An Easy Lung Capacity Experiment

We cracked open our favorite science book today: The Usborne Book of Science Experiments-Volume 3. During the week we have been studying about birds, but on Fridays, we have been learning about our bodies. Today we learned about how our lungs work.
We performed a very simple experiment to test how much air our lungs can hold.
We needed:
a plastic tub, big enough to hold quite a bit of water
a 3 liter soda bottle
flexible plastic tubing

Put about 3 inches of water in the tub. Fill the 3 liter bottle completely with water. Turn the 3 liter bottle unside down into the water in the basin. Carefully insert the plastic tubing into the neck of the soda bottle. (I found this easier to do before we submerged the bottle into the tub.)
Then, take a very deep breath and blow into the tubing. The air from your lungs forces the water out of the bottle.
We marked on the outside of the soda bottle each person's results. Above you can see how much air Mark had in his lungs. Mark's was able to blow about 2 liters of air into the bottle. Gracie blew about a 1 1/2 liters and Daddy blew the bottle right out of the water. He is the champion when it comes to lung capacity, but that didn't surprise us, since his lungs must be at least twice as big as everyone elses in the house.