- Link to the previous section, with illustrations of gymnastic balance,
eg photographs or video clips of Olympic gymnasts. Get pupils to try some balancing activities,
eg
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stand with their heels touching a wall and try to pick up an object placed about 0.5m away, on the floor.
Ask why this is impossible
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stand about three foot-lengths from the wall and try to touch the wall with their noses. This may be possible for some pupils and not for others
Ask whether there are any patterns.
- Draw out ideas about muscles and levers and 'counterbalance'.
- Demonstrate a toy crane or show photographs of cranes, explaining the role of the counterbalance weight.
- Make a model of the human back to demonstrate the tension in the muscles when we bend. Tie string to a mop about one quarter of the way down from the head. Pivot the mop at the other end by drilling a hole through it to take a rod. Now try to balance the mop as it tilts by holding the string at an angle of about 10 degrees. This will show pupils that a large force is needed.
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- describe how an object can be kept in balance,
eg human body, crane
- apply the idea of the turning effect of a force to everyday situations,
eg lifting heavy objects
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