How to Make extremely simple scales with a 9v battery and cap

Watch this video tutorial to see how to make extremely simple scales. This scale is useful when you want to weigh small portions of a substance (like a few grams of powder). It is difficult to get real weight using these scales though. To make this homemade scale, you'll need a plastic bottle cap, a plastic bottle or box, a 9v battery, clear sticky tape, glue for the plastic (epoxy or fast-hardeneing), scissors and a screwdriver.