Description: War Thunder is a next generation military MMO game dedicated to...
Rainbow is one of the most amazing phenomena nature. What is a rainbow? How does she appear? These questions have interested people at all times. Even Aristotle tried to unravel its mystery. There are many beliefs and legends associated with it (the road to the next world, the connection between heaven and earth, a symbol of abundance, etc.). Some peoples believed that the one who passes under the rainbow will change their gender.
Her beauty amazes and delights. Looking at this colorful "magic bridge", I want to believe in miracles. The appearance of a rainbow in the sky notifies that the bad weather is over and a clear sunny time has come.
When does a rainbow happen? It can be observed during rain or after a downpour. But for its occurrence, lightning and thunder are not enough. It appears only if the sun breaks through the clouds. Certain conditions are needed in order for it to be noticed. It is necessary to be between the rain (it should be in front) and the sun (it should be behind). Your eyes, the center of the rainbow and the sun must be on the same line, otherwise this magic bridge you can't see!
Surely many have noticed what happens when a ray falls on a soap bubble or on the edge of a beveled mirror. It is divided into various colors (green, blue, red, yellow, purple, etc.). The object that breaks the beam into its component colors is called a prism. And the resulting multi-colored line is a spectrum.
So what is a curved spectrum, a colored band formed as a result of the separation of a beam of light when passing through raindrops (they are a prism in this case).
The colors of the solar spectrum are arranged in a certain order. On the one hand - red, then orange, next to it - yellow, green, blue, blue, purple. The rainbow is clearly visible as long as the raindrops fall evenly and frequently. The more often, the brighter it is. Thus, three processes occur simultaneously in a raindrop: refraction, reflection and decomposition of light.
Where to see a rainbow? At fountains, waterfalls, against the background of drops, splashes, etc. Its location in the sky depends on the position of the sun. You can admire the entire rainbow circle if you are high in the sky. The higher the sun rises above the horizon, the smaller the colored semicircle becomes.
The first attempt to explain what a rainbow is was made in 1611 by Antonio Dominis. His explanation was different from the biblical one, so he was sentenced to death. In 1637 Descartes gave a scientific phenomenon on the basis of refraction and reflection sunlight. At that time, they did not yet know about the decomposition of the beam into a spectrum, that is, dispersion. Therefore, Descartes' rainbow turned out to be white. After 30 years, Newton "colored" it, supplementing his colleague's theory with explanations of the refraction of colored rays in raindrops. Despite the fact that the theory is more than 300 years old, it correctly formulates what a rainbow is, its main features (arrangement of colors, position of arcs, angular parameters).
It is amazing how light and water, which are familiar to us, create together a completely new, unimaginable beauty, a work of art given to us by nature. Rainbow always causes a surge of emotions and remains in memory for a long time.
Insafudinov Kirill Rinatovich
I learned how a rainbow is made. Conducted research and experiments, got a rainbow at home and admired its beauty.
Download:
Preview:
Ministry of Education of the Republic of Bashkortostan
department of education of the administration of the municipal district Bizhbulyaksky district
municipal educational budgetary institution
average comprehensive school No. 2 p. Bizhbulyak
Research work
on the topic:
« How is a rainbow made?
Completed: Insafudinov Kirill,
Student of the 3rd grade, MOBU secondary school No. 2, village of Bizhbulyak, Republic of Bashkortostan
Head: Nazmieva A.R.
Primary teacher
Classes MOBU secondary school No. 2 village Bizhbulyak of the Republic of Bashkortostan
Introduction ______________________________ page 3
Literature review
What is a rainbow? ____________________________ page 4
Who painted the rainbow? _____________________ page 4
The appearance of the rainbow. ____________________ page 4
Who has studied the rainbow? ____________________________page 5
The rainbow is different. _____________________ page 5
Experimental work________________page 6
Results ____________________________ page 7
4. Conclusions _____________________________p.7
5. Conclusion____________________________page 7
6. Literature____________________________ page 7
Introduction.
Which of the natural phenomena can be compared in beauty with a rainbow? Perhaps the aurora borealis, only not many people have seen it. And everyone saw the rainbow that appears immediately after the rain.Appearing in the sky, it attracts attention.
She is so beautiful that she is sung in many songs, described in literature, legends are made about her. Many people, like me, look forward to the rain to see the rainbow. What is this colorful miracle of nature? How is a rainbow formed? Is it possible to observe this beauty at home? What other rainbows exist?
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 have arisen, I decided to conduct a research work.
By investigating this riddle of nature, I can give an exact answer to the questions I have posed.
Target my work: to find out the reason for the appearance of a rainbow, getting a rainbow at home.
