A Science Experiment for a Lesson on Static

Theory

• Rubbing certain objects together can cause electrons to pass from one object to the other, creating a slight negative charge in the object that gains the electrons. The negative charge will attract positively charged materials, such as the positively charged hydrogen atoms in a water molecule. This means that holding an object with a negative static charge near a narrow stream of water can attract the water molecules enough to visibly deflect the stream of water.

Demonstration

• You can perform a classroom demonstration of static electricity's ability to bend a stream of water with a balloon, a volunteer and a water faucet. Blow up the balloon and tie it off. Ask the volunteer to rub the balloon on her hair until a static charge builds up and her hair starts standing up or sticking lightly to the balloon. Turn the faucet on to create a stream of water about 1/16-inch in width. When you hold the balloon close to the water, it will bend the stream.

Experiment

• After the initial demonstration, you can let your students explore how static electricity interacts with a stream of water. Divide the students into groups. Let each group choose one variable to alter. These variables could include the distance between the charged object and the water stream, the number of times the charged object is rubbed to build up a charge or the width of the water stream. Groups should measure the deflection caused by each trial. One way to measure the deflection is to align two horizontal rulers, one above the deflection and one below it.

Variations

• Instead of using a balloon, you can run a nylon comb through a student's hair a few times until enough static electricity builds up that the hair begins to stand up. If there are not enough sinks available to allow every group to use one, you can use disposable drinking cups instead. Puncture the bottom of one cup with a toothpick, create a static charge in a comb or balloon, then fill the punctured cup with water while holding it over a second cup. The water that drains from the punctured cup will create a stream you can try to deflect.