 Making
magnets
The stroking
method
Use a permanent magnet and stroke a piece of steel (must
be hard - you want it to stay a magnet) with a wide circular action
many times in the same direction. This causes the domains to line up.
Each stroke lines up domains. Once they are all lined up the magnet
is at maximum strength.
Using a solenoid
Put the steel (must be magnetically hard - you want it to stay a magnet!!)
rod inside a solenoid. Pass a d.c. current through the coil for a period
of time. The longer the time, the higher the current and the more turns
on the solenoid the quicker your magnet will be made. Once all of the
domains are lined up the magnet will be at maximum strength.
Destroying magnets
Bash, drop or
hammer the magnet.
This gives energy to the domains and lets them
reorientate themselves intorandom directions again.
Heat it.
Again,
this gives energy to the domains and lets them reorientate themselves
intorandom directions again.
Use a solenoid.
Put the magnet inside a solenoid (a long coil wire). Pass an AC current
through the coil for a period of time. The longer the time, the higher
the current and the more turns on the solenoid the quicker your magnet
will be demagnetised.The AC supply voltage repeatedly pulls the domains
into opposing directions. This results in them getting disorientated
and all pointing in random directions again.
Try the magnetism
wordmaze: click here
Magnetism and levitation - click here
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