Helping children understand water conductivity will become easier after explaining how electricity works. Start by outlining that electrons are the carriers of the electricity and how they bunch together and move in the same direction to start electricity. When electrons all move together in the same direction, it is called an electric current. The current moves through a source called a conductor, which contains free-moving electrical charges such as copper or aluminum. Highlight the fact that a conductor can be a substance, body or device.
Now that the children have a basic understanding of electrical currents and conductors, explain why water is a good conductor of electricity. Since free-moving electrical charges must be present to conduct electricity, ocean and lake water make suitable conductors. However, purified water is stripped of metals and naturally occurring substances, so it isn't a good conductor of electricity. Bodies of water such as oceans and lakes contain metals and other substances necessary for electrons to create a charge.
Saltwater carries electricity in the form of ions. Ions do not occur in purified water, since salt provides these ions. An ion is an atom or molecule that lost or gained an electron. After explaining this, demonstrate how ions work in saltwater to provide electricity. According to Patchogue Medford Congress of Teachers, children learn science better when they are able to investigate using hands-on experiments. This enables children to think critically and observe how water conductivity works.
Gather the following supplies: masking tape, 9-volt battery, buzzer, two craft sticks, a bowl and saltwater. Wrap the aluminum foil around both crafts sticks and tape the red wire from your buzzer to the positive end of the battery. Attach the black wire to one craft stick and tape the other craft stick to the negative terminal on the battery. Touch the sticks together to test your buzzer. Dip the tips of the craft sticks into saltwater 1-inch apart. The saltwater will cause the buzzer to go off, completing the circuit.