text: why is it that when you look in a mirror, only left and right is reversed, not up and down?   it has to do with the properties of flat mirrors and how light reflects off of them - what you are looking when you look into a mirror is a virtual image. the way you see light rays as it hits the mirror makes it look as if there is an image on the other side.   concave mirrors will give you an inverted image - that's why when you look into a spoon it looks as if you are upside down.