In a relaxed atmosphere, the position of the stars are observed. Ripstaining the mystery of outbreaks of red dwarfs
THE GOVERNMENT OF MOSCOW
Moscow Department of Education
Eastern District Governance
State budgetary educational institution
Secondary school № 000
111141 Moscow st. Persian house 44s, p. 1.2 phone
Lesson No. 5 (02.28.13)
"Work with text"
In the examination materials in physics included tasks that check the skills of students to develop new information for them to work with this information, to answer questions, the answers to which are followed from the text proposed to study. After studying the text, three tasks are offered (№16,17 - basic level, №18 - high level).
Experiments of Gilbert in magnetism.
Gilbert carved the ball from the natural magnet so that it turned out the poles in two diametrically opposite points. He called this spherical magnet (Fig. 1), that is, a small earth. Approaching the moving magnetic arrow to it, you can visually show those diverse positions of the magnetic arrow, which it takes at different points of the earth's surface: the arrow contains parallel to the horizon plane, on the pole - perpendicular to the horizon plane.
Consider the experience discovering "magnetism through influence". Suspension on threads two iron strips parallel to each other and will slowly bring a large permanent magnet to them. In this case, the lower ends of the strips are diverged, since it is magnetized equally (Fig. 2a). With a further approximation of the magnet, the lower ends of the strips are somewhat converged, since the pole of the magnet itself begins to act on them with greater force (Fig. 2b).
Task 16.
How the angle of inclination of the magnetic arrow changes as it changes ground Shar. Along the Meridian from the Equator to the Pole?
1) all the time increases
2) all the time decreases
3) first increases, then decreases
4) first decreases, then increases
Correct answer: 1
Task 17.
Which points are the magnetic poles of Terlela (Fig. 1)?
Correct answer: 2
Task 18.
In the experiment, which detects "magnetism through influence", both iron strips are magnetized. Figures 2a and 2b for both cases are the poles of the left strip.
At the bottom end of the right strip
1) In both cases, the South Pole occurs
2) In both cases, the North Pole occurs
3) In the first case, the northern arises, and in the second it arises southern
4) In the first case, southern arises, and in the second the Northern
Correct answer: 2
Experiments of Ptolemy on the refraction of light.
Greek astronomer Claudius Ptolemy (about 130 g. E.) is the author of the wonderful book, which for almost 15 centuries served as the main textbook on astronomy. However, in addition to the astronomical textbook, Ptolemy wrote another book "Optics", in which he outlined the theory of view, the theory of flat and spherical mirrors and the study of the phenomenon of the refraction of light.
With the phenomenon of the refraction of light, Ptolemy collided, watching stars. He noticed that the beam of light, moving from one environment to another, "breaking". Therefore, the star beam, passing through the earth's atmosphere, it comes to the surface of the earth not in a straight line, but by the line curve, that is, refractive occurs. The curvature of the stroke of the beam occurs due to the fact that the air density changes with a height.
To study the refractive law, Ptolemy conducted the following experiment ..gif "width \u003d" 13 "height \u003d" 24 src \u003d "\u003e (see figure). The ruler could rotate near the center of the circle on the total axis O.
Ptolemy immersed this circle into water to the diameter of AV and, turning the lower line, sought the rules to lie for the eye on one straight line (if you look along the upper ruler). After that, he took the circle from the water and compared the angles of the fall α and refractions β . It measured the angles with an accuracy of 0.5 °. The numbers obtained by Ptolem are presented in the table.
Angle of incidence α , hail | ||||||||
Defraction angle β , hail |
Ptolemy did not find the "formula" of the relationship for these two rows of numbers. However, if you determine the sines of these angles, it turns out that the ratio of the sinuses is expressed by almost the same number even with such a coarse measurement of the corners to which Ptolemy resorted.
Task 16.
Under refraction in the text it is understood
1) changes to the direction of spread of the light beam due to reflection on the border of the atmosphere
2) changes to the direction of distribution of the light beam due to refraction in the earth's atmosphere
3) the absorption of light during its distribution in the atmosphere of the Earth
4) increments of light beam obstacles and, thereby deviations from rectilinear distribution
Correct answer: 2
Task 17.
Which of the following conclusions contradictive Ptolemy's experiments?
1) the refractive angle is less than the angle of incidence when moving the beam from air to water
2) with an increase in the angle of drop linearly increasing the angle of refraction
3) the ratio of the sinus of the angle of falling to the sinus of the refractive angle does not change
4) the sine of the refractive index linearly depends on the sine of the angle of the fall
Correct answer: 2
Task 18.
Due to the refraction of light in a relaxed atmosphere, the seeming position of the stars in the sky relative to the horizon
1) above the actual position
2) below the actual position
3) shifted in one direction or another by vertical relative to the actual position
4) coincides with the actual position
Correct answer: 1
Thomson's experiments and the opening of the electron
At the end of the 19th century, many experiments were conducted on the study of an electric discharge in sparse gases. The discharge was excited between the cathode and the anode, the inside the glass tube, from which air was dumped. What took place from the cathode was called cathode rays.
To determine the nature of the cathode rays, the English physicist Joseph John Thomson (1856 - 1940) conducted the following experiment. Its experimental installation was a vacuum electron beam tube (see Figure). The glowable cathode K was a source of cathode rays, which accelerated the electric field existing between the anode A and the cathode K. in the center of the anode there was a hole. The cathode rays that have passed through this hole fell to the point G on the wall of the tube s opposite the hole in the anode. If the wall s is coated with a fluorescent substance, then the ray to the point G is manifested as a luminous speck. On the way from A to G, the rays were held between the plates of the CD condenser, which could be applied to the battery voltage.
If you include this battery, then the rays are deflected by the electrical field of the capacitor and the speech occurs on the screen S. Thomson suggested that the cathode rays behave like negatively charged particles. Creating a homogeneous magnetic field in the area between the plates of the capacitor, the perpendicular plane of the pattern (it is depicted by points), can be caused by a rejection of the stain in the same or reverse direction.
Experiments have shown that the particle charge is equal to the module charge of the hydrogen ion (CL), and its mass is almost 1840 times less than the mass of the hydrogen ion.
In the future, she received an electron name. Day April 30, 1897, when Joseph John Thomson reported on his research, it is considered the "birthday" of the electron.
Task 16.
What are cathode rays?
1) X-rays
2) gamma rays
3) electron flow
4) the flow of ions
Correct answer: 3
Task 17.
BUT. Cathodic rays interact with electric field.
B. Cathodic rays interact with magnetic field.
1) only a
2) only b
4) neither, nor b
Correct answer: 3
Task 18.
Cathodic rays (see Figure) will fall into the point G, provided that there is a CD condenser plates
1) only the electric field is valid
2) only the magnetic field is valid
3) action forces from electrical and magnetic fields compensated
4) the action of the forces from the magnetic field is negligible little
Correct answer: 3
Experimental opening of the law of equivalence of heat and work.
