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Published byCora McCoy Modified over 9 years ago
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Light Polarization
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These three are the same… Light *pure energy Electromagnetic Waves *energy-carrying waves emitted by vibrating electrons Photons *particles of light
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Polarization Light: Waves in only one direction Not polarized light: waves in random scatter
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Blue sky has some glare or polarization
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How do we make Polarized Light?
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Light Polarization Parallel, crossed, 45 degrees (100%, 0%, 70%) Each Polaroid pick only 1 direction of light
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What is crossed? Two polaroid filters at 90 degrees to another No light gets through First vertical filter blocks horizontally polarized light Second horizontal filter blocks remaining vertical light
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How do we make Polarized Light? I. Polarizers- Polarizers are made of long chained molecules which absorb light with electric fields perpendicular to the axis.
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How do we make Polarized Light? II. Reflections off non-metals
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How do we make Polarized Light? III. Refraction- -light bending -some calcite minerals
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How do we make Polarized Light? II. Reflections off non-metals
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What happened to that blue sky?
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Less and less b lue
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No blue left if look long ways across sky like at sunrise and sunset
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Space=dark=no air to scatter light
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Polarized sunglasses Most road glare is horizontally polarized
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Polarized 3-d glasses (weaker effect if use different colors/prisms)
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Check your understanding Suppose that light passes through two Polaroid filters whose polarization axes are parallel to each other. How does the final light compare to the original? A. 100% of original B. ½ light C. ¼ light D. no light
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Check your understanding Light becomes partially polarized as it reflects off nonmetallic surfaces such as glass, water, or a road surface. The polarized light consists of waves vibrating in a plane that is ____________ (parallel, perpendicular) to the reflecting surface. A. Parallel b. perpendicular
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Check your understanding Which sunglasses work best for glare A. both vertically polarized b. both horizontally polarized C. one side of each D. dark shades unpolarized
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Demos: projector light corn syrup plastic ruler scotch tape polaroid films cell phone display glare on windows/clock computer screen
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