1. To make an electromagnet stronger
The 3 C’s
More Coils
More Current
Use an iron Core
Can you copy this please? 1

2. Last lesson
Field around a wire
Electromagnetism Investigation

3. Moving charges (currents)
Moving charges (electric currents) also produce a magnetic field
Conventional current – electrons flow in the opposite direction

4. Magnetic field around a straight wire
You can use the right hand screw rule to decide which direction the field goes
Stronger field closer to wire

5. Magnetic field around a straight wire
You can use the right hand screw rule to decide which direction the field goes
Can you copy this?
Stronger field closer to wire

6. “Making electromagnets Investigation”

7. To make an electromagnet stronger?

8. To make an electromagnet stronger
The 3 C’s
More Coils
More Current
Use an iron Core

9. Today’s lesson Field patterns around a wire, solenoid and coil.
The motor effect
Making a loudspeaker

10. Field around a solenoid (coil)

11. Field around a coil

12. Can you gather around Mr Porter?

13. Can you copy this sentence into your books please.
The Motor Effect
When a current is placed in a magnetic field it will experience a force (provided the current is not parallel to the field). This is called the motor effect.
Can you copy this sentence into your books please.

14. The Motor Effect
The direction of the force on a current in a magnetic field is given by Flemming’s left hand rule.
Thumb = Motion
First finger = Field direction
Centre finger = Conventional Current

15. The Motor Effect
Can you copy this please?
WITH DIAGRAM!
The direction of the force on a current in a magnetic field is given by Flemming’s left hand rule.
Thumb = Motion
First finger = Field direction
Centre finger = Conventional Current

16. Sample question
In this example, which way will the wire be pushed? (red is north on the magnets)

17. Sample question
In this example, which way will the wire be pushed? (red is north on the magnets)
Current
Field

18. Can you gather around Mr Porter?
Again?! 18

19. Building a loudspeaker
These also use the motor effect
Coil in here
magnet

20. Let’s read!
Pages 210 and 213. The answer the questions on all pages. Finish for homework due 15th October