In 1807, the physicist J. Gay-Loussak, who studied the properties of gases, put a simple experience. It has long been known that compressed gas, expanding, cooled. Gay-Loursak forced the gas to expand into the emptiness - to the vessel, the air of which was pre-died. To his surprise, no decrease in the temperature did not happen, the gas temperature did not change. The researcher could not explain the result: why the same gas equally compressed, expanding, cooled, if it is released directly out into the atmosphere, and not cooled, if it is released in an empty vessel, where the pressure is zero?
Expert experience managed to German doctor Robert Mayer. The Mayer had the idea that work and heat can turn into another one. This wonderful idea immediately gave Mayer's opportunity to make a clear mysterious result in the experience of gay-lousham: if the heat and work are mutually turning, then when expanding gas into the void, when it does not make any work, because there is no power (pressure), opposing its increase Volume, gas and should not be cooled. If, with the expansion of gas, it has to work against external pressure, its temperature should be reduced. Give work it is impossible! The wonderful result of Mayer was many times confirmed by direct measurements; Of particular importance were the experiments of Joule, which measured the amount of heat required to heat the liquid rotating in it with a stirrer. At the same time, the work spent on the rotation of the agitator was measured and the amount of heat obtained by liquid. No matter how experienced conditions have changed, various liquids were taken, different vessels and stirrers, the result was the same: always from the same work one and the same amount of heat was obtained.
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Melting Curve (P - Pressure, T - Temperature)
According to modern ideas, most of the earthly subsoil retains a solid state. However, the agent of asthenosphere (the land shell from 100 km to 300 km deep) is located in an almost melted state. This is called a solid state, which easily goes into a liquid (molten) with a slight increase in temperature (process 1) or a decrease in pressure (process 2).
The source of the primary melts of magma is an asthenosphere. If the pressure is reduced in any area (for example, when the lithosphere sections are shifted), the solid of the asthenosphere immediately turns into a liquid melt, i.e. in magma.
But what physical reasons are the mechanism of volcanic eruptions?
In Magma, along with water vapors contain various gases (carbon dioxide, chloride and fluoride hydrogen, sulfur oxides, methane and others). The concentration of dissolved gases corresponds to external pressure. In physics, the Geminine law is known: the concentration of gas dissolved in the liquid is proportional to its pressure above the liquid. Now imagine that the pressure at the depth decreased. Gases dissolved in magma are moving into a gaseous state. Magma increases in volume, foams and begins to rise up. As the magma lifts, the pressure drops even more, therefore the process of gases is enhanced, which, in turn, leads to acceleration of the rise.
Task 16.
In what aggregate states Are there a substance of asthenosphere in regions I and II in the diagram (see Figure)?
1) i - in liquid, II - in solid
2) I - in solid, II - in liquid
3) I - in liquid, II - in liquid
4) I - in solid, II - in solid
Correct answer: 2
Task 17.
What power makes the molten foaming magma climb up?
1) gravity
2) the power of elasticity
3) the power of Archimedes
4) friction force
Correct answer: 3
Task 18.
Cable disease - a disease that occurs with a rapid rise in diver with great depths. Caisson disease occurs in a person with a rapid change in external pressure. When working in conditions increased pressure Man's fabrics absorb additional amount of nitrogen. Therefore, scuba divers must emerge slowly so that blood has time to determine the resulting gas bubbles into the lungs.
What approvals are valid?
BUT. The concentration of nitrogen dissolved in the blood, the greater the greater the depth of the diver immersion.
B. With an excessively fast transition from a high-pressure medium in a low pressure medium, excess nitrogen dissolved in tissues is released, forming gas bubbles.
1) only a
2) only b
4) neither, nor b
Correct answer: 3
Geysers
Geysers are located near the acting or recently asleep volcanoes. For the eruption of geysers, heat coming from volcanoes is necessary.
To understand the physics of geysers, we recall that the boiling point of water depends on the pressure (see Figure).
The dependence of the boiling point of water from the pressure https://pandia.ru/text/78/089/images/image013_71.gif "width \u003d" 25 "height \u003d" 21 "\u003e Pa. At the same time water in the tube
1) will move down under the action of atmospheric pressure
2) will remain in equilibrium, since its temperature is below the boiling point
3) will quickly cooled, as its temperature is lower than the boiling point at a depth of 10 m
4) boils, as its temperature above the boiling point at external pressure
Correct answer: 4
Fog
Under certain conditions, water vapors in the air are partially condensed, resulting in the fog water droplets. Water droplets have a diameter from 0.5 microns to 100 microns.
Take the vessel, half fill with water and close the lid. The fastest water molecules, overcoming the attraction from other molecules, jump out of the water and form pairs above the water surface. This process is called water evaporation. On the other hand, the water vapor molecules, encountering each other and with other air molecules, random can be at the surface of the water and go back to the liquid. This is a steam condensation. In the end, at this temperature, evaporation and condensation processes are mutually compensated, that is, a state of thermodynamic equilibrium is established. Water vapor, which is in this case above the surface of the liquid, is called saturated.
If the temperature is increased, then the evaporation rate increases and equilibrium is set at a greater density of water vapor. Thus, the density of the saturated steam increases with increasing temperature (see Figure).
The dependence of the density of saturated water vapor on temperature
For the occurrence of fog, it is necessary for steam to become not just saturated, but intended. Water pairs becomes saturated (and deserted) with sufficient cooling (AB processing) or in the process of additional evaporation of water (AC process). Accordingly, the falling fog is called the fog of cooling and fog evaporation.
The second condition necessary for the formation of fog is the presence of condensation cores (centers). The role of nuclei can play ions, the smallest droplets of water, dust, soot particles and other small contaminants. The more air pollution, the greater density differ in fogs.
Task 16.
From the graph in the figure it is seen that at a temperature of 20 ° C, a saturated water vapor density is 17.3 g / m3. This means that at 20 ° C
5) In 1 m, the mass of saturated vapor water is 17.3 g
6) at 17.3 m of the air is 1 g of a saturated water vapor
8) air density is 17.3 g / m
Correct answer: 1
Task 17.
With what process indicated on the chart can observe the fog of evaporation?
1) only AB
2) only speakers
4) Nor AB nor
Correct answer: 2
Task 18.
What approvals are valid?
BUT. City fogs, compared to fogs in mountainous areas, are characterized by a higher density.
B. Fogs are observed with a sharp increase in air temperature.
1) only a
2) only b
4) neither, nor b
Correct answer: 1
Sky color and the setting sun
Why does the sky have a blue color? Why the setting sun becomes red? It turns out that in both cases the reason is one - scattering of sunlight in the earth's atmosphere.
In 1869, the English physicist J. Tyndle made the following experience: through a rectangular aquarium filled with water, missed a weakly spending narrow beam of light. It was noted that if you look at the light beam in the aquarium on the side, then it appears bluish. And if you look at the beam from the output end, the light acquires a reddish hue. This can be explained if we assume that blue (blue) light dissipates stronger than red. Therefore, when the white light beam passes through the scattering medium, the blue light is mainly dissipated from it, so that the red light begins to prevail the beam. The larger way passes the white beam in the scattering environment, especially red it seems at the exit.
In 1871, J. Strett (Ralea) built the theory of scattering of light waves on small particles. The law established by Railel states: the intensity of the diffused light is proportional to the fourth degree of the frequency of light or, in other words, is inversely proportional to the fourth degree of the length of the light wave.
