Electricity and Magnetism

What are the types of magnets?

Natural Artificial

What is the difference between permanent and induced magnets?

• Permanent magnets never lose their magnetism

• Induced magnets have a temporary magnetic force.

What happens if you break a magnet in half?

Both parts will have a north pole and a south pole.

What happens if you place two magnets with the opposite poles together?

• They will attract each other.

What happens if you place two magnets with the same poles together?

• They will repel each other.

What happens if you suspend a magnet? Why?• It will point toward the magnetic north pole. This is how a compass works.

It happens because the Earth’s core is made of molten iron. It acts like a huge magnet.

Can you label this compass rose?North

South

EastWest

NE

SE

NW

SW

What is a magnetic field? Can we see it?• A magnetic field is the area around a magnet where it exerts its force.

• We can’t see this field, but we can see its shape using iron filings.

How does the Earth’s magnetic field protect us?•It deflects cosmic rays

• It protects our atmosphere.

The incredible light effects called Aurora Borealis and Aurora Australis are caused when cosmic rays combine with gases in the atmosphere at the magnetic poles.

Which materials are magnetic?• Materials that contain iron, nickel, or cobalt are magnetic.

• An alloy is a mixture of metals. Steel is an alloy that contains iron.

• Many common objects are made of steel, so they are magnetic.

What objects use magnets?

Hair dryer Microphone Hard disc Speakers

Key card MRI scanner Maglev train

How can you make an electromagnet? How does it work?

• Electromagnets are objects that act like magnets when an electrical current passes through them.

• They are not permanent magnets. When you switch off the electrical current, the magnet stops working.

• To make an electromagnet stronger, add more coils of wire.

What materials allow electricity to pass through them?• Conductors allow electricity to

pass through them.

• Water is a conductor (especially salt water)

• Metals are good conductors.

What materials do not allow electricity to pass through them?

• Insulators do not allow electricity to pass through them.

• Examples of insulators: wood glass plastic

rubber cloth

Electrical safety tips• Never overload sockets and extension leads.

• Never use electrical appliances which are wet.

• Never put anything into the holes of a socket.