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What shape is a rainbow - circle or arc? Why is the rainbow round?

To understand the form of this natural phenomenon, you need to understand how it is formed. Rainbow is an optical phenomenon resulting from refraction and reflection sun rays...

To understand the form of this natural phenomenon, you need to understand how it is formed. A rainbow is an optical phenomenon resulting from the refraction and reflection of sunlight in drops of water. That is, for a rainbow to appear, two components are needed:

water drops (this is why a rainbow is visible after rain, in the spray of waterfalls, in fog);
sunlight(and the sun is always behind the back of the one who sees the rainbow).

The color of the sun's rays is white, all colors are “mixed” in it. When it hits a drop, it is refracted and “breaks up” into separate rays. After refraction, these rays receive different angles, therefore, according to the laws of physics, they have different colors.

But why do we see not a straight stripe or, for example, a solid multi-colored sky, but an arc?

This is not an arc. This is a circle!

In fact, a rainbow is not an arc or a semicircle, but a whole circle. This shape is related to the spherical shape of the water drops themselves.

What happens to the beam:

Passing from the outside into the drop, the beam is refracted and breaks up into multi-colored cone rays. The cone-shaped shape is obtained due to the spherical shape of the surface of the drop (in a well-known experiment in physics lessons, “flat” rays come out of the prism because its face is flat).
Colored rays are reflected from the inner surface of the drop at the same angle that they hit it. According to the laws of physics, each color receives its own angle of reflection - the same as the angle of incidence.
Coming out of the drop (again through the sphere), the colored rays are refracted again, and their angle of deflection increases. Therefore, the color cones open up even more.

It turns out that each drop “shines” with multi-colored cone rays. We see the folding light of many drops. Moreover, we see it only when we are in relation to the drops at the same angle at which the sun shines on them.

If it were possible to be in several places at once, then it would theoretically be possible to see the entire light cones. Being in one place, you can only see colored circles that form a rainbow. This is the result of projecting a “cut” of cones onto the sky.

But why do we only see the arc?

It has been established that a rainbow is visible only when the sun is no more than 42 degrees above the horizon. And the observer is generally on the surface of the Earth, and most of the rainbow-circle is hidden from him. That's the whole secret why the arc is visible.

Each person sees their “own” rainbow. After all, observers are in different places, which means they see the glow from different drops.
The size and brightness of the rainbow depend on the size of the water droplets. The larger they are, the larger the rainbow stripes. The more uniform the droplet size, the brighter the rainbow.
If you stand closer to the sun, the rainbow will be wider; if further, then already. Of course, these distances must be quite large to notice the difference.
The lower the sun and the higher the observer, the larger the rainbow arc, and vice versa.

There are cases when people saw the whole rainbow. They were on enough high altitude: on high mountain, in an airplane or helicopter. And the most beautiful rainbow is visible from space!

People have been asking this question for a long time. In some African myths, a rainbow is a snake that envelops the earth in a ring. But now we know that a rainbow is an optical phenomenon - the result of the refraction of light rays in water droplets during rain. But why do we see a rainbow in the form of an arc, and not, for example, in the form of a vertical stripe of color?

The shape of a rainbow is determined by the shape of the water droplets in which sunlight is refracted. And droplets of water are more or less spherical (round. Passing through the drop and being refracted in it, a beam of white sun rays is transformed into a series of colored funnels inserted into one another, facing the observer. The outer funnel is red, orange, yellow, and then goes green, etc., ending with inner purple. Thus, each individual drop forms a whole rainbow.
Of course, a rainbow from one drop is weak, and in nature it is impossible to see it separately, since there are many drops in the curtain of rain. The rainbow that we see in the sky is formed by myriads of drops. Each drop creates a series of colored funnels (or cones) nested one inside the other. But from an individual drop only one colored ray enters the rainbow. The observer’s eye is the common point at which the colored rays from many drops intersect. For example, all the red rays coming from different drops, but at the same angle and falling into the eye of the observer, form a red arc of the rainbow. All orange and other colored rays also form arcs. Therefore, the rainbow is round.