Delivered by me tasks :
Find out who painted the rainbow.
Put the experience of getting a rainbow at home.
Learn the history of the study of the rainbow.
The relevance of research:instilling interest in experimental work in elementary school
Thanks to this work, activity in the cognitive sphere of activity increases.
Hypothesis: a rainbow can be obtained in the laboratory, is it possible to obtain it at home? If possible, in what way.
Research methods:
Questionnaire
Independent practical experiments for confirmation
hypotheses:
experience: with a 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 cause of the rainbow, I began by studying the literature. In the explanatory dictionary, the concept of a rainbow is given. A rainbow is a multi-colored arc in the firmament of heaven, formed as a result of refraction sun rays in raindrops.
I learned that rainbows can be seen near waterfalls, fountains sprayed by a sprinkler. At fountains and waterfalls it happened to see two or more arcs. You can create a curtain of drops from a hand sprayer yourself and, standing with your back to the sun, see a rainbow created by your own hands. When watering the plants in the garden on a bright sunny day, you can also see a small rainbow in the spray of water.
1.2. Who painted the rainbow?
Where does the amazing colorful light coming from the arcs of the rainbow come from?
I got the answer to this question from the encyclopedia for the curious. We think the light is white. But in fact it consists of several colors. It happens that during the rain the sun will come out, and then the sunlight is refracted in droplets of water and “breaks up” into several colors. There are always seven of these flowers, and they are arranged in a strict order. Red, orange, yellow, green, blue, blue, purple. So it turns out colorful rainbow. An object that can split a beam of light into its components is called a "prism". The formed colors create a strip of colored lines, which is called the "spectrum". A rainbow is a large spectrum, or a strip of colored lines, formed as a result of the decay of a beam of light passing through raindrops. AT this case raindrops act as a prism.
1.3. The appearance of the rainbow.
The rainbow always appears after the rain, I think everyone knows this. But there is another trick here. The rainbow sparkles not after, but during the rain, it just rains not with us, but not far from us. When the downpour ends, it means that the wind just carried these rain clouds farther.
And if the rain has gone 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 that falls off the washbasin faucet, so everyone will agree that it looks like a prism.Light enters the raindrop, bounces 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, splits into a spectrum. At the same time, we have a wonderful picture in the sky - a rainbow.
I had a question - is it possible to create a rainbow yourself? The answer to the question is described on page number 7.
1.4. Who has studied the rainbow?
Has anyone in the history of mankind tried to know the nature of the rainbow?
With my mother, we 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 biblical one, so he was excommunicated and sentenced to death.
The scientific explanation of the rainbow was first given by René Descartes in 1637. Descartes explained the rainbow based onlawsrefraction and reflection of sunlight in raindrops. But he did not yet know about the decomposition of white light into a spectrum upon refraction. Therefore, 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 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 multi-color spectrum of the rainbow is continuous, according to tradition, 7 colors are distinguished in it. It is believed that Isaac Newton was the first to choose the number 7, for which the number 7 had a special symbolic meaning. Moreover, initially he distinguished only five colors - red, yellow, green, blue and purple. But, later, in an effort 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.
Despite being over 300 years old, the Descartes-Newtonian theory of the rainbow correctly explains the basic features of the rainbow, including the arrangement of the colors.
1.5. The rainbow is different.
A rainbow comes 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 occur as a result of the action of the rays reflected by the moon. Undoubtedly, it is not as bright as during the day, but it can be seen remarkably. AT winter time a rainbow occurs very rarely, but in its brilliance and picturesqueness it differs from all the others.
1. Questioning
I conducted a survey with my classmates.
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 arranged?” 6 students answered "Yes", 8 - "No".
To the fifth question "Is it possible to get a rainbow at home?" three answered "Yes", 11 people - "No".
2. Experimental work
I have been experimenting with getting a rainbow at home.
Experience 1.
Equipment: mirror, glass prism.
Description: The teacher caught a "sunny bunny" with a mirror and directed it to a glass prism, which I held 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 droplets falling in the air and observe a rainbow on them.
The conditions of such an experiment are quite consistent with nature, however, it is not at all easy to obtain the required cloud.
Experience3
Equipment: a jar of soapy water, a device for blowing bubbles.
Description: we take the device, dip it in a jar of soapy foam and blow bubbles. You can see a rainbow on bubbles flying in the air.
Experience 4.
Equipment: mirror, bowl of water.
Description: I put the mirror in a shallow bowl of water. Set the bowl so that the beam of light from the sun is reflected from the mirror on the wall or ceiling.
I saw a rainbow on the ceiling. The experiment was a success.
Experience 5.
Equipment: computer disk, light source - the sun.
