2. © OCR 2012 1

3. Battling ideas A skill development activity for GCSE

4. © OCR 2012 OBJECTIVES ● Recall that science explanations are provisional ● Recognise that explanations are more convincing when their predictions are successfully tested ● Explain why the theory of plate tectonics is now accepted 3

5. © OCR 2012 1 Which number comes next? EngageSS1 4

6. © OCR 2012 3 Which number comes next? Previous number: 1 Engage 5

7. © OCR 2012 5 Which number comes next? Previous numbers: 1, 3 Engage 6

8. © OCR 2012 7 Which number comes next? Previous numbers: 1, 3, 5 Engage 7

9. © OCR 2012 9 Previous numbers: 1, 3, 5, 7 Was your prediction correct? Engage 8

10. © OCR 2012 Round 2 This time, work out a rule that predicts the next number. Engage 9

11. © OCR 2012 1 What could the next number be? Engage 10

12. © OCR 2012 2 What rule connects these numbers? Predict the next number. Engage Previous number: 1 11

13. © OCR 2012 2 Were you correct? If not, try to find a better rule. Engage Previous numbers: 1, 2 12

14. © OCR 2012 4 Were you correct? If not, try to find a better rule. Engage Previous numbers: 1, 2, 2 13

15. © OCR 2012 8 Were you correct? If not, try to find a better rule. Engage Previous numbers: 1, 2, 2, 4 14

16. © OCR 2012 32 Were you correct? Describe the rule that links the numbers. Engage Previous numbers: 1, 2, 2, 4, 8 15

17. © OCR 2012 Did your first idea produce a successful prediction? Did you change your rule when you had more numbers to base it on? Engage 16

18. © OCR 2012 The numbers are like scientific observations. Scientists keep generating new ones. The rule is like a science explanation or theory. Engage 17

19. © OCR 2012 A science explanation is convincing if it generates accurate predictions. Engage 18

20. © OCR 2012 Scientists often think of different explanations. How can we decide which one is best? © OCR 2012 Explore 19

21. © OCR 2012 Contest 1 Explore 20

22. © OCR 2012 In tonight’s Battling Ideas contest, our two boxers are competing to explain something very puzzling... Explore 21

23. © OCR 2012 The trees around Mammoth Mountain are dying. This region of California is volcanically active. Explore 22

24. © OCR 2012 In the red corner, we have ‘Rain’, his idea is...... acid rain produced by volcanic gases kills trees. Explore 23

25. © OCR 2012 In the blue corner, we have ‘Deadly’, his idea is......one of the volcanic gases is deadly and kills the trees directly. Explore 24

26. © OCR 2012 Choose which idea to support. After each round, record: Explore whether it generates a correct prediction.....and how confident you are that the explanation is correct. SS2 25

27. © OCR 2012 Round 1 Who’s right? “I predict that the rain in Europe is acidic.“ “I predict that there is a deadly gas in the air around the trees.” Round 1: Trees are also dying in Europe. Why? Explore 26

28. © OCR 2012 and the winner is... Observation: The pH of Europe’s rainwater is low, but the air is safe to breathe. 1 Rain Explore 27

29. © OCR 2012 Round 2 Himalayas Who’s right? “I predict that acid rain forms wherever volcanic gases are released.” “I predict that volcanic activity releases deadly gases without forming acid rain.” ” Round 2: Does volcanic activity cause acid rain? 1 Explore 28

30. © OCR 2012 and the winner is... Observation: The rainfall around volcanoes on Hawaii is highly acidic. The rain on other parts of the islands is not. 1 Rain 2 Explore 29

31. © OCR 2012 Round 3 Himalayas Who’s right? “I predict that acid rain falling in the lakes will kill the fish” “I predict that the deadly gas won’t harm the fish” Round 3: The lakes on Mammoth mountain contain many different types of fish. 1 2 Explore 30

32. © OCR 2012 Observation: Fish populations in the lakes are healthy. and the winner is... Deadly 11 2 Explore 31

33. © OCR 2012 Round 4 Himalayas Who’s right? “I predict that acid rain falling in the lake poisoned their drinking water.” “I predict volcanic activity released a deadly gas.” Round 4: It’s 1986, and 1700 people are going to die near Lake Nyos in Cameroon. This area is volcanically active. What do you think is going to kill them? Plants were also killed. 11 2 Explore 32

34. © OCR 2012 Observation: High levels of carbon dioxide were detected near the lake. When large amounts are released, this dense gas displaces the oxygen at ground level. and the winner is... Deadly 11 22 Explore 33

