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| Questions/instructions:
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| %
responses 2003 ('99) |
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| y8
|
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| 1.
What happened to the marbles at the ends? |
marbles
at ends swing out alternately |
42
(34) |
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they
go backwards and forwards |
41
(49) |
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| 2.
Try to explain why that happened. |
clear
explanation |
46
(41) |
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vague
idea |
40
(45) |
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Explanation:
When one end ball hits, it transfers its energy to
the next ball, which passes it on to the next ball, etc. The ball at
the other end has none to pass it on to, so it swings out (until all
the energy has been converted to potential energy). When it swings back
in, the flow goes the other way through the balls. |
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| 3.
What happened to the marbles in the middle? |
stayed
the same – didn’t move (passed energy on) |
77 (75) |
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Total
score: |
5
|
21
(12) |
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4
|
28
(36) |
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3
|
25
(25) |
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2
|
17
(16) |
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0–1
|
9
(11) |
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| Commentary There was no meaningful change in performance between 1999 and 2003. |
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