You’ll need: A plastic 2 liter bottle

cut in half, Two straws, Two balloons, Masking tape (or black

electrical tape as that is what we had around and it worked great!)

A rubber band And a piece of plastic

bag. As you are creating this model with your kids, be sure to use the proper terminology. Explain that you’ll be making a model of the lungs to show how the respiratory system works. Let them know that the plastic bottle represents the rib cage, the straws represent the trachea/bronchi, the balloons represent the lungs and the plastic bag represents the diaphragm. While assembling, use only the anatomical names! For example: “Can you hold the ribcage while I slide the trachea and lungs in?”

Step 1: Put a straw down into a balloon, almost to the bottom. Securely tape the top of the balloon to the straw so that it is air tight. Go around with the tape a few times to be sure it is sealed. Do the same to the second balloon and then secure the two straws together with more tape.

Step 2: Put the straws down into the bottle top and tape around and around the rest of the bottle-opening to be sure that it is air-tight. If air gets in, the model won’t work.

Step 3: Place the bottle onto a piece of plastic bag and use a rubber band to secure it tight to the bottom. Trim off the excess bag, if needed.

Step 4: It is helpful to tape a little piece of paper, or a string, to the bottom of the diaphragm to pull it up and down.

That’s it! Now pull the diaphragm up and down and see the lungs expand and contract! In the human body, the trachea goes down and splits into the two bronchial tubes that go into the lungs.