A Calorimeter is an instrument used for measuring the heat of chemical reactions or physical changes as well as heat capacity. The instrument is generally used in calorimetry, which is the science of measuring the heat of chemical reactions or physical changes. A basic calorimeter comprises a thermometer attached to a metal container full of water suspended above a combustion chamber. The most common types of calorimeters used by scientists are differential scanning calorimeters, isothermal microcalorimeters, titration calorimeters and accelerated rate calorimeters. Besides the above-mentioned calorimeters, adiabatic calorimeter and reaction calorimeter are also significant types used in different calorimetric processes.