Measurement of Specific Heat Capacity

Measurement of Specific Heat Capacity

The branch of heat which is concerned with the measurement of heat is called Calorimeter. A calorimeter consists of a copper vessel which is enclosed inside a wooden box. The space between these two is filled with insulating materials like paper, straw, wooden fittings, rubber, foam etc. The calorimeter is so designed as to minimize all types of heat losses. The top of the calorimeter is closed by a wooden lid which consists of two holes through which a thermometer and a stirrer are allowed to pass tightly. To measure the specific heat capacity of a solid substance like a metal piece the following procedure is adopted. First of all the mass of the calorimeter with stirrer is measured with a physical balance. After that nearly two-thirds (2/3) of the calorimeter is filled with water. The mass of the calorimeter with water is measured. The room temperature of the calorimeter with water is found by the thermometer. The metal piece is heated in a steam bath called “hypsometer” till it attains the temperature of the steam (generated at atmospheric pressure). It is then gently dropped into the water contained in the calorimeter which is now covered with the lid. The temperature of water begins to rise. The water is stirred so as to keep its temperature uniform throughout. The process of stirring is continued till the thermometer fitted in the lid of the calorimeter attains a final steady temperature. This temperature is noted. The calorimeter with water and metal piece (forming a mixture) is again weighed.