Description: On a sunny day, we direct the computer disk at an angle of 25 °. If the disc "catch" a beam of light, then as a result of the refraction of the beam on the wall or ceiling there will be a rainbow.
Results.
After studying the literature, I learned that a rainbow can be one arc, or maybe a double one.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 drops are small prisms that reflect these multi-colored rays in the sky. So I learned how a rainbow appears and why it is colored.
From the history of the study of the rainbow, I found out that many tried to explain the nature of this phenomenon, but Isaac Newton fully revealed this phenomenon more than 300 years ago.
I managed to get a rainbow at home. The experiment went well and I could admire this beauty at home.
Conclusions.
Based on the results, I came to the conclusion that:
1. The reason for the appearance of a rainbow is the refraction and "decay" of sunlight in water droplets and the reflection of this light in the sky.
2. Obtaining and observing the rainbow at home is possible.
Conclusion
Having done this work, I became convinced that the rainbow is a well-known optical phenomenon in the atmosphere; observed when the sun illuminates the veil of falling rain and the observer is between the sun and the rain. The rainbow is observed not only on the veil of rain. On a smaller scale, it can be seen on drops of water near waterfalls, fountains and in the surf. At the same time, not only the Sun and the Moon, but also a searchlight can serve as a light source.
Interesting arrangement of colors in the rainbow. It is always constant. The red color of the main rainbow is located on its upper edge, purple - on the bottom. Between these extreme colors, other colors follow each other in the same sequence as in the solar spectrum. In principle, the rainbow never contains all the colors of the spectrum. Most often, blue, dark blue and saturated pure red colors are absent or weakly expressed in it. With the increase in the size of raindrops, the color bands of the rainbow narrow, and the colors themselves become more saturated.
At the same time, I learned how, thanks to Newton, age-old ideas about the origin of flowers were destroyed.
Obtaining a rainbow by an experimental method (artificial rainbow) allows you 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. Dictionary Russian language. 4th edition., enlarged. - M.: LLC "A TEMP", 2008.
2. Travina I.V. 365 stories about the planet Earth/Scientific-pop edition for children. - M.: CJSC "ROSMEN-PRESS", 2007.
3. Encyclopedia for the curious "Where, what and when?" CJSC Company "Makhaon" - M .: 2007.
The answer is known: it is a multi-colored band in the form of an arc, which sometimes appears against the background of the sky. A rainbow is an optical, atmospheric, and weather phenomenon at the same time. It occurs when the air is saturated with tiny drops of water and light passes through them.
This happens after or during rain, fog or in clear weather near a raging river, fountain, watering machine.
Why is the rainbow colored?
A rainbow is made up of rays of light. Where does their color come from? We see white light. In fact, sunlight is made up of particles that vibrate at different frequencies. Our brain (thanks to the eyes) distinguishes it as colors. For example, we perceive rays with a high frequency of oscillation as red, with a low frequency as violet. In the general stream, rays of different frequencies are mixed, and the light appears white.
When it passes through drops of water hanging in the air, it changes direction - it is refracted. Moreover, its different rays are refracted at different angles: red at a small, and, say, purple - at a large angle. And at the exit from the drops, the "white" light breaks up into a spectrum - rays with different colors. We see them as rainbows.
A similar picture is obtained when a film of gasoline shimmers in different colors on a puddle or a soap bubble.
Why is the rainbow not always visible after the rain?
In order for a visible rainbow to be born, it is necessary that the stream of light be strong enough. On cloudy days, you won't see rainbows. 
In this case, the light should be in front of the eyes, and not behind the head. Usually some people see a rainbow, while others - at the same time as the first - do not see it. Why? If the sun is with your back, then you will see the light before it has passed through the drops and played with the spectrum.
When the sun is too high, its rays, after refraction, do not enter the eyes. The higher the sun, the smaller the rainbow arc. Therefore, the rainbow is not visible at noon, but more often it is observed in the morning or in the evening.
But when you go up (for example, up the stairs), more and more light rays enter the eyes, and the rainbow grows. And the passengers of a flying airliner see through the windows not a rainbow arc, but a full circle!
How many colors are in a rainbow?
No need to smile - the question is not as stupid as it seems.
Of course, we are used to the fact that there are seven of these colors, but this is a tribute to tradition. It comes from Isaac Newton. In experiments, he showed where the spectrum comes from. The great scientist counted five colors in the rainbow - red, yellow, green, blue and violet. However, he did not like the number very much.
Seven was considered a magic number (seven days of the week, seven wonders of the world, seventh heaven, seven deadly sins, etc.). “Looking closely” at the rainbow, Newton added two shades to the spectrum - orange and indigo (blue-violet), and there were seven colors. 