We are used to seeing a rainbow as an arc. In fact, this arc is only part of a multi-colored circle. This natural phenomenon can only be observed at high altitudes, for example, from an airplane.

When the last raindrops fall on the ground and a rainbow appears in the sky, looking at it, you wonder: why is this happening? Where does the beautiful arc of multi-colored stripes come from in the sky? The science of physics, which has already given you answers to many complex questions more than once, will help you answer this question.

Rainbow is an extraordinary natural phenomenon. And although we see her quite often, every time we rejoice at her appearance and beauty. The rainbow appears as soon as the cloud begins to leave, and the sun takes its place in the sky. It turns out that for some time the rain is visible to people as if “from the outside.” The rays of the sun illuminate a rain cloud and, passing through the raindrops, change their color. The fact is that the sun's rays are not at all white and identical, as it seems to us. They all have different lengths, and each length has its own “color”. That’s why the rainbow appears so colorful to us.

But the color of the rainbow can be bright, but sometimes it can be barely noticeable. And it depends on the size of the raindrops. If the droplets are large, the colors of the rainbow will be bright. If they are small, the celestial arc will be poorly visible. In the past, people could not explain the appearance of rainbows. And it was difficult to find a person who would remain indifferent to her. That is why there are so many legends and beliefs associated with the rainbow. The ancient Slavs, looking at the rainbow, predicted the weather. If the rainbow was low and wide, the people expected bad weather. And the tall and narrow one promised good weather.

In England, it is considered a good omen to see a rainbow and immediately make a wish. And in Ireland today they believe that in the place where the rainbow touches the ground, there is a treasure of gold. You are certainly enough man of sense, and you don’t believe in gold treasures. And you understand that there is no way to get to where the rainbow touches the ground.

Are you wondering why we only see part of the rainbow? Let's talk about it. You've probably already noticed that you can't see both the sun and the rainbow at the same time. After all, a rainbow is a reflection of the sun's rays. Only part of the celestial arc is visible from the ground. But the higher a person climbs, for example, up a mountain, the more the rainbow will look like a circle. And from an airplane window you will someday be able to see round rainbow!

Why is the rainbow semicircular? People have been asking this question for a long time. In some African myths, a rainbow is a snake that envelops the Earth in a ring. But now we know that a rainbow is the result of the refraction of light rays in water droplets during rain. But why do we see a rainbow in the form of an arc, and not, for example, in the form of a vertical stripe of color?

Two people standing next to each other see their own rainbow! Because at every moment a rainbow is formed by the refraction of the sun's rays in more and more drops. Raindrops are falling. The place of the fallen drop is taken by another and manages to send its colored rays into the rainbow, followed by the next one and so on.

The appearance of the rainbow - the width of the arcs, the presence, location and brightness of individual color tones, the position of additional arcs - very much depend on the size of the raindrops. The larger the raindrops, the narrower and brighter the rainbow turns out. Large drops are characterized by the presence of a rich red color in the main rainbow. Numerous additional arcs also have bright colors and are directly adjacent to the main rainbows, without gaps. The smaller the droplets, the wider and fainter the rainbow becomes, with an orange or yellow edge. The additional arcs are further apart from each other and from the main rainbows. Thus, by the appearance of the rainbow one can approximately estimate the size of the raindrops that formed this rainbow.

The appearance of the rainbow also depends on the shape of the drops. When falling in the air, large drops flatten and lose their sphericity. The stronger the flattening of the drops, the smaller the radius of the rainbow they form.

A celestial rainbow is a beautiful and at the same time complex physical phenomenon that can be observed after rain or during fog if the sun is shining. Many ancient beliefs and myths are associated with the rainbow. different nations, and in Rus' in the old days they used it to predict the weather. A narrow and tall rainbow foreshadowed good weather, while a wide and low rainbow foreshadowed bad weather.

