well you could do a simple project/experiment that prooves vinegar to be a mild acid and prooves other things two but i am to lazy to think of any
1) get an egg, glass jar or cup,and some vinegar
2)put the egg into the cup or jar
3)fill the cup or jar with vinegar so its a little above the egg
[4) oyu may want to cover the egg, i did. i am doin the eperiment rite now lol]
ok so what will happen is that the vinegar will have a chemical reaction with the calcium carbonate(egg shell) thus turning the calcium carbonate into carbon dioxide (its interesting, you can see the bubbles) in about 3 days the shell will be gone hopefully you have secsesfuly peeled a raw egg
i dont now if your science has gone buy yet but if it has it still would make a good experiment