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Magnets and magnetic fields (Types of magnets (Bar Magnets (Bar magnets…
Magnets and magnetic fields
Types of magnets
Bar Magnets
a bar magnet is a
permanent magnet
because it's always magnetic (always has a magnetic field)
A magnet can attract magnetic materials
these include the metals:
Iron, steel, nickel and cobalt
The space around a magnet where it can attract these magnetic materials is called a
magnetic field
Bar magnets have 2 ends, 1 called a north-seeking pole and 1 called a south-seeking pole (north and south)
If two of these magnets are placed close together the north of one magnet is attracted to the south of the other.
If 2 magnets' North Poles are put close together they will repel each other, same for 2 south
Induced magnets
When a piece of magnetic material is placed in a magnetic field it becomes a magnet itself.
it stops bing magnetic when taken out of the magnetic field
This is called an induced magnet
Uniform magnets
When magnetic field lines are the same distance apart from each other, we say that the magnetic field is uniform
Where are magnets used?
Magnets are used in:
-electric motors
-generators
-loudspeakers
-Iphones
-TV
-comuputers
-Fridge doors
Magnetic fields
The shape of a magnetic field can be found using
plotting compasses
we represent magnetic fields using lines that show how a single North Pole would move (from north to south)
The field is strongest where lines are closest together
this diagram shows the magnetic fields around a bar magnet
this diagram show show 2 magnets together can form a uniform magnet
Earth's magnetic field
The needle of a plotting compass is a very small magnet
compasses can be used to help people find their way as the needle always points to somewhere near the earths North Pole
This behaviour of compasses is evidence that the earth has a magnetic field which is similar in shape to the magnetic field of a bar magnet.
Compasses needles are weighted at one end to keep them level.
A magnet suspended on a string will tilt relative to the horizontal surface by different amounts in different places,
The earths magnetic field is thought to be caused by electric currents in the earths outer molten core, which is made from a mixture of iron and nickel.
