Thermal Properties of Matter Class 11 Physics Chapter 11 - Calorimetry - Principle and Structure of Calorimeter
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In this video we will learn about Calorimetry, Structure of Calorimeter and Principle of Calorimetry.

Isolated System -
When hot aluminium ball is inserted in water, what will happen? The temperature of water increases. In other words, heat is transferred from aluminium ball to the water. But during this action, some of the heat may escape in the surrounding. Can we make system in which heat is not allowed to escape in the surrounding. Such system is called isolated system.
In isolated system, heat is neither allowed to come inside the system, nor it is allowed to escape in the surrounding and hence, total heat in the isolated system remains constant.
In general, "Calorimetry means measurement of heat". The device is used for this purpose is called calorimeter.

Structure of Calorimeter -
It is generally made of copper vessel, containing water and stirrer of same material. Whole assembly is kept in a wooden jacket containing heat insulating material such as "Glass Wool". The speciality of this box is that the outer layer act as heat shield that does not allow heat to come inside the box. Hence, it provides thermal isolation from surrounding. The thermometer is inserted into the vessel through a small opening it helps to measure the temperature inside the vessel. A sample to be burnt is kept in the closed chamber called bomb. This chamber is supplied compressed oxygen to facilitate the burning process.
When current is pass through ignition wires the sample catches fire and burn. Heat released by the sample get absorbed by the water and the copper vessel.
Stirrer is used for uniform mixing of heat. As a result there is temperature rise in the thermometer with the formula of specific heat capacity. It is possible to find the heat transferred in the system.
Thus, principal of calorimetry states that the heat released by hot object is equal to total heat received by cold object i.e. heat loss is equal to heat gain.

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