If you take a glass of water from the sea, we will see a transparent liquid there, but if you look into the depth of the reservoir itself, the water will turn out to be blue. Why is the sea blue in one case and transparent in another?
The role of the atmosphere
It was once believed that the answer lies on the surface, and to be quite precise, it is reflected in it: the sky is blue. That's why the water in the sea is blue - it reflects the blue sky! Indeed, due to their chemical structure and physical parameters, the water masses work as an ideal mirror, reflecting the visible color of the sky and the cloud masses floating above it. Therefore, for example, the water of the B altic and Mediterranean seas cannot be confused even in a photograph. After all, the B altic Sea is dominated by gray-lead tones, and this is partly due to the fact that seventy-five percent of the time of the year heavy dark clouds hang over the horizon. But in the southern latitudes, the sky is mostly cloudless, and, when reflected, it gives the water a beautiful blue color.
But there are more significant factors. The fact is that light is refracted in water bodies, and it does this at different angles at different depths. At shallow depths, the water will appear transparent due tothe fact that rays of different colors and shades are refracted in it. They are superimposed on each other, and as a result, our eye perceives water right next to the shore or, say, in a glass, almost colorless.
Deep dependency
The greater the depth, the greater the difference in the absorption time of the rays and their length. And there is one more feature here - only shades from the spectrum of the rainbow are absorbed and scattered. Yellows, oranges and reds will scatter on the surface, at greater depths the water will be green due to the interaction with green hues, and the deep layers of the sea will absorb blue, blue and purple hues. That is why the sea is blue in color away from the shore. It is because of this phenomenon of light reflection and absorption that snow appears white - it reflects white, and ice reflects all colors, which makes it appear transparent.
Life takes its toll
But that's not all. After all, it is impossible, in detail answering the question why the sea is blue, just to discount those who live there. For example, phytoplankton has a huge impact on the color of the reservoir. Due to the chlorophyll it contains, phytoplankton absorbs blue rays and scatters green ones. Accordingly, the more of this very plankton, the more expressive the green color of the water will be. However, in addition to phytoplankton, there are many other inhabitants of the depths that give the sea different shades. These organisms can be of all colors of the rainbow, and their concentration directly affects the color of the water.
One morethe factor is the smallest particles suspended in water. Their quantity, as well as the chemical composition, can be measured with a special device on a scale of chemical compounds, which was created by Francois Forel. The chemical composition of the liquid plays a very important role in the color of the entire reservoir. Light-s alty and cool waters are dominated by blue and blue hues, while greens dominate in s alty and relatively warm waters.
The Secret of the Black Sea
To understand why rivers and seas are blue, consider the example of the Black Sea. Why was it given such a descriptive name? Scientists have two main hypotheses in this regard. Firstly, sailors noticed that during a storm the water darkens and becomes almost black (although everything gets dark during a storm, if you look closely, it really is …). Secondly, if you lower a metal object to a greater depth, it will darken. This will happen due to the content of hydrogen sulfide - a substance secreted by bacteria, whose function is to decompose the corpses of animals and plants. And again, if you draw water into a glass, the liquid will still be transparent, but from a bird's eye view it will be blue.
The answer lies in the depths
Summarizing, we can highlight the following main factors explaining why the sea is blue:
- Physical. The refraction of the sun's rays and high temperature give the depth of rivers and lakes azure hues, however, the lower the volume of water and the degree, the more transparent the water will be.
- Biological. Phytoplankton, suspended particles, algae and microorganisms thatlive in the abyss of water, give the water green or blue shades.
- Chemical. If red paint is mixed with water, there will be red water. Something similar happens with the sea: chemical compounds that are formed in it under the influence of various factors give color in different colors. Well, in fairness, we must add hydrogen sulfide to this, which colors everything that is not laziness in dark shades. We should not forget about the high content of s alt, which scatters the rays of the blue part of the spectrum.
Thus, such a seemingly simple substance as water in its different states of aggregation, having a completely different color, gives an abundance of questions. Like the dilemma "Why is the sea blue?", they can confuse not only a child, but also a well-educated adult.
