Why are rainbows multi-colored and appear after rain? Why does a rainbow appear?
My friend, have you ever dreamed of walking across a rainbow and ending up in a fairyland? My mood always improves when I see this very beautiful natural phenomenon. Today I will answer your question “How is a rainbow formed?”
A long time ago, people considered the rainbow to be the road to Heaven and believed that along it they could get to the World of the Gods.
Now the rainbow has its own scientific explanation. After rain, some droplets hang in the air without ever reaching the ground. The rays of the sun fall on the raindrops and, reflecting from them, as if from a mirror, scientifically refracted, they become multi-colored.
My friend, have you heard the saying: “Every hunter wants to know where the pheasant sits”? The first letter of each word indicates the order of colors in the amazing and very beautiful natural phenomenon that you learned about today: Red, Orange, Yellow, Green, Blue, Blue, Purple.
The scientist Newton was the first to identify the colors of the rainbow. True, at first he identified only five colors - red, yellow, green, blue and violet. But later I also saw Orange color. However, in those days the number 6 was considered for some reason not very good, and the scientist added a blue tint to the spectrum. Seven, a number equal to the number of notes in the musical scale, seemed very attractive to Newton. They left it that way, although in fact the colors in the rainbow smoothly transition into each other through many intermediate shades.
As far as scientists know, not a single one Living being In the world, except for humans, it is impossible to see a rainbow. And yet it exists. You can only see a rainbow if you are strictly between the sun (it should be behind you) and the rain (it should be in front of you). Otherwise you won't see the rainbow!
It always occurs where the rays of the sun meet droplets of water. For example, at waterfalls, fountains. Or you can make a curtain of drops yourself from a hand-held spray bottle and, standing with your back to the sun, see a rainbow created with your own hands.
Have you noticed that rainbows come in different color saturations? It depends on the size of the drops: the larger they are, the brighter the rainbow. If a rainbow appears in the morning or evening (when the Sun is close to the horizon), then it will appear big size, if during the day (the luminary stands high) - small.
Rainbows can be observed not only during the day, but also at night, in cirrus clouds and even during fog. But you can only see it in its entirety while on an airplane or high mountain. Then it turns out that in fact the rainbow has absolutely round shape, because it’s completely difficult to see it earth's surface. And all because a drop, having a spherical shape and illuminated by a beam of parallel sunlight, can only create a circle.
Inverted Rainbow
Have you ever encountered a rare natural phenomenon - an inverted rainbow? This phenomenon is quite rare. It appears under certain conditions, when cirrus clouds consisting of ice crystals are located at an altitude of 7-8 kilometers as a thin curtain. Sunlight, falling at a certain angle on these crystals, is decomposed into a spectrum and reflected into the atmosphere. The color in an inverted rainbow is located in reverse order: Purple is on top and red is below.
Double Rainbow
We already know that a rainbow in the sky appears because the rays of the sun penetrate through raindrops, are refracted and reflected on the other side of the sky in a multi-colored arc. And sometimes a ray of sunshine can create two, three, or even four rainbows in the sky at once. A double rainbow occurs when a ray of light is reflected twice from the inner surface of raindrops.
The first rainbow, the inner one, is always brighter than the second, the outer one, and the colors of the arcs on the second rainbow are located in a mirror image and are less bright. See a double rainbow - good omen- this is for luck, for the fulfillment of desires. So if you are lucky enough to see a double rainbow, hurry up and make a wish, and it will definitely come true.
Can there be a rainbow without rain?
A rainbow can also be observed on a sunny, clear day near waterfalls, fountains, or in the garden when watering flowers with a hose, holding the hole of the hose with your fingers, creating a mist of water and pointing the hose towards the Sun.
I suggest you watch the video and find out what happens if a beam of white light is passed through a glass prism, and who was the first to do such an experiment?
“Why is there a rainbow?”
Material prepared by Nadezhda Danilova
Since ancient times, people have tried to understand the mystery of the rainbow: why does it appear, what omens are associated with it? Some tribes believed that the “heavenly bridge” leads the chosen ones to the other world, while others believed that it was from these shining stripes that the gods irrigate the lands with moisture.
The double rainbow gave birth to more large quantity ideas and legends. But the scientists’ findings made it possible to understand the exact cause of this phenomenon.
It's all in the drops
Modern ideas about the rainbow are different. It consists of small drops of water, which, due to the refraction of light, create a multi-colored glow. An iridescent arc can light up in the sky immediately after heavy rain or ordinary fog; it can be easily seen by directing a stream from a hose onto the beds. You can notice it while on the shore of a lake or standing near a river.
Only 7 colors of the “sky bridge” are accessible to the human eye, but in fact there are many more shades in it! The brightness and size of the arc depend on how large the raindrops are: the largest of them provide the rainbow with rich colors.
Also, the size of the droplets determines the color of the “sky bridge”. Small ones produce dull yellow edges on the rainbow. If there are large ones, red color will predominate in it.
Scientists have found that at a refraction angle of just over 40 degrees, the rainbow will become visible to the viewer. But the light source must be behind the person’s back. The best way to observe this natural phenomenon is while on top of a mountain or looking out of an airplane window.
Two, three - who is more?
