Unit J Unit J Magnets and ElectromagnetsMagnets and Electromagnets

Form 2C

15th of November

St. Mary´s College in Crosby

Todays Lesson...Todays Lesson...

Unit JMagnets and Electromagnets

J1 – Magnetic Fields

J2 - Magnets

J3 – Making Magnets

J4 - Electromagnets

J5 - Variables

Homework Correction...Homework Correction...Page 101- Questions 1 & 2Page 101- Questions 1 & 2

1.1. a) Near the magnet, the lines are very close a) Near the magnet, the lines are very close togheter, showing that the field is strong. Further togheter, showing that the field is strong. Further away the lines are further apart and the magnetic away the lines are further apart and the magnetic field is weaker.field is weaker.

b) Tell us that the magnetic field is stronger near the b) Tell us that the magnetic field is stronger near the magnet and weaker further away.magnet and weaker further away.

c) If we look to the diagram, we can see that the c) If we look to the diagram, we can see that the magnetic field lines are also close togheter at the magnetic field lines are also close togheter at the poles than at the sides, so the magnetic field will be poles than at the sides, so the magnetic field will be stronger at the poles.stronger at the poles.

Homework Correction...Homework Correction...Page 101- Questions 1 & 2Page 101- Questions 1 & 2

2.2.

Why the Earth acts as a magnet?Why the Earth acts as a magnet?Class Notes...Class Notes...

N

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The earth´s core is made of iron and nickel, thats why the earth acts as a huge magnet.

Magnets...Magnets...

► A compass neddle is A compass neddle is a magnet that can a magnet that can move freely;move freely;

► The south pole of The south pole of the magnet will the magnet will always point always point towards the Earth´s towards the Earth´s north pole.north pole.

Magnets...Magnets...

►A A compass always point to the Earth´s compass always point to the Earth´s North Pole, unless you hold it very close North Pole, unless you hold it very close to another magnet;to another magnet;

► If that happen the pointed end of the If that happen the pointed end of the compass needle is attracted to the south compass needle is attracted to the south pole of the magnet;pole of the magnet;

Class Notes...

The direction of a magnetic field...The direction of a magnetic field...

The magnetic field lines start at the north pole of the bar magnet and end up at the south pole of the bar magnet.

Class Notes...

Which way does the field go?Which way does the field go?

Is it possible to stop the magnetic Is it possible to stop the magnetic field?field?

e.g MRI Scanners

Magnetic Shielding

Worksheet...Worksheet...

About magnets...

Some magnetic Experiments...Some magnetic Experiments...

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