Magnetism
description
Transcript of Magnetism
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MAGNETISM
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“e-bomb” video (1:19) http://www.howstuffworks.com/electromagn
et.htm
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all magnets have two opposite magnetic poles, called the north pole and south pole
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atoms can act like tiny magnets permanent magnets have their atoms
aligned creating the magnetic forces
atoms in non-magnetic materials, like plastic, are not free to move or change their magnetic orientation
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iron filings demo here
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a compass or iron filings are a great way to “see” magnetic field lines
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Earth has a magnetic field that comes from the core of the planet magnetic North and geographic
North are ~1,000 km apart poles reverse about every .5 million
years
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gauss is the unit of measurement for magnetism, so is tesla
10−9–10−8 gauss: the human brain magnetic field
.5 gauss: Earth's magnetic field on its surface 50 gauss: typical refrigerator magnet 100 gauss: a small iron magnet 15,000-30,000 gauss: a medical magnetic
resonance imaging electromagnet (MRI)
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Electromagnets created when
conductive wire, usually copper, is wrapped around a piece of metal
can change the strength AND turn on and off
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Applications/uses maglev trains
http://dsc.discovery.com/videos/extreme-engineering-season-1-shorts-maglev-train.html
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MRI machines
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construction/wrecking yards
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electric motors permanent and electromagnets work
together in order to convert electrical energy into motion
the outside electromagnet reverses back and forth to keep the permanent magnets moving
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generators opposite of electric motors
transforms motion into electrical energy
a moving magnet can produce an electric current in a coil of wire Phet
http://phet.colorado.edu/en/simulations/category/physics/electricity-magnets-and-circuits