11

2 Heat Energy Energy passed as heat from one object to another

3 Heat always passes from a hotter object to a cooler object If you hold an ice cube in your hand, it will start to melt

4 Heat energy passes from your hand to the ice cube The heat energy makes the molecules in the ice move faster

5 The ice begins to melt, or become a liquid

6 Heat energy can be passed in 3 ways 1.Conduction 2. Convection 3. Radiation

7 Conduction Heat passes through solids

8 When one object passes heat to another by conduction, The heat keeps flowing until both objects are equally hot

9 Have you ever eaten hot soup with a metal spoon? After a while, the spoon gets hot

10 The hot soup causes the molecules in the spoon to move faster Heat travels from the soup up the spoon to your hand

11 Convection Heat passes through liquids and gasses in currents

12 Molecules in liquids and gases move apart when they are heated This happens during convection

13 When you heat water on the stove, The bottom layer of water is heated first The molecules in this layer of water move farther apart Then floats to the top, and the cooler, heavier water on the top falls to the bottom

14 These molecules are called convection currents In winter, convection heats the air in your house

15 Radiation Movement of heat energy in waves

16 Solar heat comes in radiation waves

17 Microwave ovens heat food by radiation

18 Heat energy can be passed in 3 ways 1.Conduction - contact 2. Convection - current 3. Radiation - waves