Page 24 - 新思维科学学生用书6 样章

1.2 The respiratory system

Think like a scientist 1

Make a model to explain breathing

You will need:

a plastic bottle, a narrow plastic tube or straw, an elastic band, scissors,
two balloons, electrical tape, sticky putty or plasticineplay dough

1 Cut the bottom off the plastic bottle.

Safety: Take care not to cut yourself with the scissors or sharp edge

of the cut bottle.

2 Tie a knot in the narrow end of one balloon and cut off the other end.

3 Stretch the newly cut end of the balloon around the bottom of your
plastic bottle. Use the electrical tape to fix the balloon in place.

4 Put a plastic tube or straw in the neck of the other balloon and

fix it in place with the elastic band. Be sure not to make the
elastic band so tight that it crushes the straw. The air must

flow through, so blow gently through the straw to see if the balloon inflates.
5 Put the straw and the balloon into the neck of the bottle. Put the

play dough around the neck of the bottle to seal the bottle.

Again, make sure that you don’t crush the straw.
6 a Pull on the bottom balloon and observe what happens.

b Let go of the balloon. What happens?

Questions

1 Which part of the model represents each of the following parts
of the human respiratory system:

a lungs? c the windpipe?
b the chest cavity? d the diaphragm muscle?

2 Which parts of the chest that are also involved in breathing

are not shown by the model?
3 Explain how your model shows the breathing process.

4 Explain how your model lung is not like a real lung.

23