It's an old riddle, with a subtle answer. Richard Feynman gave an account of his days at Princeton, where freshman were often accosted by sophomores with such questions. Part of Feynman's genius was figuring things out in advance, so that he seemed to have the answer to impossible questions almost instantly.
Hint to the answer - when you look at your image in the mirror, what is hidden from view?
Update August 15, 2016: Mathologer (a YT channel that I just discovered and to which you should all subscribe, if you love math) has a detailed video on this
It does not reverse things. It is all perspective.
I used to ask that to my physics students. To me the answer is obvious but I can't put it into words.
We don't see our backs. But you would actually see yourself reverse if you'd be standing on a mirror placed on the floor. :-)
To confuse people. Obviously, it works.
When we look into a mirror we don't see the opposite side of our body and what is directly behind us and close to us.
Uh the back? I cannot see my back. I cannot see the back of the mirror, but I don't see how that plays into any answer.
It's a reflection.
REFLECTION? Here is the answer and there is a nice song to read while you read the answer.
Winged WHAT ARE YOU SAYING? Are you Donald Trump now? You know, but you are not going to TELL anyone?
That is what the ANSWER is for. You are supposed to ANSWER so EVERYBODY can see the ANSWER.
Yes, perspective is one aspect of it, but it does show a reversed image.
Very nice, that's totally correct, we don't see our backs. Why? And that's an excellent point about the mirror lying on the floor. That's another clue to the answer. :)
Yeah, it's confusing, for sure. So if we don't see the opposite side of our body, what exactly is reversed?
So, if we don't see our backs in the mirror, what does that tell us? Something is clearly reversed here, and although it appears that writing is reversed left to right, for example, how does that work exactly?
The answer is simply put into words, when you notice exactly what is reversed. We know it's not up/down, and although it appears to be left/right, that's not exactly it either. So what direction remains?
Thanks, this will bother me until it's explained, but I'm not looking anything up. So, I'll just guess. To answer the question, the back of the mirror is hidden from view. A mirror is not a lens. Or something.
LOL, I know what you mean, about seeing an ass in the mirror. Sometimes, I don't want to even look at myself! But actually, the ass is just what you don't see, normally (hint hint)... ;-)
It is indeed!
Nothing's reversed. If I turned around, my left is my left and my right would be right.
Yes, that's true, the back of the mirror is hidden, but I was referring to what is hidden in the mirror image. I think this gives a clue as to how the image is actually reversed.
No the image is not reversed.
I don't know the scientific explanation, but the way I see it is that when I'm looking in a mirror it is as if I am facing myself. I am seeing myself as another person facing me would see me.
You must have a big mirror. A good mirror.
LOOLOL
I SAID read my site. Do you think I am smart? Please. Don't expect that from me too.
Then how do you explain how writing appears backwards to us in a mirror? "Perspective" describes how apparent sizes change with distance, so I don't think it applies to this phenomenon. Whether the letters on a page appears big or small, they do appear to be reversed in a mirror.
Haha OK, I didn't see the link. That pretty much covers it.
Not quite. If it were an exact copy of yourself, facing yourself, then when you raised your right hand, the copy would raise its right hand also. But what you see is the image raising its left hand, when you raise your right. So this "copy" of you appears to have a subtle, but very distinct difference to yourself.