But the ancient Russians were sure that there were only four colors in it - scarlet, blue, green and crimson. The Japanese see the rainbow as six colors - they consider green to be a variety of blue. In short, among different peoples, the number of rainbow colors ranges from nine to two (light and dark).
It makes no sense to ask how many of them "really" - the colors of the spectrum imperceptibly pass into each other and you can conditionally divide it into as many bands as you like.
How to remember the order of the colors in the rainbow?
Well, it's quite easy. We remember them by the first letters of the words in a simple phrase: "Every hunter wants to know where the pheasant sits"(red, orange, yellow, green, blue, indigo, violet). There is also a modern version: “Every designer wants to know where to download Photoshop.
The English phrase about "pheasant" looks shorter: Run off you girls - boys in view("Run, girls - the boys have appeared").
There is a better option: Richard of York gave battle in vain("Richard of York fought in vain"). Pay attention to the set of colors: red, orange, yellow, green, blue, indigo, violet - the British have kept "indigo"! What can you do, in their language, blue and blue colors are denoted the same way.
How to get a rainbow at home?
You will not be able to see a full-fledged rainbow from floor to ceiling. But still…
1.
Take a CD, put it in sunlight and change the angle. So it is easy to get bright iridescent spots, stripes or a circle around its edge on the disk. 
2.
On a sunny day, place a bowl of water on a windowsill or table by the window. Place a mirror at the bottom. Taking it in your hand, move it and the mirror so that the stream of rays reflected by the mirror hits the paper. The light from it, passing through the layer of water, will decompose into a spectrum. A piece of the rainbow will appear on the paper.
As after the rain, especially if it was lingering, cheers up rainbow!
This phenomenon of nature has always surprised and delighted people. There are many legends and beliefs associated with the appearance of the rainbow.
How does a rainbow appear?
A rainbow occurs due to the fact that in droplets of water that soar in the air after rain or in fog, light is refracted and reflected many times. Different colors in light deviate differently, because of this, we observe the decomposition of white light into a spectrum, i.e. we see a rainbow.
By the way, in order to see a rainbow, the source of light, the sun, must be behind the observer.
Most often, we manage to see the primary rainbow, but there are times when a secondary rainbow was observed. The secondary rainbow is always less bright and appears around the first one. The appearance of a secondary rainbow is due to the fact that light is reflected twice in water droplets. Curiously, the order of the colors in the secondary rainbow is reversed. That is, purple is outside, and red is inside.
The sky between these two rainbows always looks darker and is called Alexander's strip.
There are known cases of observing rainbows of the third and even fourth order. True, the appearance of four rainbows was officially recorded only 5 times over the past 250 years.
It must be said that under laboratory conditions it is possible to recreate a rainbow of almost arbitrarily large order. For example, there is documentary evidence of the receipt of a 200th order rainbow.
Rainbow Legends.
Since ancient times, people have attributed miraculous properties to the rainbow and told many legends about it. In almost all nations, a rainbow is a bright and kind phenomenon, from which much good can be expected.
The ancient Greeks identified the rainbow with the goddess Irida. It was a goddess - an intermediary between people and gods. She was depicted with beautiful golden wings and in clothes painted with all the colors of the rainbow.
The Arabs believed that during rain and thunderstorms, the god Kuzah fights the forces of evil, and when the rain stops, he hangs his bow-rainbow in the sky as a sign of victory.
The Slavs also believed, but their god was named Perun. They also said that the rainbow drinks water from rivers and lakes, sends this water to the sky, then causing rain. 
In China they believed that rainbow- a heavenly dragon, an intermediary between heaven and earth.
Different peoples believed that a rainbow is a bridge between heaven and earth, or a rocker with which the goddess Lada draws water, or that this is the path to the next world, and the souls of the dead can descend into our world along the rainbow. It was believed that a witch could steal a rainbow and cause a drought.
Bulgarians generally have a belief that the one who passed under the rainbow will change his gender. Therefore, women who, for example, gave birth only to girls, tried to pass under the rainbow so that the next child was born a boy.
The Bible says that the rainbow first appeared on Earth after the Great Flood, as a sign of God that such a disaster would not happen again. In Christianity, the rainbow is also correlated with the Virgin Mary, as an intermediary between God and people.
Curiously, different nations number of colors in the rainbow. In fact, of course, the spectrum is continuous, one color comes out of another. However, individual colors can be distinguished. We believe that there are 7 colors in the rainbow. In the UK there are 6, in China - 5, and in Arab countries- only 4.
