- A spirometer is the instrument used in the health profession to accurately measure lung capacity. Lung capacity provides information about the general health of the lungs.
- In this lab, you will measure three indices of lung capacity using a balloon. Vital capacity is the maximum amount of air that is held in the lungs. The expiratory reserve is the amount of air that remains in the lungs after a normal exhalation. The tidal volume is the amount of air exchanged during a normal breath. While not as accurate as a spirometer, the balloon measurements do provide a good indication of your lung capacity.
MATERIALS:
Round balloon
Metric rulerPROCEDURE:
1. Obtain a round balloon. Blow it up and release it several times to stretch it. This will allow it to inflate easier, and make the results more consistent.
2. Take a number of deep breaths. Take a deep breath and exhale as much air as possible into the balloon. Hold the end of the balloon shut to stop the air from escaping.
3. Lay the balloon on the table next to the ruler. Measure its diameter in centimeters and record your data in the DATA TABLE as Vital capacity for Trial 1. Release the air from the balloon.
4. Repeat steps 2 and 3 to complete Trials 2 through 4.
5. Breath normally a number of times. Exhale normally. Then before inhaling again, force air in your lungs into the balloon. Measure and record the balloon's diameter as your Expiratory reserve. Repeat three more times.
6. Breathe normally a number of times. Take a normal breath and exhale a normal amount of air into the balloon. Measure the balloon's diameter as your Tidal volume. Repeat three more times.
DATA TABLE:Balloon diameter measurements Trial Vital capacity Expiratory reserve Tidal volume
1
2
3
4
Total (all trials)
Average diameter
Volume cm3
7. Add the 4 trials for each of the three sets of data. Record in the DATA TABLE
8. Calculate the average diameter of the balloon for each group of measurements. You simply divide the totals for each set of data by 4. Record the results in the DATA TABLE
9. Use the following formula to calculate the volume of air in the balloon.
- Volume = 1.33
r3where r = 1/2 of the average diameter of the balloon (radius).
and = 3.14Back to Biology Table of Contents
Back to Lab Dad's Laboratory
- In this lab, you will measure three indices of lung capacity using a balloon. Vital capacity is the maximum amount of air that is held in the lungs. The expiratory reserve is the amount of air that remains in the lungs after a normal exhalation. The tidal volume is the amount of air exchanged during a normal breath. While not as accurate as a spirometer, the balloon measurements do provide a good indication of your lung capacity.
MEASURING LUNG CAPACITY
INTRODUCTION: