Buzz
A person stands before a mirror. The individual is positioned on the right, but in the reflection, the person is on the left.This question often arises when people are wearing a T-shirt in front of a mirror. For example, imagine you're wearing a shirt with a message on it while brushing your teeth. Why does the writing on your T-shirt appear reversed in the mirror, but your head is still the right way up? Why is it that mirrors only seem to flip things horizontally? Stand in front of a mirror in a restroom and give it some thought...
For example, here’s a picture of someone in a How Stuff Works T-shirt standing in front of a mirror. The shirt reads "I Gotta Know...", and as you can see, the reflection shows the text flipped:
A simple way to grasp this concept is to hold a piece of paper with your name on it and view it in the mirror. It will appear reversed. Now turn it vertically. The letters are still reversed, but not upside down. This should give you a hint about what’s going on. Next, point to the first letter in your name, both on the paper and in the mirror. You’ll notice that the letters match up one-to-one — if the letter is on the left of the paper from your view, it also shows up on the left side of the mirror.
Take a piece of thin, transparent paper and write your name on it. Position yourself in front of a mirror and hold the paper in a way that lets you read it easily. Now, gaze into the mirror. What you see is the back of the translucent sheet, and the text remains upright -- it appears as normal. Then, flip the paper over and observe it through the mirror. The text is now reversed, but so are the letters on the opposite side of the paper. This happens because you have flipped the paper over -- essentially reversing it!
To put it another way, the reason why letters appear reversed in a mirror is that you present them to the mirror in reverse. This is also why a person approaching you can read the message on your T-shirt -- the letters on your T-shirt appear reversed from your point of view. If the words were printed on the inside of the shirt so you could read them, they would look backward to someone coming toward you, but perfectly readable in a mirror.
