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magnetism - Coggle Diagram
magnetism
magnets exert forces on each other:
1:
all magnets have a north or south pole
2:
when two magnets are close they exert a non-contact force on each other
3:
two poles that are the same repel i,e nor and north
4:
two different poles attract i.e. north and south
5:
there are also forces between magnets and magnetic materials. these forces are always attractive
6:
iron, steel, nickel and colbalt are all magnetic materials
a compass shows the direction if a magnetic field:
1:
the needle of a compass is a tiny bar magnet it points in the direction of any magnetic field thats in it
2:
you can use a compass to plot the magnetic field patterns
3:
when they're not near a magnet, compasses always point north
4:
this is because they point in the direction of the earths magnetic field
5:
so the inside (core) of the earht must be magnetic
magnets can be permanant or inducd:
1:
permanent magnets create their own magnetic field
2:
an induced magnet turns into a magnet when its put into another magnetic field
3:
when you take away the magnetic field induced magnets quickly stop being magnets (they lose there magnetism)
4:
permanent magnets and induced magnets always attract each other
a current creates a magnetic field:
1:
a current flowing through a wire creates a magnetic field
2:
you can see this by placing a compass near to the wire - the compass will move to the point in the direction of the field
3:
you can use this to draw the field
4:
the field is made up of circles around the wire
5:
you can also use the right hand thumb rule to quickly work out which way the field goes
6:
reversing the direction of the current reverses the direction of the magnetic field
7:
the closer to the wire you are the stronger the magnetic field gets
8:
and the larger the current through the wire is the stronger the field is
a solenoid is a coil of wire:
1:
if you wrap a wire into a coil its called a solenoid
2:
the magnetic field inside a solenoid is atrong and uniform
3:
uniform means the field has the same strength and direction everywhere
4:
the magnetic field outside a coil is just like the one around a bar magnet
5:
wrapping a wire into a solenoid increases the strength of the magnetic field produced by the current in the wire
6:
you can increase the field strength even more by puttinf a block of iron in the coil
7:
a solenoid with an iron core is called an electromagnet