Electricity and magnetism
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Transcript of Electricity and magnetism
![Page 1: Electricity and magnetism](https://reader035.fdocuments.us/reader035/viewer/2022062822/5880f3701a28abc3368b4e45/html5/thumbnails/1.jpg)
Electricity and Magnetism
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What are the types of magnets?
Natural Artificial
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What is the difference between permanent and induced magnets?
• Permanent magnets never lose their magnetism
• Induced magnets have a temporary magnetic force.
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What happens if you break a magnet in half?
Both parts will have a north pole and a south pole.
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What happens if you place two magnets with the opposite poles together?
• They will attract each other.
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What happens if you place two magnets with the same poles together?
• They will repel each other.
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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.
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Can you label this compass rose?North
South
EastWest
NE
SE
NW
SW
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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.
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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.
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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.
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What objects use magnets?
Hair dryer Microphone Hard disc Speakers
Key card MRI scanner Maglev train
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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.
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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.
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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
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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.