Download It must have domains (north and south poles) The

Magnetism
CH 5 – Electricity and Magnetism
1
2
3
Magnetism

Describes all phenomena caused by
magnets

A magnet is an object that can attract
other objects that contain iron, cobalt
or nickel

How do they work? It’s… complicated

Quantum physics and electron spin and
magnetic dipole moment
The short answer? Basic property of
certain substances

4
5
Magnetism Notes
In order for a substance to be considered magnetic it
must have 2 criteria:

1.
2.
6
It must have domains (north and south poles)
The domains must be aligned
Magnet Rules
1.
2.
3.
4.
7
Has a north and south pole
Opposite poles attract, same
poles repel
If you cut a magnet in half,
each piece has a north and
south pole
The more distance between
two poles, the weaker the
force will be (attraction or
repulsion)
Notes

By convention, the north pole of a magnet corresponds
to the end that naturally turns towards the Earth’s
magnetic pole that is nearest to the Earth’s North Pole

So technically speaking… the Earth’s North pole is
‘magnetically a south pole’

8
Confusing…
Magnetic Fields
https://phet.colorado.edu/en/simulation/legacy/magnetand-compass

9
10
Magnetic Fields

A magnetic field is the area around which the effects of a
magnet are felt by another magnet

A magnetic field always travels from North to South
poles and can travel in all directions as long as there is
attraction or repulsion
11
Example 1
12
Example 2
13
Example 3
14
Example 4
15
Example 5
16
17
Magnetic Shield

https://www.youtube.com/watch?v=URN-XyZD2vQ
18
19
Earth’s Magnetic Field

Inside the Earth’s surface there is a huge amount of
ferromagnetic liquids. These liquids are constantly in
motion around a solid iron core and produce a massive
magnetic field which can be felt anywhere around the
world
20
21
Poles Reversing

https://www.scientificamerican.com/article/earth-smagnetic-field-flip-could-happen-sooner-than-expected/
22
23
Magnetic Field of a Live Wire


Electrons flowing through a wire generates a magnetic
field
Right Hand Rule

Gives us current direction (which way the electrons are
flowing) and magnetic field direction

Thumb: points to current direction (-) (electrons /
electricity flows from + to -)
Fingers: curl in the magnetic field direction (N to S)

Fingertips are like the N part of the compass

24


Thumb: points to current direction (-) (electrons /
electricity flows from + to -)
Fingers: curl in the magnetic field direction (N to S)
25
26
Arrow Notation

Thumb Points Away From Paper

Thumb Points Into Paper
27
28
29
30
Ferrofluid

https://www.youtube.com/watch?v=3CgKmfInv_k
31