Monday, August 9, 2010

static electricity

firstly, what is static electricity?Static electricity refers to the build up of electric charge on the surface of objects. The static charges remain on an object until they either bleed off to ground or are quickly neutralized by a discharge.

an example of static electricity at work would be getting zapped by your own door knob.

As you walk across a carpet, electrons move from the rug to you. Now you have extra electrons and a negative static charge. Touch a door knob and ZAP! The door knob is a conductor. The electrons jump from you to the knob, and you feel the static shock.

in temperate countries, they usually only notice static electricity in the winter when the air is very dry. During the summer, the air is more humid. The water in the air helps electrons move off you more quickly, so you can not build up as big a static charge.

For example, if you rub a glass rod with a silk cloth or if you rub a piece of amber with wool, the glass and amber will develop a static charge that can attract small bits of paper or plastic.

To understand what is happening when your body or a glass rod develops a static charge, you need to think about the atoms that make up everything we can see. All matter is made up of atoms, which are themselves made up of charged particles. Atoms have a nucleus consisting of neutrons and protons. They also have a surrounding "shell" that is made up electrons. Typically, matter is neutrally charged, meaning that the number of electrons and protons are the same. If an atom has more electrons than protons, it is negatively charged. If it has more protons than electrons, it is positively charged.

The following table shows you the triboelectric series for many materials you find around the house. Positive items in the series are at the top, and negative items are at the bottom:

  • Human hands (usually too moist, though) Very positive
  • Rabbit Fur
  • Glass
  • Human hair
  • Nylon
  • Wool
  • Fur
  • Lead
  • Silk
  • Aluminum
  • Paper
  • Cotton
  • Steel Neutral
  • Wood
  • Amber
  • Hard rubber
  • Nickel, Copper
  • Brass, Silver
  • Gold, Platinum
  • Polyester
  • Styrene (Styrofoam)
  • Saran Wrap
  • Polyurethane
  • Polyethylene (like Scotch Tape)
  • Polypropylene
  • Vinyl (PVC)
  • Silicon
  • Teflon Very negative

  • video

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