1. Magnetism Chapter 5 (404) p.164-168

2. What is Magnetism?
The magnet is surrounded by an invisible force field.
All magnets have a North and South POLE
Each magnet is made up of domains. They act like tiny magnets. Draw the following picture.

3. Attraction & Repulsion
Like magnetic poles repel and unlike magnetic poles attract.

4. Definitions:
Magnetic Substance: A material that acts like a magnet.
Ferromagnetic Substance: A material which is not a magnet but is attracted by a magnet. (ex. Nickel, iron)
Non-Magnetic Substance: It’s a material not attracted or repelled by a magnet. (ex. Glass, plastic, wood)

5. Magnetic Fields(404)
All magnets have a magnetic field. A magnetic field is the space around a magnet where a magnetic force is felt.
A magnetic field can be represented by field lines.
The strength of the magnetic field is greater where the lines are closer together and weaker where they are farther apart.

6. These lines are a map of the magnetic field around a bar magnet
These lines are a map of the magnetic field around a bar magnet. These lines are called lines of force.

7. LINES OF FORCE (404) Lines of force show you the shape, direction and strength of the magnetic field. 1) Lines of force NEVER cross each other 2) Lines of force always go from NORTH to SOUTH. 3) Lines of force are more concentrated at the poles.

8. If you cut a magnet into smaller pieces, each smaller piece is a magnet with a North and South pole.

9. ELECTROMAGNETISM (404) When a current is run through a cylindrical coil of wire, a solenoid, it produces a magnetic field. The solenoid is known as electromagnet.

10. Magnetic Field of a Live Wire (404) A magnetic compass shows the presence and direction of the magnetic field around a straight current-carrying wire.

11. Use (A) a right-hand rule of thumb to determine the direction of a magnetic field around a conventional current and (B) a left-hand rule of thumb to determine the direction of a magnetic field around an electron current.

12. ELECTROMAGNETS (466)
You can transform a solenoid into an electromagnet by inserting a core (ferromagnetic substance) inside the solenoid.
The power of the electromagnet can be increased in 3 ways:
1) increase the intensity of the electric current
2) add more loops to the solenoid
3) by changing the core