Why the oceans appear blue in colour

The oceans appear blue in color due to a phenomenon known as selective absorption and scattering of sunlight by water molecules. Here’s why:

Selective Absorption: Water molecules selectively absorb longer (red) wavelengths of light from the sunlight as it penetrates the ocean’s surface. This absorption primarily occurs in the red and orange portions of the light spectrum. The shorter (blue) wavelengths are not absorbed as much and penetrate deeper into the water column.

Scattering: As sunlight enters the ocean, it interacts with water molecules and particles suspended in the water. This interaction causes the shorter (blue) wavelengths of light to scatter in all directions, giving the water a blue appearance when viewed from above. Blue light is scattered more efficiently than other colors due to its shorter wavelength.

Depth Perception: The scattering of blue light also contributes to the perception of water as blue. As light travels deeper into the ocean, it encounters more water molecules and particles, leading to further scattering of blue light. This effect causes the ocean to appear blue even at greater depths.

Reflection: Additionally, the reflection of the sky’s blue color on the ocean’s surface enhances the overall blue appearance of the water.