Define the dispersion of light. School Encyclopedia

The world filled with millions of different shades. Due to the properties of light, every object and object around us has a certain color perceived by human vision. The study of light waves and their characteristics has allowed people to take a deeper look at the nature of light and the phenomena associated with it. Let's talk about dispersion today.

The nature of light

From a physical point of view, light is a combination of electromagnetic waves with different lengths and frequencies. The human eye does not perceive any light, but only one whose wavelength ranges from 380 to 760 nm. The rest of the varieties remain invisible to us. These include, for example, infrared and ultraviolet radiation. The famous scientist Isaac Newton imagined light as a directed stream of the most small particles. And only later it was proved that it is by nature a wave. However, Newton was still partly right. The fact is that light has not only wave, but also corpuscular ...

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Decomposition of light into a spectrum due to dispersion when passing through a prism (Newton's experiment). This term has other meanings, see Variance.

Dispersion of light (decomposition of light) is a phenomenon due to the dependence absolute indicator refraction of a substance on the frequency (or wavelength) of light (frequency dispersion), or, the same thing, the dependence of the phase velocity of light in a substance on the wavelength (or frequency). Experimentally discovered by Newton around 1672, although theoretically well explained much later.

One of the most illustrative examples of dispersion is the expansion white light when passing it through a prism (Newton's experiment). The essence of the phenomenon of dispersion is the unequal speed of propagation of light rays with different wavelengths in a transparent substance - an optical medium (whereas in vacuum the speed of light is always the same, regardless of the wavelength and hence the color). Generally, the higher the frequency of the wave, the higher the refractive index...

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Newton's experiments

The first experiments with the dispersion decomposition of light were made by Newton. He directed an ordinary beam sunlight onto a prism and got what many today see every day - the prism decomposed the light beam into many multi-colored colors - from red to purple. After a series of other experiments with lenses and a prism, Newton concluded that the prism does not change sunlight, but only decomposes it into its components. But how does it work?

The fact is that light has a certain speed. As experience has shown, a light beam consists of many colors, so their speed is just different. That is, each color of the spectrum has its own speed of movement and its own wavelength. The degree of refraction of color rays also turned out to be different. Remember what it looks like...

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Chapter 1. light waves- Lesson 5. Light dispersion
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Lesson 5. LIGHT DISPERSION

The refractive index does not depend on the angle of incidence of the light beam, but it does depend on its color. It was discovered by Newton.

Making improvements to telescopes. Newton took notice. that the image given by the lens is colored around the edges. He became interested in this and was the first to "investigate the diversity of light rays and the peculiarities of colors resulting from this, which no one had even suspected before" (words from the inscription on Newton's tombstone). The iridescent coloration of the image given by the lens was observed, of course, before it. It has also been observed that iridescent edges have objects viewed through a prism. A beam of light rays passing through a prism is colored at the edges.

Newton's basic experiment was ingeniously simple. Newton guessed to send a light beam of small cross section to a prism. A beam of sunlight passed into the darkened...

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Gymnasium No. 26 LIGHT DISPERSION Completed by: student 11 B class Shelepov Dmitry Head: Pylkova L.V. Tomsk-2011 In the 17th century, the idea of ​​the wave nature of light began to develop. The first discovery testifying to the wave nature of light was made by the Italian scientist Francesco Grimaldi. He noticed that if an object is placed in the path of a very narrow beam of light, then a sharp shadow does not appear on the screen. The edges of the shadow are blurred, and colored stripes appear along the shadow. Grimaldi called the discovered phenomenon diffraction, but he failed to explain correctly. He understood that the phenomenon he observed was in conflict with the corpuscular theory of light, but he did not dare to completely abandon this theory. Correct explanation open phenomenon associated with the theory of color vision, the foundations of which were laid by the remarkable English scientist Isaac Newton. Light dispersion (decomposition of light) is a phenomenon of the dependence of the absolute refractive index of a substance on the wavelength of light ...

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Dispersion of light (decomposition of light) is the phenomenon of the dependence of the absolute refractive index of a substance on the wavelength of light (frequency dispersion), and also, on the coordinate (spatial dispersion), or, equivalently, the dependence of the phase velocity of light in a substance on the length waves (or frequencies). Experimentally discovered by Newton around 1672, although theoretically well explained much later.

One of the most illustrative examples of dispersion is the decomposition of white light as it passes through a prism (Newton's experiment). The essence of the phenomenon of dispersion is the unequal speed of propagation of light rays with different wavelengths in a transparent substance - an optical medium (whereas in vacuum the speed of light is always the same, regardless of the wavelength and hence the color). Usually, the higher the frequency of the wave, the higher the refractive index of the medium and the lower its speed of light in it:

at the red maximum speed in the medium and the minimum degree of refraction,...

