science experiments for 5th graders

[ajman2463]

I'm currently volunteering at a local backwood elementary school, where i work with 5th grade elementary students and teach them hands-on biology, chemistry, and earth-science. Nothing too complex, i think the most confusing thing i've taught them is oxidation/reduction pathways. We like doing hands-on experiments, fun things that teach them something while they have fun and spark their brain (hopefully) into thinking scientifically. We just finished studying the human body, and are now studying noncyclic photosynthesis. Does anyone have any ideas for simple science "experiments" (not actual experiments but demonstrations i could do; they think they are experiments)? we have already cultured bacteria, measured our lung capacity, and are currently growing plants with no soil. Any ideas would be graciously accepted.