Download Electricity and Magnetism

Electricity and Magnetism
Electricity and Magnetism
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What is a Magnet?
North and South Poles of a Magnet
Types of Magnets
The Earth as a Magnet
Electromagnets
Electromagnetic Induction
Motors
Generators
What is a Magnet?
An object that is
surrounded by a
magnetic field and has
the property of attracting
iron or steel
Where are Magnets?
Magnets. . .
Generate
electricity
Image courtesy of DOE/NREL
Are in motors
Image courtesy of DOE/NREL
Where are Magnets?
Magnets. . .
Power car
windows & locks
Are used in Magnetic
Resonance Imaging (MRI)
Image courtesy of NASA
North and South Poles of a Magnet
Magnets have a north and south pole.
• If a magnet is broken into smaller pieces, each
piece will still have a north and south pole.
• Opposite poles attract, like poles repel.
N
N
S
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N
S
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N
Types of Magnets
Magnets in Nature
Magnetite is a mineral that is naturally
magnetic.
Human-Made Magnets
Some materials can be magnetized
when placed near a strong magnetic
field.
Soft magnetic materials (Iron)
Hard magnetic materials (Cobalt,
Nickel)
Electromagnets
Magnets can be made by passing a
current through a coil of wire.
U.S. Geological Survey / photo by Andrew Silver
The Earth as a Magnet
The Earth is a large magnet.
Compasses work as a result
of the Earth’s magnetic field.
Electromagnets
Magnets are created by passing a current
through a wire.
Electromagnets are generally wire wrapped
around an iron core.
Electromagnets are turned on and off when
the current is switched on and off.
Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved October 20, 2008, from
http://office.microsoft.com/en-us/clipart/default.aspx
U.S. Geological Survey Photographic Library (USGS). (2006). Retrieved
October 20, 2008, from http://libraryphoto.cr.usgs.gov/index.html
National Renewable Energy Laboratory (2008). Photographic information
eXchange. Retrieved October 21, 2008, from
http://www.nrel.gov/data/pix/searchpix.html