Make Your Own Kind of Magnet
|Electromagnets are another type of
magnet. Electromagnets are usually iron-containing materials that have a
magnetic force only when an electric field is flowing through them, you
will learn more about fields as you continue this unit. The force that electromagnets
have is called electromagnetism.
You're the scientist!
You can make your own electromagnet by following the
- Insulated wire (Light wire is easiest to wind into
a coil. You need to remove the insulation from the ends that make electrical
(A lantern battery works best for this activity. It is easy to connect
the wires to it and it is a stronger source of electricity than smaller
- Clothes hanger (the type with the paper tube across
- Large iron or steel nail
- An on/off switch is optional, but helps keep your
battery from running down rapidly
- Paper clip or some iron filings to test your electromagnet.
- Remove the paper tube from the bottom of the
- Cut a short piece of wire, and remove the insulation
from both ends.
- Connect one bare metal end to the battery and the
other bare metal end to one side of the switch. Be sure the metal of
the wire, not the insulated material, is touching the connector.
- Remove the insulation from both ends of the wire you
have left. This should be a very LONG piece of wire. Be careful not
to get it tangled. Connect one bare metal end of this wire to the other
side of the switch. Be sure the switch is in the OFF position.
- Leave one foot or so of remaining wire to connect
to the other side of the battery. If you start winding the coil immediately
at the end of the wire, there will be no wire to connect it to the battery.
- Closely wind about twenty turns of wire around the
paper tube from the hanger. This wire must have the insulation on it.
- Now, connect the other bare metal end of the wire
to the other side of the battery and turn on the switch. Do you think
it will pick up iron filings now? Try it and see.
- Turn off the electricity. Slide the nail into the
center of the paper tube. Do you think this will have any effect on
the electromagnet's strength? Try it and see.
- Remove your nail from the paper tube. Remember that
it was not magnetic to begin with? Is it magnetic now? If it is magnetic,
how did it become magnetic?
If you have more than one battery, you can try making
the electricity stronger.
- Strip the insulation from both ends of a wire.
- Connect the connector at the side of one battery to
the connector in the center of another battery.
- Then, connect your electromagnet to one side of one
battery, and the wire going to your switch to the opposite side of the
Do you think this will make your electromagnet stronger?
Try it and see. Try it with and without the nail in the paper tube.
- Disconnect the electromagnet from the battery.
another twenty turns of wire around the paper core.
- Try to put the wire turns right next to each other,
and be as neat as you can.
- Test your electromagnet the same as you did before.
- Connect it to the battery, turn it on, and see how
many iron filings it picks up.
- Put the nail in and see if this makes any difference.
Connect another battery if you have one and test the electromagnet with
and without the nail in the paper core.
- Now, disconnect the electromagnet, wind another twenty
turns onto the coil, and do it all over again.
Write about it!
- Which makes the electromagnet most powerful? How it
is related to the number of turns of wire? How does having more electricity
affect it? What changes when you have the iron core in the center of
- How are permanent magnets and electromagnets alike?
- How are permanent magnets and electromagnets different?
Design your own experiment using the electromagnet that you made versus
a regular magnet. Which one is more powerful? When would a permanent magnet
be more useful than an electromagnet? When would an electromagnet be more
useful then a permanent magnet? Be sure to make a hypothesis and record
your observations and conclusions.
and magnetism are closely related. When electricity flows through a pathway,
it is called a complete circuit. When the electricity
is moving through the circuit, a magnetic field is generated around the
wire. This kind of magnet only stays magnetized as long as the electricity
is flowing through the circuit. This can be very handy. Can you think
of some situations where it would be useful to be able to turn off a magnet?
|When you turn off the electricity flowing
to an electromagnet, the magnetism is also turned off. This is a very useful
property. You can use an electromagnet to pick up a piece of iron and then
drop it someplace else. This property is used in junk yards. They use huge
electromagnets and a crane to pick up, move, and drop old, junked cars.