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Physics lesson "Dispersion of light"

Sections: Physics

Lesson objectives:

Educational: introduce the concepts of spectrum, dispersion of light; to acquaint students with the history of the discovery of this phenomenon. visually demonstrate the process of decomposition of a narrow light beam into components of various color shades. identify the differences between these elements of the beam of light. continue the formation of the scientific worldview of students. Developing: the development of attention, figurative and logical thinking, memory in the study of this topic. stimulation of cognitive motivation of students. development of critical thinking. Educational: fostering interest in the subject; fostering a sense of beauty, the beauty of the world.

Type of lesson: lesson of studying and primary consolidation of new knowledge.

Teaching methods: conversation, story, explanation, experiment. (Information-developing)

Requirements to...

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Ministry of Science and Education of Ukraine

Ukrainian Engineering and Pedagogical Academy

Report on the topic:

Light dispersion

Performed by student gr. DRE-S5-1

Fesenko A.V.

Kharkov 2006

dispersion phenomenon

dispersion of light. On a bright sunny day, we will close the window in the room with a thick curtain, in which we will make a small hole. Through this hole, a narrow beam of sunlight will penetrate into the room, forming a bright spot on the opposite wall. If you put in the path of the beam

glass prism, then the spot on the wall will turn into a multi-colored strip, in which all the colors of the rainbow will be represented - from purple to red (Fig. 1, f - purple, C - blue, G - blue, 3 - green, G - yellow , O - orange, K - red).

The dispersion of light is the dependence of the refractive index n of a substance on the frequency f (wavelength) of light or the dependence ...

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The word "dispersion" comes from the Latin word dispersio, which literally means "scattering, scattering". Light dispersion

slide 2
History of discovery Definition Newton's experience The peculiarity of the passage of a light beam through a prism Main properties Consequences Conditions for the appearance of a rainbow Questions Conclusions Contents

slide 3
The light flux when passing through a prism is decomposed into color spectrum, which Isaac Newton studied in sufficient detail in his time. The result of his research was the discovery of the phenomenon of dispersion in 1672. The first steps towards the discovery of dispersion

slide 4
About 300 years ago, Isaac Newton passed the sun's rays through a prism. It is not for nothing that on his tombstone, erected in 1731 and decorated with figures of young men who hold in their hands the emblems of his major discoveries, one figure holds a prism, and the inscription on the monument contains the words: “He ...

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Studying the dispersion of light in the 11th grade

The article is categorized under: Teaching physics

This lesson is held at the end of the study of the topic “wave properties of light” in the classes of the physical and mathematical profile.

A. Students should learn:

When falling on the interface between two media, light beams of different colors are refracted in different ways: red - less, and violet - more.

An objective characteristic of color is the frequency of an electromagnetic wave.

B. Students should learn to:

Create the concept of “dispersion of light”.

Recognize the dispersion of light among other phenomena.

Reproduce the dispersion of light in a specific situation.

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11

The dispersion of light is considered as a result of the interaction of electromagnetic waves with charged particles that make up substances. Particles of matter make forced oscillations in the alternating electromagnetic field of the wave.

The dispersion of light is the dependence of the absolute refractive index of a substance n on the frequency ...

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Observation of the phenomenon of light dispersion laboratory
In physics, the dispersion of light is the dependence of the refractive index of a substance on the wavelength of light. The phenomenon of light dispersion is most clearly demonstrated by its decomposition under the action of a prism.

1.3. First experiments with prisms. Ideas about the causes of the appearance of colors before Newton.
1.4. Newton's experiments with prisms. Newton's theory of the origin of colors
1.5. Discovery of anomalous dispersion of light. Kundt's experiments
Chapter II. dispersion in nature
2.1. Rainbow
Chapter III. Experimental setup for observing color mixing
3.1. Installation Description
3.2. Experimental setup device
Conclusion
Literature
Introduction.
dispersion of light. We always encounter this phenomenon in life, but we do not always notice it. But to be careful, the phenomenon of dispersion always surrounds us. One such phenomenon is the common rainbow. There probably isn't a person who doesn't...

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MAOU " secondary school No. 28 named after G. F. Kirdishchev "

Petropavlovsk-Kamchatsky urban district

Dispersion of light and body colors

Synopsis of a physics lesson in grade 11

Lesson of learning new material, consolidation and control

Physics teacher of MAOU "Secondary school No. 28 named after G. F. Kirdishchev" Yuryeva O. L.

Sergey Yesenin

I do not regret, do not call, do not cry,
Everything will pass like smoke from white apple trees.
Withering gold embraced,
I won't be young anymore.

Now you won't fight so much
Cold touched heart
And the country of birch chintz
Not tempted to wander around barefoot.