Reley put forward a hypothesis in which the lights scattering are air molecules. Later, in the first half of the 20th century, it was found that the main role in light scattering plays air density fluctuations - microscopic thickening and air loss arising due to the chaotic thermal motion of air molecules.
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The disc on which sound recording is made is made of a special soft wax material. From this wax disc, the copper copy (cliché) is removed by a galvanoplastic way. It uses precipitation on the electrode of pure copper when the electric current is passed through the solution of its salts. Then, with a copper copy, make prints on plastic disks. So get gramophone plates.
When playing a sound, the gramophone plate is put under the needle associated with the gramophone membrane, and lead a plate into rotation. Moving along a wavy groove plate, the end of the needle fluctuates, and the membrane hesitates with it, and these oscillations are quite accurately reproduced by the recorded sound.
Task 16.
What oscillations make the membrane of the horn under the action of sound wave?
5) free
6) Flowering
7) Forced
8) self-oscilps
Correct answer: 3
Task 17.
What is the current effect when receiving cliche from the wax disk?
1) Magnetic
2) thermal
3) light
4) Chemical
Correct answer: 4
Task 18.
Cameton is used when manual sound recording. With an increase in the sound of the camera 2 times
5) the length of the sound groove will increase by 2 times
6) The length of the sound groove will decrease by 2 times
7) The depth of the sound groove will increase by 2 times
8) The depth of the sound groove will decrease by 2 times
Correct answer: 1
Magnetic suspension
The average speed of trains on railways less than
150 km / h. Describe a train capable of competing in speed with aircraft, not easy. At high speeds, the wheels of trains do not withstand the load. Output one: abandon the wheels, forcing the train to fly. One of the ways to "hang" the train over the rails is to use the repellent magnets.
In 1910, Belgian E. Bashley built the world's first model of a flying train and experienced it. The 50-kilogram cigar-like flying trains car accelerated to speed over 500 km / h! The magnetic road of the Bashley was a chain of metal columns with coils fortified on their vertices. After turning on the current, the trailer with built-in magnets was raised above the coils and accelerated the same magnetic field over which it was suspended.
Almost simultaneously with the Bashla in 1911, Professor of Tomsk technological Institute B. Waynberg has developed a much more economical suspension of a flying train. Waynberg offered not to repel the road and the wagons from each other, which is fraught with huge energy costs, and attract them by ordinary electromagnets. The electromagnets of the road were located above the train so that their attraction compensate the strength of the severity of the train. The iron car was originally not precisely under the electromagnet, and behind it. At the same time, the electromagnets were mounted along the entire length of the road. When turning on the current in the first electromagnet, the trailer rose and moved forward, towards the magnet. But as a moment before the trailer was supposed to stick to the electromagnet, the current was turned off. The train continued to fly on inertia, reducing height. The following electromagnet was turned on, the train was raised again and accelerated. By placing your wagon in the copper pipe, from which the air was framed, Winberg dispersed the car to a speed of 800 km / h!
Task 16.
Which of the magnetic interactions can be used for magnetic suspension?
BUT. The attraction of variemety poles.
B. Repulsion of the poles of the same name.
1) only a
2) only b
3) nor, nor b
Correct answer: 4
Task 17.
When moving a train on a magnetic suspension
1) Friction forces between the train and expensive
2) air resistance forces are negligibly small
3) Used the forces of electrostatic repulsion
4) The forces of attraction of the same name magnetic poles are used.
Correct answer: 1
Task 18.
In the model of the magnetic train, B. Vainberg needed to use the trailer with a greater mass. In order for the new trailer to move in the same mode, it is necessary
5) Replace the copper pipe on the iron
6) Do not turn off the current in the electromagnets until the "sticking" of the trailer
7) increase current strength in electromagnets
8) Mounting the electromagnets along the length of the road through the larger
Correct answer: 3
Piezoelectricity
In 1880, French scientists Pierre's brothers and Paul Curie investigated the properties of crystals. They noticed that if the crystal quartz squeeze on both sides, then on its faces, perpendicular to the direction of compression, electric charges arise: on one face - positive, on the other - negative. In the same property, the crystals of the tourmaline, ferronetic salt, even sugar are possessed. Charges on the edges of the crystal arise and with its tension. Moreover, if a positive charge was accumulated during compression on the verge, then the negative charge will accumulate on this face, and vice versa. This phenomenon was called piezoelectricity (from the Greek word "Piezo" - I dance). Crystal with such a property is called a piezoelectric. In the future, the Curie brothers found that the piezoelectric effect would be reversible: if you create multi-way electric charges on the edges of the crystal, it is either denounced, or it stretches, depending on which face is attached positive and what kind of negative charge.
On the phenomena of piezoelectricity, the action of widespread piezoelectric lighters is based. The main part of such a lighter is a piezoelectric ceramic piezoelectric cylinder with metal electrodes on the grounds. With the help of a mechanical device, a short-term blow to piezoelectric is made. At the same time, on the two sides, located perpendicular to the direction of the deforming force, a variety of electrical charges appear. The voltage between these sides can reach several thousand volts. According to insulated wire, the voltage is summed up to two electrodes located in the luggage tip at a distance of 3 - 4 mm from each other. The spark discharge arising between the electrodes is set in the mixture of gas and air.
Despite the very high stresses (~ 10 square meters), experiments with piezoslazhigalki are completely safe, since even with a short circuit, the current force turns out to be negligible and safe for human health, as in electrostatic discharges when removing wool or synthetic clothing in dry weather.
Task 16.
Piezoelectricity is a phenomenon
1) the occurrence of electrical charges on the surface of the crystals in their deformation
2) the emergence of deformation of stretching and compression in crystals
3) Passage of electric current through crystals
4) the passage of the spark discharge during crystal deformation
Correct answer: 1
Task 17.
Using piezosajigali does not represent danger because
7) Current power is negligible
8) Current force in 1 and for a person safe
Correct answer: 3
Task 18.
At the beginning of the 20th century, the French scientist Paul Lanzhen invented emitter of ultrasound waves. Chargeing the edge of the quartz crystal with electricity from the alternator of the high frequency alternator, it found that the crystal does vibrations with the frequency of voltage change. The action is based on the emitter lies
1) direct piezoelectric effect
2) Reverse Piezoelectric Effect
3) an electrification phenomenon under the action of an external electric field
4) electrification phenomenon when hit
Correct answer: 2
Construction of Egyptian pyramids
Hope's pyramid is one of the seven wonders of the world. Until now, there are many questions, exactly how the pyramid was built.
Transport, raise and install stones, the mass of which was dozens and hundreds of tons, was not easy.
In order to raise stone blocks upstairs, invented very sly fashion. Funny earth ramps have erected around the construction site. As the pyramid grew, the ramps climbed higher and higher, as if when we were looking for all the future buildings. According to the ramp, the stones dragged on the sleds in the same way as on the ground, helping themselves with the levers. The angle of inclination of the ramp was very insignificant - 5 or 6 degrees, because of this, the length of the ramp grown to hundreds of meters. Thus, during the construction of the pyramid, Hefrena Radus, which combined the upper temple with the bottom, with the difference of levels, which was more than 45 m, had a length of 494 m, and a width of 4.5 m.
