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Q & A: What a mirror does to faces

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Most recent answer: 10/22/2007
Q:
One of my students is doing a Science Fair project and needs an answer to the following: Why, in a mirror, are words and letters reversed but not faces?
- Anne Marie Goetz-Rapcewicz
Pope Paul VI, Canada
A:
The anwer to your question is that a mirror does exactly the same thing to all objects, so it really DOES "reverse" your face as well as letters.

Suppose your friend writes a word on your forehead, for example the word MIRROR. If your friend wrote big enough, the first letter M would be over your right eye and the last letter R would be over your left eye. Now look in a mirror. You would see your face appearing normal, and the word would seem to be reversed.

The fact is, however, that your face is reversed also...you are just used to seeing it in a mirror so it looks normal to you. To convince yourself of this, pretend the image in the mirror is a stanger looking at you. You would say that the letter M is over the stranger's left eye (on the right side as viewed by you) and the letter R is over the right eye...the reverse of what you know is really true.

Another way to check this is to hold out your right hand toward the mirror...it looks like your image is holding out it's left hand. You can never shake hands with the image in the mirror since they will always hold out the "opposite" hand you are. This is further proof that the image is reversed.

Hope this helps.

MS

(published on 10/22/2007)

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