1. Introduction to Magnetism
Goal: I can explain basic magnetic phenomena as it appears in the real-world

2. Introduction to Magnetism
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Introduction to Magnetism
Magnets
Naturally occurring magnets are known as Iodestone
Magnetic Fields
Similar to electric fields
Force of attraction/repulsion caused by dipoles
Two defining characteristics:
Magnetic fields occur naturally in substances that have magnetic character (internal make-up)
Can effect not only other magnetic substances, but also electric charges

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Magnetic Character
Related to the condition of the atoms in the material
Not fully understood
Domain Theory
All large magnets are made up of many magnetic regions called domains
The magnetic character of domains comes from the presence of even smaller units called dipoles
Dipoles are called North and South
Dipoles interact with their neighbouring dipoles
If they align with all of the poles in one direction, then a larger magnetic domain is produced

4. Example: a diagram of domain theory
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Example: a diagram of domain theory
Materials that allow for the dipoles to be aligned to create a greater magnetic character are known as ferromagnetic materials (i.e. nickel, iron, cobalt)

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Law of Magnetic Forces
Similar magnetic poles repel each other with a force
Dissimilar magnetic poles attract each other

6. Magnetic Phenomena Magnetic Induction
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Magnetic Phenomena
Magnetic Induction
Ferromagnetic materials can be magnetized
Permanent and Temporary Magnetism
Some materials demagnetize easily, others maintain their magnetic domains
Reverse Magnetism
A magnet can have its polarity reversed
Breaking a Large Magnet
Can create smaller active magnets
Maximum Strength
There is a limit to how strong a magnet can be

7. Sketching Magnetic Fields
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Sketching Magnetic Fields
The number of field lines drawn are proportional to the strength of the field
The direction of the field is defined by the direction the north pole of the test magnet would point