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From Electrons to Electricity !

In everyday life we find bulbs in lampshades or fluorescent tubes all around us in houses, offices, restaurants etc. You must have wondered what causes the bulb or the tube

 to light up ? " Actually they need the electricity to light up. Electricity passes through wires that are attached to them and it makes the bulbs and tubes glow.

WHAT IS ELECTRICITY?

All things are made up of very thin particles called atoms. Everything from metals, wood, glass, water and gases are made of atoms. We cannot see atoms because they are

 very, very small. However, scientists have found out that even atoms are made up of smaller particles. One of the many types of particles in an atom is the electron.

We get electric current because of the movement of the electrons. So, current is the flow of electrons. One might imagine electrons traveling from one end of the wire to the

other end and making a continuous flow, just like the flow of water in a pipe ( though the twoare not exactly identical ).

Electricity travels along a path. If the path is blocked, then electricity cannot keep flowing. The whole path along which electricity travels is knownas a circuit. A broken path is

known as an 'Open Circuit' and the electricity can not flow in an open circuit.An unbroken path is known as a 'ClosedCircuit' and the electricity can flow.

CONDUCTORS AND INSULATORS

Some materials allow electricity to flow through them easily, some materials do not. The materials that allow electricity to flow through them easily areknown as conductors.

 The materials through which it is difficult for electricity to flow are known as insulators ornon- conductors. Conductors are useful to us because they allow electricity to flow

 through them. However, sometimes we do not want electricity to flow, in certain instances. And so we have to use insulators to prevent the flow ofelectricity.For example we

use rubber or plastic insulators to cover electric wires in order to prevent electricity form flowing into our body. Otherwise we will get an electric shock. So insulators are also

 useful to us.

HOW TO TURN ELECTRICITY ON AND OFF

We use electricity very often. We use electricity to work our radios, to run our fans, in electric kettles to boil water and also to getlight from the bulb. However, we do not keep

our

radio 'on' all the time. And if it is cold, we do not want the fan to keep running. After the water has boiled,we do not need electricity any more. We definitely do not need to have the

light 'on' when it is very bright. Therefore we must have a way and a device to turn electricity 'on' and 'off', whenever we need to. We use a switch to turn electricity 'on' and 'off'.

The function of the switch is mainly to 'make' or 'break' the circuit, thereby sometimes allowing the electricity to travel (ON POSITION) and otherwise making the flow of electricity

stop (OFF POSITION) .

OTHER WAYS TO OBTAIN ELECTRICITY  ( BATTERIES )

There are mainly two kinds of batteries namely primary and secondary. The primary batteries we use are known as dry cells. Many other types of dry cells are shown in the picture.
A dry cell can give a steady current for a certain time after which the current becomes weaker and weakerand finally it produces no more current. It is of no use to us anymore.This
is one type of battery.On the other hand, the secondary battery is known as wet cell. We call it a wet cell because inside the cell there is liquid. We also call the wet cellshown below
'an accumulator'. It can give us electricity for a longer time. And when it becomes weak it starts giving lesser current,we recharge it. After recharging the wet cell becomes as good
as new and starts giving normal current again.
DRY CELL WATER CELL

HOW IS ELECTRICITY PRODUCED ( Generation of Electricity )

The electricity, which we use for electric bulbs, fans, kettles and irons, is produced by 'generators'. A generator is actually a very big dynamo. It can produce a very large amount
of electricity. Number of generators produce power in Power Station. Electricity produced at a power station isallowed to flow through metallic cables, which run from the Power
Station to our houses and offices. Then they run back from our houses andofficesto the power station, forming a closed circuit ( remember the essential condition for the flow
of current - the closed circuit ! ). Don't be surprised if you don't see many cables running from pole to pole, they can be laid underground too !

ELECTRICITY CAN GIVE US HEAT

Our  common  experience  is  that  whenever  we  put  our  hand  near a lighted electric bulb, we feel the heat  coming from the bulb. Similarly, we can  feel a   touch of heat from a
lighted torch after sometime.  Also if we switch on an electric kettle containing  water the water starts boiling after sometime. Actually there is a long piece of coiled wire inside
the kettle, when electricity passes through it, heat is produced which makes the water boil.

ELECTRICITY CAN GIVE US liGHT

We notice that every time electricity is passed through the thin wire of a bulb, light is produced. We say that some of the electricity has been 'changed' to light. Actually, the
changing of electricity into heat takes place first. The electricity that passes through the thin tungsten wire inside the bulb, makes the wire very hot. The wire becomes so
hot that is glows.When it glows, it gives off light. Similarly electricity is converted to light in a fluorescent lamp too.

But whereas a tungsten bulb uses up a lot of electricity before light is produced, a fluorescent lamp uses up only a small amount of electricity to produce light. Therefore for
the same amount of electricity a fluorescent lamp gives off more light than a tungsten bulb.

ELECTRICITY IS A FORM OF ENERGY

Electricity can be converted into heat, light or magnetism. In fact electricity, heat, light and magnetism are all forms of energy. There are many more forms of energy. And they
can be converted into one another. For example electrical energy can be changed to light energy, heat energy or  magnetic energy.
ELECTRICITY CAN PROVE TO BE FATAL TOO

Electricity is very useful to us in many ways. We can use to make our lives more comfortable. But it can be very DANGEROUS to us too. Here are a fewtips to stay away from harm

  1. Do not touch a bare wire from the main electrical circuit. It may be a live wire i.e. electricity might be traveling through it. If you touch it, the electricity will flow into your body
    and might give you an electric shock.
  2. Climbing a lamppost carrying electric wires is dangerous. A lamppost is usually made of metal and is therefore a good conductor of electricity. Some electricity may escape
    from the electric wires to the lamppost and so you could be electrocuted.
  3. Do not push a needle through an electric wire. An electric wire is covered by rubber or plastic insulators. If you do so, electric current will flow through the needle to your
    body and give you a shock .
  4. Do not try to repair electrical appliances. Leave it to an electrician.
  5. Touching an electrical appliance with wet hands is dangerous ! Water can conduct electricity.

Ask an electrician to educate you about electrical safety.

MEASUREMENT OF ELECTRICITY

Electric current in a wire is something like water current in a pipe.
The amount of electricity passing through the wire per second is measured in ampere (A).
The "pressure" pushing the electricity along the wire is measured in Volt (V). For example a torch battery is 1½ Volts, a car battery is 6 Voltsor 12 Volts. Electricity running in the

cables in your house is 240 volts. The amount of electrical energy used in homes, offices, etc. is measured by an electricity meter in kilowatt-hours.

Watt is the unit of power or rate of doing work. A kilowatt-hour is the electrical energy supplied at a rate of 1,000 watts for 1 hour

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