A rainbow is a meteorological phenomenon that appears in the sky. This is a huge arc consisting of different colors. The appearance of a rainbow is facilitated by high moisture content in the air, which usually occurs after rain or fog. The multi-colored arc appears due to the refraction of sunlight in drops of water, which are contained in the atmosphere in the form of steam. Drops refract light differently, depending on the wavelength of the light. For example, red has the longest wavelengths, so this color crowns the color spectrum of the rainbow, it belongs to the widest arc. Then the red color in the spectrum smoothly turns into orange, then into yellow, etc. The weakest in terms of resistance to deviation during refraction in water is violet, its waves are the shortest, so the observer sees that this color belongs to the shortest arc of the rainbow - the inner . The method of breaking down white sunlight into a color spectrum is called “dispersion.” With dispersion, the refractive index of light depends on the wavelength of the light. In optics, the phenomenon of a rainbow is called “caustics.” A caustic is a light curved line of various shapes, in in this case- semicircle or arc. The multi-colored rays that make up a rainbow run parallel to each other, without converging, so you can observe the color transition inherent in it throughout the rainbow. From childhood, everyone is familiar with rhymes and sayings that help to remember the colors of the rainbow. For example, every schoolchild knows the saying “every hunter wants to know where the pheasant sits.” However, in fact, the color spectrum of the rainbow does not consist of seven colors, there are many more. Primary colors transform into each other through a large number of shades and intermediate colors. It should be added that a person can observe the phenomenon of a rainbow only along the path of sunlight. It is impossible to see the rainbow and the sun at the same time; the sun always remains behind. Moreover, the higher the observer is (on a hill or in an airplane), the more visible form the rainbow is approaching the circle.

Why is the rainbow round and the sky dome. WHY IS A RAINBOW SHAPE OF AN ARC?

Why is the rainbow semicircular? People have been asking this question for a long time. In some African myths, a rainbow is a snake that envelops the Earth in a ring. But now we know that a rainbow is an optical phenomenon - the result of the refraction of light rays in water droplets during rain. But why do we see a rainbow in the form of an arc, and not, for example, in the form of a vertical stripe of color?

The shape of a rainbow is determined by the shape of the water droplets in which sunlight is refracted. And water droplets are more or less spherical (round). Passing through the drop and being refracted in it, a beam of white sunlight is transformed into a series of colored funnels, inserted one into the other, facing the observer. The outer funnel is red, orange, yellow are inserted into it, then green, etc., ending with the inner violet. Thus, each individual drop forms a whole rainbow.

Of course, a rainbow from one drop is weak, and in nature it is impossible to see it separately, since there are many drops in the curtain of rain. The rainbow that we see in the sky is formed by myriads of drops. Each drop creates a series of nested colored funnels (or cones). But from an individual drop only one colored ray hits the rainbow. The observer's eye is the common point at which the colored rays from many drops intersect. For example, all red rays coming out of different drops, but at the same angle and entering the observer's eye, form a red arc of the rainbow. All orange and other colored rays also form arcs. That's why the rainbow is round.

We are used to seeing a rainbow as an arc. In fact, this arc is only part of a multi-colored circle. This natural phenomenon can only be observed at high altitudes, for example, from an airplane.

There is a group of optical phenomena called halo. They are caused by the refraction of light rays by tiny ice crystals in cirrus clouds and fogs. Most often, halos form around the Sun or Moon. Here is an example of such a phenomenon - a spherical rainbow around the Sun:

Rainbow is an atmospheric phenomenon. It appears in the sky before or after rain, and can be seen near a waterfall or above the splashes of a fountain. It looks different - it can be an arc, sometimes in the form of a circle or splashes. For a rainbow to appear after rain, you need sunlight.

