Experiment with Salt Water Conductivity
Does your child know that salt water conducts electricity? In this science experiment, your child will build a mini circuit to find out if she has salt water or fresh water. It's a simple experiment but it will show how saltwater acts as a conductor to electrical currents, while reinforcing important lessons about conductivity and electricity.
What You Need:
- Masking tape
- 9-volt battery
- Buzzer (can be bought at an electronics store such as Radio Shack)
- 2 craft sticks
- Aluminum foil
- Salt water
What You Do:
- First, cover both craft sticks with aluminum foil.
- Take your buzzer and tape the red wire to the positive end of the battery (the + sign).
- Tape one foil covered craft stick to the black wire. Tape the other one to the negative side of the battery (- sign).
- Test you buzzer by touching the two sticks together. This should make the buzzer sound. If it doesn’t work, make sure that everything is taped together in the right way.
- Now put the tips of the metal sticks in the salt water about an inch apart. Make sure the two sticks don’t touch. The salt water will act like a wire connecting the metal sticks and completing the circuit which will make the buzzer go off!
- Try the experiment in the fresh water. Why does your child think that the buzzer sounded in the salt water but not the fresh water?
What Happened? The salt dissolves into the water and breaks down into "ions". which act as a conductor. Fresh water does not have these ions, therefore it cannot conduct the electrical current.