In a storm cloud, the moving air makes tiny water droplets and ice rub together so they become charged with static electricity. The positive electrical charges float up near the top of the cloud and the larger ones, with negative charges, stay near the bottom. This separation of electrical charges is very unstable, and lightning is the way the charges become balanced.
Here are two projects that can show you what static electricity can do.
Materials:
- Balloon
- Metal object (such as a file cabinet or doorknob)
Instructions:
- Inflate balloon.
- Darken the room as much as possible.
- Rub the balloon at least 10 times quickly against a wool sweater or the top of your head.
- Move the balloon close to a metal object.
Rubbing the balloon creates static electricity. The flash or spark that jumps from the balloon to the metal is a much smaller version of lighting.
Materials:
- Aluminum pie pan
- Thumbtack
- Pencil with eraser
- Styrofoam plate
- Small piece of wool fabric
Instructions:
- Push the thumbtack through the center of the aluminum pie pan from the bottom.
- Push the eraser end of the pencil into the point of the thumbtack. The pencil is now a handle you can use to lift the pan.
- Put the styrofoam plate upside down on a table. Quickly rub the underside of the plate with the wool for one minute.
- Pick up the pie pan using the pencil "handle" and place it on top of the upside down plate.
- Touch the pie pan with your finger. If you don't feel anything when you touch the pan, try rubbing the plate again.
- Turn out the lights and repeat your experiment.
Remember, lightning happens when the negative charges are attracted to positive charges. In this experiment, the negative charges are in your finger, while the positive charges are in the pie pan. The resulting spark you see is a miniature lightning bolt.
