Show the students how to make the wires, then allow them to try making circuits (including short circuits) to light bulbs.
Then add the salted water to show bubbles being made at the electrodes.
Students were very interested in making a bulb-and-battery circuit, then dunking the bulb in a tub of salted water. They reported that the bulb glowed more brightly when immersed in the salted water.
Gordon Elementary Science Club