I am currently working on and electromagnet experiment with my 8th grade students. I have been given an experiment where we build a basic electromagnet with an iron bolt, enameled wire and a 6V Alkaline Battery, (lantern battery). The goal is to test the strength by picking up BB's, Paperclips, or small washers. My problem is the battery drains extremely fast. What can I change to prevent this from happening. I've can't continue to spend the money out of pocket for all these batteries, but the students love this experiment. Please help.