Signs say: if a double rainbow flashes in the sky, you can safely make a wish. This happens when a beam of light passes through the droplets twice. According to long-term observations, this portends inclement weather. The strip of sky between the “bridges” is always dark.
By the way, there may not be 2 rainbows after rain, but more - 3 or even 4. A magnificent sight!
The real lucky ones can be considered those people who have seen a rare event- an inverted rainbow. This only happens when rays of light strike a thin layer of cirrus clouds at a certain angle. Clouds, in turn, must consist of tiny ice crystals.
Most often, such an extraordinary “sky bridge” can be observed in the northern countries.
“Foggy”, “night”, “fiery”
What other types of rainbow are there? Scientists highlight the following:
- foggy;
- night;
- fiery;
- winter
Foggy occurs when rays of sunlight break through the tiny droplets of moisture that make up the fog. This is a pale, delicate, barely noticeable rainbow. But it can be seen even at night, during the full moon.
And if it’s raining and the Moon is shining brightly, you will be mesmerized by the spectacle of the “night” celestial arc. Why does a rainbow appear at this time of day? The Earth's satellite is low above the horizon, and its light falls on water droplets at a certain angle. Also at night, you will see a glow of a strip of seven colors if you are near flowing water: these could be fountains or waterfalls.
The fiery one is also an infrequent guest in our sky. The angle of incidence of sunlight through cirrus clouds should be about 58 degrees. And the ice crystals that make them up must have no more and no less, but 6 faces. Light breaking through them will give the desired effect - a rainbow the color of fire will appear.
And the last, also a rare guest - winter. When the time comes for severe frosts, the following factors may coincide. The sun shines brightly in a cloudless, pale blue sky, and at this time tiny ice crystals are scattered in the air. As a result of the reflection of light rays from them, a seven-color arc lights up.
A rainbow after rain is a long-studied phenomenon, and yet its appearance is perceived every time as a miracle.
Insafudinov Kirill Rinatovich
I learned how a rainbow is made. I conducted research and experiments, got a rainbow at home and admired its beauty.
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Ministry of Education of the Republic of Bashkortostan
education administration department municipal district Bizhbulyak district
municipal educational budgetary institution
average comprehensive school No. 2 p. Bizhbulyak
Research
on the topic of:
« How do you get a rainbow?
Completed: Insafudinov Kirill,
Student of grade 3b, Municipal Educational Institution Secondary School No. 2, Bizhbulyak village, Republic of Bashkortostan
Head: Nazmieva A.R.
Primary teacher
Classes MOBU secondary school No. 2 in the village of Bizhbulyak, Republic of Bashkortostan
Introduction ________________________________page 3
Literature review
What is a rainbow? _________________________________ page 4
Who colored the rainbow? _____________________ page 4
The emergence of a rainbow. ____________________ page 4
Who studied the rainbow? ________________________page 5
Rainbows come in different forms. _____________________ page 5
Experimental work________________page 6
Results ________________________________page 7
4. Conclusions ___________________________________page 7
5. Conclusion______________________________page 7
6. Literature___________________________ page 7
Introduction.
What natural phenomenon can be compared in beauty to a rainbow? Maybe Polar Lights, but not many people saw him. And everyone has seen the rainbow that appears immediately after the rain.Appearing in the sky, she attracts attention.
She is so beautiful that she is sung in many songs, described in literature, and legends are made about her. Many people, like me, look forward to the rain so they can admire the rainbow. What kind of multi-colored miracle of nature is this? How is a rainbow formed? Is it possible to observe this beauty at home? What other rainbows are there?
These questions interested me and many of my friends. This topic became interesting to me because not many people know how a rainbow is formed. To answer all the questions that arose, I decided to conduct research.
By exploring this mystery of nature, I can give an accurate answer to the questions I posed.
Target my work: find out the reason for the appearance of a rainbow, getting a rainbow at home.
Delivered by me tasks :
Find out who colored the rainbow.
Try the experience of getting a rainbow at home.
Learn the history of the study of rainbows.
The relevance of research:instilling interest in experimental work in elementary school
Thanks to this work, activity in cognitive sphere activities.
Hypothesis: Rainbows can be obtained in laboratory conditions, is it possible to obtain them at home? If possible, then in what way.
Research methods:
Questionnaire
Independent practical experiments for confirmation
hypotheses:
experiment: with prism;
experience with a spray gun;
experience with soap bubbles;
experience with a mirror;
experience with a computer disk.
1.Literature review
1.1. What is a rainbow?
In order to find out the reason for the appearance of rainbows, I started by studying literature. The explanatory dictionary gives the concept of a rainbow. A rainbow is a multi-colored arc in the sky, formed as a result of the refraction of sunlight in raindrops.
I learned that rainbows can be seen near waterfalls, fountains, and sprinklers. At fountains and waterfalls it happened that two or more arcs were seen. You can create a curtain of droplets yourself from a hand-held spray bottle and, standing with your back to the sun, see a rainbow created with your own hands. When watering plants in the garden on a bright sunny day, you can also see a small rainbow in the splashes of water.
1.2. Who colored the rainbow?
Where does the amazing colorful light that comes from the arcs of the rainbow come from?
