The construction of the calorimeter contains vessels made up of good conductors like metals. The composition of metallic vessels contains copper and aluminium in major. The contents of the metallic vessel are facilitated for stirring with the help of a stirrer. The heat loss in the stirrer is reduced with the help of an insulated jacket around the stirrer. The thermometer is allowed to be inserted through a small opening which is used to measure the thermal change that occurs inside the calorimeter. Inside the calorimeter, some sample of fuel is used to burn. The metallic vessel contains water, when the fuel inside is burnt, the water gets heated. The heat loss of the fuel is converted into the heat gained by the water. That is, energy is conserved. To increase the accuracy of results, heat loss can be terminated by the insulation of the calorimeter instrument from the environmental conditions.  The heat change of the water is measured by using the inserted thermometer. The readings are used to find the heat capacity of the water and the amount of energy conserved inside the fuel.