Why swimming pool appears shallower than its real depth?

Answer 1

refraction of light produces the shallow swimming pool illusion. As you look down at a pool, you are seeing light that has changed angle as it moves out of the water and into the air. Specifically, light moves faster through air than water. Light coming up from the bottom of the pool refracts down to arrive at your eyes at a shallower angle. You see the bottom of the pool a little higher and farther away than it actually is.

Answer 2

This is because the light that falls upon the water surface does not continu in the same direction as it hit the surface: the light refracts. Since the light is refracted along the water surface, the light travels a larger distance, giving rise to the perception of a larger depth.

Answer 3

There is a reflection in the pool that makes it seem shallow.

Answer 4

Light from objects under the water comes up into the air and in so doing, bends a fair amount, fooling your eyes into seeing the objects as closer to the surface than they really are.