I received the answer to this question from the encyclopedia for the curious. It seems to us that the light is white. But in fact it consists of several colors. It happens that when it rains, the sun comes out, and then the sunlight is refracted in water droplets and “breaks up” into several colors. There are always seven of these colors, and they are arranged in strict order. Red, orange, yellow, green, blue, indigo, violet. This creates a colorful rainbow. An object that can split a beam of light into its components is called a “prism.” The resulting colors create a stripe of colored lines called a “spectrum”. A rainbow is a large spectrum, or band of colored lines, formed as a result of the decay of a ray of light passing through raindrops. In this case, raindrops act as a prism.
1.3. The emergence of a rainbow.
Rainbows always appear after rain, I think everyone knows that. But there is another trick here. The rainbow sparkles not after, but during the rain; the rain simply no longer falls on us, but not far from us. When the rain stops, it means that the wind has simply carried these rain clouds further.
And if the rain goes towards the sun, then we can admire the rainbow. After all, drops split the sunlight, white light, because they are small prisms and reflect these multi-colored rays in the sky. I think everyone has seen a drop falling from the hole in the sink faucet, so everyone will agree that it looks like a prism.Light enters a raindrop, reflects off the other side of the raindrop, and exits. And rain is millions of such droplets.That's the whole secret of this beautiful natural phenomenon. Rain dots the entire sky with small prisms, and sunlight, passing through them, is split into a spectrum. At the same time, we have a wonderful picture in the sky - a rainbow.
I have a question - is it possible to create a rainbow yourself? The answer to the question is described on page No. 7.
1.4. Who studied the rainbow?
Has anyone in the history of mankind tried to understand the nature of the rainbow?
My mother and I found the answer to this question on the Internet.
The first attempt to explain the rainbow was made in 1611 by Archbishop Antonio de Dominis. His explanation of the rainbow was contrary to the Bible, so he was excommunicated and sentenced to death. death penalty.
The scientific explanation of the rainbow was first given by Rene Descartes in 1637. Descartes explained the rainbow based onlawsrefraction and reflection of sunlight in drops of falling rain. But he did not yet know about the decomposition of white light into a spectrum during refraction. That's why Descartes' rainbow was white.
30 years later, Isaac Newton explained how colored rays are refracted in raindrops. According to the figurative expression of the American scientist A. Fraser, who has made a number of interesting studies of the rainbow in our time, “Descartes hung the rainbow in the right place in the sky, and Newton colored it with all the colors of the spectrum.”Although the multicolor spectrum of the rainbow is continuous, according to tradition, it is divided into 7 colors. It is believed that Isaac Newton was the first to choose the number 7, for whom the number 7 had a special symbolic meaning. Moreover, initially he distinguished only five colors - red, yellow, green, blue and violet. But, subsequently, trying to create a correspondence between the number of colors of the spectrum and the number of fundamental tones of the musical scale, Newton added two more to the five listed colors of the spectrum.
Even though the Descartes-Newton theory of the rainbow was created more than 300 years ago, it correctly explains the main features of the rainbow, including the arrangement of colors.
1.5. Rainbows come in different forms.
Rainbows come with one or two arcs.Few people know, but there is also a night rainbow. At night, when the rain stops, a rainbow can also appear as a result of the action of rays reflected by the moon. Undoubtedly, it is not as bright as during the day, but it is clearly visible. IN winter time A rainbow occurs very rarely, but in its colorfulness and picturesqueness it differs from all others.
1.Questionnaire
My classmates and I conducted a survey.
To the first question, “Have you seen a rainbow?” all 14 students answered “Yes.”
To the second question, “Do you know when a rainbow appears?” 12 people answered “Yes”, two “No”.
To the third question, “Do you know how a rainbow appears?” 5 people answered “Yes”, 9 - “No”.
To the fourth question, “Do you know in what order the colors of the rainbow are located?” 6 students answered “Yes”, 8 - “No”.
To the fifth question, “Is it possible to get a rainbow at home?” three answered “Yes”, 11 people answered “No”.
2. Experimental work
I experimented with producing a rainbow at home.
Experience 1.
Equipment: mirror, glass prism.
Description: the teacher caught a “sunny bunny” with her mirror and pointed it at the glass prism that I was holding in my hand. A rainbow appeared on the ceiling.
Experience 2.
Equipment: spray bottle filled with water, sun light source.
Description: create a cloud of drops falling in the air and observe a rainbow on them.
The conditions of such an experiment are quite consistent with nature, however, obtaining the required cloud is not at all easy.
Experience3
Equipment: a jar of soapy water, a device for blowing bubbles.
Description: take the device, dip it in a jar of soap foam and blow out bubbles. You can see a rainbow on the bubbles flying in the air.
Experience 4.
Equipment: mirror, bowl of water.
Description: I placed the mirror in a shallow bowl of water. Place the bowl so that a ray of light from the sun is reflected from the mirror onto the wall or ceiling.
I saw a rainbow on the ceiling. The experiment was a success.
Experience 5.
Equipment: computer disk, light source - sun.
Description: On a sunny day, point the computer disk at an angle of 25°. If the disk “catch” a ray of light, then as a result of the refraction of the ray a rainbow will appear on the wall or ceiling.
Results.
After studying the literature, I learned that a rainbow can be one arc, or it can be double.There is a night rainbow (lunar) and a winter one, but it is very rare and not as colorful as the summer one.
