<P> The `` color '' of the ocean is determined by the interactions of incident light with substances or particles present in the water . White light from the sun is made up of a combination of colors that are broken apart by water droplets in a `` rainbow '' spectrum . Large quantities of water , even in a swimming pool , would appear blue as well . When light hits the water surface , the different colors are absorbed , transmitted , scattered , or reflected in differing intensities by water molecules and other so - called optically - active constituents in suspension in the upper layer of the ocean . The reason that open ocean waters often appear blue is due to the absorption and scattering of light . The blue wavelengths of light are scattered , similar to the scattering of blue light in the sky but absorption is a much larger factor than scattering for the clear ocean water . In water , absorption is strong in the red and weak in the blue and so red light is absorbed quickly in the ocean leaving blue . Almost all sunlight that enters the ocean is absorbed , except very close to the coast . The red , yellow , and green wavelengths of sunlight are absorbed by water molecules in the ocean . When sunlight hits the ocean , some of the light is reflected back directly , but most of it penetrates the ocean surface and interacts with the water molecules that it encounters . The red , orange , yellow , and green wavelengths of light are absorbed and so the remaining light we see is composed of the shorter wavelength blues and violets . </P>
where does the sea get its colour from
the interactions of incident light with substances or particles present in the water