Download Magnetism - Miss. Shannon`s Grade 5 Class

MAGNETISM
Grade 5
HOW ARE ELECTRICITY
AND MAGNETISM
RELATED?
USES OF ELECTRICITY AND MAGNETISM:
NATIONAL GEOGRAPHIC
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Video
ELECTROMAGNETIC FIELD
Electromagnetic fields are everywhere around us.
 An electromagnetic field is an invisible magnetic force
that exists around any conductor that is carrying
electricity.
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ELECTROMAGNETIC FIELD
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What do you think happens to the
electromagnetic field if the voltage is stronger?
Electromagnets (click for hyperlink)
ELECTROMAGNETIC FIELD
Magnetism is “mediated” by the magnetic field
An electric current creates a magnetic field, and that field
impacts magnetic forces on other particles that are in the
field
In the picture above, the force of the bar magnet is shown by
irons fillings on a piece of paper.
If we used a stronger magnet, what would happen to the
iron fillings?
ELECTROMAGNETS
Electromagnetism is created in a metal by the
flow of electrons through a coil of wire wrapped
around the metal.
 The moving electrons emit a field that causes the
electrons in the metal to “line up.”
 This creates a temporary magnet.
 As soon as the current stops flowing, the
magnetic effect is removed.
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ELECTROMAGNETS
 Electromagnets
are found in:
power door locks on vehicles
 computers
 electric motors
 coils that produce the picture in television
tubes
 cell phones
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MAGNETISM AND OUR WORLD
Magnets impact our lives in many ways…. Lets
learn how!
MAGNETISM AND OUR WORLD
Topics of investigation:
1) Earth’s Magnetic Field
 2) Magnetic Compass
 3) Magnetic levitation
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1) EARTH’S MAGNETIC FIELD
Our planets magnetic
field is generated deep
in the Earth’s core
 At the center of the
Earth is a solid inner
core
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Made of: Iron
Size: almost as large
as the moon
Temperature: 5,700°C
Pressure: very high
due to force of gravity
State of matter: solid
2) EARTH’S MAGNETIC FIELD
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Surrounding this is
the outer core
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Made of: Iron, nickel,
and smaller quantities
of other metals
Size: 2,000km
Temperature: 3,700°C
Pressure: lower
pressure than the
inner core
State of matter: fluid
2) EARTH’S MAGNETIC FIELD

What is caused by the
differences in
temperature,
pressure, and
composition?

Share ideas with a
partner!
What do we know
about:
 Cool and dense
matter?
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Warm and less dense
matter?

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Sinks!
Rises!
This creates
convection currents!
2) EARTH’S MAGNETIC FIELD
Convection Currents
are caused because of
the differences of
temperature,
materials, and
pressure of the inner
and outer core
 This flow of liquid iron
generates electric
currents, which
produces magnetic
fields
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2) EARTH’S MAGNETIC FIELD
Charged metals pass
by each other which
creates electrical
currents of their own
 The cycle then
continues
 This self-sustaining
loop is known as the
geodynamo
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2) MAGNETIC COMPASS
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What is a compass?
No matter where on
earth you stand, you
can hold a compass in
your hand and it will
point toward the
North Pole
2) MAGNETIC COMPASS
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How does a compass
work?
Think of the Earth has
having a gigantic
magnet buried inside
The South end of the
magnet is buried at the
North Pole
Using the “opposites
attract” rule, this causes
the north end of the
compass needle to point
up
3) MAGNETIC LEVITATION
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How many forms of
transportation can
you think of?
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Airplanes
Feet
Cars
Buses
Bike
Boats
Train
Order these from
fastest to slowest
3) MAGNETIC LEVITATION
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Fastest to slowest:
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Airplanes
Train
Cars
Boats
Buses
Bike
Feet
Order these from most
to least energy
efficient
3) MAGNETIC LEVITATION

Most energy efficient
to least energy
efficient
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Bike
Foot
Train
Boats
Plane
Car
Bus
3) MAGNETIC LEVITATION
What mode of
transport is fastest
and most efficient?
 Train!!
 Electromagnets are
being used to develop
high-speed trains
 These are called
maglev trains
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3) MAGNETIC LEVITATION
Maglev is short for
magnetic levitation
 These trains float over
a track
 The principles of
magnetism make this
possible!
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3) MAGNETIC LEVITATION
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There are three
components to this
system:
A large electrical
power source
 Metal coils lining a
track
 Large magnets
attached to the
underside of the train
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3) MAGNETIC LEVITATION
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How it works:
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The large magnets repel
each other
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This allows the train to
levitate 1 to 10 cm
Then power is supplied
to the coils in the track
walls
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This creates a magnetic
field that pulls and
pushes the train
The magnetic field in
front of the train pulls it
forward
The magnetic field
behind pushes it forward
What cities currently have a
Maglev train?!
HOMEWORK
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