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Author: Emma Vanstone
Date: April 13, 2012

The lungs are an essential organ to all Mammals. It is the organ that allows for gaseous exchange to ensure we get the most important product Oxygen into our bodies and also exhale the waste products. Here’s how to make a fake lung by reusing items from around your home or school.

fake lung


What you will need:
A plastic bottle
A straw
An elastic band
2 balloons

1. Remove the bottom of your bottle.

2. Tie a knot in one end of a balloon and snip of the fat end.

3. Stretch this end around the bottom of your plastic bottle.

4. Put a straw in the neck of the other balloon and secure tightly with the elastic band but not so that you crush the straw.The air must flow through so test it with a little bow through the straw to see if the balloon inflates.

5. Put the straw and the ballon into the neck of the bottle and secure with the playdough making a seal around the bottle – make sure that again, you don’t crush straw.

Your lung is finished and now for the action!

How lungs work:
1. Hold the bottle and pull the knot of the balloon at the bottom and watch what happens?
You should find that the balloon inside the bottle inflates, and that as you let go it deflates.

The science bit:
As the knotted balloon is pulled it creates more space inside the bottle. Air then comes down the straw and fills the balloon with some air to fill the space! When you let go of the knot the space no longer exist, so the air from the balloon is expelled and deflates.

This demonstrates how our lungs work. Air is taken in through the mouth and nose, passes down the windpipe and into our lungs. The diaphragm at the bottom of our chest moves down dot create more space. As we breath out the diaphragm raises again. The knotted balloon represents the diaphragm and balloon inside the container the lung!

Many thanks to Science Sparks for this experiment. Here’s their accompanying video: