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 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 8

9. V. Magnetic Field Lines
Like Poles 9

10. VI. Magnetic Field Strength (Magnetic Flux)
V. Magnetic Field Lines
Unlike Poles
VI. Magnetic Field Strength (Magnetic Flux)
Field is strongest where lines are ___________
( )
Earth’s Magnetic Field (7 min)
MOST DENSE
CLOSEST TOGETHER 10

11. 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 11

12. VII. Magnetic Fields Created by Current Carrying Wires
Note: Farther you move away from wire, weaker the magnetic field 12

13. VIII. Charge Moving through a Magnetic Field
When a charged object moves through a magnetic field its experiences a ___________
This is the principle behind _______________ and __________________
MAGNETIC
FORCE
TELEVISIONS (video)
PARTICLE ACCELERATORS 13

14. IX. Current-Carrying Wire in Magnetic Field
When a current-carrying wire is placed in a magnetic field it also experiences a
 ________________
This is the principle behind ______________ and ___________________
MAGNETIC FORCE
ELECTRIC MOTORS
SPEAKERS
How a speaker works 14

15. X. Inducing a Current in the wire current creates generators
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 _______
Principle behind _______________ and _______________________
in the wire
current
creates
generators
power plants 15

16. XI. 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 16

17. XII. 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 17