Grade Level/Subject
Unit
Enduring
Understanding
SOL Objectives
Physical Science 8th grade
Electricity
Electricity and magnetism interact to make
electromagnetism.
Title
Lesson Objective:
Build a DC Motor
Build a model of an electric motor. Analyze the
workings of the parts of a motor.
2
Battery 4.5 v, foam cup, disc magnet (4)
magnet wire, permanent marker, paper clips,
sandpaper, tape, tube, cardboard, alligator clips
Teacher provides the research question and the
methodology. Students gather data after
performing a routine procedure. Students draw
conclusions from guided questions.
Inquiry Level
Materials Needed
How is it Level 2?
PS.11 The student will investigate and understand basic
principles of electricity and magnetism. Key concepts
include:
b) electromagnets; and
c) motors and generators.
Build a DC Motor Lab- Electromagnetism
Name _______________________
Date ________
Per ___________
Teacher’s note: This lab can be conducted with small dc motors for
data collection and evaluation separately. Stretch images as needed.
Introduction: You have learned that electricity moves through wires to
make electromagnetism. Electric motors can be used for many things.
They cause motion in elevators and fans. Even some cars and buses are
powered by electric motors. In this lab, you will build a direct
current electric motor—the basis for the electric motors you use every
day.
Hypothesis:
How will reversing polarity affect a motor’s spin? ________________
_____________________________________________________________________
Objectives:
Build a model of an electric motor.
Analyze the working motor parts.
Explain the effect of current on motor motion.
Procedures:
1. Make the spinning armature for the motor by winding the wire
around the tube. Wind the ends of the wire around the loops on
each side of the coil. Leave about 5 cm of wire free on each end.
2. Hold the coil on its edge. Sand the wire coating from the top
half of each wire end. Partially unfold two paper clips to make
“Y” holders for the coil, see image.
3. Place two magnets in the bottom of the cup and two on the outside
of the inverted cup. The attraction holds the magnets in place.
4. Tape the paper clips to the sides of the cup. The hooks should
suspend the coil. Test the coil that it rotates freely.
5. Attach the alligator clips to the battery and the bottoms of the
paper clips to get a current through the coil.
6. Spin the coil clockwise and record your observations. Spin it
counter-clockwise and record you observations.
7. Reverse the alligator clips on the battery. Repeat step 6.
8. Re-clip two batteries in series. Repeat step 6.
9. Reverse the polarity at the batteries. Repeat step 6.
10.
Clip two batteries in parallel configuration, spin the coil.
Repeat step 6.
11.
Reverse the polarity of the batteries. Repeat step 6.
Gathering Data:
Battery
configuration
Single
Single
Single
Single
Two in Series
Two in Series
Two in Series
Two in Series
Two Parallel
Two Parallel
Two Parallel
Two Parallel
Polarity
Spin direction
normal
normal
reversed
reversed
normal
normal
reversed
reversed
normal
normal
reversed
reversed
clockwise
counter clockwise
clockwise
counter clockwise
clockwise
counter clockwise
clockwise
counter clockwise
clockwise
counter clockwise
clockwise
counter clockwise
Explain Coil motion
Analyzing Results:
1. Did your motor always spin in the direction you started it?
Explain.
2. How does changing polarity affect the coil motion?
Drawing Conclusions:
3. How does changing the polarity affect the electron motion?
4. How might electric cars promote less pollution than gas
cars?
5. How could your motor be used to lift an elevator? (Think of
your motor in a bigger scale and using simple machines.)
Reviewing Vocabulary:
1. An _________motor converts electrical energy into mechanical
energy.
2. An electrical __________ uses electromagnetic induction to
change mechanical energy into electrical energy.