Why the boy takes his hand away from the kettle? Why the boy feels the heat of the kettle?

1. Why the boy takes his hand away from the kettle? Why the boy feels the heat of the kettle?

2. HEAT THERMAL EQUILIBRIUM

3. LEARNING OBJECTIVES

4. Relationship between temperature and heat • Temperature • Temperature is a measure of the degree of hotness of a body/ an object. • A hot body has high temperature, whereas a cold body has lower temperature.

5. Heat • Heat is a form of energy being transferred from a hot body to a cold body. • Total amount of heat in a body depends on the mass, material and temperature of the body. • Heat and temperature are 2 different physical quantities.

7. Thermal Equilibrium • Two object are in thermal contact when heat energy can be transferred between them. • When two object with different degrees of hotness come into thermal contact, heat energy is transferred between the two objects.

11. Thermal equilibrium can be summarized as: There is no net flow of heat between two objects that are in thermal equilibrium. Two object in thermal equilibrium have the same temperature. • Thermal equilibrium does not depend on the: • Mass • Types of material • Size • Shape Of the two object

12. The following are some examples of objects in thermal equilibrium.

14. Liquid –in – glass Thermometer • The liquid- in – glass Thermometer works on the principle that liquids expands as the temperature rises. • The liquid used in thermometer must have the following characteristics: A) Easily visible B) Expands or contracts rapidly over a wide range of temperature C) Does not stick to the inside of the capillary tube • The most commonly used liquids in the construction of a liquid-in-glass thermometer are MERCURY and COLOURED ALCOHOL.

16. How thermometer calibrate?

20. EXERCISE 1

22. EXERCISES 2

24. EXERCISES 3