Sunlight is refracted in water droplets and “breaks up” into several colors. These colors are called the spectrum. And the drops are small prisms that reflect these multi-colored rays in the sky. This is how I learned how a rainbow appears and why it is colored.
From the history of studying the rainbow, I found out that many tried to explain the nature of this phenomenon, but this phenomenon was fully discovered by Isaac Newton more than 300 years ago.
I managed to get a rainbow at home. The experiment was successful and I could admire this beauty at home.
Conclusions.
Based on the results obtained, I came to the conclusion that:
1. The cause of a rainbow is the refraction and “disintegration” of sunlight in drops of water and the reflection of this light in the sky.
2. Obtaining and observing rainbows at home is possible.
Conclusion
Having completed this work, I became convinced that rainbows are a well-known optical phenomenon in the atmosphere; observed when the sun illuminates a sheet of falling rain and the observer is between the sun and the rain. Rainbows are seen not only in the veil of rain. On a smaller scale, it can be seen on drops of water near waterfalls, fountains and in the surf. In this case, not only the Sun and the Moon, but also a spotlight can serve as a light source.
The arrangement of colors in the rainbow is interesting. It is always constant. The red color of the main rainbow is located on its upper edge, violet - on the lower edge. Between these extreme colors, the remaining colors follow each other in the same sequence as in the solar spectrum. In principle, a rainbow never contains all the colors of the spectrum. Most often, blue, dark blue and rich pure red colors are absent or weakly expressed. As the size of raindrops increases, the color stripes of the rainbow narrow, and the colors themselves become more saturated.
At the same time, I learned how, thanks to Newton, centuries-old ideas about the origin of flowers were destroyed.
Obtaining a rainbow by an experimental method (artificial rainbow) allows us to study this rainbow. The results obtained during the study may be of interest to schoolchildren.
Literature:
1. Ozhegov S.I. and Shvedova N.Yu. Explanatory dictionary of the Russian language. 4th edition, expanded. - M.: LLC “A TEMP”, 2008.
2. Travina I.V. 365 stories about planet Earth / Popular science publication for children. - M.: JSC "ROSMAN-PRESS", 2007.
3. Encyclopedia for the curious “Where, what and when?” CJSC Company "Makhaon" - M.: 2007.
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Introduction
Relevance of the work
In the summer, I often went with my parents to the garden, which is located outside the city. One evening, we were sitting and having dinner on the street, suddenly clouds gathered and rain began to pour down. We hid under a canopy and watched surrounding nature. It smelled of wet earth and grass, and the air became clean and fresh. And then the rain subsided, in some places blue gaps appeared in the sky, the sun's rays slipped through them. And suddenly, a multi-colored arc spread across the entire sky, like a huge gate in the sky. Not just one, but two! We were all very happy and began to admire and photograph the double rainbow. But the rainbow did not delight us with its beauty for long.
Rainbow is one of the most beautiful phenomena nature. She brings so much joy to both children and adults. Her appearance causes positive emotions, lifts people's spirits. Konstantin Dmitrievich Ushinsky has a fable “The Sun and the Rainbow”. “Once after the rain the sun came out, and a seven-color arc of a rainbow appeared. Whoever looks at a rainbow, everyone admires it. The rainbow became proud, and began to boast that it was more beautiful than the sun itself. The sun heard these speeches and said: “You are beautiful - this is true, but without me there is no rainbow.” And the rainbow just laughs and even praises itself. Then the sun got angry and hid behind a cloud - and the rainbow was gone.” So is it really possible for a rainbow to appear without the sun? Why doesn't a rainbow happen in sunny weather without rain, or in rainy weather without sun?
Today, not every person can explain the appearance of a rainbow. Where does a rainbow come from? Why do her colors appear in a certain order? Why is there a double rainbow? Is it possible to get a rainbow artificially, for example, at home? To answer all these questions, I decided to conduct my own research.
Research hypotheses:
Rainbows appear in nature only on sunny and rainy days;
You can get a rainbow at home using an artificial light source.
Goal of the work:
Find out the reason for the appearance of a rainbow.
Tasks:
Define a rainbow;
Find out the conditions for the appearance of rainbows in nature;
Find out how many colors a rainbow has and what the solar spectrum is;
Find out what rainbows are;
Try to get a rainbow at home in different ways.
Object of study: rainbow
Research methods :
Studying specialized literature and Internet sources;
Conducting experiments on obtaining a rainbow at home, using an artificial light source;
Analysis of the results obtained.
2. Theoretical material
2.1. What is a rainbow?
There are several theories explaining its origin. According to one of them, radoga is derived from the Proto-Slavic root radъ, the meaning of which is similar to the Anglo-Saxon rot (joyful, noble).
Some language researchers are inclined to assume that the word "rayduga", as this word is pronounced in a number of dialects of the modern Russian language, has a folk etymology, formed as a result of the merger of the words "paradise" and "arc". It sounded the same way in Russian in the 17th and 18th centuries. In this case, rainbow literally means “variegated arc.”
IN Slavic myths and in legends, the rainbow was considered a magical heavenly bridge, spanned from heaven to earth, a road along which angels descend from heaven to collect water from rivers. They pour this water into the clouds, and from there it falls as life-giving rain.
