So I just got a new toy for a great price, and need to learn how to operate it (I have an operators manual, but have not really tried to go through it yet). I need experiment ideas you guys might like to see. The toy is a Mettler H10 Analytical Balance, and apparently is for accurate measurements in chemistry. "The balance case, of formed aluminum sheets with glass doors, is 16 1/2" high, 9 1/2" wide and 20" deep. The balance has a capacity 160 g., a range of 1,000 mg on the optical scale, an accuracy of ±0.1 mg, and weights adjusted to within Class S tolerances." So I assume it is accurate to the 0.0001th of a gram, and can do up to 160 grams (hmm most of our batteries are heavier sadly, so I could do it with some ≤1400mAh batteries? and then graph that data) Here are some ideas I have currently and will update it with suggestions: Test a couple batteries of different characteristics both full and discharged to see how it changes weight in micrograms (±100 I think). Batteries, Discharged vs Charged Plant growth over small ammount of time EDIT: (due to conservation of mass there is no feasible way to test it as for every bit of plant grown it uses dirt, water, or CO2) How much carbon dioxide is in different fizzy drinks @holtneil @HDtallrider @Mike H.