This is a puzzle that I created for my own amusement when I was about 10 years old:
A mirror is 2-dimensional, and it reflects a projection of 3-dimensional objects. Those two dimensions are: up-down and right-left. Now have a look at a mirror and raise your right hand. Your reflection seems to raise his left arm. If your T-shirt has some text, it also seems to have inverted from left-to-right to right-to-left, making it difficult to read. Conclusion: mirror seems to invert its left-right axis, but NOT its up-down axis. This is odd. How can it be? As scientists, we should make a hypothesis on what could cause this phenomenon ant test it!
Maybe mirrors have some kind of grid creating a polarization-like quality that explains this effect. Let's try to rotate the mirror 90 degrees. if this quality is in the mirror, then it should stop inverting left-right axis and start inverting up-down axis. A good scientist will always test his theory. After rotating the mirror, no change. No luck here, so this is obviously not the cause.
Another theory: maybe this is because of the alignment of human eyes: after all they are aligned horizontally and not vertically. Horizontally alighed eyes cause left-right to be inverted. If eyes would be aligned differently, the result would be different. Can this be tested? I close my other eye, no change. I even tilt my head so that my eyes are in different alignments, and still all text reads backwards, never upside-down.
After some thinking, naturally, I did come to a conclusion. What about you?
