Air creates an invisible shield

Using a few materials from around the house you can learn how your lungs work.

Materials

* Balloon

* Transparent plastic bottle

* Funnel

Instructions

STEP 1: Inflate the balloon several times.

STEP 2: Secure the balloon around the neck of the funnel.

STEP 3: Push the balloon and the neck of the funnel into the opening of the transparent plastic bottle.

STEP 4: Continuously squeeze the sides of the transparent plastic bottle.

Explanation

When you release the sides of the bottle, the air fills the balloon. When you squeeze the sides of the bottle, the air is forced out of the balloon.

This is similar to how your lungs work. When you breathe in, your diaphragm and muscles contract and expand in your chest. When this happens, the pressure in your chest becomes lower when compared to the air pressure outside of your chest allowing air to rush into your lungs.

When you breathe out, your diaphragm and muscles relax in your chest. When this happens, the air rushes out of your lungs.

Jason Lindsey is a Science Outreach Educator with Hooked on Science. Check out his website "Hooked On Science" at hookedonscience.org for webcasts and experiments that might get you hooked on science. Send him your science questions at jlindsey@hookedonscience.org. More science experiments can be found at www.semissourian.com.