Equipment:

Bottle (plastic)

Playdough or clay

Straw

2 Balloons

Rubber bands

How to make lungs:

1) Cut your bottle in halve and take the top part.

2) Get one of your balloons and tie the end and cut on the top.

3) Put part of the balloon which you cut and put it over the bottom of the bottle.

4) Get your other baloon and a straw and put the straw in the balloon.

5) Get a small rubber band and put it round the balloon and straw.

6) Put the ballon through the bottle so the straw is pocking out the top and cover it with playdough.

7) Pull back the end of the balloon on the bottom and let go to see your other balloon blow up.