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Build an Electromagnet
Problem: How can I make a stronger magnet
that I can turn off and on?
Assessment:
A: One World
B: Communication
C: Scientific Knowledge and Concepts
F: Attitudes in Science
Research: You have experimented with magnets in class, but scientist sometime
need to use very powerful magnets. But a powerful magnet has a problem, how
can the magnet be turned off and on? In 1820, a Danish physicist Hans Christian
Oersted discovered that there was a relationship between electricity and
magnetism. Thanks to Oersted and a few others, by using electricity, we can now
make huge magnets. We can also cause them to release their objects.
Electricity and magnetism are closely related. The movement of electrons causes
both and every electric current has its own magnetic field. This magnetic force
in electricity can be used to make powerful electromagnets that can be turned on
and off with the flick of a switch. But how do you make an electromagnet?
By simply wrapping a wire that has an electrical current running through it
around a nail, you can make an electromagnet. When the electric current moves
through a wire, it makes a magnetic field. If you coil the wire around and around,
it will make the magnetic force stronger.
Hypothesis: If I wrap 1, then 2, then 3 nails with 50 coils one layer, 50 coils two
layers, 100 coils one layer, 100 coils 2 layers then the magnet with 100 coils 2
layers will hold the most paper clips because the more coils the magnet has, the
stronger the magnet is. And because the coils are so close together, the magnet
will be stronger and more focused on that spot.
Variables: Independent Variable: Number of nails, number of coils, layers of wire
Dependent Variable: How many paper clips stick to the magnetized
nail/s
Materials
Item
Iron Nails
Copper Wire
Batteries
Paper Clips
Number
3
1
2
100
Size
10cm
2m
9Volt
Small
Procedure:
1. Wrap the wire in a tight even coil around the nail 10 X. Leave 10 to 15
cm of wire free on each end of the nail so that you can attach this to the
battery.
2. Look at the wire coiled around the nail. The ends of the wire must be free
of any plastic coating. If the plastic is on the wire, strip off the plastic
using scissors.
3. Attach one end of the wire to the positive + side to one of the batteries.
Attach the other end of the wire to the negative side of the same battery.
4. The nail should now be magnetic. Lay the paperclips flat on the table and
pick up as many paperclips as possible. Remember the paperclip must be
lifted completely off the table to be included in your data.
5. Record how many paperclips the nail picks ups in your data table.
6. Now remove the coils from around the nail. Can the nail still pick up
paperclips? Try dropping the nail several times, is it still magnetic?
7. Repeat the experiment but instead of 10 coils of wire in one layer, have 10
coils in 2 layers (5 coils down, 5 coils back). Record the number of
paperclips the electromagnet holds.
8. Repeat the experiment with 20 coils in one layer then 20 coils in 2 layers
(10 coils down, 10 coils back) Record the number of paperclips the
electromagnet holds.
9. Repeat the above experiment but with 2 nails then with 3 nails. Record
the number of paperclips the electromagnet holds.
10. Optional: If you have time: try part of the experiment above but with two
batteries. Do you think the electromagnet will be stronger or weaker?
Estimate how many paperclips you think a 2 battery electromagnet would
pick up.
Data Table:
Number of Paper Clips the Electromagnet Lifted off the Table
Number
Number of Paper Clips
of Nails
50 coils
50 coils
100 coils
100 coils
2 layers
2 layers
1
12
8
0
0
2
8
11
5
6
3
3
0
3
5
Data Processing: (optional)
Here you may include compressed photos of your lab if you wish.
Photos must be labeled.
Conclusion: Answer the following questions in complete sentences:
1. What are the independent variables in this experiment? Number of coils,
number of nails, number of layers of wire.
2. What was the dependent variable in this experiment? How many paper
clips stuck to the magnetized nail/s.
3. What happens to the magnetic domain of the iron nail when the
electricity passes through the nail? The magnetic domains align and make
it magnetized.
4. How does adding more coils change the strength of an electromagnet?
Adding more coils makes the electromagnet stronger.
5. What proof do you have to support your answer to question 4? In the first
attempt of the lab, we used 10 coils instead of 50, and 20 coils instead of
100. We changed it because we couldn’t get any paper clips. However,
when we increased the number of coils we got some paper clips to stick to
the electromagnet.
6. How does adding more layers change the strength of an electromagnet?
The electromagnet gets stronger.
7. What proof do you have to support your answer to questions 6? In the
lab, when the 50 2 layers, we got less than when it was 1 layer. For the
100, the number of paper clips in the 1 layer was 0. For the 2 layers, it
was still 0.
8. How does adding more nails change the strength of an electromagnet?
The magnetic domains go in a line, so the magnetism gets stronger.
9. What proof do you have to support your answer to question 8? In my data
table, the 50 coils 2 layers, kept getting more and more paper clips the
more nails I added, it was the same thing for the 100 coils 1 layer, and 2.
10. From this experiment: What would be the strongest possible
electromagnet you could make? 2 layers, 100 coils, 3 nails 9 Volt battery.
11. From this experiment: How do you know that an electromagnet is
temporary? How do you know you can switch it off?
12. Write a sentence that summarizes how the strength of an electromagnet
can be changed? Number of coils, layers, nails and the power of the
battery can change the strength.
13. Could any other material besides iron be used to make an electromagnet?
Cobalt and Nickel.
14. What is the advantage of an electromagnet over a permanent magnet?
You can turn it on and off.
15. When in real life are electromagnets used? To lift large masses of
magnetic material, electric generator, electric motor, doorbells, circuit
breakers, television receivers, loudspeakers, atomic particle accelerator,
electromagnet breaks and crutches.
16. Cite the source where this you obtained this information: MLA format
"How are electromagnets used in real life." The Q&A wiki. N.p., n.d. Web.
20 Oct. 2013.
<http://wiki.answers.com/Q/How_are_electromagnets_used_in_real_life>
.
17. Where at IST would you expect to find an electromagnet? Speakers,
science lab.