This experiment enables pupils to measure the amount of air their lungs can hold and to work out the average lung capacity of their class.
Each group will need a four-litre plastic bottle, a measuring jug, a washing up bowl, water, 50cm of plastic tubing, tape and a straw for each child.
Pour 200ml of water into the bottle and make a mark in permanent ink.
Repeat until you have a scale on the side of the full bottle. Half fill the washing-up bowl with water. Cover the top of the bottle with your hand or a piece of card and turn it upside down, ensuring no water escapes. Lower it into the bowl and remove your hand (or card). You may need to support the bottle in the bowl with a few blocks.
Feed at least 10cm of the tubing into the bottle. Tape a straw to the other end of the tube, ensuring it is airtight. The first pupil should take a deep breath and blow into the straw. The group measures how much air from the lungs collects in the bottle. Repeat the experiment using a different straw for each pupil.
Make a note of all the measurements and help your pupils work out the average lung capacity of the class.