Wandering spirit! you are less and less
You stir the flame of your mouth
Oh my lost freshness
A riot of eyes and a flood of feelings!

Now I have become more stingy in desires,
My life, or did you dream of me?
Like I'm a spring echoing early
Ride on a pink horse.

All of us, all of us in this world are perishable,
Quietly flowing...

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14

What waves are called coherent?

waves that have the same frequency

waves that have the same amplitude

waves having the same frequency and constant phase difference

The polarization of light proves that light is
flux of neutral particles
transverse wave
longitudinal waves

What is diffraction of light?
splitting white light into a spectrum using a glass prism
amplification or attenuation of light when two coherent waves are superimposed
light avoidance of obstacles

The colors of the spectrum (red - k, orange - o, blue - s, yellow - g, cyan - g, green - h, violet - f) in order of decreasing wavelength are correctly indicated in the answer:
1.f, s, d, s, f, o, k
k, o, f, s, g, s, f
f, g, z, s, f, o, k

The iridescent coloration of thin films of petroleum products in puddles is caused by the phenomenon
diffraction
dispersion
interference

Enlightenment of lenses is explained by ...

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15

Abstract: Theme of the lesson: “Light is a stream of particles”
Teacher Pylkova L.V., MOU gymnasium No. 26

Lesson topic: "Light is a stream of particles"

Lesson Type: Modified Debate

The organization of "modified" debates allows some changes in the rules, it is possible to increase or decrease the number of players in teams; questions from the audience are allowed, support groups are organized that teams can contact during the game, a group of experts performs the functions of refereeing, develops a compromise solution when it is necessary to achieve educational goals. The main stages of the organization educational process based on the use of the debate methodology are: orientation (selection of topics); preparation for the event; holding debates; game discussion.

^ Lesson objectives:

Generalization and systematization of knowledge

MOU Alekseevskaya secondary school

Work theme

"Dispersion of light, color and man"

Type of work - problem-abstract

Physics teacher 1 qualification category

Stekolnikov Vsilii Georgievich

2010

Introduction ………………………………………………………….. 3

1. Light dispersion ………………………………………………………4

2. A bit of color history ………………………………………….5

3. The influence of color on a person…………………………………………….7

4. What color is your character? ................................................. ............eight

5. Color and sound …………………………………………………………..9

6. Therapeutic effect of color ………………………………………..11

7. Blood group and color ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

8. Color of the car and accidents on the road…………………………………… 13

classrooms ………………………………………………….14

10. Conclusion ………………………………………………………… 15

11. List of used literature …………………………….. 16

Introduction

In this work, the following tasks are set:

To uncover Interesting Facts about how color affects the character of a person, what a healing effect color has, what is the relationship between color and sound, the prospects for the “color sounding” of the cosmos that are fantastic at first glance, what is the relationship between a person’s blood type and color, about what an interesting relationship exists between man and color. The little-studied facts of the existence of a human biofield and any object, their mutual influence on each other, are slightly touched upon. Also, the fact of the skillful use of the influence of the color design of paintings and works by great artists and composers for their better perception by a person at a subconscious level through color.

Show the influence of the color design of classrooms, school corridors, gyms and workshops on successful learning students, on their mental state, and depending on this, their health.

1. Light dispersion

Being engaged in the improvement of telescopes, Newton drew attention to the fact that the image given by the lens is colored at the edges. He became interested in this and was the first to "investigate the diversity of light rays and the peculiarities of colors resulting from this, which no one had even suspected before" (words from the inscription on Newton's tombstone). The iridescent coloration of the image given by the lens was observed, of course, before it. It has also been noticed that iridescent objects are viewed through a prism. The beam of light rays passing through the prism is colored at the edges.

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I. Newton () Newton's experiment Dispersion of light

Newton's basic experiment was ingeniously simple. He guessed to send a light beam of small cross section to the prism. A beam of sunlight entered the darkened room through a small hole in the wall. Falling on a glass prism, it refracted and gave on the opposite wall an elongated image with iridescent alternation of colors. Following the centuries-old tradition that the rainbow was considered to consist of 7 colors, Newton also identified 7 colors: purple, blue, blue, green, yellow, orange, red. Newton called the rainbow strip itself a spectrum.

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Types of spectra

Newton's important conclusion was formulated by him in his treatise on "Optics" as follows: "Light rays that differ in color differ in their degree of refraction." Violet rays are most strongly refracted, red ones are less than others. Newton called the dependence of the refractive index of light on its color dispersion.

2. A bit of color history

There was such a case in England. Residents of houses located opposite complained about their neighbor in court. The fact is that the canary color, in which the Englishman painted the facade of his house, and the black frames caused a headache among the locals. By order of the court, the owner of the bright mansion was forced to repaint it.

