A Calorimeter is a metallic vessel on which two or more substances at different temperature will be mixed. It is an insulated container that allows no heat loss to the surrounding. One widely used type of calorimeter consists of an insulated container of water, a stirring device, and a thermometer (Figure 9).

After the two objects are mixed in the calorimeter, then by applying the law of heat exchange the specific heat capacity of one of the substances will be determined. This method of determining the specific heat capacity of substances using a calorimeter is known as calorimetry. For this reason calorimetry is also known as the method of mixtures. It is an experimental method of determining the specific heat of a substance.