Students become human electrical conductors! Completely safe to touch and handle, the Energy Stick features electrodes on each end of its 7½" tube. When these electrodes are touched simultaneously, long-lasting LED lights inside the tube flash and the tube makes a noise. Release one or both of the electrodes and the flashing lights and noise stop. Do it over and over again—experimenting with open and closed circuits has never been so fun! Also works with an entire circle of people holding hands. 1¼" diameter.