Creating Electromagnets Lab
Background:
A magnetic field exists around any wire that carries an electric current. By coiling the wire
around a bolt or nail, the strength of the magnetic field will increase. A coil around a bolt or nail
will become an electromagnet if the wire is connected to a battery or other source of current.
Changing the electric current can control the magnetic force exerted by an electromagnet.
Problem:
Does the number of coils wrapped around the nail or bolt affect the strength of the magnetic
field exerted by the electromagnet?
Materials:
Large iron nail
6V lantern battery
Insulated wire
Small paper clips
Small plastic beaker (2)
Wire with alligator clips
Procedure:
1. Place all the paper clips into one of the beakers.
2. Test the nail for magnetic properties. Touch the nail to the paper clips and lift. Did it pick
up any paper clips? __________________
3. Using the insulated wire, wrap 10 full turns (coils) around the nail. Make sure you keep
the coils snug and organized.
4. Clip one of the connecting wires to each end of the insulated wire.
5. Connect the other ends or the connecting wires to the 6V Lantern battery. You have now
created an electromagnet.
6. Test he strength of your 10-coil electromagnet by touching it to the paper clips and lifting.
Hold the electromagnet over the empty beaker and disconnect one of the wires from the
battery. Make sure the paper clips fall into the beaker.
7. Count the number of paper clips that you moved into the other beaker. Record the total in
Data Table 1.
8. Repeat steps 3-7, but add 5 coils each time. Continue this process until you have made
an electromagnet with 40 coils.
9. Use the blank graph to plot the relationship between the number of coils and the number of
paper clips picked up. Remember to graph the independent variable (# of coils) along the
X-axis and the dependent variable (# of paper clips) along the Y-axis and give your
graph a title.
Data table 1
Number # Paper Number # Paper Number # Paper
of coils Clips of coils clips
of
clips
coils
10
25
40
15
30
20
35
_______________________________
Analysis and Conclusion: MUST ANSWER A COMPLETE SENTENCES FOR CREDIT.
1. What happened to the number of paper clips picked up as a number of coils increased?
2. What does this indicate about the magnetic force of the electromagnet?
3. Explain how your graph supports your answer to questions 1 & 2.
4. Use your graph to predict how many paper clips would be picked up is the nail had 50
coils of wire wrapped around it.
5. A magnetic field exists around a single loop of wire carrying electric current. Explain why
coiling a wire around a piece of iron increases the strength of an electromagnet.
6. List 2 ways to make a 40-coil electromagnet exert a stronger magnetic force.
7. Is the current generated always in the same direction? How do you know?
8. If I covered the nail with rubber or cardboard, would the electromagnet be made? Why or
why not.
9. Compare and contrast a bar magnet and an electromagnet. (What do they have in common
and what makes them different.)
10. Write a sentence that describes how the number of coils affects the strength of the
electromagnet.
11. Can the electromagnet pick up paper clips when it is disconnected? (why or why not)