by Helena Whyte

Created on: November 10, 2009

Static electricity was observed in ancient Greecein 600 B.C. when amber rubbed with wool attracted wood shavings. William Gilbert discovered other materials produced static electricity in the late 1500s. Gilbert named this phenomena electricity from the Greek word for amber, elektron. Modern physicists produce static electricity by rubbing rubber or Bakelite rods with flannel or fur or when they rub a glass or plastic rod with silk.

We observe static electricity through friction. We hear the crackle of sparks when we stroke the cat's fur. We hear the crackle of sparks when we comb our hair. You can actually see the sparks if you comb your hair in front of a mirror in a dark room. The charged comb will attract bits of paper. Children like to drag their shoes across the carpet and produce a spark when they touch your hand or the door knob.

We learned in general science that matter is made up of atoms and that atoms have protons and electrons. The electrons are held more tightly in rubber molecules than in fur molecules. When the rubber rod is rubbed with flannel or fur, electrons are transferred to the rubber rod. The rubber is then negatively charged because it now has an excess of electrons and the flannel or fur are positively charged because they lost electrons. If we rub the glass rod with silk, the glass rod is positively charged because the silk has an affinity for electrons. Electrons are rubbed onto the silk from the glass rod. We can charge a balloon by rubbing it against our hair. Of course this makes your hair stick out. Then the charged balloon sticks to the wall.

Benjamin Franklin used this information when he conducted his famous kite flying experiment. Lightening is an electrical discharge from clouds to the ground. Franklin determined that electrical charge leaks off fingers and sharp points. He made the first lightening rod so that the electrical charge would leak into the lightening rod instead of discharging directly into the ground. Even if lightening strikes anyway, the lightening will strike the lightening rod instead of the house or barn.

Photocopiers use static electricity to make copies. A drum is charged with static electricity and coated with a thin layer of toner or powder. A light is reflected onto the drum so that the white or blank part of the paper reflects onto the drum. The black print does not reflect the light so the charge stays on the drum. The charged parts on the drum discharge the toner onto the paper which creates the image copy on the paper.

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