Examining the relationship between lung capacity and age
The experimental data and analyzed results support the hypothesis that a person’s lung capacity will increase until he is in his 20’s, after which his lung capacity will slowly decline as he grows older.
Our lung capacity is an indicator of our health condition. As lungs supply oxygen to the blood vessels in our bodies and remove any carbon dioxide generated as waste gases from our blood stream, it is very important for us to keep our lungs healthy. Habits such as smoking not only reduce our lung capacity but will also damage our lungs, leading to lung cancer.
This science fair project can be repeated to compare the lung capacity of smokers and non-smokers.
Try to repeat the experiment to compare the lung capacity of athletes and non-athletes.
Human lung - http://en.wikipedia.org/wiki/Human_lung
What should I know about lung capacity - http://www.wisegeek.com/what-should-i-know-about-lung-capacity.htm
Lung volumes - http://en.wikipedia.org/wiki/Lung_volumes
Basic safety requirements