Why do mirrors reverse left and right but not up and down?
In: Physics
They don’t reverse anything left to right (or up and down).
You’re thinking of a word printed on a shirt, and when you stand in front of the mirror it looks ‘backwards’ to you. It’s your perception that makes it seem as though it’s flipped around, but it’s actually you who is flipped around relative to the shirt.
To prove to yourself that things aren’t actually flipped around, think about the rear-view mirror in a car. When you look in the mirror the driver in the car behind you is still on the driver’s side of the car (i.e. on the left side of the mirror, if you live in most of the Americas or continental Europe).
All the mirror is really reversing is *depth* relative to the mirror. Things that are closest to the mirror appear closer to you, in the mirror, than things that are further from the mirror.
Here’s a fun little experiment you can try at home, if you have something clear like a transparent plastic sheet to write on: write a word on that sheet, then hold it in front of you so that you can read it. It will appear in the exact same orientation in the mirror, and the mirror image will be easily readable to you too. Flip it around, as though you were wearing it on a shirt, and you’ll quickly see why words look ‘backwards’ in mirrors.
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