Download Date Class Period

Name ____________________________________________ Date ______________ Class Period _________ ELECTROMAGNETS
PROBLEM: Can the strength of an electromagnet be changed by changing the voltage of
the power source? Can the strength of an electromagnet be changed by changing the
amount of wire wrapped around its core?
BACKGROUND RESEARCH:
1. Heating or hitting a permanent magnet can ruin it.
2. Iron is a good metal to use to make an electromagnet.
3. The north pole of one magnet will attract the south pole of another magnet.
4. Magnets and electromagnets are used in many devices.
5. The “V” stands for volts. A volt is a unit used to measure the amount of electricity
in something, like meters is a unit used to measure the length of something.
HYPOTHESIS: If I increase the voltage, then the electromagnet’s strength will ___.
(increase, decrease or not change).
If I increase the number of wire coils, then the electromagnet’s strength will ____.
(increase, decrease or not change).
MATERIALS:
-1 meter of wire
-a nail
-2 batteries
-masking tape
- paper clips
PROCEDURE:
1. Take the wire and straighten it.
2. Take the wire and wrap it neatly around the nail. Start wrapping at the flat part of
the nail and work your way towards the nail’s point.
3. Wrap the wire around the nail 10 times to build the first electromagnet.
4. Assign jobs to different students
a. Crane Operator
b. Power Operator
c. Data Recorder
Name ____________________________________________ Date ______________ Class Period _________ We will test the electromagnet 2 ways:
Using the magnetic field sensor
COLLECT DATA FOR ZERO COILS
1. Tape a magnetic field sensor to the
tabletop. The white side of the
sensor (or white dot) should face up
and be parallel to the tabletop.
2. Zero the sensor
3. Write down the data in your data
table for zero winds. Simply write
down the number shown in the
sensor window when it is nowhere
near the nail or a magnet. This
should be close to zero!!
COLLECT DATA FOR 10 COILS
4. Power Operator - Now take the
wire wrapped nail and tape one bare
end of the wire to the + end of a D
battery (1.5 Volts).
5. Firmly press the other bare end to
the – end of the D battery.
6. Crane Operator – touch the pointed
end of the nail to the top of the
sensor at its very own as shown
Using the Paperclips
The other way we will test the
electromagnet is to see how many paperclips
it will pick up.
COLLECT DATA FOR 10 COILS
1. Power Operator - Now take the
wire wrapped nail and tape one bare
end of the wire to the + end of a D
battery (1.5 Volts).
2. Firmly press the other bare end to
the – end of the D battery.
3. Crane Operator –Gently mix the
paperclips with the electromagnet.
4. Carefully lift the electromagnet out
of the paper clip container and move
it to a clean spot over your desk.
5. Turn off the electromagnet by
removing the wire from the battery
pack and let the paper clips fall.
6. Count how many paper clips the
electromagnet picked up and record
that number in your data table.
7. Repeat the above steps for 15,
20, 25, 30, 35, 40 coils. Record all
data in tables similar to the ones
shown below.
7. Data Collector – record number on
handheld computer in data table.
The units are mT (milliTeslas).
8. Repeat steps above for 15, 20, 25,
30, 35, 40 coils. Record all data in
tables similar to the ones shown
below.
9. Now, connect 2 batteries and
record the magnetic field with 40
coils. Then, reduce the number of
coils to 35 and record the magnetic
field and so on.
8. Now, connect 2 batteries and
record the magnetic field with
40 coils. Then, reduce the
number of coils to 35 and record
the magnetic field and so on.
Name ____________________________________________ Date ______________ Class Period _________ DATA:
One battery
Number of Coils
Magnetic Field (mT)
Number of
Paperclips Picked up
10
15
20
25
30
35
40
Two batteries
Number of Coils
Magnetic Field (mT)
Number of
Paperclips Picked up
10
15
20
25
30
35
40
Magnetic Field Strength (mT) Number of Paper Clips Picked Up Graph your data! A sample graph is shown below.
Number of coils Name ____________________________________________ Date ______________ Class Period _________ Conclusion:
1. What happened to the strength of the electromagnet when more turns of wire
were used? Use data from your experiment to explain.
2. What happened to the strength of the electromagnet when more volts were used (2
batteries)? Use data from your experiment to explain.
3. Explain successes and challenges of testing the magnetic field using the magnetic
field sensors.
4. Explain successes and challenges of testing the magnetic field using the paper clip
pick-up method.