Why does the water in the sea seem blue. Why is the sea blue

Why the sea of blue color?

Because water absorbs the rest of the color waves. Blue can penetrate deep under water, unlike red, yellow and green. Because of this, deep waters are often bluer than shallows.

Well, and one more obvious reason- the sea reflects the sky, copying its color.

Because blue sky reflected in it.

But the sea really seems to us blue at a superficial glance, and the whole point is in two reasons. The first, the most obvious, is the reflection of the sky in the water. The second reason lies in the scattering of sunlight by the sea water itself. And the spectrum in = blue is less absorbed by water, which is why the blue sea. The color of the sea will also depend on the pollution and calmness of the sea.

If you need an answer for a child, say that in the deep sea, like in a mirror, the blue sky is reflected. And in the shallow one can see the bottom and therefore the sea is of the same color as the bottom.

And that's why the pools so want to be like the sea that they are laid out with blue tiles.

For the same reason the sky blue.

The sun's rays are scattered in the atmosphere according to Rayleigh's Law, which states that the intensity of radiation scattering is inversely proportional to the fourth power of the wavelength. That is, the answer given at the Physicotechnical Institute sounded like this: because, lambda is in the fourth degree . That is, beams with a shorter wavelength are scattered more strongly. In the spectrum, this will be the blue-blue part of the spectrum.

The color of the sea depends on its depth, time of day, sky color, amount of plankton, water pollution, light scattering. If the sea is calm, clear, and the sky is blue or blue, then the water will also be blue. This can be said to be the normal standard state of the sea and its standard color, which is why the sea is called blue in folklore.

The reflection of the sky has its own effect on the color of the sea, but it is not significant. And blue is the result of the scattering of sunlight. sea ​​water... The fact is that water, like all other substances, absorbs some rays and reflects others. And white sunlight, as many know, in turn consists of other rays different color... Light passes through the water column; unevenly short light waves (red, yellow), water scatters better, and long (blue) waves are much worse.

Taken if that from http://whyy.ru/pochemu_more_sinee/ but I think this answer is enough for you

Sea water appears to be blue to us, as does the sky, for reasons related to the molecular scattering of sunlight. Short-wavelength (ultraviolet) radiation of light waves, which belongs to the blue part of the spectrum, is much better scattered by water and air molecules than long-wavelength light radiation. Therefore, the transparent environment looks blue to us.

The color of the sea that we see is just the result of the scattering of sunlight by the thickness of the sea water. Water transmits light unevenly - it usually scatters short waves better, and long ones worse. Short waves usually correspond to the blue part of the spectrum, and long ones - to the red. And looking at the sea, we see it blue, or greenish, but it is transparent.

Why is the sea blue, isn't the water itself transparent? This question also interested François Forel, who, back in the 19th century, created an analogue of the current xantometer... Trout tried to measure the shade of water on a scale of chemical solutions. But, no matter how the experiments took place, the color remained transparent anyway. Sometimes, there is an opinion that the sea reflects the sky in itself. The most famous experiments in this matter were carried out by the researcher Spring

Thus, the sea does not reflect the sky, but it emits the blue color of the spectrum.

In addition, the color of the sea depends on other factors:

• sea ​​plants. Especially algae and corals, as well as sand or clay;
• depth. As a rule, where the water is deeper it is darker, and vice versa, near the coast it is almost transparent.

• This is due to the fact that the seawater column scatters sunlight. And since blue is less absorbed by water, the sea appears to be blue.

  Vodicka transmits light unevenly, water scatters short waves better, and long waves dissipates water worse. Short waves correspond to the blue part of the range, and long waves correspond to the reddish part of the range. In a glass you are looking at a thin layer of water, as a result of this, the discrepancy in the transmission of rays is hardly noticeable. And in the sea we see the effect of light scattering by the water column of many meters. As a consequence, blue light is absorbed to a lesser extent in water, and in the light that is obtained from water, blue is most significant. By the way, the water displays better not blue, but purple, displays more ultraviolet rays better. This is why the risk of acquiring on the shore of the ocean sunburn higher than in the distance from the seas.

On maps and pages of atlases, seas are drawn in blue and light blue. In the literature, they are also often credited with this color. Children who learn from fairy tales often ask their parents: "Why is the sea blue?" Not every adult will correctly and easily answer a child to such a question. A person who has been to the sea may be confused, because he knows that the color of the water is changeable and depends on many factors.

