LUNG CAPACITY

BACKGROUND EXERCISE

Imagine that you are sitting in a bathtub full of water. You are holding a glass full of water. If you hold the glass up in the air and tip it, the water runs out. If, instead, you hold the glass under the water and tip it, the water stays in the glass. If you want to get the water out of the glass without taking the glass out of the water in the tub, you'd have to force it out somehow and then replace it with something else. How could you do this?

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HYPOTHESIS

What do you think your lung capacity is?

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How do you think it will compare to your classmates?

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MATERIALS NEEDED

1 gallon milk bottle with lid
1 rubber tube
1 10 quart dish pan
1 measuring cup
2 straws (one per student)
1 funnel
1 calculator

PROCEDURE

1. Stick one straw in one end of the rubber tube so that at least half of it sticks out.

2. Fill the dish pan with 2 inches of water.

3. Fill the milk bottle with water. When you get it back to you desk, fill it right up to the top with the measuring cup and funnel using water from the dish pan. The water should actually stick up above the rim of the bottle. This is due to

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4. Put the lid tightly on the milk bottle. If it was full enough, some water should squirt out.

5. Hold the lid while you turn the bottle upside down. Put the mouth of the bottle under the water in the dish pan. Be very careful to keep the mouth of the bottle under the water until instructed to remove it.

6. Reach under the water and remove the bottle lid.

7. Put one end of the rubber tube into the bottle.

8. Put a straw in the other end of the tube.

9. Have the first subject take a deep breath, hold their nose closed, and blow out all of the air in their lungs into the straw. What happens to the water in the bottle?

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10. Reach under the water and put the milk bottle lid back on.

11. Hold the lid, take the bottle out of the water and set it upright.

12. The subject's lung capacity is the same as the amount of water that was displaced by air. You can measure it by seeing how much water is needed to completely fill the milk bottle again. Use the measuring cup, the funnel and water from the dish pan to do this. Be sure to measure the water carefully as you put it back in the milk bottle. Record the lung capacity below.

13. Since this method of measuring lung capacity has lots of room for variation, you will get a more accurate reading by repeating the measurement three times and taking the average.

SUBJECT:
TEST	LUNG CAPACITY
1
2
3

14. Once you are done with one subject, switch straws and repeat for the other subject. Why do we switch straws?

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DATA ANALYSIS

1. Let's find out how your lung capacity compares to your classmates. First, record all of their lung capacities in the summary table.

2. There are probably differences among them. Let's see if we can explain the differences by looking for any correlation between lung capacity and other characteristics such as height, age, participation in sports, etc. For example, let's see if lung capacity increases as the subjects' height increases.

3. Pick one of the following characteristics or choose your own. Some of the characteristics will only have a small number of choices (for example, sex) and some will have a whole range (for example, height). Collect this data for your class and record it in the summary table.

Characteristic:	Choices:
Height	Height In Inches
Type of Shoes	Sneakers or Not Sneakers
Sex	Boy or Girl
Participation In Sports	None, Some, Lots
Age	Age In Months

4. Now draw a graph of your data with lung capacity as the vertical axis and your selected characteristic as the horizontal axis. If your characteristic is numeric (for example, height), plot the data in numeric order (for example, from shortest to tallest). Remember to label all the parts of your graph.

CONCLUSION

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