Imagine that a rainbow is one ray of sunshine. Usually the sun's rays are invisible because they are scattered by the air. Daytime sunlight is often called white light. In fact, the sensation of white light is caused by mixing colors such as red, orange, yellow, green, cyan, indigo and violet. This combination of colors is called the solar spectrum; their combination gives white color.
green foliage, blue sky, the bright colors of nature are all the refraction of the sun's rays, which, passing through a thin layer of the atmosphere, reflect the constituent parts of white color.
The concept of the spectral composition of white color was introduced by Isaac Newton. He conducted an experiment in which a beam from a light source was passed through a narrow slit behind which a lens was placed. From it, a beam of light was redirected to a prism, where it was refracted and split into components.
Remember that a prism is a polyhedron with a base, the sides of which form a three-dimensional figure. A drop of water is a real prism. Falling through it, a ray of sun is refracted and turns into a rainbow.
Sunlight is split in different ways because each wave of the spectrum has its own length. Distinctive feature is also the fact that two observers standing next to each other will see their own rainbow.
The effect will occur due to the fact that the drops cannot be the same, and the arrangement of colors, their brightness, and the width of the rainbow arcs directly depend on the size and shape of the drops.
If you want to see the rainbow in all its glory, you need to have the sun shining at your back. The rainbow will be brighter and more saturated if the light is refracted through large drops; if they are small, the arcs will be wider, but their color will be less bright. It happens that when raindrops fall they become flattened, in which case the radius of the rainbow will be small. If the drops stretch out when falling, then the rainbow will be tall, but its colors will be pale.

Rainbow is one of the most amazing natural phenomena. People have been thinking about the essence of this phenomenon for a long time. The rainbow is the companion of rain. The time of its appearance depends on the movement of the cloud producing rainfall. A rainbow can appear before rain, during precipitation, or at the end of the process.

What is a rainbow?
Typically, a rainbow is an arc of color with an angular radius of 42°. The arc is visible against the background of a rain curtain or streaks of falling rain, which do not always reach the surface of the earth. A rainbow is observed in the side of the sky that is opposite to the sun, while the sun is not covered by clouds. Most often, such conditions are created in the summer, during the so-called “mushroom” rains. The center of the rainbow is the antisolar point - this point is diametrically opposite to the Sun. There are seven colors in a rainbow; in addition, a rainbow can be seen near a fountain or waterfall, against the backdrop of a curtain of drops from a sprinkler.

Where does the amazing colorful light emanating from a rainbow come from? The source of the rainbow is sunlight decomposed into its components. This light moves across the sky in such a way that it appears to come from that part of the sky that is opposite to the Sun. The main features of the rainbow are correctly explained by the Descartes-Newton theory created more than 300 years ago.

An object that can split a beam of light into its components is called a “prism.” If we talk about a rainbow, then the role of a “prism” is played by raindrops. A rainbow is a large curved spectrum or a strip of colored lines formed as a result of the decomposition of a ray of light passing through raindrops. The colors are in the following order, if you count from the outer radius to the inner (it’s quite easy to remember this spectrum by learning a simple acrostic phrase: “Every hunter wants to know where the pheasant sits,” here the first letter of each word corresponds to the first letter of the color):

One is Red;

Hunter - Orange;

Wishes - Yellow;

Know - Green;

Where - Blue;

Sitting - Blue;

Pheasant - Purple.

A rainbow can be seen at a time when the Sun is shining in parallel with the rain. To see it, you need to be strictly between the Sun and the rain. In this case, the Sun should be behind, and the rain should be in front.

Quick answer: There are 7 colors in the rainbow.

What is a rainbow? This is an optical phenomenon that can be observed when the Sun (and in some cases the Moon) illuminates a large number of water drops (we are talking about fog or water). A rainbow is an arc-shaped circle with seven colors of the spectrum: blue, violet, green, cyan, orange, yellow and red. It is worth noting that the Sun at the moment of observing a rainbow is always behind the observer, so it is impossible to see both of them at the same time, unless with the help of special equipment.

