2. LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END COMPUTER PRESENTATIONS FOR KS3 SCIENCE - PHYSICS ©2003, STEVE PARKER COMPUTER PRESENTATIONS FOR KS3 SCIENCE - PHYSICS ©2003, STEVE PARKER

3. 1 1 KS3 SCIENCE - PHYSICS KS3 SCIENCE - PHYSICS Energy Transfer Energy Transfer

4. ENERGY TRANSFERS 2 2

5. 3 3 Energy can never be created or destroyed - it is only ever converted to a different form Energy can never be created or destroyed - it is only ever converted to a different form

6. ENERGY TRANSFERS 4 4 Devices and machines convert energy from one form to another Devices and machines convert energy from one form to another DEVICE ENERGY INPUT ENERGY INPUT USEFUL ENERGY OUTPUT USEFUL ENERGY OUTPUT

7. ENERGY TRANSFERS 5 5 Devices and machines convert energy from one form to another Devices and machines convert energy from one form to another DEVICE ENERGY INPUT ENERGY INPUT USEFUL ENERGY OUTPUT USEFUL ENERGY OUTPUT Wasted energy - e.g. heat, sound Wasted energy - e.g. heat, sound However, they usually “lose” some However, they usually “lose” some

8. ENERGY TRANSFERS 6 6 E.g. fireworks convert chemical energy into kinetic and light energy E.g. fireworks convert chemical energy into kinetic and light energy DEVICE ENERGY INPUT ENERGY INPUT USEFUL ENERGY OUTPUT USEFUL ENERGY OUTPUT Wasted energy - e.g. heat, sound Wasted energy - e.g. heat, sound

9. ENERGY TRANSFERS 7 7 While domestic lamps are used to convert electrical energy into light energy While domestic lamps are used to convert electrical energy into light energy DEVICE ENERGY INPUT ENERGY INPUT USEFUL ENERGY OUTPUT USEFUL ENERGY OUTPUT Wasted energy - e.g. heat, sound Wasted energy - e.g. heat, sound

10. HEAT TRANSFER 8 8

11. 9 9 “Conduction” is a process which occurs mainly in solids “Conduction” is a process which occurs mainly in solids Suppose heat is applied at one end of a solid rod Suppose heat is applied at one end of a solid rod

12. HEAT TRANSFER 10 The heat makes molecules vibrate faster at the hot end The heat makes molecules vibrate faster at the hot end “Conduction” is a process which occurs mainly in solids “Conduction” is a process which occurs mainly in solids

13. HEAT TRANSFER 11 This vibration is then passed along to neighbouring molecules This vibration is then passed along to neighbouring molecules “Conduction” is a process which occurs mainly in solids “Conduction” is a process which occurs mainly in solids

14. HEAT TRANSFER 12 So the heat gradually moves along the rod So the heat gradually moves along the rod “Conduction” is a process which occurs mainly in solids “Conduction” is a process which occurs mainly in solids

15. HEAT TRANSFER 13 Metals tend to be good conductors of heat Metals tend to be good conductors of heat

16. HEAT TRANSFER 14 “Convection” of heat only happens in liquids and gases “Convection” of heat only happens in liquids and gases Suppose we heat some water in a pot Suppose we heat some water in a pot

17. HEAT TRANSFER 15 “Convection” of heat only happens in liquids and gases “Convection” of heat only happens in liquids and gases This area of water heats up so it expands This area of water heats up so it expands

18. HEAT TRANSFER 16 “Convection” of heat only happens in liquids and gases “Convection” of heat only happens in liquids and gases Once expanded it is less dense, so each ml of it weighs less and it tends to rise Once expanded it is less dense, so each ml of it weighs less and it tends to rise

19. HEAT TRANSFER 17 “Convection” of heat only happens in liquids and gases “Convection” of heat only happens in liquids and gases Colder water sinks and is itself heated, also as the hot water rises, it transfers its heat to surrounding molecules through the process of conduction Colder water sinks and is itself heated, also as the hot water rises, it transfers its heat to surrounding molecules through the process of conduction

20. HEAT TRANSFER 18 “Radiation” of heat is caused by electromagnetic waves in the infra-red part of the spectrum “Radiation” of heat is caused by electromagnetic waves in the infra-red part of the spectrum

21. HEAT TRANSFER 19 “Radiation” of heat is caused by electromagnetic waves in the infra-red part of the spectrum “Radiation” of heat is caused by electromagnetic waves in the infra-red part of the spectrum White materials reflect a lot of radiation and stay cooler White materials reflect a lot of radiation and stay cooler

22. HEAT TRANSFER 20 “Radiation” of heat is caused by electromagnetic waves in the infra-red part of the spectrum “Radiation” of heat is caused by electromagnetic waves in the infra-red part of the spectrum Darker materials absorb radiation and heat up Darker materials absorb radiation and heat up

23. HEAT TRANSFER 21 “Radiation” of heat is caused by electromagnetic waves in the infra-red part of the spectrum “Radiation” of heat is caused by electromagnetic waves in the infra-red part of the spectrum Radiation passes through transparent materials and also through a vacuum Radiation passes through transparent materials and also through a vacuum