Tuesday, October 26, 2004

Electricity - Lesson 1

Here's the Electricity Concepts we Covered for our First Class in Electricity:


Static Electricity

To understand what static electricity is, 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 will have 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.


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 positive charges (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."


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 good insulators. Other materials have some loosely held electrons, which move through them very easily. These are called conductors. Most metals are good conductors.


OPPOSITES ATTRACT

Now, positive and negative charges behave in interesting ways. Did you ever hear the saying that opposites attract? Well, it's true. Two things with opposite, or different charges (a positive and a negative) will attract, or pull towards each other. Things with the same charge (two positives or two negatives) will repel, or push away from each other.

A charged object will also attract something that is neutral. Think about how you can make a balloon stick to the wall. If you charge a balloon by rubbing it on your hair, it picks up extra electrons and has a negative charge.

To learn more go to the following websites:

http://www.sciencemadesimple.com/static.html

This website is like a video/slideshow to help show how opposites attract and like charges repel.
http://chemmovies.unl.edu/Chemistry/DoChem/DoChem025.html

hwk
pg. 52, 53 C.P.

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