Wednesday, February 27, 2008

Electricity that can make your hair stands on end:

Electricity doesn’t always flow through circuits. Electricity can also stay just where it is. This is called static electricity.
You can produce static electricity by rubbing together two different materials. We say that we have charged the materials with electricity.

Is all static electricity the same?

You can rub two strips of plastic with a cloth. This charges them with static electricity. The diagrams show what the charged strips of plastic will then do.
Charged objects sometimes attract and sometimes repel. This means that there must be different types of electrical charge.

Two types of charge

Two polythene strips that are rubbed with the same cloth must have the same kind of charge. These charges repel. Two acetate strips rubbed with the same cloth must have the same kind of charge. These charges also repel.
Here is a simple way to remember what happens:
Like charges repel, unlike charges attract.
The charge you get on a polythene strip when you rub it is called negative (-).
The charge you get on an acetate strip when you rub it is called positive (+).

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