I Didn’t Know That. . .

Q: Why is an image in a mirror inverted left to right but not top to bottom?

A: In fact, mirrors do not invert images from left to right either, only from front to back. If you stand in front of a mirror and point to the right, your image points in the same direction. If you point up or down, the image does the same. Only when you point in the direction of the mirror is the image reversed--in this case, pointing back at you.