Koll" href="/text/category/koll/" rel="bookmark">colleagues Russian textile factories in the 90s produced mainly fabrics of three gloomy colors; gray, brown and black. According to psychologists, such a color scheme The complex colors of withered autumn, last year's leaves and withering, beloved by post-perestroika Russians, are called by psychologists dirty, rotten and unhealthy.

The development of color is associated with a 100-year cycle, says Svetlana Zhuchenkova, candidate of sciences, one of the first Russian scientists-colorists, teacher at the Moscow Textile Academy. The end of the century, as a rule, corresponds to complex colors; lilac, swamp green, gray-blue, as well as pale and delicate colors. simple colors; white, black, red and yellow are more typical for the beginning of the century.

At the same time, national psychology cannot be ignored. So, for example, if in America a man goes to work in a brown suit, then he is unlikely to get this job. The French prefer sharp tones and love contrasts, the Italians prefer softer colors. Asia gravitates towards yellow, blue and a little vulgar, red, the Balts - towards green and brown. Moscow is notable for its variegated range, and St. Petersburg - for its "aesthetic" one.

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At one time, Stalin, following the example of Napoleon, who created an elaborate and pompous color style to perpetuate the splendor of his victories in architecture and painting, demanded that portals and arches be built in the majestic style of Napoleon, demonstrating his own greatness with the face of the country. The leader of the peoples treated the color scheme more severely. Of the 160 flowers, each of which had its own name in Tsarist Russia, only a few dozen have survived. Post-revolutionary colors in the history of coloring in Russia are generally absent as a genre. There were limited colors during the Stalin era. In the 40s and 50s, the country was dressed in steel gray and green tones, in the 60s the colors of increasing productivity were used. Fluorescent dyes were developed in the 70s. According to some reports, almost all the developers of these poisonous flowers died of cancer.

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3. The influence of color on a person.

There is a strange and complicated relationship between man and color. According to scientists, color is not just an element of aesthetics and culture, but rather a complex mental substance that demonstrates a person’s mood, his state of mental health, and even can influence him.

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Red color activates muscle strength. Psychologists say that if a weightlifter wears red glasses, he will “take” more weight than without them. At the same time, being surrounded by "red", a person will try to get out of it faster. Red telephone boxes were designed for high traffic. Children almost also react to this color. A child sleeping facing a wall with red wallpaper is more irritable and restless.

Purple could replace drug addicts with a hallucinogen. If a person is put in a room where everything: the ceiling, floor, walls, windows and doors are painted purple, then he will begin to hallucinate.

Blue colour promotes reflection, calms and reduces pressure.

Blue sets melancholy.

White color creates a sense of unreality.

Black color the most complex, on the one hand, mystical, symbolizing dedication to something inaccessible to others, on the other hand, official.

4. What color is your character?

Psychologists say that a person's character can be determined by his color tastes. By the way, the Swiss scientist M. Lumar came to such conclusions. He believes that if you like the color red, then your main features are a strong will, quick decision making. Preference for yellow indicates that you are an optimist and an idealist. You like everything new, unexpected, unusual and sensational.

If you like the color orange, then you tend to easily perceive successes and failures, you have enough will to make decisions. You are strong physically and mentally.

If you like the color green, then you are self-confident and critical person. You are solid, conservative, you know your worth. You are almost perfect family life.

If you are attracted to blue or Blue colour, then you are a person of a weak character, emotional and good-natured, with a rich inner life.

If you like the color purple, then you are more of an intuitionist than a logician.

5. Color and sound

The connection between color and sound is most clearly expressed in the phenomenon of color music. Color music was close to the composer, who preferred to create his works in a specific key for a given color. The music of color was one of the main elements in many of the artist's paintings. For the first time, the composer succeeded in the large-scale implementation of color-musical influence in the symphonic poem "Prometheus" ("Poem of Fire", 1910). To enhance the impact of music, he introduced an organ, bells into the orchestra, used the sound of the choir without words and special lighting ("parts of color").

Roerich's paintings:

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A person's perception of musical works simultaneously with a certain color scheme of light significantly affects the impression of using these works. First of all, because the sensitivity of the eye and ear are interconnected. So, the sensitivity of the eye to the green-blue rays of the visible spectrum under the influence of sounds and noise noticeably increases, and to orange-red it decreases; the sensitivity of our hearing aid decreases with increasing light intensity. It is also influenced by the fact that the fastest person perceives objects of red color and the slowest of all, objects of purple color. And since the world in colors is always perceived by a person as sharper and deeper than a gray background, the author of music has the opportunity to use the features of a person’s color vision to enhance the impact of music on him.