35. © OCR 2012 Round 5 Himalayas Who’s right? “I predict that carbon dioxide levels around Mammoth Mountain Are normal” “I predict that carbon dioxide levels are high around Mammoth Mountain. Round 5: Are there high carbon dioxide levels around Mammoth Mountain? 11 22 Explore 34

36. © OCR 2012 Observation: In the soil around the dead trees, the carbon dioxide level is 100 times the normal value. and the winner is... Deadly 11 22 3 Explore 35

37. © OCR 2012 Tonight’s overall winner is... Deadly Explore 36

38. © OCR 2012 Contest 2 Explore 37

39. © OCR 2012 In tonight’s Battling Ideas contest, our two boxers are competing to explain something very puzzling... Explore 38

40. © OCR 2012...mysterious ridges on the surface of the planet Mercury. Photographs from the Messenger spacecraft Explore 39

41. © OCR 2012 In the red corner, we have ‘Shrink’, his idea says... The ridges are formed as Mercury cools and shrinks. Explore 40

42. © OCR 2012 In the blue corner, we have ‘Plates’, his idea says... The ridges are pushed up when the plates of Mercury’s crust push together. Explore 41

43. © OCR 2012 “I predict that they will shrink.” “I predict that they will crack.” Round 1: What happens to the shape of hot rocks as they slowly cool? Round 1 Explore 42 Who’s right?

44. © OCR 2012 and the winner is... Observation: Measurements of hot objects show they get smaller (contract). 1 Shrink Explore 43

45. © OCR 2012 “I predict that mountain ridges are found anywhere on Earth.“ “I predict that mountain ridges are found where the Earth’s plates meet and push together.” Round 2: Where are there mountain ridges on Earth? Round 2 Himalayas Who’s right? 1 Explore 44

46. © OCR 2012 Observation: Mountain ranges are found where the Earth’s plates are moving towards each other. and the winner is... Plates 11 Explore 45

47. © OCR 2012 “I predict NO. The planet has cooled so there will be no molten lava.” “I predict YES. Molten lava can escape between the plates.” Round 3: On Earth, lava flows are found only in certain places. Are there lava flows on Mercury? Round 3 Himalayas Who’s right? 1 1 Explore 46

48. © OCR 2012 Observation: The smooth area shows where lava has covered the craters. and the winner is... Plates 11 2 Explore 47

49. © OCR 2012 “I predict NO. With no plates there can be no active volcanoes.” “I predict YES. They will exist where the plates meet.” Round 4: Are there active volcanoes on Mercury? Round 4 Himalayas Who’s right? 1 1 2 Explore 48

50. © OCR 2012 and the winner is... Observation: There are lava flows on Mercury dated at about 3 billion years old but no evidence of active volcanoes. 1 Shrink 1 22 Explore 49

51. © OCR 2012 “I predict Mercury has a wrinkled appearance” “I predict that Mercury has mountains only in some places.” Round 5: What is Mercury’s surface like? Round 5 Who’s right? 1 1 22 Explore 50

52. © OCR 2012 and the winner is... Observation: Images from probes have shown great curved cliffs hundreds of km long across much of Mercury’s surface. 1 Shrink 1 22 3 Explore 51 This cliff is over a mile high.

53. © OCR 2012 “I predict Mercury’s diameter has got smaller.” “I predict that Mercury’s diameter has stayed the same. Round 5: Has Mercury’s diameter changed over time? Round 5 Who’s right? 1 1 22 diameter Explore 52

54. © OCR 2012 and the winner is... Observation: New measurements show that Mercury’s diameter has shrunk by 1 or 2 km. 1 Shrink 1 22 3 Explore 53

55. © OCR 2012 Shrink Tonight’s overall winner is... Explore 54

56. © OCR 2012 A science explanation is always provisional. It could change. Explain 55

57. © OCR 2012 A science explanation becomes more convincing if the predictions it makes are confirmed by observations. Explain 56

58. © OCR 2012 As observations confirm predictions, more scientists may be convinced by the explanation.....but this does not prove it is correct. Explain 57

59. © OCR 2012 Then the provisional explanation will be revised, or replaced with a better one. New observations could be made in the future.....that disagree with our predictions. Explain 58

60. © OCR 2012 Treekill, Erzgebirge 19, 23 and 37 wikipedia.org Mammoth mountain ski area in summer 25 and 31 wikimedia.org Dead vegetation at Lake Nyos28wikipedia.org Mercury – large expanse of smooth plains material 36 NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington Mercury’s vast expanses of smooth plains 45Messenger.edu Lobate scarps49 NASA PictureStudent sheet Credit Credits GENERAL QUALIFICATIONS Telephone 01223 553998 Facsimile 01223 552627 science@ocr.org.uk 1 Hills Road, Cambridge CB1 2EU www.gcse-science.com Skillup is created by science upd8

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