This document describes an activity using a bottle balloon model to demonstrate how lungs work. The model uses a plastic bottle to represent the chest cavity, straws for the bronchi, and balloons for the lungs and diaphragm. Pulling down the diaphragm balloon expands the lungs by lowering pressure in the chest cavity and allowing air in. Pushing up the diaphragm balloon decreases lung size by raising pressure and pushing air out. The diaphragm's movement controls air flow in and out by changing the chest cavity's pressure and volume. Puncturing a lung balloon would prevent its inflation.

1. Activity 2:
Bottled Balloons
Group 6 Science

2. Objectives:
 Explain how the lungs work
• Describe how the movement of the
diaphragm helps the air go in and
out of the lungs

3. Figure 3&4
Figure 3. The two straws with the
balloons are inserted into the plastic
bottle cap.
Figure 4. A constructed model of the
human chest cavity

4. Q4. What does each part of the constructed lung model
represent?
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Guide
Questions:
Q5. What happens as you pull down the balloon at
the bottom of the model?
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Q6. What happens as you push up the balloon?
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Q7. How does the movement of the diaphragm cause the air to go in
and out of the lungs?
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Q8. What might happen if you prick the balloon?
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5. Q4. What do you think does each part of the
constructed lung model represent?
2-liter plastic bottle = chest cavity
Two straws = bronchi
Two balloons = lungs
Larger balloon = diaphragm
Q5. What happens as you pull down the balloon at
the bottom of the model?
The two balloons expand. The air pressure inside the
bottle is lowered by increasing the space inside the
bottle. The outside air then enters through the tube,
which makes the two balloons inside the bottle
'chest' expand.
Answer:

6. Q6. What happens as you push up the balloon?
The two balloons loosen up and return to their original
size.The air pressure inside the bottle is increased by
decreasing the space inside the bottle. The inside air then
exits through the tube, which makes the two balloons
inside the bottle return to their original size.
Q7. How does the movement of the diaphragm cause the
air to go in and out of the lungs?
The movement of the diaphragm affects the air pressure
inside the chest cavity by either decreasing or increasing
the space, thus allowing air to go in and out of the lungs.
Q8. What might happen if you prick the balloon?
If one of the balloons is pricked, it will not inflate
anymore because the air will escape.
Answer: