1. Unit 12
Magnetism

2. I. Applications of Magnetism
Credit cards, electric motors, MRI scanning, Maglev Trains, car alternator 2

3. II. Review of Electric Field
Electric Field - Created by objects that have a _________
charge
Electric Force - Experienced by charges within an ____________
electric field
What happens if the charges are moving…? 3

4. The ___________ of __________ particles creates a _____________ MOTION
III. Cause of Magnetism
The ___________ of __________ particles creates a _____________
MOTION 
CHARGED 
MAGNETIC FIELD 
A. Magnetic Domains:
ALIGNED ATOMS
Clusters of ________________
Each domain is perfectly magnetized and is made of billions of aligned atoms 4

5. Becomes a magnet when domains line up.
III. Cause of Magnetism
Becomes a magnet when domains line up. 5

6. B. Ferromagnets: Naturally Occuring Magnets
III. Cause of Magnetism
B. Ferromagnets: Naturally Occuring Magnets
Examples:
Iron, Nickel, Cobalt, magnetite
Created by:
1. Leaving ferromagnetic material in a strong magnetic field
2. Running an electrical current through a conductor 6

7. Every magnet has two poles: Called North and South
IV. Laws of Magnetism
Every magnet has two poles: Called North and South
2. Like poles repel ( N near a N or S near a S)
 And opposite poles attract ( N near a S)
3. Magnetic poles on a magnet cannot be separated 7

8. V. Magnetic Field Lines N S Characteristics:
Magnetic field lines form loops around magnet
2. Lines go from North to South
3. Closer the field lines are, stronger the magnetic field is
4. Lines NEVER OVER LAP N S 8

9. V. Magnetic Field Lines
Like Poles S N N S 9

10. VI. Magnetic Field Strength (Magnetic Flux)
V. Magnetic Field Lines
Unlike Poles N S N S
VI. Magnetic Field Strength (Magnetic Flux)
Field is strongest where lines are ___________
( )
MOST DENSE
CLOSEST TOGETHER 10

11. Earth’s Magnetic Field (7 min)
V. Magnetic Field Lines
Earth’s Magnetic Field (7 min) 11

12. VII. Magnetic Fields Created by Current Carrying Wires
A current carrying wire carries _____________, therefore it creates a _________________
Oersted Demo
Bose Electromagnetic Suspension
(never used due to cost and weight)
CHARGES (e-)
MAGNETIC FIELD 12

13. VII. Magnetic Fields Created by Current Carrying Wires
Note: Farther you move away from wire, weaker the magnetic field 13

14. VIII. Force on a Current in a Magnetic Field
Current carrying wire are essentially _______________
B. Moving electrical charges experience a ________________ if placed in a __________________
MOVING ELECTRICAL CHARGES
MAGNETIC FORCE
MAGNETIC FIELD 14

15. VIII. Force on a Current in a Magnetic Field
Jumping wire demo 15

16. VIII. Force on a Current in a Magnetic Field
C. Direction of Force (LHR)
Thumb points in direction of __________
Fingers point in the direction of __________
Palm points in the direction of ___________
Jumping wire demo
Current (e-)
Magnetic Field
Magnetic Force 16

17. IX. Inducing a Current
A current in a wire produces a magnetic field surrounding the wire.
Question: Can a magnetic field cause a current to be induced in a wire?
Conceptual Development: phet simulation
Electrons in the wire experience a magnetic force and are pushed _________________
Movement of the electrons _____________ a _______
in the wire
induces (creates)
current 17

18. X. How do we create this Current (Faraday's Law)?
1. Move a coil in and out of a magnetic field
2. Rotate a coil in a magnetic field
3. Vary the intensity of the magnetic field 18

19. XI. How do we gain Maximum Current
1. Wire must be perpendicular to field
2. Increase number of coils of wire
3. Increase speed of wire or magnet
4. Increase the strength of magnetic field 19

20. XII. Magnetic Forces on Charged Particles
Moving charges ____________
If a charged particle moves through a magnetic field, it will experience a ___________________
Cathode Ray
Tube TV with
Magnet Deflection Demo
(1 min)
CREATE MAGNETIC FIELDS
MAGNETIC FORCE 20

21. A. Direction of Magnetic Force (Right Hand Rule)
magnetic field
1. Point fingers in the direction of _____________________
2. Point thumb in direction of _______________________
3. Palm points in the direction of ____________________
moving + charge
magnetic force
**NOTE**
For __________ charges, use _______ hand (force is in the ___________ direction)
negative
left
opposite 21

22. 1. Charge must be _________________
Rules:
1. Charge must be _________________
Velocity of moving charge must have a component _______________ to the direction of the __________________
moving perpendicular
perpendicular
magnetic field 22

23. XIII. Magnetic Field in 3D23