1. Electromagnetic Force Teaching Slides, 3.2
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Electromagnetic Force Course, 3.2: Electromagnetism

2. Review magnetic fields in circuits
We know that a magnetic field surrounds a magnet. What did you learn about magnets and electricity in the last part of the investigation?
What questions do you have about the relationship between electricity and magnetism?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 1

3. Introduce the challenge
Can you make a magnet that turns on and off?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 2

4. Discuss strength of magnetic field
When you tested a complete circuit with a compass, how strong was the magnetic field surrounding the wire?
What ideas do you have to make the magnetic field surrounding the wire much stronger?
What experiments have we done in class that resulted in a stronger magnetic field?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 4

5. Focus question How does an electromagnet work?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 5

6. Build electromagnets
A. Wrap the thin wire 40 times around the rivet. Be sure to leave about 10 cm of wire free at the start end so you can attach it to a D-cell.
B. Make sure all wraps are in the same direction. Keep the wraps between the head of the rivet and the first black washer.
C. Put the rivet/wire system into a circuit, using one D-cell in a holder and a switch.
D. When connecting wires to the D-cell, connect to the spring closest to the terminal for the best results.
E. Always leave the switch open unless you are testing the rivet, or you might drain the D-cells.
F. See if you can use the rivet as a magnet by testing it with paper clips.
Electromagnetic Force Course, 3.2: Electromagnetism
Step 6

7. Discuss electromagnet designs
What can you tell me about your system?
What details of the design were important to get the electromagnet working?
What does wrapping the wire around the core accomplish?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 7

8. Label the components
Make a detailed illustration of your electromagnet in your notebook.
What are the components of this electromagnet circuit?
Add a label for each component on your illustration.
Electromagnetic Force Course, 3.2: Electromagnetism
Steps 8-9

9. Define electromagnet
An electromagnet is a magnet made using the flow of electricity through an insulated wire to produce a magnetic field. the magnetic field gets stronger when you wrap the wire around a piece of iron or steel, which becomes a temporary magnet when the magnetic field of the wire induces magnetism in the core.
Electromagnetic Force Course, 3.2: Electromagnetism
Step 8

10. Explore interactions
Test the interaction between a permanent magnet and the rivet head. Reverse the direction of the current flow and then test the magnet again.
Electromagnetic Force Course, 3.2: Electromagnetism
Step 10

11. Discuss magnetic force
How would you compare the magnetic force of a single wire in a circuit with an electromagnet coil?
What makes the magnetic force of the electromagnet coil so much stronger?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 12

12. FOSS Science Resources
Read “Electromagnetism” on page 38.
Electromagnetic Force Course, 3.2: Electromagnetism
Steps 13-14

13. FOSS Science Resources
Electromagnetic Force Course, 3.2: Electromagnetism
Steps 13-14

14. Discuss the magnetic field
In an electromagnet, is electricity flowing through the wire? What is your evidence?
Is electricity flowing into the core? Why or why not?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 15

15. Discuss the magnetic field
Is the core a magnet? Why or why not?
Can magnetic fields pass through materials like the plastic insulation on the wire?
What is happening to the core when the magnetic field around the core is present?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 15

16. Review vocabulary
Spend a few minutes reviewing the vocabulary for this part. Update the vocabulary index and table of contents in your notebook.
core
electromagnet
Electromagnetic Force Course, 3.2: Electromagnetism
Step 16

17. Answer the focus question
How does an electromagnet work?
Electromagnetic Force Course, 3.2: Electromagnetism
Step 17

18. Homework
Explore the online activity “Kitchen Magnets,” then look for electromagnets at home.
Electromagnetic Force Course, 3.2: Electromagnetism
Step 19

19. Wrap-Up/Warm-Up
Share your response to the focus question with someone from a different group. Take turns explaining to each other. Give each other constructive feedback and revise your entry as needed.
Electromagnetic Force Course, 3.2: Electromagnetism
Step 20

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Notebook image: © photastic/Shutterstock
Electromagnetic Force Course, 3.2: Electromagnetism