By Brian Baer • Updated March 24, 2022
Saltwater is a simple electrolyte solution that allows electric current to flow. When sodium chloride dissolves in water, it separates into positively charged sodium ions (Na⁺) and negatively charged chloride ions (Cl⁻). These free ions carry charge, enabling the solution to conduct electricity.
In a basic circuit, a power source (battery), a load (light bulb), and a conductive path are required. Saltwater provides that conductive path, allowing electrons to move from the positive to the negative terminal and light the bulb.
Wrap a strip of aluminum foil around the top of each popsicle stick. Cut three pieces of insulated copper wire, each 6–8 inches long, and strip about ½ inch of insulation from both ends. Attach one end of a wire to the foil on the first stick and the other end of a second wire to the foil on the second stick. Secure each connection with duct tape.
Connect one of the electrode wires to the positive (+) terminal of the battery. Attach the second electrode wire to the threaded base of the light bulb. Use the third wire to tie the battery’s negative (–) terminal to the bulb’s bottom. Ensure all connections are snug with tape.
Fill the beaker about halfway with distilled water. Add 3 Tbsp of table salt and stir until the salt is completely dissolved, creating a clear electrolyte solution.
Place the two electrode sticks into the beaker so that each is submerged on opposite sides. The salt ions will conduct the current from the battery through the solution and into the bulb, causing it to illuminate.
• Keep the setup away from children and pets.
• Do not use a higher‑voltage battery; the 9‑volt battery is sufficient for a 3.7‑volt bulb.
• Avoid splashing the saltwater, as it can corrode metal surfaces.
• Disassemble and dry all components after use to prevent short circuits.
By following these steps, you’ll witness how a simple electrolyte solution can power a light bulb—an excellent demonstration of basic electrical principles.
