Fire extinguisher
Volcano
Something like salt tests but to extract a byproduct from it
Those little grains that turns to artificial snow when you put water on them.
I would personally like to extract graphene once, I am very much fascinated with the idea. But no lab, no money, no guidence
Invisible ink
Extract raw soap from crude materials
Lactometer
Tea quality establisher
You can google many more ideas and watch some practically on youtube before you decide which one you want to work on. There are many fascinating ideas out there. Just think chemistry and that there are all lots and lots of chemicals and elements around you. Something may hit you to think of it, which you could also present practically in a short span on time.
