Born in the sky, preserved in the earth. Folklore festival for children and parents
Whose footsteps do I hear all night?
I can hardly sleep now
Maybe the cats were shod?
We invite you and your children to absorb a little folk wisdom by using riddles about rain in games. This is not only a fun game, but also the development of a child’s speech, the manifestation of erudition, and simply a wonderful pastime at home and on the street.
Moreover, riddles inspire the child to new discoveries, charging him with positive energy.
M We ask him, we are waiting for him,
And when he comes, we will start hiding.
Who beats on rooftops all night
Yes he taps, yes he mumbles,
Sings us songs
Lulls you to sleep?
He will go, we will run,
He's still catching up!
We will hurry to take shelter in the house,
He will knock on our window,
And a knock on the roof, knock-knock-knock!
No, we won’t let you in, my friend!
The lanky man walked and got stuck in the damp ground.
Without a path and without a road
The longest-legged one is coming,
Hiding in the clouds, in the darkness,
Only feet on the ground.
He makes noise in the groves and gardens,
But it won't get into the house.
And I won't go for a walk,
Until it passes.
He is not a pedestrian, but he is walking.
The people at the gate got wet.
The janitor catches him in a tub.
So, is it a difficult riddle?
He walks on the ground without legs,
Without hands he knocks on the house.
We won't let him in,
So as not to get wet.
From a cloud, like from a sieve,
Drop by drop - water drips!
Flowers and birds are happy for her,
Tell me, what kind of water is this?
He has no arms and no legs,
There's a knocking under the window,
He asks to come to our hut
It's like he's a hateful guest
Sad, he won’t shake hands
He knocks sadly on the window,
The guys are bored!
Only complaints and sighs,
Our guest is just shedding tears.
Who drops these "oohs"
Outside the window? Autumn...
Of course it's raining.
Who among us has not smiled, watching how little pioneers in rubber boots test the depth of a puddle, sometimes jumping in it, raising a wave. Or how little fashionistas snatch their curls under their children's umbrellas.
Riddles are actively used by teachers and educators, because kids are interested in them. Children in kindergartens and primary schools pull their hands to be the first to offer the answer to the riddle.
It's dripping from dark ships,
And washes the flowers with drops.
It’s long and thin, but when it sits it’s not visible in the grass.
What always falls and never rises?
They're waiting for me, they can't wait,
And as soon as they notice, everyone will run away.
Fractionally, coarsely, frequently,
Yes, the whole earth was watered.
He came from heaven
And he went into the ground.
They often ask me, wait for me,
And as soon as I appear, they will start hiding.
Thin and tall
Fell into the sedge
I didn’t come out myself
And he brought the children out.
Wet the grove, forest and meadow,
City, house and everything around!
Clouds and clouds - he is the leader,
You know this is...
He neither walks nor jumps,
He floats and cries noisily.
Couldn't stay in the sieve
Silver threads
And, jumping out into freedom,
They sewed a cloud to the field.
I'll look out the window -
Long Antoshka is coming.
It is long and huge.
He is from the clouds to the ground...
Let him go faster, faster,
So that the mushrooms grow faster.
Who doesn't cry
Are the tears flowing?
He lives in the sky
How to go for a walk -
He will lower his feet to the ground.
He was born in the sky
And he buried himself in the ground.
We hope that riddles about rain will help you develop your child’s cognitive abilities in a playful way.
“Prince Vladimir” - Campaigns of Vladimir Svyatoslavovich Architecture of the period of the baptism of Rus'. In 980, Vladimir, having killed his half-brother Yaropolk, became the Grand Duke of Kyiv. Prince Vladimir. Strengthening princely power; Strengthening the international authority of Kievan Rus; Christians and pagans. Vladimir Svyatoslavich is the youngest son of Prince Svyatoslav and housekeeper Princess Olga Malushi.
"Monomakh" - The blinding of Prince Vasilko Rostislavich. Basil the Great. Give to the orphan. Hiking. Dolobsky Congress of Princes. Monomakh's hat. Princes. Through prayer a person defeats the devil. Mosaic of St. Sophia. Witnesses and evidence. Orthodox culture. Monomakh. How to study native history. Nickname Monomakh. Honor the old.
