The taller a person is the larger the maximum volume of air that the person can breathe out of that person's lungs is.
Equipment
- Large, callibrated (with a scale marked on) container
- Wide plastic tube
- Sterilised mouthpiece (with supply of sterilising solution e.g. Milton)
- Large bowl of water
- Metre rules
Method
Fill the large container with water and turn upside down so that the opening is under water in the large bowl. Thread one end of the plastic tubing into the large container. Either attach the sterilised mouthpiece to the other end of the tubing or sterilise the end of the tubing directly. Record the height of the first volunteer using the metre rules to measure this. Get your first volunteer to pinch their nose and breathe in and out deeply several times. Now, get them to take a deep breath in and exhale deeply into the tube/mouthpiece. Using the scale on the side of the container, record how much air has been breathed out into it. Repeat these steps for another 5 volunteers.
Variables
Independent - Height of person
Dependent - Volume of air breathed out
Control - Diameter of tube, temperature of air, position of person (seated/standing), pulse rate of person
Risk Assessment
The risks in this experiment are low but care must be taken to ensure the mouthpieces and tube are properly sterilised between uses. This will prevent any infection/germs being spread from one person to the next.
For a bit of extra background reading try https://en.wikipedia.org/wiki/Lung_volumes