Why swimming pool appears shallower than its real depth?

When we look at an object underwater, it appears closer to the surface than it actually is. This is because light bends when it passes from air to water. This phenomenon is called refraction.

The amount of refraction depends on the angle at which the light hits the water. The more direct the light, the less it bends. This is why objects that are close to the surface appear to be almost in their normal position, while objects that are deeper down appear to be much closer.

In a swimming pool, the water is usually very clear, so the refraction of light is very noticeable. This makes the pool appear shallower than it actually is. This can be a dangerous illusion, especially for children who may not realize how deep the water is.

To avoid any accidents, it is important to always know the actual depth of a swimming pool before getting in.