Typically, a rainbow is a colored arc with an angular radius of 42°, visible against the background of a curtain of heavy rain or rainfall streaks, often not reaching the Earth's surface. The rainbow is visible in the side of the sky opposite the Sun, and always with the Sun not covered by clouds.
The center of the rainbow is a point diametrically opposite to the Sun - the antisolar point. The outer arc of the rainbow is red, followed by orange, yellow, green arcs, etc., ending with the inner purple.
All rainbows are sunlight broken down into its components and moved across the firmament in such a way that it appears to come from the part of the firmament opposite that of the Sun.
The scientific explanation of the rainbow was first given by Rene Descartes in 1637. Descartes explained the rainbow on the basis of the laws of refraction and reflection of sunlight in drops of falling rain.
30 years later, Isaac Newton, who discovered the dispersion of white light upon refraction, supplemented Descartes' theory by explaining how colored rays are refracted in raindrops.
Despite the fact that Descartes-Newton's theory of the rainbow was created more than 300 years ago, it correctly explains the main features of the rainbow: the position of the main arcs, their angular dimensions, the arrangement of colors in rainbows of various orders.
So, let a parallel beam of sunlight fall on a drop. Due to the fact that the surface of the drop is curved, different rays will have different angles of incidence. They vary from 0 to 90°. Let us trace the path of the beam passing through the drop. Having refracted at the air-water boundary, the beam enters the drop and reaches the opposite boundary. Part of the energy of the beam, refracted, leaves the drop, part, having experienced internal reflection, again goes inside the drop to the next place of reflection. Here again, part of the beam energy, having been refracted, leaves the drop, and some part, having experienced a second internal reflection, goes through the drop, etc. In principle, the beam can experience any number of internal reflections, and each beam has two refractions - at the entrance and at exit from the drop. A parallel beam of rays incident on a drop turns out to be strongly divergent upon exiting the drop (Fig. 2). The concentration of rays, and hence their intensity, is the greater, the closer they lie to the beam that has experienced the minimum deviation. Only the minimally deflected beam and the beams closest to it have sufficient intensity to form a rainbow. Therefore, this ray is called the ray of the rainbow.
Each white ray, refracted in a drop, decomposes into a spectrum, and a beam of divergent colored rays emerges from the drop. Since red rays have a lower refractive index than other colored rays, they will experience minimal deviation compared to the rest. The minimum deviations of the extreme color rays of the visible spectrum of red and violet are as follows: D1k \u003d 137 ° 30 "and D1ph \u003d 139 ° 20 \". The remaining colored rays will occupy intermediate positions between them.
The sun's rays that have passed through a drop with one internal reflection turn out to be emanating from points in the sky located closer to the antisolar point than to the Sun. Therefore, to see these rays, you must stand with your back to the Sun. Their distances from the antisolar point will be equal respectively: 180° - 137°30" = 42°30" for red and 180° - 139°20" = 40°40" for violet.
Why is the rainbow round? The fact is that a more or less spherical drop, illuminated by a parallel beam of rays of sunlight, can form a rainbow only in the form of a circle. Let's explain this.
The described path in the drop with a minimum deviation on leaving it makes not only the ray that we followed, but also many other rays that fell on the drop at the same angle. All these rays form a rainbow, which is why they are called rainbow rays.
How many rays of a rainbow are there in a beam of light falling on a drop? There are many of them, in fact, they form a whole cylinder. The locus of the points of their fall on the drop is a whole circle.
As a result of passing through the drop and refraction in it, the cylinder of white rays is transformed into a series of colored funnels inserted one into the other, centered at the antisolar point, with open bells facing the observer. The outer funnel is red, orange is inserted into it, yellow, then comes green, etc., ending with the inner violet.
Thus, each individual drop forms a whole rainbow!
Of course, the 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. In the laboratory, it was possible to observe not one, but several rainbows formed by the refraction of light in one suspended drop of water or oil when illuminated by a laser beam.
The rainbow that we see in the sky is mosaic - it is formed by myriads of drops. Each drop creates a series of colored funnels (or cones) nested one on top of the other. But from a single drop, only one colored ray enters the rainbow. The eye of the observer is common point, in which colored rays from many drops intersect. For example, all red rays that come out of different drops, but at the same angle and hit the eye of the observer, form a red arc of the rainbow, and so do all orange and other colored rays. Therefore, the rainbow is round.
Two people standing side by side see each their own rainbow. If you walk along the road and look at the rainbow, it moves with you, being formed at every moment by the refraction of the sun's rays in more and more drops. Next, raindrops fall. The place of the fallen drop is occupied by another and manages to send its colored rays into the rainbow, followed by the next one, and so on. it's raining we see a rainbow.
