Help with Science Fair Project ideas!!!?

Not required that every experiment is new or original. It is part of the scientific process that new discoveries need to be repeated to verify the results. If someone comes up with an original combination of chemicals and processes to, say, cure a certain disease, it's not enough to simply say they have done it. The process and results get published so that other people can duplicate the experimants and REPEAT the results.

So, if the previously done science fair projects are interesting, and, you carfully follow standard scientific procedures, then it should be accepted for what it is: a demonstration of a scientific experiment.

Just remember, even though you already know the expected results, you shouldn't do anything to bias the procedure in any way. If the original experiment was done properly, and you do yours properly, you should yield the same results. If your results are significantly different, either the original process was flawed, ot it was yours. Do everything carfully and don't rush the results.

Good luck.