Did you know that you can use salt water to make a light bulb shine? It sounds crazy, but it's true! This is because salt water is a good conductor of electricity.
Salt molecules are made of sodium ions and chlorine ions. (An ion is an atom that has an electrical charge because it has either gained or lost an electron.) When you put salt in water, the water molecules pull the sodium and chlorine ions apart so they are floating freely. These ions are what carry electricity through water. Watch it work in this project! (Adult supervision recommended.)
Step 1: Electrodes
Wrap two tongue depressors in aluminum foil. These will be your electrodes
Step 2: Conductors
Cut three 6-inch pieces of insulated copper wire and strip a half-inch of insulation off each end.
Step 3: Connections
Connect one end of a wire to the positive terminal of the battery - hold it in place with masking tape. (If you are using a battery cap, connect it to the red wire.) Connect the other end of the wire to the light bulb socket. (Just wrap the wire around the bottom of the bulb, if you don't have a socket. You may have to secure it with tape.)
Step 4: Connection 2
Take the second piece of wire and connect the light bulb socket with one of the electrodes. Use masking tape to stick the bare end of the wire on the aluminum foil near the top the electrode.
Step 5: Negative Connections
Use the third piece of wire to connect the negative terminal of the battery with the other electrode.
Step 6: Testing
Test out your circuit by touching the two electrodes together. This should complete the circuit and allow electricity to flow from one terminal of the battery to the other, lighting up the light bulb in the process. If the bulb doesn't light up, check your wire connections to make sure they are all secure and then try again