I read the meaning of the word “rainbow” in various dictionaries:
"Rainbow - a multi-colored arc on the vault of heaven, formed due to the refraction of sun rays in raindrops" (Ozhegov's Explanatory Dictionary). "Rainbow- a multi-colored arc in the sky. Observed when the Sun illuminates a curtain of rain located on the opposite side of the sky from it. Explained by the refraction, reflection and diffraction of light in raindrops.” (Modern Dictionary. Astronomical Dictionary).
So, I found out that a rainbow is a multi-colored arc in the sky, formed due to the refraction of sun rays in raindrops.
2.2. The reason for the appearance of the rainbow
Aristotle, ancient Greek philosopher, tried to explain the reason for the appearance of the rainbow. He determined that "a rainbow is an optical phenomenon, not a material object." Aristotle theorized that rainbows arise from the unusual reflection of rays of sunlight from clouds.
The phenomenon of rainbows was explained by the refraction of sunlight in raindrops in 1267 by Roger Bacon.
The first to understand the reason for the rainbow was the German monk Theodoric from Freiberg, who in 1304 recreated it on a spherical flask with water. However, Theodoric's discovery was forgotten.
An attempt to explain the rainbow as a natural phenomenon was made in 1611. Archbishop Antonio Dominis. His explanation of the rainbow was contrary to the Bible, so he was excommunicated and sentenced to death. Antonio Dominis died in prison before his execution, but his body and manuscripts were burned.
A scientific explanation of the rainbow was also given by the French philosopher, mathematician, and mechanic Rene Descartes in 1637. Descartes explained the rainbow based on the laws of refraction and reflection of sunlight in raindrops. At that time, the decomposition of white light into a spectrum during refraction had not yet been discovered. That's why Descartes' rainbow was white.
The founder of the seven-color rainbow was Isaac Newton, who revealed the reason for the appearance of the rainbow.
2.3. Refraction of rays. Range
Back in 1666, Isaac Newton proved that ordinary white light is a mixture of rays different color. “I darkened my room,” he wrote, “and made a very small hole in the shutter to let in the sunlight.” On a way sunbeam The scientist placed a special triangular piece of glass - a prism. On the opposite wall he saw a multi-colored strip - a spectrum. Newton explained this by saying that the prism split white light into its component colors. Newton was the first to realize that the sun's rays are multicolored.
Rainbow is the most famous, well-known spectrum. When it rains, there is a huge amount of water droplets in the air. Each drop of rain plays the role of a tiny prism. The sun's rays that pass through raindrops, as if through prisms, are refracted in the raindrops. As a result of the decomposition of light rays, a large curved spectrum appears - a strip of colored lines and is reflected on opposite side sky. When it rains, there is a huge amount of water droplets in the air. And since there are many of them, the rainbow turns out to be half the sky.
Let's trace the path of the beam passing through the drop. Having refracted at the boundary of the drop, the beam enters the drop and reaches the opposite boundary. Part of the beam, having refracted, leaves the drop, part again goes inside the drop to the next boundary. Here again, part of the beam, having refracted, comes out of the drop, and some part goes through the drop, and so on. Each white ray, refracted in a drop, is decomposed into a spectrum, and a beam of diverging colored rays emerges from the drop.
There are seven colors in the solar spectrum: red, orange, yellow, green, blue, indigo and violet.
2. 4. Colors of the rainbow
And now in more detail about the colors of the solar spectrum or the rainbow. Research has shown that the human eye can distinguish 160 shades of color. This happens because there is no clear boundary between colors; one color passes into another through all shades. The main colors of the rainbow are red, yellow and blue. From them you can get all the other colors of the rainbow. The colors observed in a rainbow alternate in the same sequence as in the spectrum obtained by passing a beam of sunlight through a prism. In this case, the inner (facing the Earth's surface) extreme region of the rainbow is colored violet, and the outer extreme region is red.
Sometimes as many as 2, 3, 4 rainbows are visible in the sky - one of them is very bright, the second is paler. This means that the sun's ray is reflected twice in the water drops. At the same time, in another rainbow, the colors of the stripes are arranged in the reverse order - top part the arc is purple, and the lower one is red. Second rainbows are formed due to the double reflection of sunlight within raindrops.
Rainbow colors: red, orange, yellow, green, blue, indigo, violet. There are also many shades between these colors, so there is no clear transition from one color to another. The colors of the rainbow are arranged in strict sequence. To better remember their sequence, people came up with the following phrase: “ TO every ABOUT hunter AND wants Z nah, G de WITH goes F adhan." The first letters of words are used to remember colors. The outer edge of the arch is usually red, and the inner edge is purple.
Rainbows have always been seen differently in different periods history and in different peoples. It distinguished three primary colors, and four, and five, and as many as you like. The Rainbow Serpent of the Australian Aborigines was six-colored. Some African tribes They see only two colors in the rainbow - dark and light. So where do the seven colors in the rainbow come from? As I reported earlier, only Newton thought of analyzing light. And, first, he counted five colors. Subsequently, seeing another color (orange), he considered it a theological obsession (the number 6 was devilish for him), trying to create a correspondence between the number of colors in the spectrum and the number of basic tones of the musical scale. Newton added one more to the six listed colors of the spectrum - indigo. Indigo is a variety of violet color, intermediate between dark blue and violet. The name comes from the indigo plant, native to India, from which the corresponding dye was extracted and used to dye clothes. Thus Newton became the father of the seven-color rainbow.