Physics of light

In the second half of the 18th century, the genius Isaac Newton first decomposed ordinary sunlight into its constituent color spectrum. For this, the scientist passed a thin beam through triangular prism... The light was refracted and displayed on the receiving screen in the form of a tape consisting of seven colors. In all experiments, the color sequence was kept the same. Today children remember it with a simple phrase:

• Everyone (the first letter of the word means red);
• Hunter (orange);
• Desires (yellow);
• Know (green);
• Where (blue);
• Sits (blue);
• Pheasant (purple).

Newton went further: he sent the decomposed colored rays of the spectrum to a converging lens and again received white light. Having understood the nature of the sunbeam, the great physicist continued his experiments, revealing deeper and deeper physical properties light and mechanisms of color appearance.

With the help of filters, he removed individual colors from the spectrum, mixed different shades with each other, studied their relationship, which he reflected on the spectral circle, which later received the name "Newton's Color Circle".

Based on his research, the scientist made three fundamental conclusions:

1. Color does not exist without light.
2. White light contains all colors, it is just that the eye is not able to distinguish them, for example, as it is able to distinguish individual sounds in a musical chord.
3. For the colors of the spectrum, the principle of addition operates, mixing different spectral waves with each other, you can get all kinds of color shades.

On a clear day, under a deep blue sky, and the sea is blue.

The bluest sea in the world - where the Ross Sea juts deep into the Antarctic continent, it is the southernmost water on Earth, further - to the pole - only ice. Everyone knows that the ozone layer of the atmosphere is disturbed over Antarctica, and the entire blue-violet part of the flow of sunlight, including ultraviolet light, reaches the surface of the earth - and the sea ... The color of the waves there is such a deep blue blue that it is only from looking at them - takes your breath away. But this also happens on the Black Sea, take a look ...

The colors of the sky are brightest - at sunset, they are reflected in the sea ...

So the color of the sea is reflected light and the color of the sky? Correct, but not quite. White sunlight consists of rays of different colors. In a wonderful way, their entire gamut is paraded to us by rainbows - both those that we see in the humid air after rain, and those that form in the mist, behind the crests of sea waves.

All substances, and sea ​​water- also, the rays of some colors absorbs, absorbs, and others - partially reflects, partially passes through itself. Hardest of all, sea water absorbs the red and yellow rays of sunlight - blue and green remain, reflecting into our eyes - and we see the color of the sea, which is usually called "Aqua". This is the most beautiful color of the sea.

It is caused not only by the properties of the water itself, but also by microscopic planktonic algae - the basis marine life... Plankton algae absorb the red light of the sun's rays - they need it for photosynthesis. And because of this, sea water gains green shade. And the more phytoplankton in the sea, the more lively the sea, the greater the proportion of green in the color of the sea wave.

If there are few planktonic algae in the water, and it is completely transparent, then the sea seems bright blue Is the color ultramarine - this is the name of color and paint, given by Italian artists, means "super-marine", "most marine". V clear weather such crystal clear sea water acquires turquoise coloring.

This color of water, in its purest form, can be seen on tropical shoals with white coral sand, or off the coast of Mediterranean islands, composed of white limestone - reflecting from the white bottom Sun rays, and a thin layer of water is still illuminated from below. Both ultramarine and turquoise are extraordinary, wonderful colors of the sea, but they mean that this sea is - alas - poor in life.

The pure colors of sea water are better visible when looking at the sea at a right angle, from above - from the slopes of the mountains, leaning from the pier or side of the ship - in this case, less sun glare gets into the eyes. But you can completely get rid of them by submerging under the water - descending from the surface to the bottom, with each meter passed down, we observe changes in light and color.

A few meters below the surface of the sea, in the festive, transparent, turquoise water, the sun's rays play, all colors are bright and real.

The deeper we go, the more faded the colors become - 25 meters from the surface we are surrounded by a blue-green water column, the red and yellow rays of the sun, absorbed by the water column, barely reach here, and everything that is painted in blue and green colors- is lost, dissolves in such light.

That is why the scales on the sides of fish living in the water column are colored in blue-violet tones - here it makes them invisible. And therefore, bright yellow colors are always used in divers' equipment: they, on the contrary, highlight divers so that they do not lose each other in the blue haze.

At a depth of 40 meters, especially in the not very transparent Black Sea water, a violet-gray twilight reigns, because the violet rays, the most powerful in the solar spectrum, penetrate deeper into the water than others.

There are no more colors here, fish appear and disappear like gray ghosts, in complete silence. Only the light of a flashlight can show that the fish here are no less bright than at the surface - in fact, these are the same species of fish that we saw above - we did not sink so deeply. You look further down the slope, covered with black silt and fragments of mussel shells - there is only darkness.

Since there is practically no light at a depth of 50 meters in the Black Sea, the life that exists there is secondary, because without light, there is no photosynthesis, algae do not live there, new living matter is not created. The upper 50 meters of the sea - a thin surface film - feeds its entire thickness. Those animals that live deeper feed by rising to the surface, or picking up what falls from above.

