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Unit 11: Magnetism Page 23

Activities, Experiments, Projects

Lesson 2: Electromagnetism

Note: This section is an abbreviated overview of the experiments online.

If you had a stronger magnet, or
Experiment: Motors and
many more coils in your wire, then
Generators
you could make a greater amount
of electricity each time you moved
Have you noticed that stuff sticks
the magnet past the wire.
to your motor? If you drag your
motor through a pile of paperclips,
A motor has a coil of wire wrapped
a few will get stuck to the side.
around a central axis, so instead of
What's going on? rubbing back and forth (which is

tough to going fast enough,
Inside your motor are permanent
because you have to stop, reverse
magnets and an electromagnet.
direction, and start moving again
Normally, you'd hook up a battery
every so often), it rotates past a
to the two tabs (terminals) at the
set of magnets continuously.
back of the motor, and your shaft
would spin.
When you add a battery pack to
the motor terminals at the back,
However, if you spin the motor
you energize the coil inside the
shaft with your fingers, you’ll
motor, and it begins to rotate to
generate electricity at the
attempt to line up its north and
terminals. But how is that possible?
south poles. But the magnets are
That's what this experiment is all
lined up in a way that it will
about.
continually 'miss' and overshoot,
which keeps the shaft spinning
If you move a magnet along the
over and over, faster and faster.
length of a wire, it will create a
very faint bit of electricity inside
You can transform a motor into a
the wire. If you moved that
generator by doing the opposite:
magnet back and forth fast enough
you could power a light bulb.
1. You can turn your motor into a
However, by fast enough, I mean
generator by simply giving the
like 1000 times a second or more!
shaft a quick spin with your

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