In 2007, the French architect Jean-Pierre Udan suggested that during the construction of the Hope's pyramid, the ancient Egyptian engineers used the system of both external and internal ramps and tunnels. Udan believes that with the help of external ramps, only the bottom was erected,
The 43-meter part (the overall height of the peyramid of the cheops is 146 meters). For lifting and installing the remaining boulders, the system of internal ramps located spiral-like was used. For this, the Egyptians disassemble external ramps and transferred them inside. The architect is confident that the cavities found in 1986 in the thicker pyramid of Heops are tunnels, in which ramps gradually turned.
Task 16.
What kind of simple mechanisms is the ramp?
5) Movable block
6) fixed block
8) inclined plane
Correct answer: 4
Task 17.
Refers to ramps
5) Cargo elevator in residential buildings
6) Arrow of lifting crane
7) Gate for raising water from the well
8) inclined venue for the entry of cars
Correct answer: 4
Task 18.
If you neglect friction, then the ramp, which connects the top temple with the bottom in the construction of the pyramid, allowed to get a win
5) in force approximately 11 times
6) in force more than 100 times
7) at work approximately 11 times
8) in the distance of about 11 times
Correct answer: 1
Albedo Earth
The temperature at the surface of the Earth depends on the reflectivity of the planet - albedo. Albedo surface is the ratio of the energy flow of reflected solar rays to the energy of the energy falling on the surface of the sun's rays, expressed as a percentage or fractions of the unit. Albedo Earth in the visible part of the spectrum is about 40%. In the absence of clouds it would be about 15%.
Albedo depends on many factors: the presence and state of clouds, changes in glaciers, season, and, respectively, from precipitation. In the 90s of the 20th century, a significant role of aerosols - the smallest solid and liquid particles in the atmosphere became apparent. When burning fuel in the air, gaseous sulfur and nitrogen oxides fall; Connecting in an atmosphere with water droplets, they form sulfur, nitric acids and ammonia, which turn into sulphate and nitrate aerosols. Aerosols not only reflect sunlight, I do not pass it to the surface of the earth. The aerosol particles serve as the cores of the condensation of atmospheric moisture in the formation of clouds and, thereby contribute to the increase in cloudiness. And this, in turn, reduces the inflow of solar heat to the earth's surface.
Transparency for sunlights in the lower layers of the earth's atmosphere also depends on fires. Due to the fires, dust and soot are raised into the atmosphere, which are covered with a dense screen and increase the albedo surface.
Task 16.
Under the albedo surfaces understand
1) Common stream falling on the surface of the land of sunlight
2) the ratio of the flow of reflected radiation energy to the stream of absorbed radiation
3) The ratio of the flow of the energy of reflected radiation to the flow of incident radiation
4) The difference between the falling and reflected radiation energy
Correct answer: 3
Task 17.
What approvals are valid?
BUT. Aerosols reflect the sunlight and, thus, contribute to the decrease in the albedo of the Earth.
B. Volcanic eruptions contribute to an increase in the albedo of the Earth.
1) only a
2) only b
4) neither, nor b
Correct answer: 2
Task 18.
The table shows some characteristics for the planets. Solar system - Venus and Mars. It is known that albedo Venus A \u003d 0.76, and Albedo of Mars A \u003d 0.15. Which of the characteristics, mainly, influenced the difference in the albedo planets?
Characteristics | Venus | Mars |
BUT. The average distance from the Sun, in the radius of the earth orbit | ||
B. Middle radius of the planet, km | ||
IN. Number of satellites | ||
G. Availability of atmosphere | very dense | related |
Correct answer: 4
Greenhouse effect
To determine the temperature of the heated Sun object, it is important to know its distance from the sun. The closer the planet of the solar system to the Sun, the higher its average temperature. For an object removed from the Sun as Earth, a numerical estimate of the average temperature on the surface gives the following result: T Å ≈ -15 ° C.
In fact, the land climate is significantly softer. Its average temperature on the surface is about 18 ° C due to the so-called greenhouse effect - heating the lower part of the atmosphere by the radiation of the earth's surface.
In the lower layers of the atmosphere, nitrogen predominate (78%) and oxygen (21%). The remaining components account for only 1%. But it is precisely this percentage and determines the optical properties of the atmosphere, since nitrogen and oxygen almost do not interact with radiation.
The effect of "greenhouse" is known to all those who have dealt with this uncomplicated garden structure. In the atmosphere, he looks like this. A portion of the radiation of the Sun, not reflected from the clouds, passes through the atmosphere, performing the role of glass or film, and heats the ground surface. The heated surface is cooled, the emitting heat radiation, but this is another radiation - infrared. The average wavelength of such radiation is much larger than that coming from the Sun, and therefore almost transparent for visible atmosphere passes infrared radiation much worse.
Water pairs absorb about 62% of infrared radiation, which contributes to heating lower layers Atmosphere. The water vapor in the list of greenhouse gases should follow carbon dioxide (CO2), absorbing 22% of the infrared radiation of the Earth in the transparent air.
The atmosphere absorbs the flow of long-wave radiation that is ascending from the surface of the planet, heats up and, in turn, heats the surface of the Earth. The maximum in the Sun radiation spectrum accounts for a wavelength of about 550 nm. The maximum in the Earth's radiation spectrum accounts for a wavelength of about 10 microns. The role of the greenhouse effect illustrates Figure 1.
Fig.1 (a). Curve 1 - the estimated spectrum of the radiation of the Sun (with a temperature of the photosphere 6000 ° C); Curve 2 - Estimated Earth Radiation Spectrum (with surface temperature 25 ° C)
Fig.1 (b). Absorption (percentage terms) of the earth's radiation atmosphere at different wavelengths. The absorption bands of CO2, H2O, O3, CH4 are located on the spectrum section of the spectrum of 10 to 20 microns. They are absorbed by radiation coming from the surface of the earth
Task 16.
Which gases play the greatest role in the greenhouse effect of the Earth's atmosphere?
10) Oxygen
11) carbon dioxide
12) water vapor
Correct answer: 4
Task 17.
Which of the following statements correspond to the curve in Figure 1 (b)?
BUT.Visible radiation, corresponding to the maximum of the solar spectrum, passes through the atmosphere almost unhindered.
B.Infrared radiation with a wavelength exceeding 10 microns practically does not pass beyond the terrestrial atmosphere.
5) only a
6) only b
8) nor, nor b
Correct answer: 3
Task 18.
Thanks to the greenhouse effect
1) In cold cloudy weather, woolen clothing protects the body of a person from supercooling
2) Tea in the thermos remains a long time to hot
3) Solar rays that have passed through glazed windows heated air in the room
4) On a summer sunny day, the water temperature in the water bodies below the sand temperature on the shore
Correct answer: 3
Rumor man
The lowest tone perceived by man with normal hearing has a frequency of about 20 Hz. The upper limit of the auditory perception is greatly different from different people. Of particular importance here has age. At eighteen years, with an impeccable hearing, you can hear the sound to 20 kHz, but on average the boundaries of hearing for any age lie in the range of 18 - 16 kHz. With age, the sensitivity of the human ear to high-frequency sounds gradually falls. The figure shows a graph of the level of sound perception level from frequency for people of different ages.
