The Rail Gun - University of California,...
Transcript of The Rail Gun - University of California,...
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The Rail Gunaka the Slide-wire Generator
Maria Chiara Simani (UCR ALPHA Center)
& Owen Long (UCR Department of Physics)
Copernicus SSI 07 - Follow-up, Nov. 6th 2007
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Slide-wire generator: How does it work?
• A changing magnetic flux creates an electricfield and vice versa
Examples you already know:
• Speakers/microphone• Wind-powered generator• Seismometer
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Slide-wire generatorB field out of screen
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F F
Area becoming larger => increasing magnetic flux
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F−
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−F
Area becoming smaller => decreasing magnetic flux
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Slide-wire generatorUnfortunately, induced voltage too small to bedirectly detected with PASCO probe.
Some options:
• Build amplifier to increase signal (instructionsare available on the Seismometer Web Pages)• Buy sensitive multimeter• Add more magnets to increase B
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Rail gun and magnetic forceB field pushes (sideways!) on moving charges.
m
Mass on the end of a ropeswinging in a circle.
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Negative charge moving in a Bfield coming out of screen.
B pointing outof screen
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Rail gun and magnetic force
The Aurora: charged particles fromthe solar wind spiral along theearth’s B field lines. Collisions withatoms in the atmosphere excite theelectrons, which emit light when thede-excite to lower energy levels.
B fieldlines
Charged particlesfrom solar wind
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Rail gun physics
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Battery
B field into screen
B field into screen
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F
Battery drives a current through the sliding bar.The moving charges inside the bar get pushedsideways by the magnetic force.
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Rail gun parts and tools
Parts list• Section of 2x4• Screws & washers• Metal coat hanger• 1 or 2 6V lantern batteries• Strong magnets• Aluminium (not steel!) tube• Alligator clips
Tools list• Drill for drilling holes in 2x4• Screw driver