Why study Thermodynamics? Essential study of the internal motions of many-body systems is Thermodynamics. Substances that we encounter in everyday life are the body system of solid, liquid, gaseous, and light. Therefore, thermodynamics has a wide range of applicability in the field of physics. Thermodynamics is governed by four laws: 1. Zeroth law of thermodynamics 2. The First law of thermodynamics 3. The Second law of thermodynamics 4. Third law of thermodynamics Zeroth law The Zeroth Law is the basis for the measurement of temperature. It states that two bodies that are in thermal equilibrium with a third body are in thermal equilibrium with each other. Eg: Thermometer In the Thermometer, there are few things, 1) a glass bulb 2) a glass column 3) liquid, normally Mercury 4) temperature scale on the glass tube Explanation Normally mercury is stored in the glass bulb and thi...