Hold your nose closed and exhale normally into the straw end of the hose. That is the tidal volume. To get a measure of the vital capacity, repeat the activity with the students exhaling a deep breath into the hose. To set-up easily for the next student, use a funnel to carefully pour water from the tub back into the emptied 2 liter bottle. There are three different measurements of lung capacity that can be done.
Vital capacity is the largest amount of air that can be exhaled after taking a deep breath.
Tidal volume is the amount of air taken in during normal breathing. Expiratory reserve is the air that is left in the lungs after exhaling in normal breathing. A well-trained athlete has a greater lung capacity. Language Arts Connection Have students work in groups in order to discuss and write a comparison on the two different methods of lung capacity measurement. This method is neat and inexpensive, but probably not as accurate as the others.