# The Naked Scientists Forum

### Author Topic: How does a mirror work?  (Read 11058 times)

#### MikeS

• Neilep Level Member
• Posts: 1044
##### Re: How does a mirror work?
« Reply #25 on: 13/01/2012 09:49:47 »
I think the best explanation of how a mirror works was made by Richard Feynman.  I believe the explanation is covered in his video lectures available here
http://vega.org.uk/video/subseries/8

#### FredL

• Jr. Member
• Posts: 12
##### Re: How does a mirror work?
« Reply #26 on: 17/01/2012 01:30:45 »
Sorry for butting in but---I just want to know---why does a mirror reverse things left and right but not up and down and how does it know the difference?

#### burning

• Full Member
• Posts: 71
##### Re: How does a mirror work?
« Reply #27 on: 17/01/2012 03:10:54 »
Sorry for butting in but---I just want to know---why does a mirror reverse things left and right but not up and down and how does it know the difference?

Keep in mind that "right" and "left" are concepts defined relative to an individual, while "up" and "down" are concepts defined relative to the surface of the Earth.  This is, I think, where most of the confusion comes from in this question.  You can just as easily ask "When I'm talking face-to-face with someone, why do we agree on which directions are up and down but disagree on which directions are left and right?"

To see what's really going on in a mirror, you need to think about directions that are on the same footing.  So for the sake of argument, let's suppose you have a mirror on the north wall of your house.  When you look at yourself in the mirror, your up and down are your image's up and down, your east and west (directions on the same relative footing as up and down) are your image's east and west, but your north is the mirror's south and vice versa.

#### Geezer

• Neilep Level Member
• Posts: 8328
• "Vive la résistance!"
##### Re: How does a mirror work?
« Reply #28 on: 18/01/2012 01:26:27 »
Fred,

The reason it works that way is because the mirror does not actually reverse anything. The image in a mirror is a true reflection of reality. Relative to you, up is up and right is right.

When you look at a photograph, the image in the photograph was taken from a completely different position in space, so what you see is relative to that position in space.

#### Don_1

• Neilep Level Member
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• A stupid comment for every occasion.
##### Re: How does a mirror work?
« Reply #29 on: 18/01/2012 12:34:36 »
The image in a mirror is a true reflection of reality.

WHAT??? No, no, no. This can't be true......

#### The Naked Scientists Forum

##### Re: How does a mirror work?
« Reply #29 on: 18/01/2012 12:34:36 »