If phytoplankton, unicellular algae, develop rapidly in the sea, they give the water their color, it can be green, brown, red, orange, and even white. Such phenomena are called "Water bloom", sometimes they are also called "Red tides".They most often occur in coastal waters, sea bays, rich in minerals necessary for the growth of algae. There are many such bays and coves along the northeastern coast. North America- and when you fly by plane from Europe to the east of the United States during the phytoplankton bloom season - in spring, it is very curious to observe from the window the change of water colors along the coast - in one bay the water is brown, in the other - green, in the third - yellow ...

But sometimes phytoplankton blooms develop in the water area of ​​the whole sea. The Red Sea got its name precisely because of the extensive blooms of blue-green algae repeating in it (although it is more correct to call it cyanobacteria) trihodesmia - it is red in color, due to the phycoerythrin pigment it contains.

Coastal blooms are the most interesting in the Black Sea planktonic algae noctylus - it paints the water a fiery red color.

But at night it becomes even more interesting - each noctiluka glows - and the whole sea flickers! Noktiluka is the largest unicellular algae in our sea - up to 1 mm in diameter, and each of them is visible as a separate green sparkle. Translated from Latin, noktiluka means - night light. In the Utrish Bay, not far from Anapa, last time such flowering was in 2000. We will discuss the glow of the sea in more detail in the chapter "Plankton".

The pure colors of sea water are almost always disturbed by the haze of evaporation over the water surface - it conceals, blurs the true color, adding white to it. This is especially noticeable when the water in the sea becomes warmer than the air - in autumn and winter there are days when thick steam swirls over the sea.

The wind, creating ripples on the water, forms many mirrors that glare, letting sunbeams into our eyes; then the color of the sea is difficult to make out. When the wind makes the sea chill on a bright summer afternoon, at least half of the sea will turn into one blinding mirror for our eyes!

If the wind ripples on the surface of the sea on a gloomy day, then a gray-steel space spreads before our eyes, this is more a lack of color than a color.

Such a picture can be observed in the vastness of the World Ocean very often, especially in northern seas... When a storm plays out and a hurricane wind rips and mixes the tops of the waves with the air, whips them into a gray-white foam ...

And the glare of the sun on the surface of the sea, and the foam of the waves are almost always visible in the sea - and, in fact, the white-gray dull shine is the most normal view ocean. That is why warships are painted with gray paint - they are trying to make them invisible “on the gray plain of the sea”.

We admire the color of the water of the seas and oceans, we say that it is dark blue, or sky blue, or something else, but it is not enough for scientists to see and admire, they need to know why all this is happening.

In the 19th century, the Swiss geographer F.A. Forel invented a device that measures the color of water. He created a scale from chemical solutions that always have the same shades. This scale is called a xantometer.

It was necessary to prove the obvious. The color of water, like the color of any body, is determined by the ability to transmit, or reflect, any colors of the solar spectrum. Snow, for example, reflects White color, ice transmits sunlight through and through, and therefore is transparent, and water in the ocean transmits and reflects at the same time the blue color of the spectrum. At the same time, it was believed that the water itself is absolutely colorless.

In 1883, the Belgian scientist Spring conducted an experiment with distilled water. He proved that even in a closed tube even purified water retains the blue color obtained from the spectrum for some time.

In addition, it became clear that the color of the water does not depend on the smallest particles, the dispersion of which is the cause of the heavenly blue. Spring proved that water, getting into the rays of the spectrum, absorbs the red and dark parts of the spectrum, and lets through the blue, and itself turns blue for a while.

In addition, the color of the water in the seas and oceans is influenced by its chemical composition... In the oceans, most often it is dark blue, only in some places it takes on a slightly different shade.

Occasionally, the ocean water appears red or takes on an olive tint. Studying the phenomenon, scientists came to the conclusion that such staining occurs due to algae in the water and having a similar color. It is they who give the ocean such a disturbing color.

Suspended particles, which the sky owes its blue, sometimes end up in the ocean. Off the coast of the oceans, you can often pay attention to the green shades of the water, which can be explained by the presence of suspended particles in it. But most often we can admire the blue surface of the ocean.

Why is the sea blue?

Why is the sea blue, because the water itself is transparent? And even if you take seawater and pour it into a decanter, it will also be transparent.

Wrong answer: because the sea reflects the sky and it is blue.

The color of the sea that we see is the result of the scattering of sunlight by the thickness of the sea water.

