Why is Water Blue?

We often ask ourselves: Why is water blue? Despite the fact that water is a colorless substance, it is the most visible liquid in the world. The blue hue is not a scattering effect of light, but rather the result of absorbed red light by water molecules. The light that reaches the ocean’s surface is reflected back to the Earth by the molecules in the water. This is why we see the color of the ocean as blue.

why is water blue

In the visible spectrum, water is a bright blue color because of its selective absorption of red light. Light absorbed by water promotes transitions to high overtone states, combination states, and highly excited vibrations. Another form of water is “heavy,” in which two hydrogen atoms have been replaced by deuterium atoms. It is about 10% heavier than regular drinking-water. Its absorption curve is the same as that of regular water, though the heavier molecules absorb higher wavelengths outside the visible spectrum.

The reason for water’s color is due to refraction. Essentially, the blue light reflects in a large area, and therefore it is more likely to reflect in the sky than in ordinary liquid. The blue light refracts into the Earth’s atmosphere because the molecules in liquid water are so highly reflective. This phenomenon is the reason why the daytime sky is blue. Its low frequency of oscillation is the cause of the color of the ocean.