Where does this optical phenomenon come from? It occurs as a result of the refraction of light in water droplets that float in the atmosphere. Droplets tend to deflect light of different colors differently. White color decomposes into a spectrum, resulting in light dispersion - refraction of a substance, depending on the frequency or phase speed of light. Roughly speaking, the color of the sun passes through the smallest droplets of water, is refracted and is visible to the human eye as several colors at once.

There are two types of rainbows - primary and secondary. In the first case, the light inside the drop is reflected only once, and the shades in this case are quite bright. In the second case, the light is reflected twice and the colors that our eyes perceive are no longer so bright. There are also rainbows of the third and even fourth order, but no one has witnessed this miracle of nature with their own eyes for several centuries.

It is worth noting that the colors in the rainbow are arranged in a sequence that corresponds to the spectrum of visible light. To remember them, in some countries they even came up with such rhymes and phrases. Russia was no exception. In our country several phrases are used at once, here they are:

How Jacques the bell-ringer once broke a lantern with his head.

Every hunter wants to know where the pheasant is sitting.

The mole sewed blue sweatshirts for the sheep, the giraffe, and the bunny.

Every designer wants to know where to download Photoshop.

Who feels the cruel ringing of the gong of resistance to fatality?

The quark is surrounded by a hot curtain of gluons that create fluids.

It is not difficult to guess that the initial letter of each word indicates the initial letter of the color:

Like - red.

One day - orange.

Jacques - yellow.

The bell ringer is green.

The head is blue.

Broke - blue.

Lantern - purple.

A rainbow is an amazing and incredibly beautiful meteorological and optical natural phenomenon. It can be observed mainly after rain, when the sun comes out. This is the reason that we can see this wonderful phenomenon in the sky, and also distinguish the colors of the rainbow, arranged in order.

Causes

A rainbow appears because light emanating from the sun or another source is refracted in droplets of water slowly falling to the ground. With their help, white light “breaks”, forming the colors of the rainbow. They are in order for a reason various degrees light deviations (for example, red light is deviated by fewer degrees than violet). Moreover, a rainbow can also appear due to moonlight, but it is very difficult for our eyes to distinguish it in low light. When the circle formed by the “sky bridge” is formed, the center is always on a straight line passing through the Sun or Moon. For those who observe this phenomenon from the ground, this “bridge” appears as an arc. But the higher the vantage point, the more complete the rainbow appears. If you observe it from a mountain or from the air, it can appear before your eyes in the form of a whole circle.

Order of the colors of the rainbow

Many people know a phrase that allows them to remember the order in which the colors of the rainbow are located. For those who don’t know or don’t remember, let’s remember how this line sounds: “Every Hunter Wants to Know Where the Pheasant Sits” (by the way, now there are many analogues of this famous monostich, more modern, and sometimes very funny). The colors of the rainbow are, in order: red, orange, yellow, green, blue, indigo and violet.

These colors do not change their location, imprinting in memory the eternal appearance of such an incredibly beautiful phenomenon. The rainbow we often see is primary. During its formation, white light undergoes only one internal reflection. In this case, the red light is outside, as we are used to seeing. However, a secondary rainbow can also form. It's pretty a rare event, in which white light is reflected twice in the droplets. In this case, the colors of the rainbow are already arranged in the opposite direction (from purple to red). At the same time, the part of the sky that is located between these two arcs becomes darker. In places with very clean air, you can even observe a “triple” rainbow.

Unusual Rainbows

In addition to the familiar arc-shaped rainbow, you can also observe its other forms. For example, you can observe lunar rainbows (but they are difficult for the human eye to catch; for this, the glow from the moon must be very bright), foggy, ring-shaped (these phenomena have already been mentioned above) and even inverted. In addition, rainbows can be seen in winter. At this time of year it sometimes occurs due to severe frosts. But some of these phenomena have nothing to do with “sky bridges”. Very often it is mistaken for a rainbow (this is the name of a luminous ring that forms around a certain object).

