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Author Topic: Why do mirrors appear to reverse images?  (Read 1520 times)

Offline thedoc

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Why do mirrors appear to reverse images?
« on: 27/06/2014 18:30:01 »
Derek asked the Naked Scientists:
   
Why do mirrors appear to only reflect by reversing an image left to right, but not up to down?
What do you think?
« Last Edit: 27/06/2014 18:30:01 by _system »


 

Offline McKay

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Re: Why do mirrors appear to reverse images?
« Reply #1 on: 27/06/2014 23:42:38 »
They dont reverse anything. They reflect exactly as it is.
Think about it: light from your left arm travels straight to the mirror, reflects from the point of "impact" and you see your left hand.. on the left side of the mirror.
Light from the top of your head does the same and you see the top of your head at the top of the mirror..

It is way more creepy to look at myself in a live, frontal webcam feed from my own computer.
« Last Edit: 27/06/2014 23:44:55 by McKay »
 

Offline syhprum

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Re: Why do mirrors appear to reverse images?
« Reply #2 on: 28/06/2014 09:01:13 »
Because your eyes are separated in a horizontal line, lie on your side and you will think you have an up-down reversal.
 

Offline McKay

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Re: Why do mirrors appear to reverse images?
« Reply #3 on: 28/06/2014 11:10:29 »
Because your eyes are separated in a horizontal line, lie on your side and you will think you have an up-down reversal.

Umm, no. It really has nothing to do with it. The "illusion" works with one eye :D
Like I said, mirrors dont actually reverse anything - your left is still at the left side of the mirror.
You may think of the mirror image of you as a sort of a projection of you. You see the image-you from its back, not front, but it has texture that makes it seem like the image-you is looking outside the mirror, swapping left and right.
 

Offline David Cooper

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Re: Why do mirrors appear to reverse images?
« Reply #4 on: 28/06/2014 21:04:07 »
Mirrors do reverse things, but front to back. The top stays at the top and the left stays to the left, but what is behind you can now be seen in front of you in the mirror.
 

Offline chiralSPO

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Re: Why do mirrors appear to reverse images?
« Reply #5 on: 03/07/2014 17:53:29 »
Mirrors show a reflection of the image (this is not meant to sound condescending)--everything is reversed. When compared to a 180 rotation, a reflection appears to switch which sides things are on from one side of the rotational axis to the other. Because of our experience, we primarily think about rotating about the axis that goes from our head to our feet (turning left or right)--a rotation about this vertical axis switches right and left as compared to a reflection. If we grew up in space or under water, we would probably also be used to rotation about other axes. If you were to rotate 180 about an axis that goes through your hips (left to right or right to left), that would flip you upside-down with respect to the reflection (apparently inverting top and bottom, while retaining left/right directionality). Rotation through the axis perpendicular to the first two I mentioned would keep you facing the mirror, and there would be no change in perception there (but you would still be upside-down).
 

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Re: Why do mirrors appear to reverse images?
« Reply #5 on: 03/07/2014 17:53:29 »

 

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