Soreness "href \u003d" / text / category / buleznennostmz / "REL \u003d" Bookmark "\u003e painful reactions. Transport or production noise acts depressingly on a person - tires, annoying, prevents focusing. As soon as such a noise is clentched, a person is experiencing a sense of relief and peace. .
The noise level of 20-30 decibels (dB) is almost harmless to humans. This is a natural noise background, without which human life is impossible. For "loud sounds" the maximum allowable boundary of about 80-90 decibels. The sound of 120-130 decibels already causes pain in humans, and in 150 it becomes intolerable for him. The effect of noise on the body depends on age, hearing sensitivity, duration of action.
The most detrimental for hearing long periods of continuous effects of high intensity noise. After exposure to strong noise, the normal threshold of auditory perception is noticeably increased, that is, the lowest level (volume) in which this man still hears the sound of one or another frequency. Measurements of the thresholds of auditory perception are produced in specially equipped rooms with a very low level of ambient noise, feeding audio signals through the headphones. This technique is called audiometry; It allows you to get a curve of individual hearing sensitivity, or an audiogram. Usually, deviations from normal hearing sensitivity are noted on audiograms (see Figure).
0 "STYLE \u003d" MARGIN-LEFT: -2.25PT; Border-Collapse: COLLAPSE "\u003e
Source of noise
Noise level (dB)
BUT. Working vacuum
B. noise in the metro car
IN. Pop Music Orchestra
G. car
D. Whisper at a distance of 1 m
8) B, b, g and a
Correct answer: 1
In the atmosphere there are cold and hot air flows. Where the warm layers above the cold are formed by aerial vortices, under the action of which the light rays are twisted, and the position of the star occurs.
The brightness of the star changes for the reason that rays deviating incorrectly, unevenly concentrated above the surface of the planet. In this case, the entire landscape is constantly shifting and varies due to atmospheric phenomena, for example, due to wind. Owning behind the stars turns out to be in a more illuminated area, then, on the contrary, in more shaded.
If you want to watch the flicker of stars, then keep in mind that Zenith can only occasionally detect this phenomenon at a relaxed atmosphere. If you transfer your view to the celestial objects, located closer to the horizon, you will find that they flicker much stronger. This is explained by the fact that you look at the stars through a denser layer of air, and, accordingly, permeate a greater number of air flows. You will not notice changes in the color of stars located at an altitude of more than 50 °. But detect the frequent color change in the stars below 35 °. Sirius flickes very beautifully, overflowing with all the colors of the spectrum, especially in winter months, low above the horizon.
Strong flickering stars proves the inhomogeneity of the atmosphere, which is associated with various meteorological phenomena. Therefore, many think that flicker is associated with the weather. Often it is gaining momentum at low atmospheric pressure, lowering temperature, increasing humidity, etc. But the state of the atmosphere depends on such a large number of various factors that this moment It is not possible to predict the weather by flickering stars.
This phenomenon stores its riddles and ambiguities. It is assumed that it is enhanced in the twilight. It may be optical illusionAnd the consequence of unusual atmospheric changes that often occur at this time of the day. It is believed that the flickering of stars is due to the northern shine. But it is very difficult to explain if you consider that the Northern Light is at an altitude of more than 100 km. In addition, it remains a mystery why white stars flicker less than red.
Stars are the sun. The first person who discovered this truth was a scientist of Italian origin. Without any exaggeration, his name is known to everything modern world. This is the legendary Jordan Bruno. He argued that among the stars there are similar in the sun and sizes, and the temperature of their surface, and even the color that directly depends on the temperature. In addition, there are stars that differ significantly from the Sun, the giants and supergiant.
Tabel about ranks
The manifold of countless set of stars in the sky forced astronomers to set some order among them. For this, scientists decided to split the stars to the corresponding classes of their luminosity. For example, stars that radiate light a few thousand times more than the sun, got the name of the giants. On the contrary, the stars with minimal luminosity are dwarfs. Scientists found out that the sun, according to this characteristic, is a middle star.
Differently shine?
For a while, astronomers thought that the stars were shining unequal due to their different location from the Earth. But it is not so. Astronomers found out that even those stars that are located at the same distance from the ground may have a completely different visible shine. This brilliance depends not only on the distance, but also on the temperatures of the stars themselves. To compare stars according to their visible brilliance, scientists use a certain unit of measure - an absolute star magnitude. It allows you to calculate the relevant star. Using this method, scientists calculated that there are only 20 brightest stars in the sky.
Why are the stars of different colors?
Above it was written that astronomers distinguish the stars by their size and their luminosity. However, this is not all their classification. Along with the size and visible glitter, all stars are divided into their own color. The fact is that the light that determines one or another star has a wave radiation. These are rather short. Despite the minimum wave of light length, even the very insignificant difference in the size of light waves sharply changes the color of the star, which directly depends on its surface temperature. For example, if you split into the iron pan, it will acquire the corresponding color.
The color spectrum of the star is a kind of passport that determines its most characteristic features. For example, the sun and chapel (a star similar to the sun) were allocated by astronomers in the same way. Both are yellow-pale color, the temperature of its surface is 6000 ° C. Moreover, their spectrum has the same substances in its composition: lines, sodium and iron.
Stars like Bethelgeuse or Antares generally have a characteristic red color. The temperature of their surface is 3000 ° C, in their composition, titanium oxide is isolated. White color has stars like Sirius and Vega. The temperature of their surface is 10000 ° C. Their spectra have hydrogen lines. There is also a star with a surface temperature in 30000 ° C - this is a bluish-white Orion.
Passing through the earth's atmosphere, the rays of light change the straight line. Due to the increase in the density of the atmosphere, the refraction of light rays is enhanced as they approach the surface of the Earth. As a result, the observer sees heavenly shine as if raised above the horizon at an angle, called the astronomical refraction.
Refraction is one of the main sources of both systematic and random errors of observations. In 1906 Newcomb wrote that there is no such industry of practical astronomy, which would write as much as refractive, and which would be in such an unsatisfactory condition. Until the mid-20th century, astronomers reduced their observations on refractive tables, compiled in the 19th century. The main disadvantage of all old theories was inaccurate idea of \u200b\u200bthe structure of the earth's atmosphere.
We will take the surface of the Earth AV for the sphere of radius of OA \u003d R, and the atmosphere of the Earth will be imagined as a concentric layer aB, A 1 in 1, and 2 in 2... with densities that increase as the layers of the earth's surface approaches (Fig.2.7). Then the SA beam from some very distant shining, refraarting in the atmosphere, will come to a point A in the direction S ¢ A, devastating from its initial position of SA or from the direction parallel to it S² for some angle s ¢ as² \u003d r., called astronomical refraction. All elements of the curvilinear beam SA and the final visible direction AS will lie in the same vertical zaos plane. Consequently, astronomical refraction only increases the true direction on the luminaries in the vertical plane passing through it.
The angular elevation of the shone above the horizon in astronomy is called the height of the shone. Angle s ¢ ah \u003d h ¢ It will be visible height of the shine, and the angle S²AH \u003d h \u003d H ¢ - R There is a true height. Angle z. - the true anti-aircraft distance of the shining, and z.¢ is a visible value.
