WOW !

Magnet Magic

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Magnetic materials are attracted by magnets

Object Made of ? Magnetic? Yes or No?

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A paperclip is attracted to the ends of a bar magnet

The paperclip is made of steel.

The arrow shows the force on the paperclip.

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Representing forces with arrows

The magnet also is pulled towards the paperclip.

The two forces are the same size

and in opposite directions.

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2 magnets

These ends attract

These ends push apart – (repel)

There are two sorts of magnetic poles.

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Making a compass When a magnet is hung

up one end will point North. so it lines up

North/South

The same end always points North

The end that points North is called the north seeking pole

N S

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The Earth is a magnet

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A compass uses a tiny magnet

which can swing round.

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The Earth is a magnet

NORTH POLE

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Using a compass to find directions A compass needle always points to

the Earth’s North Pole.

Some birds use the Earth’s magnetism to find directions.

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A magnet

has anorth poleand a south pole.

S N

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The north pole attracts the south pole of the other magnet.

S N S N

S N S N

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The north pole repels the north pole of the other magnet.

You can feel the magnets pushing apart.

This is called repulsion

Note - south poles also repel each other

S N S N

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Now for some games!

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Something very new !

• A computer that will stay booted up when you switch it off – it will be on sale in a few year’s time.

• It will have memory called MRAM and use special magnets !

(Magnetoresistive Random Access Memory)

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What have we learned? Magnets will attract magnetic materials

iron and steel Magnets have two sorts of poles

north and south Magnets repel each other as well as

attract similar poles repel opposite poles attract

A compass is a little magnet The Earth is like a magnet

compasses are used to find directions Special magnets are used in computers

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Magnets are used in lots of ways

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It moves !

A motor causes movement.

An electric current and a magnetic field can make a simple motor.

magnet + electric current movement

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Spot the motors

Can you think of other examples?

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Very tiny motors can be made When the drawer for a CD opens and

closes a tiny motor makes it move A tiny motor moves the camera lens when

the camera is switched on Many small toys have motors in them

robots, Artificial limbs can use tiny motors to act

like muscles

Magnets are

amazing ! Magnets + electric currents

make things move !