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Can You Calculate Your Lung Capacity? Copy

Have you ever wondered how much air your lungs hold? This is an easy activity for measuring and calculating the volume of air that you exhale. Normally this is done by using a spirometer. In this activity, you will calculate the volume by determining the radius of a balloon that you have inflated.

Engaging Questions

  • Explain where there may be a source of error in your conclusions.

  • Why would there be any differences in lung capacity among people?

  • How do you think the average amount of air you exhale would be affected if you were to exercise?

  • Count the number of breaths you normally take in one minute. Then calculate the average volume of air you exhale in one minute (number of breaths taken in one minute x the average volume of air you exhale in one breath).  What is your answer?

  • How much air do you exhale in one class period?  Show your calculations.

Teacher Goals

  • By determining the volume of a balloon that you inflate, you will be able to calculate your lung capacity.

Required Resources

  • Materials

    • Lung Capacity Chart Checklist
    • Balloon that is round when inflated
    • Metric ruler
    • String
    • Graph paper
    • Pencil

Steps

  1. Lung Capacity Chart

    You and your partner must obtain a Lung Capacity Chart, which is found in the rubric, and the rest of the materials listed in the Required Resources.

  2. Balloon

    Stretch the balloon several times so that it is easy to inflate.

  3. Vital Capacity

    1. Have your partner take 2 -3 deep breaths, then exhale as much air as possible into the balloon. Twist the end of the balloon shut to prevent the escape of any air. DO NOT TIE THE END - YOU WILL REUSE THE BALLOON!
    2. "Vital capacity" is the maximum amount of air the lungs will hold.

  4. Measure

    Lay the balloon on top of a ruler and measure the diameter of the balloon in mm.  This information will be recorded under the "Vital Capacity diameter" column.

    Repeat the trials 2 - 3 more times and record.

  5. Expiratory

    "Expiratory Reserve" is the amount of air that remains in the lungs after a normal exhalation.

    Breathe and exhale normally several times.  Before inhaling again, force the remaining air that is in your lungs into the balloon.  Measure and record the information in the "Expiratory diameter" column.
     
    Repeat 2 - 3 times.

  6. Tidal Volume

    "Tidal volume" is the normal amount of air that is exchanged during breathing.

    Take several normal breaths.  Take a normal breath and exhale a normal amount of air into the balloon.  Measure and record in the "Tidal Volume diameter" column.
     
    Repeat 2 - 3 times.

  7. Average

    Calculate the average for each of the columns.

  8. Volume

    Calculate the Vital, Expiratory Reserve, and Tidal capacities using the average diameters you just calculated. Since the balloon is basically round, you will be able to calculate the volume of air by using the following formula.

     
     4/3 ∏ r3
         or
     (1.33)(3.14)(1/2 the diameter of the balloon)3

  9. Graph

    Make a bar graph comparing the three measurements for each person.  Post your graphs on the board for comparison.

  10. Engaging Questions

    Answer the "Engaging Questions" found in the Teacher's Guide of this lesson.

  11. Share and Compare

    As per teacher instructions, enter your personal average results for each values using the attached form.

Teacher Notes

  • Divide the class into pairs of students. Use only round balloons. Each student must have his or her own balloon.

Learner Notes

  • Be sure to use your own balloon.  DO NOT SHARE!