The refractive value depends on many factors and can change in every place on Earth even during the day. For medium conditions, an approximate refraction formula was obtained:
DH \u003d -0.9666ctG H ¢. (2.1)
The coefficient of 0.9666 corresponds to the density of the atmosphere at a temperature of + 10 ° C and a pressure of 760 mm of the mercury pillar. If the atmosphere characteristics are other, then the refraction amendment calculated by formula (2.1) must be adjusted for the temperature and pressure.
Fig.2.7. Astronomic refraction
To take into account the astronomical refraction in the zenital methods of astronomical definitions during observation of anti-aircraft distances, the lights measure the temperature and pressure of the air. In the exact methods of astronomical definitions, anti-aircraft distances are measured from 10 ° to 60 °. The upper limit is due to instrumental errors, the lower - errors of the refractive tables.
The anti-aircraft distance of the shine, corrected by the refraction amendment, is calculated by the formula:
Average (normal at a temperature of + 10 ° C and a pressure of 760mm Hg. Art.) Refraction calculated by z.¢;
The coefficient that takes into account the air temperature calculated by the temperature value;
B. - coefficient taking into account air pressure.
Many scientists were engaged in refractive theory. Initially, as the initial one, it was assumed that the density of various layers of the atmosphere decreases with an increase in the height of these layers in arithmetic progression (Bug). But soon this assumption was recognized in all respects unsatisfactory, as it led to the too low of refraction and to a too rapid decrease in temperature with a height above the ground surface.
Newton expressed a hypothesis about reducing the density of the atmosphere with a height of the law geometric progression. And this hypothesis was unsatisfactory. According to this hypothesis, it turned out that the temperature in all layers of the atmosphere should remain a constant and equal temperature on the surface of the Earth.
The Hypothesis of Laplace turned out to be the most witty, intermediate between the two above. On this hypothesis of Laplace, refractive tables were founded, which were placed annually in the French Astronomical Calendar.
The earth's atmosphere with its instability (turbulence, variations of refractive) imposes a limit to the accuracy of astronomical observations from the Earth.
When choosing a place of installation of large astronomical instruments, the astroclimate of the area is pre-comprehensively studied, under which the combination of factors distorting the form of the heavenly objects passing through the atmosphere of the wave front. If the wave front comes to the device undefected, then the device in this case can work with maximum efficiency (with a resolution approaching theoretical).
As it turned out, the quality of the telescopic image is reduced mainly due to the interference made by the surface layer of the atmosphere. The earth due to its own thermal radiation at night is significantly cooled and cools the air layer adjacent to it. The change in air temperature is 1 ° C changes its refractive index by 10 -6. On the isolated mountain peaks, the thickness of the surface layer of air with a significant drop (gradient) of the temperature can reach several tens of meters. In the valleys and on the placed places at night, this layer is much thicker and can be hundreds of meters. This explains the choice of places for astronomical observatories on the spurs of the ridges and on isolated vertices, from which the more dense cold air can flush into the valleys. The height of the telescope tower is chosen such that the device is above the main area of \u200b\u200btemperature heterogeneities.
An important factor of astroclimate is the wind in the surface layer of the atmosphere. Stirring the layers of cold and warm air, it causes the appearance of density heterogeneities in the air column over the device. Heterogeneity, the dimensions of which are smaller than the diameter of the telescope, lead to the defocusing of the image. Larger density fluctuations (several meters and larger) do not cause sharp distortion of the wave front and lead mainly to offset, and not to defocusing the image.
In the upper layers of the atmosphere (in the tropopause), fluctuations of density and refractive index are also observed. But perturbations in the tropopause do not affect the quality of the images given by optical instruments, since the temperature gradients are significantly less there than in the surface layer. These layers cause not trembling, but flickering stars.
In astroclimatic studies, the relationship is established between the amount of clear days registered by the meteorological service, and the number of nights suitable for astronomical observations. The highest areas, according to the Astroclimatic analysis of the territory of the former USSR, are some mountainous areas of the Central Asian states.
Earth refraction
Rays from land items if they pass in the atmosphere a large enough path, also experience refraction. The trajectory of the rays under the influence of refraction is twisted, and we see them not in those places or not in the direction where they are in reality. Under some conditions, Mirage appear as a result of earth refractures - false images of remote objects.
The angle of earth refractive A is called the angle between the direction on the visible and real position of the observed item (Fig. 2.8). The angle A value depends on the distance to the observed object and from the vertical temperature gradient in the surface layer of the atmosphere, in which the rays from ground items occurs.
Fig.2.8. Manifestation of earth refractive when visiting:
a) - bottom up, b) - from top to bottom, a - the angle of earth refractive
A geodesic (geometric) visibility range is associated with earth refraction (Fig. 9). We will approve that the observer is at point A at some height of H n above ground surface And the horizon in the direction of the point V. The plane of the NAN is a horizontal plane passing through the point A perpendicular to the radius of the globe, is called the plane of the mathematical horizon. If the rays of light spread in the atmosphere straightly, then the most distant point on Earth, which an observer could see from point A, would be point V. Distance to this point (tangent AB to the globe) and there is a geodesic (or geometric) visibility distance D 0. Circular line on the earth's explosion - geodesic (or geometric) horizon of the observer. The value of D 0 is due only to geometrical parameters: radius of Earth R and the height H H H Observer and is equal D o ≈ √ 2RH H \u003d 3,57√ H HWhat follows from fig.2.9.
Fig.2.9. Earth Refraction: Mathematical (NN) and geodesic (explosive) horizons, geodesic visibility range (AV \u003d D 0)
If the observer observes some object, which is at the height of H and the surface of the Earth, then the geodetic range will be distance Ac \u003d 3.57 (√ h h + √ hd). These statements would be true if the light had spread in the atmosphere straightforwardly. But it is not. With a normal temperature distribution and air density in the surface layer, the curve depicting the trajectory of the light beam is facing the ground with its concave side. Therefore, the most distant point that the observer will be seen from A will be not in, but in ¢. The geodesic range of visibility AV ¢ taking into account the refraction will be on average by 6-7% more and instead of the coefficient of 3.57 in the formulas there will be a coefficient of 3.82. Geodesic range is calculated by formulas
, h - in m, d - in km, r - 6378 km
where h. N I. h. pr - in meters, D - in kilometers.
For a man of medium growth, the horizon range on Earth is about 5km. For cosmonauts V.A.Satalov and A.S. Liseeva, flying on space ship Soyuz-8, the distance of the horizon in perigue (height 205km) was 1730km, and in the apogee (height 223km) - 1800km.
For radio waves, the refraction almost does not depend on the wavelength, but in addition to the temperature and pressure depends on the content of water vapor in the air. Under the same conditions, changes in temperature and pressure radio waves are refracting stronger than light, especially with high humidity.
Therefore, in the formulas to determine the range of the horizon or the detection of the subject beam, the radar beam before the root will be the coefficient 4.08. Consequently, the horizon of the radar system is further by about 11%.