Doctors have long established that major music accelerates the secretion of digestive juices in the body, has an exciting effect on the human body, mainly accelerates the rhythms of breathing and heartbeat. Its impact is enhanced if orange-red tones are used in the coloring of rooms and objects. Melodious music causes a person to slow down breathing; music therapy is based on the perception of quiet, non-anxious sounds in a person. Its effectiveness is enhanced if it is carried out in a room dominated by blue-green color tones.

This is no coincidence. Psychologically, red colors excite and alert a person - this is the color of fire and blood, and in the historically developed ideas of a person, they serve as harbingers of trouble. Blue-green tones are the colors of fresh vegetation and clear skies; they are not usually associated with danger. Thus, color affects the psycho-physiological state of a person, his perception of various phenomena, including music.

The reverse process is also observed. When comparing major and minor melodies, most people who love music have a feeling of chiaroscuro, because the major is identified with the “light” mode, and the minor with the “dark” one. This takes place, for example, when perceiving the picture of dawn in the introduction to the opera "Khovanshchina" and the picture of the night sky in the introduction to the opera "The Night Before Christmas" by Korsakov.

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In addition to the "multi-color" that accompanies the sound of music, its range of influence can be expanded by the use in orchestras of musical instruments with a special sound spectrum - like old ones, but not found wide application(for example, the invented theremin), and new ones.

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At the same time, such a fantastic way is possible: to create a special musical instrument and music of extraordinary sound, recoding the radiation with their rich and original colors into the sound spectrum. Despite the seeming utopia of the idea, such work was done by the employees of the Paris Astronomical Observatory, who, using electroacoustic technology, converted the light of individual stars into sound frequencies. As a result, the vault of heaven "spoke" to people in the language of sounds. Pythagoras dreamed of the perception of the "music of the heavenly spheres". Now his dream has come true, but in a different way than he expected (not at the expense of mechanical movement celestial bodies in their orbits).

6. Healing effect of color

It has long been proven that each person has his own biofield. But as confirmed by special scientific studies, the presence of a biofield is also characteristic of works of art; paintings, sculptures. Moreover, during the experiment, it was possible to prove that through this biofield they can affect our health in some cases more than drugs. selection of works and colors you can normalize the pressure, soothe nervous system, relieve pain, relieve stress. At regular treatment works of art noted good results in neurosis, diseases of the heart, liver, thyroid gland, gallbladder and intestines. In addition, a person receives a strong psycho-emotional impulse, which contributes to the overall healing of the body.

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The therapeutic effect of color is associated with the influence of wave vibrations of a certain length on our organs and mental centers, and the action of different colors has a specific effect in certain diseases.

Red color helps with viral diseases, stomach ulcers, anemia, hypotension, stimulates the immune system, the activity of the endocrine glands and metabolism, strengthens memory, gives vigor and energy.

Pink color has a sedative effect on the nervous system, improves mood.

Orange color improves the processes of digestion, regeneration, helps with diseases of the spleen and lungs, increases blood circulation.

Yellow effective for atonic constipation, insomnia, skin diseases. It stimulates appetite, has a cleansing effect on the entire body, stimulates vision and liver function, and tones the nervous system. It is considered to be the physiologically optimal color.

Green color normalizes cardiac activity, stabilizes blood pressure, reduces headaches, pain in diseases of the spine, helps with acute colds, improves metabolism and performance.

Blue used for diseases of the eyes, liver, larynx, spine. It reduces appetite and intestinal spasms, normalizes cardiac activity.

Blue colour affects the thyroid gland, helps with kidney diseases and Bladder, lungs, eyes, treats insomnia, mental illness, jaundice, skin diseases.

Violet color- the color of spirituality and creativity. It has a calming effect on the nervous system, helps with mental disorders, neuralgia, concussions. This color is recommended for diseases of the kidneys, liver, urinary and gallbladder, and various inflammatory processes. Its positive effect on the vascular system has also been noted.

7. Blood type and color

Scientists have found that there is also a close relationship between a person's blood type and color.

1st group blood. The most favorable are red, orange and purple tones.

3rd group. Wider choice. Red and orange colors stimulate vital processes and enhance mental activity. The blue and green tones will calm the nerves, while the purple tone will help create a mood for reflection and remembrance.

4th group. People with this blood type are similar in their energy characteristics to the second one, they should come into contact more often with blue and green.

8. Car color and traffic accidents

According to official figures, silver-colored cars are 50% less likely to get into serious accidents than cars of other colors. White, yellow, grey, red and blue cars have about the same level of risk. Drivers who drive black, brown and green cars are especially at risk because their risk of having an accident and serious injury is increased by 2 times.

https://pandia.ru/text/78/320/images/image026_10.jpg" align="left" width="335" height="209 src=">The most "dangerous" car in terms of the probability of getting into an accident.

The risk is doubled.

Color psychological studies have shown that children prefer one or another color depending on age.

AT early age they prefer red or purple, with girls being pink.

