Space journey —launching

1. 9.4 Space journey —launching

2. The force of gravity keeps us on the Earth’s surface.

3. How can we overcome the force of gravity and travel into space?

4. The principle behind a rocket launch

5. Action and reaction Forces always occur in pairs Action (作用力) Reaction (反作用力)

6. 9.7 Experiment video Pull and push 1 A B rope wooden trolley

7. 9.7 a What happens? Both move towards each other. Pull Hold

8. 9.7 b A B force actingon B by A force actingon A by B

9. 9.7 c What happens? Both move towards each other. Pull Pull

10. 9.7 2 A B wooden trolleys

11. 9.7 a What happens? Both move away from each other. Push gently

12. 9.7 b A B force actingon A by B force actingon B by A

13. 9.7 c What happens? Both move away from each other. Push gently Push gently

14. 9.8 Experiment video Forces between a pair of trolleys 1 trigger trolley A B

15. 9.8 What happens to the trolleys? 2 A B

16. 9.8 2 What happens to the trolleys? Trolley A moves _______________. Trolley B moves _______________. to the left to the right A B

17. 9.8 3 force actingon A by B force actingon B by A

18. Action and reaction action-and-reaction pair pulling force actingon B by A pulling force actingon A by B A B

19. Action and reaction action-and-reaction pair pushing force actingon A by B pushing force actingon B by A A B

20. Action and reaction Are the sizes of action and reaction the same or different? A B

21. 9.9 Experiment video Comparing the sizes of action and reaction 1 newton balance A newton balance B A B

22. 9.9 2a record record pull hold A B

23. 9.9 3 force acting on balance B by balance A force acting on balance A by balance B A B

24. 9.9 4 Compare the readings of balances A and B. What can you tell from the results? The readings are the same. The action and the reaction are of the same size.

25. Action and reaction When we exert a force on an object, a force of equal size in the opposite direction will act on us. A B force acting on balance A by balance B

26. Action and reaction act on different bodies A B

27. Action and reaction force exerted on the pool side by the swimmer force exerted on the swimmer by the pool side the swimmer is pushed to the other side of the pool

28. Action and reaction the diver is allowed to jump off the diving board force exerted on the diver by the diving board force exerted on the diving board by the diver

29. Action and reaction Forces always occur in pairs. When object A exerts a force on object B, object B exerts a force of equal size on object A in the opposite direction. These two forces are an action-and-reaction pair.

30. How does the rocket produce the force to push itself upwards?

31. 9.10 Experiment video Launching a water rocket 1 air pump water rocket water trigger

32. 9.10 What happens? The water inside the water rocket moves ____________. The water rocket moves ____________. 3 downwards upwards

33. 9.10 4 force acting on rocket by water force acting on water by rocket

34. How does a rocket propel itself?  Makes use ofaction and reaction 3D animation

35. How does a rocket propel itself? pushes the rocket upwards reaction the rocket ejects hot gases downwards

36. How does a rocket propel itself? When a rocket is launched, it ejects hot gases downwards and the reaction pushes the rocket upwards.

37. Rocket design Problems when launching a rocket: air resistance  When the rocket is flying at a high speed, air resistance is very large.

38. Rocket design Problems when launching a rocket: There is no air in space, the rocket fuel cannot burn.  fuel oxygen high temperature

39. Rocket design Problems when launching a rocket:  The force of gravity acting on the rocket is very large. force of gravity

40. Rocket design Problems when launching a rocket: large air resistance no air for burning fuel in space large force of gravity    How can these problems be solved?

41. Rocket design Problems when launching a rocket: large air resistance no air for burning fuel in space large force of gravity   

42. Streamlined shape • designed to have a streamlined shape • air resistance is reduced

43. Rocket design Problems when launching a rocket: large air resistance no air for burning fuel in space large force of gravity   

44. Carrying its own supply of oxygen no oxygen in space needs to carry its own supply of oxygen

45. Carrying its own supply of oxygen no oxygen in space oxidizer (used with solid fuels) need to carry its own supply of oxygen liquid oxygen (used with liquid fuels)

46. Carrying its own supply of oxygen Solid-fuel rocket Liquid-fuel rocket liquid fuel liquid oxygen solid fuel grain igniter combustion chamber nozzle nozzle

47. Carrying its own supply of oxygen Solid-fuel rocket Liquid-fuel rocket Structure more complicated simple

48. Carrying its own supply of oxygen Solid-fuel rocket Liquid-fuel rocket Structure fuel and oxidizer are mixed to form grains fuel and liquid oxygen are stored separately

49. Carrying its own supply of oxygen Solid-fuel rocket Liquid-fuel rocket Structure grains can be stored at room temperature fuel and oxygen are kept at low temperature and high pressure

50. Carrying its own supply of oxygen Solid-fuel rocket Liquid-fuel rocket Operation grains are burnt at launch fuel and oxygen are mixed and burnt at launch