When an atom (like hydrogen) or molecule (like water) loses an electron (negative charge), it becomes an ion and takes on a positive charge. When an atom (or molecule) gains an electron, it becomes a negative ion. An electrolyte is any substance (like salt) that becomes a conductor of electricity when dissolved in a solvent (like water).
This type of conductor is called an ‘ionic conductor’ because once the salt is in the water, it helps along the flow of electrons from one clip lead terminal to the other so that there is a continuous flow of electricity.
This experiment is an extension of the Conductivity Tester experiment, only in this case we’re using water as a holder for different substances, like sugar and salt. You can use orange juice, lemon juice, vinegar, baking powder, baking soda, spices, cornstarch, flour, oil, soap, shampoo, and anything else you have around. Don’t forget to test out plain water for your ‘control’ in the experiment!
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Here’s what you need:
- 2 AA batteries
- AA battery case
- 2 alligator clips
- LED
- water
- salt
- glass jar (like a clean jam jar)
Download Student Worksheet & Exercises
Exercises
- Why does electricity flow through some solutions but not all of them?
- What is a salt?
- How are electrolytes used today in real life?
- Which substance was your top conductor?
- Which substance didn’t conduct anything at all?
- What happens if you mix an electrolyte and non-electrolyte together?
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