The division of the spectrum into seven colors took root, and in English language the next memory appeared - Richard Of York Gave Battle In Vain (In - for blue indigo). And over time, they forgot about indigo and there were six colors. American children are taught the six primary colors of the rainbow. English (German, French, Japanese) too. But it's even more complicated. In addition to the difference in the number of colors, there is another problem - the colors are not the same. The Japanese, like the British, believe that there are six colors in the rainbow. And they will be happy to name them for you: red, orange, yellow, blue, indigo and violet. Where did the green go? Nowhere, it's in Japanese simply no. Japanese people rewriting Chinese characters, the green hieroglyph was lost (in Chinese he is). The British will agree with the Japanese on the number of colors, but not on the composition. The English don't have it in their language blue color. And if there is no word, then there is no color. American orange is by no means our orange, but often rather red (in our understanding). By the way, in the case of hair color, on the contrary, red is a red color.
2.5. Unusual Rainbows
During the research, I learned that on earth there are different rainbows, but most often an ordinary rainbow is observed. There are many other optical phenomena known to occur for similar reasons or appear to appear. Let's look at what rainbows are.
Lunar (night)
Rainbows can also be seen at night under the light of the moon. A lunar rainbow (also known as a night rainbow) is a rainbow created by the moon. A lunar rainbow is comparatively paler than a normal rainbow. This is explained by the fact that the Moon reflects less light from the Sun than the Sun shines during the day. A lunar rainbow is visible when the night star is very bright - the Moon. At night, when the full, definitely full moon hangs high in the dark, necessarily dark, sky, and at the same time opposite the moon is coming rain, you might be lucky enough to see a rainbow at night! And she will also seem white to us. Although in fact it is multi-colored.
Hazy (white) rainbow
A white or misty rainbow is a rainbow that appears as a wide, brilliant white arc. A fog rainbow appears when the sun's rays illuminate a faint fog consisting of very small droplets of water. Why does the rainbow seem white to us? The point is the size of the droplets from which the sun's rays are reflected. The sizes of the fog particles are so small that the individual colored stripes into which a sunbeam breaks up when refracted do not spread out to the sides like a wide multi-colored fan, but barely open. The colors seem to overlap each other, and the eye no longer distinguishes colors, but sees only a colorless light arc - a white rainbow. A foggy rainbow can also appear at night during fog, when there is a bright moon in the sky. A foggy rainbow is a rather rare atmospheric phenomenon.
Inverted Rainbow
An inverted rainbow is a fairly rare phenomenon. . Unlike a traditional rainbow, a “smile in the sky” appears in a clear sky, without rain clouds. The sun's rays must illuminate at a certain angle a thin haze-like curtain of clouds at an altitude of 7 - 8 thousand meters. At this altitude, cirrus clouds are made of tiny ice crystals. Sunlight, falling at a certain angle on these crystals, is decomposed into a spectrum and reflected into the atmosphere. An inverted rainbow is much brighter than a normal rainbow, and the colors are in reverse order, from purple to red. But as soon as the order of the crystals is disrupted, the colorful effect disappears, and the “smile in the sky” dissolves.
Double Rainbow
We already know that a rainbow in the sky appears because the rays of the sun penetrate through raindrops, are refracted and reflected on the other side of the sky in a multi-colored arc. And sometimes a ray of sunshine can create two, three, or even four rainbows in the sky at once. A double rainbow occurs when a ray of light is reflected twice from the inner surface of raindrops. The first rainbow, the inner one, is always brighter than the second, the outer one, and the colors of the arcs on the second rainbow are located in a mirror image and are less bright. The sky between rainbows is always darker than other parts of the sky. The area of sky between two rainbows is called Alexander's stripe. Seeing a double rainbow is a good omen - it means good luck, fulfillment of desires. So if you are lucky enough to see a double rainbow, like me, then hurry up and make a wish, and it will definitely come true.
winter rainbow
The most amazing thing is the rainbow in winter! This is very strange and unusual. The frost is crackling, and suddenly a rainbow appears in the pale blue sky. A winter rainbow can only be observed in winter, during severe frost when the cold Sun shines in the pale blue sky and the air is filled with small ice crystals. The sun's rays are refracted when passing through these crystals, as if through a prism, and are reflected in the cold sky in a multi-colored arc. A ray of sun passes through these crystals, is refracted, as in a prism, and reflected in the sky as a beautiful rainbow.
Ring rainbow
As I explained above, the rainbow itself is round. But we see only part of it in the form of an arc. But under certain circumstances it is possible to see a ring rainbow. This is only possible with high altitude, for example, from an airplane.
Round-horizontal or fiery rainbow
A round-horizontal or fiery rainbow is formed when sunlight passes through light cirrus clouds and occurs only when the sun is very high in the sky. It turns out that the mysterious heavenly “fire” is born from ice! After all, cirrus clouds are located very high above the earth, where it is very cold at any time of the year, and therefore they consist of flat ice crystals! The sun's rays, passing through the vertical edges of an ice crystal, are refracted and ignite a fiery rainbow or a rounded horizontal arc, as science calls a fiery rainbow. A fire rainbow is a relatively rare and unique phenomenon.
