well i graduated from 5th grade last year. I did nail polish remover can melt styrofoam. Get some nail polish removed from a supermarket or beauty shop then pour in is a container then put and drop styrofoam objects it it and watch it dissolve.
eating your butt
What is the difference in the hardness between glass and fiber glass
You can say: does the mass of an object affect how far you throw it
The grade is up to how diligent you are. Below are some sites that have lots of science fair projects.
I would say a rube goldberg machine
some type of diorama i guess.i did that for my 2nd grade project.
there are some about circulatory system and nervous system
How the heart works.
A clay volcano
bread
people are crazy
i was in 5th grade before and i did how volcanoes are formed and i won 3rd place in the city run off yay