Wednesday, 10 October 2012

MAGNETS


What is Magnet?
Magnet is an object consists of iron and steel. Magnets are used in many objects around us.


How Magnets Attract or Repel?
A magnet has two poles namely, north pole (N-pole) and south pole (S-pole). When the N-pole of a magnet is placed near the N-pole of another magnet, the poles will repel or push away each other. The outcome will be the same if the S-pole of a magnet is placed near the S-pole of another magnet. They will only attract or pull each other if the N-pole of the magnet is placed close to the S-pole of another magnet.

Another way of explaining: different poles or unlike poles of two magnets brought near each other, the magnets will attract. When the same poles or like poles of two magnets brought near each other, the magnets will repel.

Picture 1:  Magnet Attract & Repels

Picture 2: Magnectic Field Lines


Handling Magnets The Proper Ways
Magnets can lose their magnetism or strength if we knock them, drop them or heat them.  Thus, magnets must be handled with care to preserve their strength. The strength of the magnets can be preserved by storing the magnets with iron keeper or magnet keeper. Placing keepers at the poles of the magnets can help them last longer.


Magnets Attract some Materials & Objects 

Objects that can be attracted by magnets are called magnetic objects whilst those objects that cannot be attracted by magnets are called non-magnetic objects. Magnetic objects are made of iron or steel. Non-magnetic objects are made of plastic, cloth, wood, glass, rubber and gold.

          Magntic Objects                               Non-Magnetic Objects


Strengths of Magnets
The strength of magnets are different from magnet to magnet. The size of the magnets of the same type and the type of magnet does affect its strength. A strong magnet can attract more objects than a weak magnet.


Uses of Magnets
Magnets are used in many things such as in refrigerator, pencil case, and compass. Do you know how magnets are used in these things?
Refrigerator- Magnetic strip is used to close the door firmly.
Pencil case- Magnetic bar is used to close the pencil case tightly.
Compass- Magnetic needle helps to show directions.


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WORKSHEET




1. Look the diagram above, what happens when these magnets are brought close to each other?


    a) The magnet ( repels / attracts ) the other magnet.

    b) The magnet ( repels / attracts ) the other magnet.

    c) The magnet ( repels / attracts ) the other magnet.

    d) The magnet ( repels / attracts ) the other magnet


2. Complete the table below.

Objects Attracted to a Magnet

 Objects Not Attracted to a Magnet










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