Daily water use is transparent. Why is the sea mostly blue and green?

When we pick up a glass of sea water, we will find that the sea water is transparent, but when we see the vast sea with our naked eyes, it will actually appear blue or green. It may be bright blue in good weather and green in bad weather. In fact, in the eyes of many of us, we will think that the sea is blue, but in fact, it is not only blue. Why?

First, the wavelengths of light are different. When it comes to daily water use, it is transparent, but most of the seawater is blue and green. This is also because the wavelengths of light in sunlight are different. The sunlight we see now looks like white light, but it actually contains seven colors of light, and the light waves of these seven colors are different in length. The blue and green we usually see on the sea, that is, the blue light with relatively short wavelength, can't penetrate the seawater when the sun shines on the sea, so it is directly reflected and appears as blue light.

Second, light that is not absorbed includes red, orange, yellow, green, blue and purple. Of the seven kinds of light, red and orange have longer wavelengths, so they can directly penetrate the sea surface. It enters the ocean and is absorbed by other objects, but for blue and green, it may be that the particles in seawater are different, resulting in different colors. For some oceans with high sediment concentration, they may appear green. This is because there are some yellowish substances in the sand, which makes the light appear green.

Third, when the weather is good, like when the weather is good, most of the sea water we see is actually blue, and the water in the middle of the ocean is also blue. This is also because when the shore is closer to the beach, its color refraction will weaken. So we can't see blue or other colors. When the weather is bad, we may see green, because the sunlight is not very strong at this time, so its wavelength may not reach the sea.