In this bite sized science experiment you’ll get to make your very own model lung and see it inflate and deflate as it "breathes".  Always remember to ask your parent or guardian to help you.

What you'll need

For this experiment you'll need the following material:

An empty 500ml drink bottle (clear, without sport cap) Drinking straw Balloon Water Balloon (or another normal size balloon) Scissors Tape Small piece of blu-tac or plasticine

Step 1 Rinse out your bottle with clean water and remove the label.  With help from an adult cut off the bottom 1/4 to 1/3 of your bottle.  Ask your adult to make a hole in the centre of the lid. This can be done in a couple of ways either by being very careful with a pair of sharp scissors, or by using a drill.

Step 2 Carefully tape the water balloon over one end of the straw and try to make sure that no air can escape between them.  Feed the straw through the lid of the bottle and screw the lid on.   It is also a good idea to put some blutac or plasticine around the hole where the straw goes in to make a seal. Now cut off the top of your other balloon and discard the top part.

Step 3 Now you need to stretch your balloon over the bottom of your bottle tightly.  For this you might need someone to help you by holding the bottle.  Once the balloon is stretched tightly, tape it in place sealing the edge.  Your model lung is now complete!

Step 4 To see your model lung work you need to pull down on the balloon at the bottom and if you watch the water balloon you can see it inflate.  If you let go of the balloon or push it back in you can see it deflate.

How Does it Work?

This model shows how your lungs work with the balloon on the bottom of your model being a muscle called the diaphragm – as this muscle moves down, the air flows into your lungs and as it relaxes the air flows back out. Breath in and out - can you feel your diaphragm muscle working?

Fun Things You Can Try!

A slightly more advanced model involves taping two straws together and using two balloons inside your model to show the air flowing into both of your lungs.