Water transmits light unevenly - it scatters short waves better, and long ones worse. The short waves correspond to the blue part of the spectrum, and the long ones correspond to the red. In a decanter, you are looking at a thin layer of water into the light, so the difference in the transmission of the rays is invisible. And in the sea, you see the result of the scattering of sunlight by the water column of many meters. Therefore, blue light is absorbed less in water, and in the light that comes out of the water, blue is the most.
by the way

Best of all, water reflects not blue, but purple. And even better - ultraviolet rays. That is why there is a higher risk of sunburn on the seashore than away from water bodies.

Why is the ocean blue? August 12th, 2017

Blue ocean. Green ocean. Transparent colorless drinking water in glass. So what color is the water? There is an amazing answer to this question. Clear water is blue. This color is very weak, so it is invisible in a small glass.

But if we pour water into a huge glass aquarium, we will see a distinct blue tint of the water.

What determines the color of the water? The color of water depends on the characteristics of absorption and reflection of light by water molecules. White light, for example sunlight, can be decomposed into its constituent colors. The combination of these colors is called a spectrum. The spectrum of white light is composed of the colors of the rainbow. Water molecules absorb light in the red-green part of the spectrum. The rays in the blue part of the spectrum are reflected by molecules. Therefore, we perceive the color of water as blue.

However, in natural reservoirs, the color of the water can be very diverse. In the middle of the ocean, the water is deep dark blue, almost purple, in color. Along coastline the shades of the water range from blue to green to yellow-green. Why is there such a difference? The variety of shades depends on what kind of particles are suspended in the water and what is the depth of the reservoir. Near the coast, ocean water is filled with small floating plants and organic particles that enter it from land. Just like their earthly brethren, aquatic plants, which are called phytoplankton, contain chlorophyll.

Chlorophyll absorbs the rays of the red and blue parts of the spectrum and reflects green light. Therefore, near the coast, water often has green tint.

Water color and depth Deep blue waters oceans are like deserted white deserts - there is very little life here and there. When viewed from space, you can see which oceans are teeming with life and which are not. Green waters like tropical jungle continents filled with life. Deep blue waters are poor in life and are like white lifeless deserts of dry land. The absorption of light by particles suspended in water alters the perception of color underwater. Imagine that you are diving in a yellow submarine.

Close to the surface, your submarine will look exactly like the original color - yellow. But the deeper you go, the more distance light must travel from the surface to reach the submarine. When it descends to a depth of 30 meters, most of the rays of yellow, orange and red will be absorbed by water molecules.

The rays of the blue and green parts of the spectrum will reach the boat. And you look your submarine will not be yellow, but blue-green. If you go deeper, green rays will be cut off. The underwater boat now appears dull blue. The muddy ocean waters, in which organic debris is suspended, absorb more light than transparent pure water... Therefore, when immersed in muddy water darkness comes faster.

The ocean is made of salt water. He himself, if you throw out all the luminous living creatures, does not glow. That is, all the light that we see coming from the ocean is reflected sunlight. But the sunlight isn't blue either. The spectrum of sunlight near the ocean surface is like this.

Intensity Falling to Earth solar radiation depending on the wavelength at sea level. As you can see, the maximum radiation falls on the green and yellow parts of the visible range.

The color of the ocean is determined by the mechanism by which the sun's color is absorbed and scattered by water molecules. The mechanism is very complex. It was fully described only in 1923 by geophysicist Vasily Shuleikin. It turned out that water molecules make vibrational and rotational movements and, as a result, absorb different wavelengths in different ways. Red is absorbed most of all, and blue is absorbed least of all. The blue color is scattered and reflected back into the air, while the red remains absorbed into the interior of the ocean. This leads to the fact that the ocean looks blue to us, and under water all photos are blue. So, if you are thinking of photographing fish, do not forget the flash.

Diagram showing how sunlight travels through the ocean. Red is absorbed almost immediately, therefore, already at a shallow depth, there are almost no red flowers under water. Green reaches up to a hundred meters. And blue - up to 200-300 m.

The transparency of the ocean is determined not only by water molecules, but also by the small creatures that live there. Plankton, suspended matter, mud - all this reduces the transparency in the ocean. NASA recently conducted research and found that the lowest concentration of plankton is found off the coast of Easter Island.

That is why the ocean there is the most transparent in the world.
If you haven't seen it, I recommend that you look at the page of the Earth Observatory (NASA) project and see absolutely amazing observations of phytoplankton concentration in the world's oceans over the past ten years. In the same place - the behavior of the ocean temperature. There you can see, for example, where on Earth is the warmest sea, why whales spend their summer in northern latitudes off the coast of Alaska and the Aleutian Islands, or why in three weeks of sailing The Pacific Ocean we hardly saw any living creatures far from the coast.

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