From my experiment I found out that being exposed second hand smoke does not decrease your lung capacity.  I actually found out that the students that have been exposed to second hand smoke had a higher lung capacity than those who weren't.  I think that this could be because people exposed to second hand smoke have to learn to breathe harder which would make them have a higher lung capacity.  Also second hand smoke may not affect their lung capacity right now, but if I tested them when they were thirty or so, they could have a decreased lung capacity.  Also the fitness levels of the students could have affected the results.  Even though I excluded the people that had cold symptoms there could have been others that were still in incubation period at the time.  I also don't know what the smoking patterns were in the houses of the students that I tested.  For example, in some homes, smoking is restricted to certain areas of the house, or outdoors on a patio or a balcony.  In the homes where the parents did not smoke, I do not know what other exposure students may have had, such as friends and relatives who smoke. 

    I also found out that there were more people who had asthma that were exposed to second hand smoke that those who weren't.  Nineteen percent of those people tested who have been exposed to second hand smoke regularly in their homes had asthma while only five percent of those people tested that have not been exposed to second hand smoke in their homes had asthma.

    If I was to expand on this science fair project I would like to add more controls, and use an actual respirometer so that I could more accurately test lung capacities.  I would also lengthen the years that they had to be exposed to second hand smoke regularly for. 

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