Question

how can we define calorie and kilocalorie?how can we measure them?

Answer 1

The calorie is a pre- SI metric unit of energy. It was first defined by Nicolas Clement in 1824 as a unit of heat , entering French and English dictionaries between 1841 and 1867. In most fields its use has been replaced by the SI unit of energy, the joule . However, it remains a commonly used unit for energies in the field of chemistry, and in many countries it remains in common use as a unit of food energy .

Kilocalorie is a non-SI unit of energy equal to 1,000 calories, used in chemistry or physics; equal to 1 calorie or Calorie as used in nutrition.

As calorie is the unit of energy so there are various ways to measure energy also you can convert energy measured in joules to calories

1 Calorie= 4.2 J