Another New and Better Idea

I decided yesterday that I should open up my options.....why just chem? I'm really interested in physics too, but really I can't think of any physics experiment that is feasible. However, I have another idea.

I would test whether liquid hand soap that claims to kill 99.9% of all bacteria really do kill that much bacteria. Actually I have already thought of this idea before but I was put off by the fact that I cannot observe bacteria conveniently. However, now I think that I can develop bacteria cultures easily in our school labs, Moreover, using bacteria from my hands, it would fit in the experiment about hand soaps as the bacteria-killing agent in hand soaps would be targeting bacteria commonly found on hands, if there are distinctive types of bateria there.

For the control for this experiment, I would use a) a non-bacteria-killing hand soap or b) water. I can do a comparison between the two different types of hand soaps or I can test the ability to kill bacteria by the same hand soap but of different states of dilution by water, for example, 25% diluted, 50% diluted, 75% diluted and not diluted at all, as well as a control of water.

But then, I had another idea in incorporating chemistry into this almost purely bio experiment. i can try killing bacteria with different substances: water, lime juice, lemon juice, normal hand soap, bacteria-killing hand soap. The essence of this experiment is the different pH of the independent variables. Because I know that too acidic or alkaline substances would kill bacteria, but since the underlying (or should I say, overall) purpose of this investigation is to find out if other, natural, non-harmful substances can kill bacteria on hands as well and therefore replace hand soap, and strong acids like HCl will definitely damage the human skin, I cannot use strong acids that would definitely kill bacteria for this experiment.  This also adds a mystery to the experiment, the result is not known (at least not yet, I still need further research): can lime juice and lemon juice kill, at the very least with a small extent, bacteria?

This post is too long so I would post my procedure and other notes in the next post. The proposal seems to be due this week and some say that it is graded. :(( i would also need to arrange for coming back to school labs during school hols.