Radio waves are well reflected from the earth's surface and from lower border Inversion or layer of reduced humidity. In such a peculiar waveguide formed by the earth's surface and the base of inversion, radio waves can spread to very long distances. These features of radio wave propagation are successfully used in radar.
The air temperature in the surface layer, especially in its lower part, is far from always falling with a height. It can decrease at different speeds, it may not be changed in height (isothermia) and can increase with a height (inversion). Depending on the magnitude and sign of the temperature gradient, the refraction can affect the visible horizon range differently.
Vertical temperature gradient in a homogeneous atmosphere, in which air density with height does not change, g. 0 \u003d 3.42 ° C / 100m. Consider what the trajectory of the beam AU With different temperature gradients at the surface of the Earth.
Let, i.e. Air temperature decreases with high height. This condition decreases with a height and refractive index. The trajectory of the light beam in this case will be addressed to the earth's surface with its concave side (in fig. 2.9 trajectory AU¢). Such refraction is called positive. Fallen point IN¢ The observer will see in the direction of the latter tangent to the beam trajectory. This tangent, i.e. visible at the expense of refraction horizon, is with a mathematical horizon NAN Corner D, Little Angle d.. Angle d. - This is the angle between the mathematical and geometric horizon without refraction. Thus, the visible horizon rose to the angle ( d -D) and expanded because D. > D 0.
Now imagine that g. gradually decreases, i.e. The temperature with a height decreases everything slower and slower. The moment will occur when the temperature gradient becomes equal to zero (isothermia), and then the temperature gradient becomes negative. The temperature is no longer decreasing, but grows with a height, i.e. There is a temperature inversion. With a decrease in the temperature gradient and switching it through zero, the visible horizon will rise above and above and the moment will occur when D becomes zero. The visible geodesic horizon will rise to mathematical. The earth's surface as it was straightened, became flat. Geodesic visibility range is infinitely large. The radius of the beam curvature has become an equal radius of the globe.
With an even stronger temperature inversion, D becomes negative. The visible horizon rose above mathematical. An observer at the point a will seem that it is located at the bottom of a huge basin. Due to the horizon rise and become visible (as if so far in the air) items are far behind the geodesic horizon (Fig. 2.10).
Such phenomena can be observed in polar countries. Thus, from the Canadian coast of America through the Scholiv Smith, you can sometimes see the shore of Greenland with all buildings on it. The distance to the Greenland coast is about 70km, while the geodetic range of visibility is no more than 20 km. Another example. FROM english side The Para de Calais Strait from Hastings was to see the French bank, lying through the shed at a distance of about 75km.
Fig.2.10. Phenomenon of unusual refraction in polar countries
Now let's say that g.=g. 0, therefore, the air density with a height does not change (homogeneous atmosphere), the refraction is absent and D \u003d D. 0 .
For g. > g. 0 The refractive index and the air density with a height increase. In this case, the trajectory of light rays is drawn to the earth's surface with its convex side. Such refraction is called negative. The last point on the ground, which will see an observer in A, will be in². Visible horizon Av² narrowed and sank at an angle (D - d.).
From the considered the following rule: if the density of air along the spread of the light beam in the atmosphere (A, which means, the refractive index) changes, then the light beam will bend so that its trajectory is always addressed in the direction of reducing the density (and refractive index) air .
Refraction and mirage
The word mirage of French origin and has two meanings: "reflection" and "deceptive vision." Both values \u200b\u200bof this word reflect the essence of the phenomenon. Mirage is an image of a really existing object on Earth, often enlarged and strongly distorted. There are several types of mirages depending on where the image is located in relation to the subject: the upper, lower, side and complex. The most commonly observed the upper and lower mirages, which arise with an unusual density distribution (and, consequently, the refractive index) in height, when at some height or the surface of the earth itself there is a relatively thin layer of very warm air (with a small refractive index) in which Rays coming from terrestrial objects are complete internal reflection. This occurs when the rays fall on this layer at an angle of more than the angle of complete internal reflection. This is a heavier air layer and plays the role of an air mirror reflecting the rays falling into it.
The upper mirage (Fig.2.11) arise in the presence of strong temperature inversions, when the air density and refractive index with a height is reduced rapidly. In the upper mirages, the image is located above the subject.
Fig.2.11. Upper Mirage
The trajectories of light rates are shown in Figure (2.11). Suppose that the earth's surface is flat and layers of the same density are located in parallel to it. Since the density decreases with a height, then. A warm layer, which plays the role of the mirror, lies at the height. In this layer, when the ray drop angle becomes equal to the refractive index (), turns the rays back to the earth's surface. The observer can see the subject itself (if it is not beyond the horizon) and one or more images above it are direct and twisted.
Fig.2.12. Sophisticated top mirage
In fig. 2.12 The scheme of the occurrence of complex Upper Mirage is presented. Vidden item itself aBover him direct image a ¢ b ¢Overteaded in B². And again direct a² ¢ b² ¢. Such a mirage may occur if the air density decreases with a height at first slowly, then quickly and again slowly. The image is turned out to be turned out if the rays coming from the extreme points of the subject will cross. If the subject is far away (beyond the horizon), then the object itself may not be seen, and its images highly raised into the air are visible from large distances.
The city of Lomonosov is on the shore Finnish Gulf in 40km from St. Petersburg. Usually from Lomonosov St. Petersburg is not visible at all or visible is very bad. Sometimes St. Petersburg is visible "like a palm". This is one of the examples of the upper mirages.
At least part of the so-called ghost land should be attributed to the number of the upper mirages, which for decades were found in the Arctic and did not find it. Esnikov's land was looking for especially for a long time.
Yakov Sannikov was a hunter, engaged in fur clan. In 1811 He went on the ice dogs to the group of Novosibirsk Islands and from the northern tip of the island of the boiler saw an unknown island in the ocean. He could not achieve him, but reported on the opening of a new island to the government. In August 1886 E.V. Tol, during his expedition to the Novosibirsk Islands, also saw Sannikov Island and made a record in the diary: "The horizon is absolutely clear. In the direction of the northeast, 14-18 degrees, the contours of the four tables of the mountains were clearly seen, which in the east were connected to the lowland earth. Thus, the Sannikov message was fully confirmed. We are entitled, therefore, in the appropriate place on the map a dotted line and to put on it: "Land Sannikov".
Land finding Sannikova Tol gave 16 years of life. He organized and spent three expeditions to the Novosibirsk Islands area. During the last expedition on the schoon "Zarya" (1900-1902), the expedition of Tole died and not finding the lands of Sannikov. More land Sannikova has not seen no one. Perhaps it was a mirage, which at a certain time of the year appears in the same place. Both Sannikov and Tol, saw the Mirage of the same island, located in this direction, only significantly further in the ocean. Maybe it was one of the de Long Islands. Perhaps it was a huge iceberg - a whole ice island. Such icy mountains, up to 100km 2, travel over the ocean several decades.
Not always the mirage deceived people. English Parliamentary researcher Robert Scott in 1902. In Antarctica, I saw the mountains, as if hanging in the air. Scott suggested that the mountain chain is further behind the horizon. And, indeed, the mountain range was discovered later by the Norwegian polar researcher Raoule Amundsen just where she assumed to find Scott.
