system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is the reflection in the front of a spoon upside down and 'normal' in the back?
gpt
The back side of the spoon acts as a convex mirror and the front acts as a concave mirror.

A mirror works by bouncing light back at you. With a flat mirror the light enters and bounces straight back at you giving an image which is the same size as the object no matter how far away you are from the mirror. 

With a convex mirror the angle of the returning light is changed in such a way that the image is expanded and appears to be larger than the object but still at the same orientation. 

With a concave mirror the angle of the returning light is changed in such a way that the image is compressed and made a lot smaller than the object. These “rays” of light all cross at a point called a focal point, if you are between the focal point and the mirror then the image appears to be the same orientation but smaller than the object. If you are just past the focal point the image appears small and upside down. If you are far past the focal point the image appears large and upside down.

The focal point distance from the mirror is determined by the curvature of the mirror. Since a spoon is a small object with a large degree of curvature then it’s focal point is close to the spoon and you can’t get between the spoon and its focal point so your reflection will always look upside down.