At the age of 9-11 years, the interest in red is gradually replaced by an interest in orange, then yellow, yellow-green, and then green.

After 12 years, the favorite color is blue.

Chalkboards should be painted dark green or dark blue. You should not create a color contrast on the wall where the board hangs, so as not to tire the students' eyesight. The front wall can in many cases be painted in a color that is more intense than the back and side walls.

In preparatory and first grade, intense pure red tones can be recommended.

For second-graders, red can be gradually replaced by orange-red or orange, for 10-11 year olds - yellow, yellow-green, and then green.

For children of adolescence, blue begins to play a certain role, but always in combination with orange, since a class with a lot of blue creates a "cold" impression.

In classrooms where manual labor is involved, the color blue should be used. The music class should be painted with the same color. In the gym, it is better to use blue and light green colors.

Halls and corridors can be painted light blue and yellow

10. Conclusion

This work aims to show what great importance has knowledge of the effect of color on the human body, health, mental and physical state, on the effective perception of artistic and musical works. And the life and safety of a person is directly related, for example, to the color of the car, which of course must be taken into account. At the same time, this direction in physics is little studied, for example, the biofield of a person and objects. Or "poorly lit" in scientific and educational literature. This direction in physics has great prospects for further study.

12. List of used literature

1., Handbook of Physics, 2005

1. Soros Scientific and Educational Journal, 2005, 2006

2. Journal "Physics at school", 2005

After a thunderstorm and rain, when the sun peeks out from behind the clouds, we often observe a very beautiful phenomenon in the sky - a rainbow.

It consists of multi-colored arcs. Moreover, the colors in it always alternate in a certain sequence: red, orange, yellow, green, blue, indigo, violet. It turns out that ordinary sunlight is decomposed into such colors.

What is light dispersion

The decomposition of white light into colors is called light dispersion .

To get acquainted with this phenomenon, we will conduct a simple experiment. Let's direct a narrow beam of white light at a transparent trihedral glass prism located in a dark room. After passing through the edges of the prism, the beam is refracted twice and deflected. In addition, behind the prism, instead of one white beam, we will see seven multi-colored, painted in the same colors as the rainbow, rays arranged in the same sequence. Moreover, it turns out that the violet ray was refracted the most, and the red ray least of all. That is, the angle of refraction depends on the color of the beam.

If another prism is placed on the path of the color spectrum, rotated by 180 ° relative to the first, then after passing through it, all the color rays will again gather into a beam of white light.

Experience with the passage of white light through a prism was first conducted by Isaac Newton. He also explained that color is a property of light.

From his experience, Newton made 2 conclusions:

1. White light has a complex structure. It consists of a stream of particles of different colors.
2. All these particles move at different speeds, so the rays are of different colors and are refracted at different angles. The most high speed for red particles. It is refracted through a prism less than all other colors. The lower the speed, the higher the refractive index.

It was Newton who divided the color spectrum into 7 colors, because he believed that there is a connection between colors and musical notes, which are also 7, seven days of the week and seven objects of the solar system (at the time of Newton, only 7 planets were known: Mercury, Venus, Earth, Moon, Mars, Saturn, Jupiter), seven wonders of the world. True, in Newton's spectrum, blue was called indigo.

To make it easier to imagine the sequence of colors in the spectrum, it is enough to remember the phrase in which the capital letters match the first letters of the names of the colors: " Every Hunter Wants to Know Where the Pheasant Sits".

In the general sense, the spectrum in physics is the distribution of values physical quantity(energy, mass or frequency).

Visible spectrum

Light that has the same wavelength and the same color is called monochromatic . White light is a collection of electromagnetic waves of various lengths. Therefore he is polychromatic .

Why does white light decompose into other colors when passing through a prism? The reason is that each color that is part of white light has its own wavelength of light and propagates in a transparent optical medium with its own phase velocity, which is different from the wave speeds of other colors. For red, this speed in the medium is maximum, and for violet it is minimum. By the way, these speeds are different only in the optical medium. In a vacuum, the speed of rays of different colors remains constant and equal speed Sveta.

Rays of different colors (of different wavelengths) have different refractive indices, so they deviate differently when passing from one medium to another. The dependence of the refractive index of light on the wavelength is the essence of the phenomenon of light dispersion. For this reason, the spectrum arises.

The ratio of the speed of light in a vacuum to its speed in a given medium is calledabsolute refractive index environment.

n = c/v ,

where With - the speed of light; v is the speed of light in the optical medium.

Knowing the wavelength, one can calculate the refractive index of the medium for each color in the visible spectrum.

So, white light decomposes into different colors, because each color has its own refractive index.