“The first Kyiv princes” - Prince Svyatoslav (957 – 972). Princess Olga (945 - 957). Why Svyatoslav decided to make the city of Pereyaslavets the capital. What conclusions can be drawn? Polyudye. Consolidation. The Drevlyans, leaving the city of Iskorosten, killed Igor and his warriors, since there were few of them. Olga's reforms. Eastern direction of hikes.
“Monomakh Vladimir” - Red - I didn’t like it. About the Orthodox religion. Conclusions: Outdated words. What did Monomakh write about the Orthodox religion and Christian commandments? We welcome the friendly tribes of the Eastern Slavs!!! Physical education minute. V. Monomakh went down in Russian history as an outstanding historical figure. What new did you learn about Prince Vladimir Monomakh himself?
“Princes in Rus'” - Results of the reign of the first Russian princes. 882. Establishing influence on the path “from the Varangians to the Greeks.” 962 – 972. 945. Kievan Rus. Igor Rurikovich (Old) - Grand Duke of Kyiv, son of Oleg. Oleg 882-912 Activities: Oleg (Prophetic) - Prince of Novgorod and (from 882) Kyiv. The first Russian princes. Vladimir 956-1015
“Igor Oleg Olga” - List the prerequisites for the formation of a state among the Eastern Slavs. Formation and expansion of the borders of the state of Rus'. Eastern direction (Pecheneg, Bulgarian, Khazar). Understand the organization of the prince’s power over the conquered tribes. The main directions of the campaigns of the first Kyiv princes: What changes did Princess Olga make to the administration of the Old Russian state?
There are a total of 40 presentations in the topic
Doctor of Technical Sciences, Professor G. ZAMULA, Deputy Director of TsAGI; Doctor of Technical Sciences, Professor G. NESTERENKO, Head of the TsAGI Department.
Air travel, according to statistics, is much safer than car travel. Nevertheless, every plane crash causes a wide public outcry and is most carefully analyzed by commissions of experienced experts. Leading TsAGI experts talk about why planes break up in the air and what is being done to prevent accidents.
Science and life // Illustrations
Alexander Petrovich Fan der Fleet (1870-1941) - Russian scientist in the field of applied mechanics and aerodynamics.
Vladimir Petrovich Vetchinkin (1888-1950) - Russian and Soviet scientist in the field of aerodynamics, aircraft engineering and wind energy.
Alexander Ivanovich Makarevsky (1904-1979) - Soviet scientist in the field of strength and aeroelasticity of aircraft.
The life test cycle consists of two parts.
In the endurance testing room, aircraft are tested for fatigue strength. The wings, fuselage and other components of the aircraft are subjected to variable loads.
TsAGI laboratories are testing new aviation materials. In installations with a powerful hydraulic drive, samples are subjected to variable loads.
The advent of jet passenger airliners required the reconstruction of the hull, where strength tests took place. The new mainline Tu-334 aircraft was tested in the new hall.
Aviators began to think about the strength of airplanes immediately after the Wright brothers’ flight. Almost half of the attempts to get into the air then ended in accidents and disasters. The machines were destroyed because the first aircraft manufacturers did not know how to calculate the design, what safety margins to take, and sometimes could not determine the real characteristics of the materials used.
An additional difficulty was that the aircraft obviously had to be as light as possible. And the designers, who often created according to their intuition, had to balance on the line between excess weight and safety.
Scientists from different countries, using aerodynamic methods that were rather poorly developed at the beginning of the twentieth century, attempted to analyze the loads that act on an aircraft during takeoff, landing, and other maneuvers. The design of aircraft in those days was a wooden frame covered with canvas, made in the form of trusses. Therefore, during strength calculations, the experience of bridge builders was used much more.
In Russia, during the First World War, a Technical Commission was organized under the Directorate of the Air Force, headed by an outstanding specialist in the field of hydro- and aerodynamics A.P. Fan der Fleet. N.E. Zhukovsky, A.N. Tupolev and Professor S.P. Timoshenko, who worked on bridge problems, also worked there (see “Science and Life No.”). By the way, S.P. Timoshenko, having found himself in Ukraine after the revolution, literally in a few months wrote the first domestic work in this area, “On the Strength of Airplanes.”