Fig.2.13. Nizhny Mirage
Lower Mirage (Fig.2.13) occurs with a very rapid decrease in temperature with a height, i.e. With very large temperatures. The role of the air mirror plays the thin surface of the air cooler layer. Mirage is called lower, as the image of the subject is placed under the subject. In the lower mirages it seems that there is a water surface under the subject and all objects are reflected in it.
In calm water, all the objects standing on the shore are well reflected. The reflection in a thin heated surface of the air layer is completely similar to the reflection in the water, only the role of the mirror plays the air itself. The condition of the air at which the lower mirage arise is extremely unstable. After all, at the bottom, the Earth is very heated, and hence the easiest air, and above it is colder and heavy. Rising hot air jets permeate cold air layers. Due to this, the Mirage is changing in front of the eyes, the surface of "water" seems to be worried. A sufficiently small impulse of the wind or push and collapse will occur, i.e. Out of air layers. Heavy air rushes down, destroying the air mirror, and the mirage will disappear. The favorable conditions for the emergence of the lower mirage is a homogeneous, smooth underlying surface of the Earth, which takes place in the steppes and deserts, and solar windless weather.
If the mirage has an image of a really existing subject, then the question arises - the image of which water surface see the travelers in the desert? After all, there are no water in the desert. The fact is that the apparent water surface or the lake visible in Mirage is actually an image of a water surface, and the sky. Sky sections are reflected in the air mirror and create a complete illusion of a brilliant water surface. Such a mirage can be seen not only in the desert or in the steppe. They arise even in St. Petersburg and its surroundings on sunny days over asphalt roads or a smooth sandy beach.
Fig.2.14. Side Mirage
Side Mirages arise in cases where air layers of the same density are located in the atmosphere not horizontally, as usual, but obliquely and even vertically (Fig.2.14). Such conditions are created in summer, in the morning shortly after sunrise at the rocky shores of the sea or the lake, when the shore is already lit by the sun, and the surface of the water and the air over it is still cold. Side Mirages were repeatedly observed at the Lake Geneva. The side mirage may appear at the stone wall at home heated by the sun, and even on the side of the heated oven.
A complex view of Miragei, or Fata Morgan, arise when at the same time there are conditions for the appearance of both the upper and lower mirage, for example, with a significant temperature inversion at some height over a relatively warm sea. The air density with a height is first increases (the air temperature decreases), and then also quickly decreases (the air temperature rises). With this density distribution, the state of the atmosphere is very unstable and exposed to sudden changes. Therefore, the type of Mirage is changing in front of her eyes. The most ordinary cliffs and homes due to multiple distortions and increasing in front of the eyes turn into wonderful castles of the Fairy Morgana. Fata Morgana is observed off the coast of Italy, Sicily. But it may occur in high latitudes. This is how the famous researcher Siberia F. P.P.Vrangel: "The action of the horizontal refraction was produced by him:" The action of horizontal refraction produced the genus of Fata-Morgana. The mountains lying to the south seemed to us in different distorted species and hanging in the air. Far Mountains were presented with topped tops. The river narrowed to the fact that the opposite shore seemed to be almost from our ours. "
There are many interesting things in the world. Flickering stars is one of the most amazing phenomena. How many of all sorts of belief is connected with this phenomenon! The unknown always scares and attracts at the same time. What is the nature of such a phenomenon?
Effect of atmosphere
Astronomers made an interesting discovery: the flickering stars is not connected with their changes. Then why stars flicker at the night sky? It's all about the atmospheric movement of cold and hot air flows. Where are the warm layers over cold, the vortices of air are formed there. Under the action of these vortices, the rays of light are distorted. So light rays are twisted by changing the visible position of stars.
Interesting the fact that the stars do not flicker at all. Such a vision is created on Earth. The eyes of observers perceive the light emanating from the star after it pass through the atmosphere. Therefore, to the question of why the stars are flickering, you can answer that the stars do not flicker, but the phenomenon that we observe on Earth are a distortion of the light that has passed the path from the star through atmospheric air layers. If there were no such air movements, then the flicker would not have been observed, even from the most distant star in space.
Scientific explanation
If you disclose more detail about why stars flicker, it is worth noting that this process is observed when the light from the star moves from a more dense atmospheric layer into less dense. In addition, as mentioned above, these layers are constantly moving relative to each other. From the laws of physics, it is known that warm air rises, and the cold, on the contrary, is descended. It was when the light passes this border of the layers, we are witnessing flicker.
Passing through the air layers, different in density, the light of the stars begins to flicker, and their outlines are blurred and the image increases. In this case, the intensity of radiation and, accordingly, brightness changes also. Thus, studying and observing the processes described above, scientists understood why the stars flicker, and their flicker differs in intensity. In science, such a change in light intensity is called scintillation.
Planets and stars: what's the difference?
Interesting and the fact that not from each cosmic luminous object outgoing light gives the phenomenon of scintillation. Take the planets. They also reflect the sunlight, but do not flicker. It is by the nature of the radiation that the planet is distinguished from the star. Yes, the star of the star gives flicker, and there is no planets.
Since ancient times, mankind has learned from the stars to navigate in space. In those times, when accurate devices were not invented, the sky helped find the right path. And today, these knowledge has not lost their meaning. Astronomy as science originated in the 16th century, when the telescope was first invented. Then they became close to observe the light of the stars and study the laws by which they flicker. Word astronomy Translated from Greek - this is the "Star Act".
Science of Stars
Astronomy studies universe and celestial bodies, their movement, location, structure and origin. Thanks to the development of science, astronomers explained than the flickering star in the sky differs from the planet, how the development of celestial bodies, their systems, satellites occurs. This science looked far beyond the borders of the solar system. Pulsars, quasars, nebula, asteroids, galaxies, black holes, inter-storage and interplanetary substance, comets, meteorites and everything concerns outer space, studies the science of astronomy.
The intensity and color of the flickering stars affects the height of the atmosphere and the approximateness to the horizon. It is easy to see that the stars, located close to it, shine brighter and shimmer different colors. Especially beautiful it becomes a spectacle in frosty nights or immediately after the rain. At these moments, the sky is cloudless, which contributes to more bright flicker. Special radiance in Sirius.
Atmosphere and Star Lights
If you wish to observe the star flicker, it should be understood that during a relaxed atmosphere, Zenith is only possible occasionally. The brightness of the light flux is constantly changing. This again is associated with the deviation of light rays, which are unevenly concentrated above the ground surface. The wind has an influence on the star landscape. In this case, the star panorama observer is constantly alternately in the darkened or illuminated area.
When observing the stars located at an altitude of more than 50 °, the color change will not be noticeable. But the stars that are below 35 ° will flicker and change the color is quite often. Very intense flicker indicates the inhomogeneity of the atmosphere, which is directly related to meteorology. During the observation of the star flicker, it was seen that it has a property to enhance under low atmospheric pressure, temperature. Strengthening the flicker can also be seen by increasing humidity. However, it is impossible to predict the weather on scintillation. The state of the atmosphere depends on a large number of different factors, which does not allow to draw conclusions about the weather only on star flicker. Of course, some moments work, but so far this phenomenon has its own ambiguities and riddles.
