What should I do for my Science fair project?

I want lots of ideas on what I could do for my Science fair project. They need to be fairy simple and very cheap. Have any ideas? I was thinking of doing it on what type of bubble gum blows the biggest bubbles, but that's too popular. Something similar to that would be good though! Thanks!!!What should I do for my Science fair project?
how about if bubble gum actually helps with test scores?

acne