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Imagine if you wake up one day and find that you have the ability to
attract things towards yourself!
Then that would be real fun. Isn't it?
Well, there is a material in this world
which attracts iron objects towards itself.It's called
a Magnet. Magnets can pull or
push things made of nickle, cobalt, iron
and steel.So these materials are referred to as Magnetic Substances.
And those materials like plastic,
paper, cloth etc. which are not affected by a magnet
are called non-magnetic substances. Natural magnets are magnets
made from loadstone. Artificial magnets
are those magnetic materials which can be converted into magnets.
Magnets can be temporary..
that is attract magnetic materials only for some time
or permanent. That is they can always remain
a magnet.
Magnets can be of many shapes too. Here are some of them:
A bar magnet, a horse-shoe magnet, a disc shaped magnet
or a cylindrical magnet.
Children do you know that you can convert
any piece of iron into a magnet.
Try this. Take an iron nail,
rub a magnet on the nail for about 20 to 30 times
in the same direction with the same end of the magnet.
And Bingo! you will get another temporary magnet.
Now rush. Pick up some Al-pins with them.
This ability of magnets to attract
or repel magnetic particles is called Magnetism
and the area around a magnet in which the effect of the
magnet can be experienced is called magnetic field.
Magnets, can either pull or push objects
that enter their magnetic field.
Let me now tell you about the properties of a magnet.
Magnets exert their influence through various materials.
The effect of magnet works through air,
water and even through solid things.
Children, try putting some pins into a glass
and bring a magnet near the glass. See
what happens. Now add some water into the glass
and repeat the action. What do you see? Magnets
exert more magnetic force at the ends
as compared to the middle. Try
rolling a bar magnet on a plate containing iron filings.
You will find that more filings stick on the
ends. The ends of the magnets show more magnetic force
and are called the poles of the magnet.
A magnet always comes to
rest in north south direction.
Suspend a bar magnet with the help of a thread tied
at its center. When it comes to rest you will find that its resting
in the north-south direction. The pole pointing towards the north
is called the North Pole and the pole which points towards the south
is called the South Pole.
Based on this property of a magnet a simple device
called a Compass is designed. A magnetic needle
is allowed to rotate freely inside a small circular box
made of brass or aluminum. Since the needle is a magnet,
it comes to rest only in the north south direction.
The end pointing north is usually painted red.
Like poles repel,
unlike poles attract each other.
If two bar magnets are kept end to end
then you will find that either the two magnets will stick
to each other with a lot of force or
it will be difficult to bring them together. This is because
the north pole of one magnet attracts
the south pole of the other magnet in the first case.
And in the next case
the north pole of one magnet strongly repels
the north pole of the other magnet. Magnetic poles
always exist in pairs. If a magnet is broken,
then each piece will behave as a complete
magnet. So children,
isn't a magnet very fascinating? Enjoy magnetizing
and have fun. Thank you.