WEBVTT - How Rearview Mirrors Work

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<v Speaker 1>Welcome to brain Stuff from how stuff Works dot com

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<v Speaker 1>where smart Happens. Hi, I'm Marshall Brain. Have you ever

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<v Speaker 1>used the glare resistance setting on your car's rear view

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<v Speaker 1>mirror and wondered what's going on? How can the same

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<v Speaker 1>piece of glass have two different amounts of reflection. If

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<v Speaker 1>you stand in front of a normal window in your

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<v Speaker 1>house at night, inside the house with the indoor lights on,

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<v Speaker 1>you'll be able to see your reflection in the glass

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<v Speaker 1>quite clearly. A car's mirror takes advantage of that same effect.

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<v Speaker 1>The mirror in your car isn't ground flat. The front

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<v Speaker 1>glass surfaces at an angle to the back mirrored surface,

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<v Speaker 1>so if you were to look at this mirror out

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<v Speaker 1>of its casing, it would be wedge shaped, with the

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<v Speaker 1>thicker edge up at the top. When you flip the mirror,

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<v Speaker 1>the back mirrorred surface usually points towards the dark ceiling,

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<v Speaker 1>so you don't see that image. What you see instead

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<v Speaker 1>is the image reflecting off the front of the glass,

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<v Speaker 1>and this is much dimmer than the pure reflected image,

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<v Speaker 1>so it doesn't hurt your eyes. Be sure to check

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