The dispersion explains the appearance of the rainbow. Spherical water droplets hovering in the atmosphere refract and then reflect sunlight from their inner surface. As a result, it decomposes into a spectrum, and we see a multi-colored glow. The facets of a diamond “play” with colors also due to dispersion.

The colors in the spectrum are called spectral colors . But the spectrum does not contain all the colors that the human brain perceives. For example, it does not have pink. It is obtained by mixing other colors.

There is no sharp boundary between colors in the spectrum. All colors blend seamlessly into each other.

The wavelengths corresponding to each color were determined by one of the creators of the wave theory of light, an English physicist, mechanic, physician, astronomer and orientalist Thomas Young.

light and color

The complex structure of white light explains the diversity of colors in the world around us. Due to the fact that light rays of different colors are reflected from objects in different ways or absorbed by them, we see the world in color.

Remember the expression: "All cats are gray at night"? But it really is. In the dark, the color cannot be distinguished. Where there is no light, all objects appear black to us. But one has only to direct a beam of light at the cat, as it immediately acquires color.

The color of an object is the color of the reflected spectrum wave. White objects reflect all colors, which is why we see them as white. Black, on the other hand, absorbs all colors and reflects nothing. We see grass as green, because in sunlight it reflects green, and absorbs all the rest. A banana is yellow because it reflects yellow, and so on.

A beam of light passing through a triangular prism is deflected to a face opposite the refracted angle of the prism. However, if it is a beam of precisely white light, then after it passes through the prism, it will not only be deflected, but also decomposed into colored beams. This phenomenon is called light dispersion. It was first studied in a series of remarkable experiments.

The source of light in Newton's experiments was a small round hole located in the shutter of a window illuminated by the rays of the Sun. When a prism was placed in front of the hole, instead of a round spot, a colored strip appeared on the wall, called Newton's spectrum. Such a spectrum consists of seven main colors: red, orange, yellow, green, blue, indigo and violet, which gradually passed one into another. Each of them occupies a space of different size in the spectrum. The purple stripe is the longest and the red stripe the shortest.

The next experiment consisted in the fact that from a wide beam of colored rays obtained with the help of a prism, narrow beams of a certain color stood out by a screen with a small hole and were directed to a second prism.

The prism deflecting them does not change the color of these rays. Such rays are called simple or monochromatic (one-color).

Experience shows that red rays feel less deflection than violet ones, i.e. Rays of different colors are refracted differently by a prism.

Collecting beams of rays that emerged from the prism, Newton received on a white screen instead of a colored stripe a white image of a hole.

From all the experiments carried out, Newton drew the following conclusions:

• white light is inherently complex light, which consists of colored rays;
• rays of light of different colors also have different refractive indices of the substance; as a result, when a beam of white light is deflected by a prism, it decomposes into a spectrum;
• if you combine the colored rays of the spectrum, then again you get white light.

Thus, the dispersion of light is a phenomenon that is due to the dependence of a substance on the wavelength (or frequency).

The dispersion of light is noted not only when light passes through a prism, but also in various other cases of light refraction. So, in particular, the refraction of sunlight in water drops is accompanied by its decomposition into multi-colored rays, this explains the formation of a rainbow.

To obtain the spectrum, Newton directed a rather wide cylindrical beam of sunlight through a round hole made in the shutter onto a prism.

The spectrum obtained in this way is a series of multi-colored images of a round hole, partially superimposed on each other. To obtain a purer spectrum, when studying such a phenomenon as light dispersion, Newton suggested using not a round hole, but a narrow slot parallel to the refracting edge of the prism. Using a lens, a clear image of the slit is obtained on the screen, after which a prism is installed behind the lens, which gives the spectrum.

The purest and brightest spectra are obtained using special devices- spectroscopes and spectrographs.

Light absorption is a phenomenon in which the energy of a light wave decreases as it passes through a substance. This is due to the transformation of the energy of a wave of light into the energy of secondary radiation, or, in other words, a substance that has a different spectral composition and other directions of propagation.

The absorption of light can cause heating of a substance, ionization or excitation of molecules or atoms, photochemical reactions, and other processes in a substance.

(or wavelength) of light (frequency dispersion), or, the same thing, the dependence of the phase velocity of light in matter on the wavelength (or frequency). Experimentally discovered by Newton around 1672, although theoretically well explained much later.

• Spatial dispersion is the dependence of the dielectric permittivity tensor of a medium on the wave vector. This dependence causes a number of phenomena called spatial polarization effects.

One of the most illustrative examples of dispersion is the decomposition of white light as it passes through a prism (Newton's experiment). The essence of the phenomenon of dispersion is the unequal speed of propagation of light rays with different wavelengths in a transparent substance - an optical medium (whereas in vacuum the speed of light is always the same, regardless of the wavelength and hence the color). Usually, the higher the frequency of the wave, the higher the refractive index of the medium and the lower its speed of light in it:

• red has the maximum speed in the medium and the minimum degree of refraction,
• at purple the minimum speed of light in the medium and the maximum degree of refraction.

