A calorimeter is a device which measures the heat flow from the system to the surroundings or vice-versa. This process requires knowledge of heat capacity; the amount of energy required to change a material's temperature by 1 K.

Specific heat capacity (c) is the value for 1 g of material while molar heat capacity (C) is the value for 1 mole of material. Let's consider an example in which three blocks of equal mass are exposed to the same amount of heat from sunlight. The blocks are made from glass, steel, and wood.