Purpose: To observe the effects of electricity on water
Materials:
- Beaker, Jar or large glass
- 2 insulated wires(ideally one red & one black, but use what you've got) each equipped with an alligator clip at one end (or with an inch or two of uninsulated wire at each end)
- Water
- Salt
- Spoon
- 6V battery
CAUTION: THIS EXPERIMENT IS TO BE CONDUCTED ONLY WITH ADULT SUPERVISION!
Procedure:
PART ONE:
1) Fill the beaker with water until water is about an inch from the top (amount is not critical).
2) Clip the end of the black wire to the NEGATIVE ( - ) pole of the 6V battery.
3) Place the other end of the black wire into the water, so that the exposed end is fully submerged (bending the wire over the lip of your beaker/container will help keep the wire in there).
4) Clip the end of the red wire to the POSITIVE (+) pole of the 6V battery.
5) Carefully place the other end of the red wire into the water so that the exposed end is fully submerged.
What, if anything happened when you placed the second wire into the water? Nothing, right?
CAUTION: AT NO TIME SHOULD THE TWO ENDS OF THE WIRES IN THE WATER BE ALLOWED TO TOUCH. If they do, you're setting up a 'no load' or 'short' circuit and the wires and battery will begin to heat up.
PART TWO:
1) Disconnect the wires from the battery and remove them from the water.
2) Repeat steps 2) through 5) from Part One, EXCEPT THIS TIME, first add 5 or 6 spoonfuls of salt to the water and stir until it is completely dissolved.
3) Allow this setup to run for several minutes.
Did anything different happen this time (if it didn't, add more salt--amount needed will vary based on the size of your container)?
What’s Going On?
Despite its bad reputation from movies and TV, fresh water does not really conduct electricity well, as you observed from Part One of our experiment. When Salt is added to water, it dissolves into ions of Sodium and Chlorine, which conduct electricity very well indeed! The gross stuff that started to form in the water (starting out yellow and turning green if you watched long enough) is Sodium Hydroxide (also known as Caustic Soda or Lye), a major ingredient in soap!
Think and Talk About This!
Sodium Hydroxide is made of Sodium, Oxygen and Hydrogen. The Sodium comes from the salt. Where does the Oxygen and Hydrogen come from? (HINT: Think about the chemical formula for water).
Optional Method for enhancing the results:
To make the reaction a bit more noticeable, try wrapping a small strip of aluminum foil around the end of the black wire that goes into the water.
