1. Electromagnetic Force Teaching Slides, 4.1
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Electromagnetic Force Course, 4.1: Electric Motors

2. Review electromagnetism properties
What are some things you have learned about the relationship between electricity and magnetism?
What happens when you bring a compass near a wire with electric current running through it?
Electromagnetic Force Course, 4.1: Electric Motors
Step 1

3. Focus question How does an electric motor work?
Electromagnetic Force Course, 4.1: Electric Motors
Step 3

4. Observe a motor Look at the outside of the motor.
What parts can you identify?
How can we get information about the inside of the motor, without taking it apart?
Electromagnetic Force Course, 4.1: Electric Motors
Step 4

5. Data from compasses
What can you determine by using the compass as a tool?
Could the compass needle be moving because there is an electrical current in the motor? Why or why not?
What can you conclude about the internal structure of this motor?
Electromagnetic Force Course, 4.1: Electric Motors
Step 5

6. Complete a motor circuit
Complete a circuit with the motor.
Electromagnetic Force Course, 4.1: Electric Motors
Step 6

7. View dissected motor Teacher master I, Dissected Motor in Three Parts
Electromagnetic Force Course, 4.1: Electric Motors
Step 7

8. View dissected motor What parts can you identify?
What do you think they will do?
Electromagnetic Force Course, 4.1: Electric Motors
Step 7

9. Confirm findings What does this thin, coiled wire indicate?
Where is the core of the electromagnet?
Through what pathway does the electromagnet get its energy from the battery?
Electromagnetic Force Course, 4.1: Electric Motors
Step 8

10. Commutators
What do you notice about the commutator when you look closely?
Teacher master J, Motor Shaft and Commutator
Electromagnetic Force Course, 4.1: Electric Motors
Step 9

11. Discuss the plastic cap
What is the shape of those wires at the contact point?
How might the shape of the wires relate to their function?
Teacher master K, Motor Cap and Brushes
Electromagnetic Force Course, 4.1: Electric Motors
Step 10

12. Test the dissected electromagnet
Carefully reattach the cap on the shaft by sliding the shaft and commutator between the brushes and cap.
The brushes must be in contact with the commutator. Do not add the case at this time.
Set up the circuit with the battery and test each section of the electromagnet, using the paper clip as a tool for detecting magnetic fields.
Record your cause-and-effect observations in your notebook.
Electromagnetic Force Course, 4.1: Electric Motors
Step 11

13. Review implications
What happens to each electromagnet when a current runs through that section?
How will the electromagnet interact with the permanent magnet inside the metal casing?
Why would the motor be designed so only two of the three electromagnet sections are turned on at any one time?
Electromagnetic Force Course, 4.1: Electric Motors
Step 12

14. Review implications
Make a model of what you think is happening inside the motor.
Electromagnetic Force Course, 4.1: Electric Motors
Step 12

15. Consider energy transfer
Think about how energy is being transferred in this system. Return to your model and add arrows and labels to show evidence and transfer of energy through the circuit.
Electromagnetic Force Course, 4.1: Electric Motors
Step 13

16. Consider energy transfer
What evidence do we have of energy in this system?
Where did the energy come from that transferred to the shaft to make it move?
Where did the electrical energy in the circuit come from?
Electromagnetic Force Course, 4.1: Electric Motors
Step 13

17. Analyze diagrams
Turn to “Motor Dissection A-B” in FOSS Science Resources pages
Electromagnetic Force Course, 4.1: Electric Motors
Step 14

18. Review vocabulary
Spend a few minutes reviewing the vocabulary for this part. Update the vocabulary index and table of contents in your notebook.
brush
commutator
motor
rotate
shaft
Electromagnetic Force Course, 4.1: Electric Motors
Step 15

19. Answer the focus question on a plain piece of paper:
How does an electric motor work?
Draw and label a diagram of a dissected electric motor.
Make sure to describe:
the roll of electric current
Permanent magnets
Electromagnets
Shaft
Step 16