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SECTION 2

UNDERSTANDING ELECTRICITY

I

Read the texts, give a summary and discuss them:
The word electric comes from the Greek word for amber,
electron. Amber is a fossil resin, yellowish in colour. It is found on
the southern shores of the Baltic Sea.
Thousands of years ago, man discovered that when amber is
rubbed with fur or cloth it will attract small light objects, for
example, particles of dust. It does this in the same way that a
magnet will attract pieces of iron. This discovery was, perhaps, the
first step made towards man’s understanding of electricity.
Today we know that this attraction of small particles or
objects is caused by an electrical charge, which is given to the
amber by the friction, or rubbing together, of the materials. This is
known as static electricity.
An electric current is the flow of electrons. To understand
what an electron is, we must first think of matter and how it is
constructed, or made up.
The smallest piece of any substance is called an atom. An
atom is made up of a proton, which has a positive electrical
charge, and a number of electrons, which have a negative charge.
When the two charges are equal, the atom is said to be neutral.
Until an atom is charged, it will remain in its original form.
It is held together because opposite charges are attracted to each
other. Similar charges of electricity will repel. These are the two
fundamental laws of electricity.
Electricity is made in many ways.
One way is by battery, as used in a transistor radio. A simple
battery has a positive terminal, or pole, connected to a carbon rod.
The terminal may be coloured or marked with a cross. The carbon
rod is placed in a chemical paste inside a zinc container. Attached
to the zinc container is the negative terminal, coloured dark or
marked with a short horizontal line. The action of the chemical
causes the poles to be charged.

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