Magnet
Magnetic and Non-magnetic Materials
● Magnetic Materials: The material which gets attracted towards a magnet is called a
magnetic material.
For example: Iron, nickel or cobalt.
● Non-magnetic Materials: The materials which are not attracted towards a magnet are
called non-magnetic materials.
For example: Wood, Plastic, Rubber etc
Types of Magnet:
1. Temporary magnet
2. Permanent magnet
Types of magnets: (Shape)
1. Bar magnet
2. Circular magnet
3. Horseshoe magnet
4. Cylindrical magnet
Poles of magnet
● The two ends of a bar magnet are called the poles of a magnet.
● One is the North Pole and the other is the South Pole.
● The magnetic strength of a bar magnet is maximum at the poles.
● Ulike poles of two magnets attract each other i.e. the north pole of one magnet
attracts the south pole of another magnet
● Like poles repel each other i.e. the north pole repels the north pole and the south
pole repels the south pole.
● If a bar magnet is suspended freely, it will always remain in the north-south
direction. This is called the directive property of a magnet.
● The end of the magnet that points towards the north is called the north-seeking
end or the north pole (N).
● The other end, which points towards the south is called the south-seeking end or
the south pole (S).
● Every magnet has a north pole and a south pole.
● A circular magnet, a horseshoe magnet and a rod magnet also have a north pole
and a south pole.
● Earth itself is like a giant magnet
Magnetic compass
●
● The magnetic compass is a simple device, which has been used since ancient times by
sailors and other travelers to find directions.
● A magnetic compass is composed of a small box with a glass top and a magnetic needle,
which moves and indicates the directions.
A magnetic compass is used:
● To find the north-south direction.
● To find the direction of a magnetic field at a place.
● To plot the magnetic field lines.
● To test the polarity of a magnet.
Properties of magnet
● Attraction: Magnets attract certain metals, such as iron, nickel, and cobalt.
● Polarity: Magnets have two poles, a north and a south pole.
● Repulsion: Like poles repel each other, while opposite poles attract each other.
● Direction: When freely suspended, the north pole of a magnet points toward the Earth's
north pole.
● Pair property: If a magnet is cut in half, each piece will have a north and south pole.
● Directive property: If a magnet is suspended in mid-air, the directive property can help
determine which pole is north and which is south.
Why does an ordinary iron needle become a temporary magnet?
An ordinary iron needle becomes a temporary magnet when a magnet is rubbed on it in one
direction. The iron molecules in the needle, which are initially jumbled, start aligning in a
north-south direction, similar to a magnet. This alignment makes the iron needle temporarily act
like a magnet until the magnetic influence is removed.
Care of magnet
● Magnets can lose their magnetism over time. To avoid this, magnets must be
stored with their opposite poles beside each other.
● A magnet should not be taken near heat as it loses its magnetism.
● A magnet should not be hammered or dropped on a hard surface.
Uses of magnets
● Magnets are used in compass needles, helping us find directions.
● Magnets can be used to hold things together, like pieces of paper on a refrigerator or a
magnetic board.
● Magnets are used in various toys, such as magnetic building blocks, to create interesting
shapes and structures.
● Some doors use magnets in their latches to keep them closed.
● Magnets can help in separating items like iron from a mixture of different materials.
● In credit and debit cards, information is stored in magnetic strips
● Some trains use magnets to levitate above the tracks, reducing friction and allowing for
faster and smoother travel.
● Magnets are used in some jewellery items for decorative purposes.
● Magnets are used in security systems
