Cool project! A few easy ideas: Zn: outside of a zinc/carbon battery He: balloons Ni: welding rods Am: smoke detector sensor Pt/Ir: spark plug central elec

Cool project! A few easy ideas: Zn: outside of a zinc/carbon battery He: balloons Ni: welding rods Am: smoke detector sensor Pt/Ir: spark plug central electrodes (your mechanic's more likely to give you an old spark plug than a whole cat converter ;) Hg: thermometer Trying to think up easy/cheap ways to get elements is quite fun