The simple initial challenge of making a one cell battery with salt water, a dime and a penny can be easily extended to multiple cells in series to generate higher voltage. The LED allows experimentation with polarity. If you have a volt meter, students can measure voltages and design batteries for any number of applications from lighting an LED to powering a motor. They can measure the capacity of the battery, calculate the currents, and experiment with ways to improve the battery performance. (Bigger cells, polished electrodes, bigger multi-penny electrodes.) It’s a great open ended exploration: “Okay, now make your battery better!” or, “Okay, now can you make the same battery cheaper?”

Chemistry, Physics, Electrical Engineering and Electronics in one simple and inexpensive activity! Woohoo!