries between 1841 and 1867.The energy needed to increase the temperature of a given mass of water by 1 °C depends on the atmospheric pressure and the starting temperature.In other scientific contexts, the term caloriealmost always refers to the small calorie. Even though it is not an SI unit, it is still used in chemistry. For example, the energy released in a chemical reactions per mole of reagent is occasionally expressed in kilocalorie s per mole.In a nutritional context, the kilojoules (kJ) is the Si unit of food energy, although the kilocalorie is still in common use.The word calorie is popularly used with the number of kilocalories of nutritional energy measured. As if to avoid confusion, it is sometimes written Calorie(with a capital "C") in an attempt to make the distinction, although this is not widely understood.