To make a working model of your lungs, you need an empty 2-liter bottle, a large balloon and a plastic storage bag or two large balloons and some tape.
- Cut a plastic bottle across the middle to remove the bottom. We used a 2-liter, but any size will do.
- Cut the narrow part off of a second balloon or cut the zipper off a plastic storage bag and stretch it over the bottom of the bottle. The balloon works better for smaller bottles and the storage bag works better if you are using a 2-liter bottle. If you are using a balloon, it should fit over the opening pretty tightly. If you are using the storage bag, it should fully surround the bottom of the bottle but has plenty of slack in it. Tape to secure it to the bottle. Make sure there is a good seal. If you are using the storage bag, push the bag's slack into the bottle.
- Blow up a balloon and let the air out a few times to stretch the balloon a bit. Place a balloon in the neck of the bottle, and stretch the opening of the balloon over the opening of the bottle, putting the balloon upside-down in the top opening of the bottle.
- The balloon at the bottom or the plastic bag represents your diaphragm. The balloon inside represents your lungs.
- When you breathe in, the diaphragm contracts. To simulate this, pull the diaphragm bag/balloon down. This lowers the air pressure in the chest cavity, because there's more room, and air fills the lungs.
- When you exhale, the diaphragm relaxes. To simulate this, release the bag/balloon, and push the slack up. The air pressure in the chest cavity increases and air flows out of the lungs.
Sources and Resources:
- Exploring Creation with General Science, Jay Wile
- Exploring Creation with Human Anatomy and Physiology, Jeannie Fulbright and Brooke Ryan