How does human vision change underwater?

The answer to the question "How does a person's vision change underwater?" prepared by diving club "Diving" diver Margarita Zommere.

Table of Contents

Refraction coefficients of light in water

Water and air have different refractive indices that affect how light travels through the medium. Because our eyes are in the air inside the glasses and the object is in the water, light is refracted at the boundary surface, causing underwater objects to appear about 25% closer and 33% larger than they actually are.

What happens to colors underwater as seen by a diver?

Under water, objects also lose their colors. This process is related to the absorption of light. Each color has its own energy, characterized by a wavelength. The longer the wavelength, the less energy it has. Because there are many more molecules or particles in water than in air, there can be much more absorption, which reduces the energy of the light.

Light and energy under water

Red light has the lowest energy, so the water of this color absorbs it first, which means that at a depth of about 4-5m, the red color is completely extinguished. After red, orange, yellow, green, ... until the last color of the rainbow starts to disappear.