However, in some substances (for example, in iodine vapor), an anomalous dispersion effect is observed, in which blue rays are refracted less than red ones, and other rays are absorbed by the substance and escape observation. Strictly speaking, anomalous dispersion is widespread, for example, it is observed in almost all gases at frequencies near the absorption lines, but in iodine vapor it is quite convenient for observation in the optical range, where they absorb light very strongly.

The dispersion of light made it possible for the first time to quite convincingly show the composite nature of white light.

• White light is also decomposed into a spectrum as a result of passing through a diffraction grating or reflecting from it (this is not related to the phenomenon of dispersion, but is explained by the nature of diffraction). The diffraction and prismatic spectra are somewhat different: the prismatic spectrum is compressed in the red part and stretched in the violet and is arranged in descending order of wavelength: from red to violet; the normal (diffraction) spectrum is uniform in all areas and is arranged in ascending order of wavelengths: from violet to red.

By analogy with the dispersion of light, similar phenomena of the dependence of the propagation of waves of any other nature on the wavelength (or frequency) are also called dispersion. For this reason, for example, the term dispersion law, applied as the name of a quantitative relationship relating frequency and wavenumber, applies not only to an electromagnetic wave, but to any wave process.

Dispersion explains the fact that the rainbow appears after the rain (more precisely, the fact that the rainbow is multi-colored, not white).

Dispersion is the cause of chromatic aberrations - one of the aberrations of optical systems, including photographic and video lenses.

Cauchy came up with a formula expressing the dependence of the refractive index of the medium on the wavelength:

Dispersion of light in nature and art

Due to dispersion, different colors can be observed.

• The rainbow, whose colors are due to dispersion, is one of key images culture and art.
• Due to the dispersion of light, one can observe the color "play of light" on the facets of a diamond and other transparent faceted objects or materials.
• To some extent, iridescent effects are found quite often when light passes through almost any transparent object. In art, they can be specially amplified, emphasized.
• The decomposition of light into a spectrum (due to dispersion) during refraction in a prism is a fairly common topic in fine arts. For example, the cover of Pink Floyd's album Dark Side Of The Moon depicts the refraction of light in a prism with decomposition into a spectrum.

see also

Literature

• Yashtold-Govorko V. A. Photography and processing. Shooting, formulas, terms, recipes. - Ed. 4th, abbr. - M .: Art, 1977.

Links

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See what "Dispersion of light" is in other dictionaries:

The dependence of the refractive index n in VA on the frequency n (wavelength l) of light or the dependence of the phase velocity of light waves on their frequency. Consequence D. s. decomposition into a spectrum of a beam of white light when it passes through a prism (see SPECTRA ... ... Physical Encyclopedia

light dispersion- Phenomena due to the dependence of the speed of light propagation on the frequency of light vibrations. [Collection of recommended terms. Issue 79. Physical optics. USSR Academy of Sciences. Committee of Scientific and Technical Terminology. 1970] Topics… … Technical Translator's Handbook

light dispersion- šviesos skaida statusas T sritis radioelektronika atitikmenys: engl. dispersion of light vok. Light dispersion, f; Zerteilung des Lichtes, f rus. dispersion of light, fpranc. dispersion de la lumière, f … Radioelectronics terminų žodynas

light dispersion- šviesos dispersija statusas T sritis fizika atitikmenys: angl. dispersion of light vok. Light dispersion, f; Zerlegung des Lichtes, f rus. dispersion of light, fpranc. dispersion de la lumière, f … Fizikos terminų žodynas

The dependence of the refractive index n of a substance on the frequency ν (wavelength λ) of light or the dependence of the phase velocity (See Phase velocity) of light waves on frequency. Consequence D. s. decomposition into the spectrum of a beam of white light during the passage of ... ... Great Soviet Encyclopedia

Dependence of the refractive index n in va on the frequency of light v. In the region frequencies of light, for which ryh is transparent, n increases with increasing v normal D. s. In the region frequencies corresponding to the bands of intense absorption of light in the voi, n decreases with ... ... Big encyclopedic polytechnic dictionary

The dependence of the absolute refractive index of a substance on the wavelength of light ... Astronomical dictionary

Would you like to improve this article?: Add illustrations. Find and issue in the form of footnotes links to authoritative sources confirming what is written. Put down a card template that creatures ... Wikipedia

Dependence of the phase velocity of harmonic waves in a medium on the frequency of their oscillations. wave dispersion is observed for waves of any nature. The presence of wave dispersion leads to a distortion of the signal shape (for example, a sound pulse) when propagating in a medium ... Big Encyclopedic Dictionary