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    In a Puff of Smoke:
    Take a Deep Breath
    Lung Capacity

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    Introduction
    Materials
    General Safety Guidelines
    Advance Preparation
    Notes
    Relevant National Science Education Standards
    Relevant New Jersey State Science Education Standards

    Introduction

    The tidal volume is the volume of air inhaled or exhaled with each normal breath. The inspiratory reserve volume is the extra volume of air that can be inspired above the tidal volume. The expiratory reserve volume is the extra volume of air that can be expired by forceful expiration after the end of a normal tidal expiration. The residual volume is the volume of air remaining in the lungs after the most powerful expiration.

    The inspiratory capacity is the sum of the tidal volume and the inspiratory reserve volume. It resembles the amount of air a person can breathe beginning at the normal expiratory level and distending the lungs to the maximal amount. The functional residual capacity equals the expiratory reserve volume plus the residual volume. This is the amount of air that remains in the lungs at the end of normal expiration. The vital capacity equals the inspiratory reserve volume plus the tidal volume plus the expiratory reserve volume. This is the amount of air a person can expel from the lungs after first filling the lungs to his or her maximum extent and then expiring to the maximum extent. The total lung capacity is the maximum volume to which the lungs can be expanded with the greatest possible inspiratory effort. It is the sum of the vital capacity and the residual volume.

    Materials

    • Balloons, 9 inch, one for each student in your class.
    • Plastic soda bottles, 1 or 2 liter, one for every student.
    • Rubber tubing, 2 foot sections.
    • Bucket or other similar reservoir large enough to contain the plastic soda bottle.
    • Water source.
    • Volume measuring device, graduated cylinders, if available.
    • Newspapers (optional).

    Advance Preparation

    1. Assemble materials.

    2. The balloons should be large enough to offer some resistance. Standard party balloons are about 9-inch capacity.

    3. If the class is not familiar with the concept of volume and its measurement, you need to conduct a short discussion of the topic.

    Notes

    1. If you do not have sinks in your classroom, you will want to supply newspapers. This activity can be messy.

    2. You might present the setup for this lab as a challenge to your students if they are familiar with collecting gases. If they are not familiar with gases, you might want to demonstrate the setup.

    3. Once the rubber tubing is inserted into the full plastic bottle, remind students to keep the tubing pinched off or keep the open end of the tubing above the water level in the bucket.

    4. Flattening the balloon to rid it of residual air gives better data.

    5. You may have to help student seal off the balloon by hand to make sure the escaping air goes into the plastic soda bottle. By gripping with your finger or hand the point of contact between the balloon and the rubber tubing, you can make a seal that will withstand the pressure of the escaping air.

    6. You may suggest an alternative method for finding the volume of air that enters the soda bottle. Marking the bottle with a permanent marker, emptying the bottle once it is removed from the bucket, and refilling it to the mark is a variation on the method in the student procedure.

    7. Collect class data in a manner that is appropriate for your class.

    8. In a typical "quiet" cycle of breathing, a person takes in about one-half quart of air, but the lungs actually hold about 4 quarts. Thus, most people breath in only about 12% of the total capacity of the lungs!

    Relevant National Science Education Standards

      Unifying Concepts and Processes — The activity involves measurement of lung capacity.

      Physical Science — The activity is centered on a physical property of matter, that it occupies volume. In this case, the volume of expired gas is measured.

      Science in Personal and Social Perspectives — The activity involves a public and personal health question regarding smoking and its effects on respiratory health.

    Relevant New Jersey State Science Education Standards

      5.1 The activity involves conducting systematic observations, interpreting and analyzing data, drawing conclusions, and communicating results.

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    Bibliography

      Respiration — part of the Web site Pulmonology from Universiteit Maastricht.

    Copyright ©2001 The Chemical Heritage Foundation