Does the length of the wire in an
electromagnet affect how strong the
electromagnet is?
By Abum Okemgbo
Hypothesis
My hypothesis is the length of the wire will
not effect the strength of the electromagnet
because the same amount of energy will
be going through the wire.
Materials
•
•
•
•
•
•
•
9 cm. iron nails (for core)
860 cm. of 22-gauge insulated wire
4 D-cell batteries
Tape
Scissors
A ruler
7 cm. iron nails
Procedure
1.
2.
3.
4.
5.
6.
7.
Measure out 860 cm. of 22-gauge insulated wire. Wrap the wire around a
9 cm iron nail. Leave 21 cm. free on each side.
Tape 4 D-cell batteries together having each positive and negative ends
(except for one) touching.
Skim both side of the wire. Tape one end of the wire to the negative end
of the 4 batteries so you can turn off and on the electromagnet.
Put the other end of the wire on the positive side of the batteries and try
to pick up as many 7cm nails as possible. Record the data. Repeat with
trials 2 and 3.
Cut 20 cm. of wire off the electromagnet. Don’t cut off the end of the wire
taped to batteries.
Unwind the wire. Skim the end of the wire you cut off. Repeat steps 4 and
5.
Repeat step 6 three times. Then repeat only step 4.
Results
Number of nails held by electromagnet
Length
of wire
(cm)
Trial 1 Trial 2 Trial 3 Averages
860
840
820
800
780
760
740
9
7
6
5
3
3
2
9
7
6
4
3
2
1
9
7
6
4
3
2
1
9
7
6
4
3
2
1
Number of nails held by electromagnet
Graph showing the relationship between length of wire
and the magnetic strength
No of Nails
magnetized
10
8
6
Number of Nails
4
Linear (Number of Nails)
2
0
700
750
800
850
Length of wire core (cm)
900
Conclusion
My hypothesis was wrong. The length of the wire did
affect its strength. As the wire got longer, it was able to
pick up more nails. The electromagnet that had a wire
that was 860 cm long was stronger that all the other
electromagnets. The electromagnet with a wire that was
860 had an average of 9 nails. The electromagnets with
wires that are 740 cm had an average of 1 nail.