Why do mirrors seem to switch left and right, but not top and bottom?
I found a link to this video on Reddit: Physicist Richard Feynman explains why do mirrors seem to switch left and right, but not top and bottom.
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Category: Science



Was there really any confusion on this? It doesn’t switch anything, it just bounces the light back?
I guess the only confusion is our mind is used to the idea that someone facing us would have their right hand on our left side.
Feynman’s explanation obscures the real reason why a mirror appears to reverse left and right but not up and down. The real reason a mirror appears to reverse left and right but not up and down is because our eyeballs are oriented side-by-side, along a horizontal line. Relative to a horizontal line, ‘up’ is always ‘up’ and ‘down’ is always ‘down,’ but ‘left’ and ‘right’ depend upon which side of the line you are standing on. Feynman brings up the latter point, but misses the reason why it matters. Had humans evolved with eyeballs along a vertical line (which we can simulate by lying down on the floor), then a mirror would appear to reverse ‘up’ and ‘down’, but not ‘right’ and ‘left’.
Thank you, Grumpy. That works for me.