Magnetism

Magnetism is a natural force that attracts or repels certain materials. This force is caused by the movement of tiny charged particles, called electrons, inside atoms. Objects that show strong magnetic properties are called magnets.

Magnetic Materials

Not all materials are magnetic. The ones that can be magnetized or attracted by a magnet are called magnetic materials. Examples include:

• Iron
• Nickel
• Cobalt

Materials like wood, plastic, and rubber are non-magnetic because they do not respond to magnetic forces.

Types of Magnets

There are three main types of magnets:

1. Permanent Magnets: These keep their magnetism for a long time.
   Example: A fridge magnet.
2. Temporary Magnets: These behave like magnets only when near a strong magnet.
   Example: A paperclip near a magnet.
3. Electromagnets: These are magnets made using electricity. When the electric current is switched off, they stop being magnets.
   Example: Magnets in cranes used to lift heavy iron objects.

Magnetic Poles

Magnets have two poles:

• North Pole (N)
• South Pole (S)

The rule of magnetism says:

• Opposite poles attract each other (N attracts S).
• Same poles repel each other (N repels N or S repels S).

Magnetic Field

The space around a magnet where its force can be felt is called the magnetic field. You can see the magnetic field lines if you sprinkle iron filings around a magnet. The lines are strongest near the poles.

Earth’s Magnetism

The Earth itself acts like a giant magnet because its core is made of iron and nickel. This is why compasses work—they align with the Earth’s magnetic field, helping travelers find direction.

Uses of Magnetism

Magnets are used in many ways in our daily lives, such as:

1. In compasses for navigation.
2. In speakers and headphones to create sound.
3. In refrigerators to keep the door sealed.
4. In MRI machines in hospitals to scan the human body.

Fun Fact

Did you know that some animals, like birds and sea turtles, use the Earth’s magnetic field to navigate while migrating?