
Have you ever heard of
electromagnetism? If so, what is it? If
not what do you think it is?


Take a stroll down science history lane to
investigate the discovery of one of my
personal favorite areas of physics!
Aka learn what electromagnetism is.


In 1826 Andre-Marie Ampere discovered his
own law.
While experimenting with electrical current in
his laboratory Monsieur Ampere made a
ground breaking discovering that led to the
combination of two phenomena that were
previously thought to be separate.

His law stated that when current is moving
through a wire a magnetic field is produced.



Before his discovery we thought that magnets
were just these magical things that pointed
north all the time.
After it scientists knew that magnets were
somehow related to electricity, but they just
had no idea how or why.
So we started messing around!



In 1831 both British scientist Michael
Faraday, and American scientist Joseph Henry
made a remarkable discovery about the
interaction of wires and magnets.
Faraday published his findings first so he
received all the credit for it.
http://en.wikipedia.org/wiki/Michael_Faraday

Let’s go through Faraday’s original discovery
and his further experiments thereafter
◦
◦
◦
◦
◦
◦
◦
Original setup
Induced current
Amount of coils
Size of coils
Induced magnetic field
Magnetic field to current to magnetic field
Current to magnetic field to current



Electromagnetic Induction is the production
of a voltage across a conductor when it is
exposed to a varying magnetic field.
So moving magnets around a conductor
produces electricity.
Moving electric charges also produce a
magnetic field.

Faraday’s Law of Induction is a basic law of
electromagnetism predicting how a magnetic
field will interact with an electric circuit to
produce an electromotive force (EMF).

It is the fundamental principle of
transformers, electric guitars, inductors,
electrical motors, speakers, generators, the
modern electrical power grid, solenoids, rail
guns, electromagnets, levitating trains,
launching rollercoasters, MRI machines, and
particle accelerators.

https://www.youtube.com/watch?v=1SZaBNUqPZ
0
◦ Roller coaster

https://www.youtube.com/watch?v=9hqm9Cdkk0
◦ Navy (https://www.youtube.com/watch?v=9G6bZrleAZA)

https://www.youtube.com/watch?v=Ev0G49jXJX0
◦ Army

https://www.youtube.com/watch?v=NJUTUFA
WfEY


Which scientist discovered that a magnetic
field is produced when charge is moved
through a wire?
Which scientist discovered electromagnetic
induction and the EMF force?

Investigate the shape of different magnetic
fields.

Awesome results!
◦ Class average was a 90!!!

SLC if you scored below an 80…

When drawing magnetic field lines your
arrows should go from North to South.

Which way does a magnetic field point?

From north to south

Finish investigating the majesty of magnetic
fields.


Take a minute to read over the lab…it’s a
good one!
Once you’re done reading meet me in the
back!

What is “Electromagnetic Induction”?

Finish lab

Be able to properly draw magnetic field lines

Understand more modern applications of
electromagnetism.


Which is the best way to map a magnetic field
with a compass, or with iron filings? Why?
Both have their benefits. Compass method
will give you the direction of the field, but
iron filings will give you more magnetic field
lines.

Cow Magnet Demo


Magnetic field lines
are similar to electric
field lines
The field lines show
which way a
ferromagnetic material
will align itself.

When drawing magnetic field lines your
arrows should go from North to South.


Ferromagnetic materials have a large
susceptibility to an external magnetic field.
They exhibit a strong attraction to magnetic
fields and are able to retain their magnetic
properties after the external field has been
removed. Iron is a good example.
1.
2.
3.
Magnetic field lines go from ___ to ___.
The magnetic force acts on objects that
are…
What can people use instead of a bar
magnet to produce a uniform magnetic
field?

Demo

Can you make one?


How strong can you make an electromagnet?
https://www.youtube.com/watch?v=gzCXow
hks80
1.
2.
What can you add to a coil of wire to
increase the magnetic field it produces?
Why do we have transformers?

Opposite poles attract, this definition means
that the Earth's North Magnetic Pole is actually a
magnetic south pole.

N
Draw in the magnetic
field lines.
DO
STOP
WORK
S
N
S

N
Explain why there
are transformers on
the power lines
between your home
and that power
plant.
S
DO
STOP
WORK

Investigate electric motors and generators.

SLC this Thursday after school

Test grade sheets

Electromagnetism quiz this Friday
◦ Short, less than a mod?


10 questions
3 MC, 6 written, 1 drawing
◦
◦
◦
◦
◦
Scientists
Electromagnetic Induction, Electromotive force
Magnetic field lines
Electric motors/generators
Transformers, solenoids, railgun, speakers, etc.



Every magnet has a north and a south pole.
Even if you break a magnet in half, the two new
pieces will each have a north and a south pole.
No one has ever broken a magnet or even a piece
off of a magnet so that it only has a single pole.


As we go through these demos you will be
taking notes about the trends and discoveries
we make.
Study your notes, and lab data.


Solenoid Demos
Jumping Ring
◦ What makes the ring jump higher? Why?




Large Magnets
Electron beam deflection
Electric Motor
Electromagnets



Demos
Draw this
diagram
How fast
can it spin?

Speakers use a coil of wire and a magnet to
vibrate the cone and produce sound


What will happen to
the electron beam
when a magnet is
placed near it?
What if we use a
really big magnet?


Some of these demos
will involve high
voltages and liquid
nitrogen so any
foolishness will not be
tolerated.
If you listen to me you
will not be electrocuted
or frozen.
Liquid Nitrogen
is about-320
Degrees
Fahrenheit!


Special thanks to Mark
Stephens for supplying
us with the variable
high voltage power
supply and the liquid
nitrogen
Without him the
demos would be
boring


10 questions
3 MC, 6 written, 1 drawing
◦
◦
◦
◦
◦
Scientists
Electromagnetic Induction, Electromotive force
Magnetic field lines
Electric motors/generators
Transformers, solenoids, railgun, speakers, etc.
https://www.youtube.com/watch?v=yEYy_nVC4L
0
1. What would happen if we didn’t have this
shield?
2. What is our shield called?
3. Why is the shape of the field distorted?
4. What is the size of the field?
5. What happens to Earth when some radiation
gets through the first layer of defense?

https://www.youtube.com/watch?v=P9AZTGc
NecA
 Answer the following questions:
1. What are the benefits of space exploration?
2. Do you support space exploration? Why or
why not?


https://www.youtube.com/watch?v=XFF2ECZ
8m1A

My version
https://www.yout
ube.com/watch?v
=w7Xh28hNRBQ
1. How fast did
their railgun go?

https://www.youtube.com/watch?v=7r3FNtgOFM – 1 min
1. How did Tesla change the world we live in
today?
2. Why isn’t Tesla one of the most famous
scientists?
3. Did Tesla care more about money or helping
people? What evidence supports your claim?

https://www.youtube.com/watch?v=NJUTUFA
WfEY
1. Why does Earth need a strong magnetic
field?
2. At the current rate how long will Earth’s
magnetic field last?