Red
A red rainbow appears in the sky only at sunset and is the last chord of an ordinary rainbow. Sometimes it can be extremely bright and remain visible even 5-10 minutes after sunset. At sunset, rays travel a longer path through the air, and since the refractive index of water for longer wavelength (red) light is less than for shorter wavelength (violet), red light bends less when refracted. When the Sun drops below the horizon, the rainbow first loses its shortest violet waves, they dissipate immediately. Then the blue, cyan, green and yellow waves disappear. The most persistent one remains - the red arc.
3. Practical part
3.1 Own research.
Experiments with producing rainbows at home
I conducted several experiments on obtaining a rainbow under an artificial light source:
Experience #1: making a rainbow at home using a CD.
Equipment: CD, light source - flashlight.
I took the CD and, using it to “catch” the light from the flashlight, directed it at the wall. It turned out to be a rainbow. (Appendix No. 1, photos No. 1,2)
Experience No. 2: making a rainbow at home using a mirror, water and a flashlight.
Progress of the experiment:
Filled the glass container with water;
I placed a tilted mirror in the water;
She directed the light of the flashlight onto the part of the mirror immersed in water;
As a result of the refraction of the ray in water and its reflection from the mirror, a rainbow appeared on the cabinet door (Appendix No. 1, photos No. 3, 4).
Experience No. 3 : Making a rainbow at home using a glass prism and a flashlight. The experience of decomposing light into a spectrum when a white beam of light passes through a prism.
To do this, I took a glass keychain, directed a white beam of light from a flashlight onto it, and got an image of a rainbow on the wall. The light, which seemed white, played on the wall with all the colors of the rainbow. These seven-color, bright rainbow stripes are called the solar spectrum. So I repeated Newton's experiment, but only with an artificial light source . (Appendix No. 1, photos No. 5,6)
Conclusion : You can get a rainbow at home even with the help of an artificial light source.
Experience No. 4: obtaining white color due to the merging of the seven colors of the spectrum, using a seven-color disk and a drill.
If light consists of seven colors, then seven colors must give White color. I divided the white circle into 7 parts and colored it in rainbow colors. My brother and I attached a multi-colored circle to a drill. Having turned on the drill, we saw that when rotating, the multi-colored disk changed color and became white (Appendix No. 1, photos No. 7,8,9).
Conclusion: light consists of seven colors.
Experience No. 5: making a rainbow using soap bubbles.
I prepared a soap solution and blew a soap bubble. A rainbow appeared on the bubble. Light passing through a soap bubble is refracted and splits into colors, resulting in a rainbow. A soap bubble is a prism. (Appendix No. 1, photos No. 10,11)
Experience No. 6: getting a rainbow on a sunny day using a water hose.
If the sun shines bright there's another one the right way make a rainbow. But for this you will have to go outside and take a hose and connect it to a water tap. Now all that remains is to pinch the end of the hose so that the water is finely sprayed when it comes out of the hole in the hose, and direct it upward into the sun. We will see a rainbow in the splashes of water. A rainbow can be seen near waterfalls, fountains, against the background of a curtain of drops sprayed by a sprinkler or field sprinkler. (Appendix No. 1, photo No. 12).
conclusions
While working on the topic: “How does a rainbow appear?”, I achieved my goal research work. Now I know the reason why rainbows appear and I was able to create a rainbow at home. It is hypothesized that rainbows appear in nature only on a sunny and rainy day, turned out to be wrong. I found out that a rainbow can appear on a moonlit night (without the sun), during fog (without rain), without rain on a sunny day (inverted and fiery rainbows), and also in winter (without rain) during frost. Of course, the appearance of a rainbow on a sunny and rainy day happens most often, but not only. I found out what the connection is between rain, sun and the appearance of a rainbow. I think that I helped solve the mystery of the sunbeam and gave an explanation of the rainbow as a natural phenomenon. I have experimentally proven that the rainbow effect can be achieved at home and at any time of the year. All assigned tasks have been completed. Now I know when a rainbow appears and how it is formed. Whenever you want to admire a rainbow, I hope that now you can get a rainbow at home. Rainbow - amazing phenomenon nature, one might say a miracle of nature that will never cease to amaze us.
5. References
1. I.K. Belkin “What is a rainbow?”, Kvant. - 1984 - No. 12.
2. V.L. Bulat " Optical phenomena in nature" - M.: Education, 1974.
3. A. Bragin “About everything in the world.” Series: Great Children's Encyclopedia.
4. Ya.E. Geguzin “Who creates the rainbow?” - Kvant, 1988
5. V.V. Mayer, R.W. Mayer "Artificial Rainbow." Quantum 1988 - No. 6.
6. “What is it? Who it?" - children's encyclopedia, comp. V. S. Shergin, A. I. Yuryev. - M.: AST, 2007.
