Hmmm. tough one. my son is in preschool and i was shocked when he came home with a paper about this same project. only his teacher assigned the specific science activity. We have yet to practice.
Ok i know i have seen a few done in a college sci class for el ed majors.
has anyone put different amounts of water in glasses and talked about the differences. you can play music on it if you fill them right.
can she shine a flash light on a ball and demonstrate the phases of the moon.
I think the acid in ketchup will shine dirty pennies.
a white carnation in a vase of blue water will turn blue --capillary action
surface tension using a medicine dropper to add drops of water to a penny and it mounds up --surface tension
take a cake pan of milk and you add colors to it and they swirl can't remember if it's straight food coloring or dish soap or what.
there's one where you put pepper on water and add a drop of dish soap and the pepper scatters to the edge of the water
i think that's surface tension too.
Science isn't exactly my strong suit. but you could google those and might find something.
Personally i would ask the teacher.
There is a series of simple science experiment books.
Janice Van Cleve (???)
and also the KIDS CONCOCTIONs books. You could look for them at the library and see if there is anything that hasn't been done that appeals to her.
Phew good luck