Class 6 Science · Chapter 4 NotesExploring Magnets

Magnets are objects that attract certain materials like iron, nickel, and cobalt. The first magnets discovered were natural magnets called lodestones. These are pieces of a mineral called magnetite, which is a natural magnet. Later, people found that they could make magnets from pieces of iron. Today, we have magnets made from different materials and in various shapes, such as bar magnets, U-shaped magnets, and ring magnets. These are called artificial magnets and are used in many everyday items like pencil boxes, purses, and toys.

• Natural magnets are called lodestones
• Artificial magnets are made from materials like iron
• Magnets come in various shapes, such as bar, U-shaped, and ring

Magnets have some special properties. They attract objects made of magnetic materials like iron, nickel, and cobalt. This means that if you bring a magnet near these materials, they will stick to the magnet. However, magnets do not attract all materials. For example, they do not attract materials like plastic, wood, or glass. Another important property of magnets is that they have two poles: a North pole and a South pole. These poles are the regions where the magnetic force is the strongest. If you break a magnet into smaller pieces, each piece will still have a North pole and a South pole.

• Magnets attract magnetic materials like iron, nickel, and cobalt
• Magnets do not attract non-magnetic materials like plastic, wood, or glass
• Magnets have two polesNorth and South
• Each piece of a broken magnet will still have a North and South pole

The area around a magnet where its magnetic force can be felt is called a magnetic field. You can see this field by sprinkling iron filings around a magnet. The iron filings will align themselves in a pattern that shows the shape of the magnetic field. This pattern is made up of lines called magnetic lines of force. These lines always run from the North pole to the South pole of a magnet. They never cross each other and are always closer together near the poles, where the magnetic force is strongest.

• The area around a magnet where its force can be felt is called a magnetic field
• Iron filings can be used to see the pattern of a magnetic field
• Magnetic lines of force run from the North pole to the South pole
• Magnetic lines are closer together near the poles

Earth itself behaves like a giant magnet. This is why a freely suspended magnet, like a compass needle, always points in the north-south direction. The end of the magnet that points towards the North is called the North-seeking pole, or North pole, and the end that points towards the South is called the South-seeking pole, or South pole. This property of magnets is used in compasses to help people find directions. The compass needle, which is also a magnet, aligns itself with Earth's magnetic field, pointing towards the North and South poles.

• Earth behaves like a giant magnet
• A freely suspended magnet points in the north-south direction
• The North pole of a magnet points towards Earth's North pole
• Compasses use this property to help find directions

When two magnets are brought close to each other, they can either attract or repel each other. This depends on which poles are facing each other. Unlike poles, that is, the North pole of one magnet and the South pole of another, attract each other. This is why magnets can stick to each other if their unlike poles are facing. On the other hand, like poles, that is, the North poles of both magnets or the South poles of both magnets, repel each other. This means that if you bring the North pole of one magnet close to the North pole of another, they will push away from each other. This property of magnets is used in many applications, such as in magnetic toys and devices.

• Unlike poles of magnets attract each other
• Like poles of magnets repel each other
• This property is used in many applications, such as magnetic toys and devices

An electromagnet is a special type of magnet that can be turned on and off. It is made by wrapping a wire around an iron core and passing an electric current through the wire. When the current flows, the iron core becomes a magnet. When the current is turned off, the iron core loses its magnetism. Electromagnets are used in many applications, such as in electric bells, cranes to lift heavy objects, and even in medical devices. They are very useful because their magnetic strength can be easily controlled by changing the amount of electric current.

• An electromagnet can be turned on and off by controlling the electric current
• Electromagnets are used in many applications, such as electric bells and cranes
• Their magnetic strength can be easily controlled