Project Question: "To explain all nature is too difficult a task for any one man. 'Tis much better to do a little with certainty and leave the rest for others that come after you, than to explain all things by conjecture without making sure of anything." - Sir Isaac Newton
The title of the post and the question you ask don't seem to match up. Can you be more specific? Is there a science fair experiment you are conducting? If so, can describe it? That way we will be able to provide much better help.