Page 22 - 新思维科学学生用书8 样章

1.3 Breathing

Think like a scientist

Using a model to represent breathing movements

You will need:

• rubber bung with a hole in it • syringe with end cut off • balloon

Method
1 Set up the apparatus as shown in the diagram.
Your teacher may do this for you. small hole
2 Carefully and steadily, pull the plunger of the rubber bung

syringe out. Note what happens.
3 Now push the plunger back in again. 10 syringe with end cut o
Note what happens. 20 balloon

Questions 30
1 Which parts of the model represent these 40 plunger
structures in the body? 50
• the lungs

• the trachea
• the diaphragm
• the rib cage

2 Explain why the balloon inflates when you pull the plunger out.
3 Explain how pulling the plunger out represents what happens in your body
when you breathe in.
4 Describe one way in which this model does not completely represent what
happens when you breathe in.

Questions

1 Copy and complete this table.
Use these words:
contract relax

Action What do the diaphragm What do the intercostal

muscles do? muscles do?
Breathing in

Breathing out

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