7. E. Permyak “Magic Rainbow”, 2008 Publishing house Eksmo
8. Internet sources.
Appendix No. 1
Experience No. 1
Photo No. 1 Photo No. 2
Experience No. 2
Photo No. 4
Photo No. 3
Experience No. 3
Photo No. 5 Photo No. 6
Experience No. 4
Photo No. 7 Photo No. 8 Photo No. 9
Experience No. 5
Photo No. 10 Photo No. 11
Experience No. 6
According to the Bible, the rainbow is a symbol of God's promise to mankind to never again cause . Indeed, often a rainbow is evidence that it has rained somewhere nearby. As a rule, we see a rainbow in sunny weather, when there are rain clouds (usually cumulonimbus) at a short distance. To find out what a rainbow is, in this article we will talk about its two components: sunlight and raindrops.
Primary and secondary rainbows.
Why and where do rainbows come from?
Sunlight is a mixture of colors. When light rays pass through a glass prism, some of them are bent and refracted more than others. Light emerging from a prism spreads out into a continuous band of colors called a spectrum. The colors go from red, which is the least curved, through orange, yellow, green and blue to the most purple. Purple curved the most.
Sunlight passing through water droplets is refracted in the same way as sunlight passing through a prism. This creates an atmospheric solar spectrum in the sky that we call a rainbow.
In short, a rainbow is a group of semi-circular arcs of color that appears as a huge arch in the sky. Rainbows are often visible after rain. They are formed when sunlight breaks through rain clouds. Raindrops act like miniature prisms that refract or break up sunlight into different colors and also reflect it to create a spectrum.
We can easily create an artificial rainbow at home using a garden hose. You just need to stand with your back to the sun and adjust the watering of the hose to a fine spray, thus creating a water “mist”. A rainbow can also be seen opposite the place where the spray of the waterfall falls.
Rainbow at Victoria Falls (on the border of Zambia and Zimbabwe)
If there is only one rainbow, or if it is the main one, then such a rainbow always has a red color on the outside (top) of the arc and blue on the outside. inside. Typically, the radius of a rainbow is about one-quarter of the visible sky, or 42 degrees. When there is rain nearby, we need to look at that part of the sky that is opposite the sun at an angle of 42 degrees relative to our shadow; This is where the rainbow should appear.
Sometimes you can see another, less bright rainbow around the main one. This is a secondary rainbow, which is formed by light reflected twice in drops. In a secondary rainbow, the order of colors is “inverted” - red is on the inside, purple is on the outside. A secondary rainbow forms at an angle of 50-53° relative to our shadow. The area between the two rainbows appears relatively dark because it lacks both once and twice reflected rays. The secondary rainbow is weaker than the main one and usually disappears faster.
There is even evidence of a third or tertiary rainbow, but this phenomenon is considered extremely rare. Several observers also reported seeing quadrangular rainbows in which the faint outer arc had a rippling and pulsating appearance.
Who was the first to define what a rainbow is?
We cannot say with absolute certainty who was the first to give the correct explanation of what a rainbow is. Primacy is usually given to the Frenchman René Descartes (1596-1650), the philosopher and writer who systematically addressed this issue in an appendix to his famous work Discourse on Method in 1637.
Descartes supposedly made an accurate calculation of the paths that light rays took in different points glass globe filled with water (imitation of a raindrop), thereby determining the angles of their refraction. This was the solution to a mathematical problem that had eluded scientists for two millennia and was the key to explaining what a rainbow is.
But note that Descartes only “supposedly” made this calculation. As it turns out, Willebrord Snell, a Dutch astronomer and mathematician, discovered the mathematical law of light refraction 16 years before Cartes' dissertation on the subject. However, Snell was unable to publish his work and died in 1626. Then, some 80 years after Snell's notes were discovered, controversy arose that Descartes had somehow seen Snell's manuscripts and passed off their conclusions as his own. 
The end result was that in the West, especially in English speaking countries, the law of refraction of light became known as Snell's Law, and in France it is called Descartes' Law.
So, although Descartes explained what a rainbow was, he really couldn't do it without precise calculations of the refraction of light. But to whom exactly, Descartes or Snell, this part of the work belongs, we may never know.
Where and when can you see a rainbow?
Sailors know that rainbows can be used to predict the weather. Generally speaking, showers and thunderstorms move from west to east, so sailors are guided by the old adage:
Rainbow in the morning - it will rain; rainbow in the evening - good weather.
In the morning the sun is in the east, and to see the rainbow we must face the west, where it's raining. Since rains usually come from the west, a morning rainbow can warn us about this. Late in the evening the sun is in the western part of the sky. After the rain or thunderstorm has passed over or past us, it usually retreats to the east, where we will see the rainbow.
And since thundershowers are more common in the late afternoon than in the early morning, rainbows are much more common in the evening. It is for this reason that the appearance of a rainbow is usually associated with the beginning of better weather.
If the sun sets or rises, the full arc of the rainbow can be seen. If the sun is at an angle of 42 degrees or higher above the horizon, we will not be able to see the rainbow because it will be below the horizon. A clenched fist held at arm's length is approximately 10 degrees; therefore, if the sun is approximately "four fists" above the horizon, we will not see a rainbow. The only way to see a rainbow at this time will be from an airplane or from the top high mountain. The plane will provide best opportunity see the entire 360-degree rainbow projected onto the earth, but this sight is so rare that only a few are lucky enough to see it.
Source: Environmental blog(website)
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