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SCIENCE QUOTES "Chance favors the prepared mind." Louis Pasteur

Static Electricity?

Copyright © 1995-2009 by Science Made Simple, Inc.

You walk across the rug, reach for the doorknob and..........ZAP!!! You get a static shock.

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Or, you come inside from the cold, pull off your hat and......BOING!!! Static hair - that static electricity makes your hair stand straight out fromyour head. What is going on here? And why is static more of a problem in the winter?
To understand static electricity, we have to learn a little bit about the nature of matter. Or in other words, what is all the stuff around us made of?

EVERYTHING IS MADE OF ATOMS
Imagine a pure gold ring. Divide it in half and give one of the halves away. Keep dividing and dividing and dividing. Soon you willhave a piece so small you will not be able to see it without a microscope. It may be very, very small, but it is still a piece of gold. If you could keep dividing it into smaller and smaller pieces, you would finally get to the smallest piece of gold possible. It is called an atom. If you divided it into smaller pieces, it would no longer be gold.

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Everything around us is made of atoms.Scientists so far have found only 115 different kinds of atoms. Everything you see is made of different combinations of these atoms.

PARTS OF AN ATOM
So what are atoms made of? In the middle of each atom is a "nucleus." The nucleus contains two kinds of tiny particles, called protons and neutrons. Orbiting around the nucleus are even smaller particles called electrons. The 115 kinds of atomsare different from each other because they have different numbers of protons, neutrons and electrons.
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It is useful to think of a model of the atom as similar to the solar system. The nucleus is in the center of the atom, like the sun in the center of the solar system. The electrons orbit around the nucleus like the planets around the sun. Just like in the solar system, the nucleus is largecompared to the electrons. The atom is mostly empty space. And the electrons are very far away from the nucleus. While this model is not completely accurate, we can use it to help us understand static electricity.

(Note: A more accurate model would show the electrons moving in 3- dimensional volumes with different shapes, called orbitals. This may be discussed in a future issue.)

ELECTRICALCHARGES
Protons, neutrons and electrons are very different from each other. They have their own properties, or characteristics. One of these properties is called an electrical charge. Protons have what we call a "positive" (+) charge. Electrons have a "negative" (-) charge. Neutrons have no charge, they are neutral. The charge of one proton is equal in strength to the charge of one electron.When the number of protons in an atom equals the number of electrons, the atom itself has no overall charge, it is neutral.

ELECTRONS CAN MOVE
The protons and neutrons in the nucleus are held together very tightly. Normally the nucleus does not change. But some of the outer electrons are held very loosely. They can move from one atom to another. An atom that looses electrons has more positivecharges (protons) than negative charges (electrons). It is positively charged. An atom that gains electrons has more negative than positive particles. It has a negative charge. A charged atom is called an "ion."

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Some materials hold their electrons very tightly. Electrons do not move through them very well. These things are called insulators. Plastic, cloth, glass and dry air are goodinsulators. Other materials have some loosely held electrons, which move through them very easily. These are called conductors. Most metals are good conductors.
How can we move electrons from one place to another? One very common way is to rub two objects together. If they are made of different materials, and are both insulators, electrons may be transferred (or moved) from one to the other. The...