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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 65 coils one layer, 65 coils two
layers, 130 coils 2 layers then 130 coils with 2 layers will hold the most paper
clips because : with more coils and layers will make it more magnetic.
Variables: Independent Variable: Number of nails, number of coils, layers of wire
Dependent Variable: Number of paper clips
Materials
Item
Iron Nails
Copper Wire
Batteries
Paper Clips
Number
3
1
2
1 Box
Size
6 cm
2m
D size and 9V
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
10 coils
10 coils
20 coils
2 layers
1
3
7
24
2
7
10
29
3
12
15
42
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 nails,
number of coils and layers of wire.
2. What was the dependent variable in this experiment? Number of paper
clips.
3. What happens to the magnetic domain of the iron nail when the
electricity passes through the nail? By making the nail aligned.
4. How does adding more coils change the strength of an electromagnet?
The more coils it have, the more electricity it will have, so it will be
stronger.
5. What proof do you have to support your answer to question 4? It shows
on my data table that the more coils and layers it have the more paper
clips it had picked up.
6. How does adding more layers change the strength of an electromagnet? It
changes the strength of an electromagnet by adding more layers because
the more layers it have the more energy the electromagnet will have.
7. What proof do you have to support your answer to questions 6? It shows
on my data table that there are two same amount of coils but one of them
is one layer and the other one is two layers. The one with two layers
picked up more paper clips than the one with one layers.
8. How does adding more nails change the strength of an electromagnet?
It makes the electromagnet stronger.
9. What proof do you have to support your answer to question 8?
The nail is made by iron; iron is a magnetic material, more magnetic
materials make a magnet stronger.
10. From this experiment: What would be the strongest possible
electromagnet you could make? 130 coils, 3 layers and 3 nails.
11. From this experiment: How do you know that an electromagnet is
temporary? How do you know you can switch it off? I know it is
temporary because when I drop it to the floor many times, it will not pick
up paper clips anymore.
12. Write a sentence that summarizes how the strength of an electromagnet
can be changed? I make a electromagnet stronger by adding more coils,
more layers of coils, more nails and more batteries.
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? An
electromagnet is better than a permanent magnet because it can turn on
when you need it and off when you don’t need it.
15. When in real life are electromagnets used? Computer, car, phone.
16. Cite the source where this you obtained this information: WikiAnswers.
Answers, n.d. Web. 21 Oct. 2013.
17. Where at IST would you expect to find an electromagnet? In science lab.