Chapter Graphic
 :Dead Mouse
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  Level: Year 4 and year 8
Approach: One to one
Focus: Identify and explain the application of a lever to shift a heavy object, and choose a suitable arrangement from three options.
488k
Resources: Video
Download the videoclip 5.6MB (requires QuickTime plug-in)

Questions / instructions:
Note: Do not allow student to see recording book until Question 3.
This activity starts with a video about a woman who has a problem at home. Let's watch the video.
Play video clip one.

  a a
% response
y4
y8
a
a
1. In the video the woman discovered a dead mouse under the fridge. It's a big old fridge that doesn't have wheels. The fridge is too heavy for her to lift by herself and there's nobody around to help her.
What could she use to help her lift the fridge?
not marked
a
a
Play video clip two.
a
a
2. The woman used two pieces of wood to lift the fridge.
    Explain to me how the wood helped her lift it.
Prompt: Why was it easier when she used the pieces of wood?
small force at long end can exert bigger force at shorter end:
a
a
clear and adequately full explanation
3
21
on right track but vague
38
46
Show the student the last page of the recording book.
a
a
3. Here are some pictures that show pieces of wood being used to lift a heavy box.
Which picture shows the best way to lift the heavy box?
picture: A
7
2
B
48
57
C
45
41
4. Why is that the best way to lift the weight?
clearly understood principle of the ratio of two lever arms
3
14
dealt only with part of lever person was touching
(longer = better)
13
19

Commentary:
Questions three and four proved not very satisfactory, because picture C showed the heavy object so far onto the lever and close to the fulcrum that it would have needed to be lifted directly. For this reason some well-informed students chose picture B. Overall, the results show useful progress between year 4 and year 8.
 
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