Begin the Experiment
While two students continue to hold the jug in the water, a third student should carefully remove the lid and insert one end of the plastic tubing up into the mouth of the jug. The tip of the tubing should remain under water inside the the jug. The lungometer is now ready for testing.
Before each student uses the lungometer, he or she should insert his or her own clean mouthpiece into the plastic tubing; be sure to wash tubing before storing. Use antibacterial soap or soak the tubing in a 10% mild bleach solution).
To measure vital lung capacity, each student will breathe in deeply and then blow out all the air that he or she can through the tubing into the jug. This will cause air to travel into the jug, forcing water out of the jug and into the plastic tub. The amount of air blown into the jug represents each person’s vital lung capacity.
After each student has taken his or her turn, the students holding the jug under water should put the lid back on and carefully turn the jug upright. This will enable the team to measure the amount of water remaining in the jug (and the amount of water displaced by the person blowing through the tube).
- Moreno N., B. Tharp, and J. Dresden. (2011). The Science of Air Teacher’s Guide. Third edition. Baylor College of Medicine.
- Illustration by M.S. Young © Baylor College of Medicine.
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