Why does the reflection in a spoon look upside down?



When light reflects off a smooth object like a spoon, it is reflected in a direction normal (at 90 degrees) to the surface. Imagine light rays from your face travelling in a straight line towards the spoon (which had bounced off your face from other light sources). When it hits the curved surface of, say, the top of the spoon, the ray will bounce at an angle - downwards. Similarly, light hitting the bottom of the spoon will bounce upwards because it is angled upwards. By the time the light gets to your eyes, all the light that hit the top of the spoon and all the light that hit the bottom of the spoon has pretty much switched places.

To understand this a bit better, try moving the spoon towards your face. I haven't played with a spoon for a while, but I'm pretty sure your face will become almost invisible at a certain point (this is because you've reached a point where the lines of reflection all meet at the same place). Continue moving it closer, and your face will appear the right way up, but a little smaller than it should be. That's because the light from the top still enters your eye at the top, but a bit further down than it would in a flat mirror.

Believe it or not, this is actually what happens in your eyeball. Your eye is round, so the light bounces in such a way that you receive an upside down image. Once again, I haven't read about this since I was a kid, but from what I remember the back of your brain has some sort of mechanism where it flips it the right way up before you start processing the image.

Aug 5 at 6:5

becuase the surface of the spoon acts like a concave mirro and froms a real image which looks upside down. a phenomenon related to images formed by reflection of light.

Aug 5 at 9:51


you can find an answer in this article

Aug 5 at 14:0