The rainbow is semicircular, of course, what else could it be? This is the correct answer, but can you explain why the rainbow has this shape?

This question occurred to you not only; long before we were born, people observed such a phenomenon as a rainbow and wondered why it is semicircular?

The inhabitants of the African continent even have many legends about a rainbow snake that rings the Earth. It’s just that, of course, their science was not so developed that they even then understood that a rainbow is sunlight that passes through droplets of water and is refracted into them.

But why is the rainbow semicircular? Why not completely round? Not long horizontal? Not vertical? Is it not curved in the shape of a figure eight or, for example, an oval? The shape of the rainbow depends on the shape of the water through which the ray of sunlight is refracted.

As a rule, this beam passes through droplets that have a round, so-called spherical, shape. That is, a ray of light that passes through a drop and is refracted in it, as if breaking up into many colors. But not just chaotically located, but like cones of different colors that fit one in one.

Imagine that you are looking into such a “pyramid” of cones that fit inside each other. The largest of them is red, there is an orange cone in it, then yellow, green, blue, blue, and purple is the smallest, it is inside. And so, each drop of water produces its own, separate rainbow. But she is so tiny that we would never even notice her.

But there are a great many droplets in the air after rain, so the same large iris that is visible to our eyes consists of the same many small irises. Each droplet transmits its specific color to the overall, larger rainbow. All these color rays enter our eye, making up a certain sequence of colors perceived by our vision. It depends on the angle at which light rays of each color fall into our eye, converging in it as if at one point.

“But people see differently,” you will say, and you will, of course, be right. Because no matter how many people find themselves outside after the rain, each of them will see their own, individual rainbow! The droplets change all the time, some of them go down, others, on the contrary, rise up, so the rays are constantly changing, so the rainbow is new every second! And from each new point of view there is also its own, new rainbow.

Why are rainbows more or less bright? This depends on the size of the drops: the larger they are, the brighter the rainbow we see. The color stripes of the rainbow are wide and narrow, adjacent to one another - and with intervals. Rainbows can be taller and narrower, or wider and shorter. It all depends on the size and shape of the droplets through which the light beam is refracted. “Stop,” you say.

“Why do we see a colored semicircle if we were just told about cones inserted into each other?!” Logical question. The fact is that the rainbow is actually round!!! But you can see this only by rising high. And since we observe this natural phenomenon from the ground, we see only half of such a cone, or a little more or a little less. By the way, rainbows happen not only during the day, sometimes such a phenomenon can be observed around the Moon at night, and then we call it a halo. The very word “rainbow” most likely appeared from the combinations “paradise” and “arc”; it is very beautiful.

You can either write your own.

Reverse rainbow

A very rare optical phenomenon. Such a rainbow appears only when several conditions are met. In the sky at an altitude of 7-8 km there should be a thin curtain of cirrus clouds consisting of ice crystals, and sunlight should fall on them at a certain angle in order to be decomposed into a spectrum and reflected into the atmosphere. The colors in an upside down rainbow are also arranged in reverse: purple is at the top and red is at the bottom.

Moon Rainbow

The moonbow phenomenon is observed in only a few places in the world. Moonbows are created using sunlight reflected from the moon. Since this light is much weaker than direct sunlight, to the human eye a lunar rainbow usually appears just white, but a camera with a long exposure can capture it in color.

Fire Rainbow

A fire rainbow is one of the types of halo, a relatively rare optical effect in the atmosphere, expressed in the appearance of a horizontal rainbow.

Round rainbow

Rainbow - this is a ring. Usually we don't see the lower part of it. Bottom part The Earth prevents you from seeing rainbows. In order to see a round rainbow, you must have illuminated drops of water below you.This can be seen from an airplane, looking at the rain from above.