The bureau became the forerunner of TsAGI. Immediately after the organization of the institute, V. P. Vetchinkin, who studied under S. P. Timoshenko, became the main strength specialist in it. In the first years at TsAGI, scientific research and practical design of aircraft proceeded in parallel. Only later did engine building and the development of aviation materials become independent industries, and then special aviation design bureaus appeared.
From the first days, one of the main goals of the institute’s staff was to develop strength standards and methods for calculating aircraft structures. This was done by V.P. Vetchinkin and one of the future directors of TsAGI A.I. Makarevsky.
In the 1930s, airplanes began to be made of metal, and TsAGI strength engineers had to develop and master new methods for calculating and testing structures.
The technology was continuously improved, posing more and more new problems for scientists. The flight speed increased, and accidents began to occur: spontaneous vibrations with large amplitude suddenly arose in the structural elements, and the plane was destroyed in the air, as if from an explosion. This phenomenon was called "flutter". Sometimes self-oscillations also occurred on the ground. For example, during acceleration, the wheels of the chassis began to turn unpredictably to the right and left, until the chassis broke down. These vibrations are called "shimmies". TsAGI studied in detail the problem of self-oscillations and learned to deal with them (M.V. Keldysh and others).
The pre-war years were marked by the construction of a building for testing the strength of full-scale aircraft. The project provided that it would be possible to accommodate aircraft weighing up to 50 tons. The legendary designer S.V. Ilyushin in his review expressed doubts about the possibility of creating such giant aircraft. Apparently, even geniuses make mistakes, because now, in a rebuilt and significantly expanded body, we are testing airplanes weighing more than 200 tons.
The history of another building that appeared on the territory of TsAGI in the mid-1950s is interesting. Fatigue strength tests are carried out in it. During its construction, elements of a hangar were used, which was taken from Germany by J.V. Stalin’s son Vasily. He wanted to use the hangar as a playpen, but after the death of the “father of nations,” the hangar moved to the city of Zhukovsky.
The strength engineers had a lot of work to do during the Great Patriotic War. It was necessary to ensure maximum combat survivability of the aircraft. TsAGI tested all our aircraft, as well as those received under Lend-Lease and even captured ones. Airplanes had to fly when hit by bullets and even shells of a certain caliber. The recommendations developed based on these studies greatly helped designers. At the front, it happened that the entire fuselage and wings were riddled with shrapnel, but the plane continued to fly.
With the advent of jet aircraft and supersonic aircraft in the 1950s, new challenges arose. At speeds above sound, the air friction against the body becomes so great that the surface heats up to hundreds of degrees. For example, at a speed three times the speed of sound, the surface temperature reaches 300°C, and in aluminum the loss of strength occurs already at 90-130°C. Sometimes the body collapsed even without load - just from the stresses arising due to the high temperature gradient. Aluminum alloys in many cases had to be replaced by titanium and steel.
The development of strength standards and test methods for civil aircraft acquired particular importance - after all, these standards were written in the blood of dead passengers. Until 1954, official strength standards stated that an aircraft was serviceable if it could withstand a single static load. The magnitude of this load is chosen such that it can occur no more than once during the entire life of the aircraft. Based on many years of experience in operating civil aircraft, it was established that it should be 3.75 times the weight of the aircraft.
But in 1954 there were two crashes of the English Comet jetliners. The planes crashed over the Mediterranean Sea, but the wreckage of one of them was recovered from the bottom. After their examination, it turned out that the loads on the structure did not exceed permissible limits, and the cause of destruction was a so-called fatigue crack.
Fatigue is the formation inside a metal subjected to repeated exposure to variable loads of microcracks that gradually grow. Ultimately, the metal fails under loads significantly less than its tensile strength. During flight, variable loads act on the airplane body. For example, this occurs in turbulent zones where vertical air currents exist. And on the ground, during takeoff and landing, the plane shakes violently. In the case of the Comets, however, a different phenomenon took place. These planes flew at an altitude of about 10 km. The air there is rarefied, and excess pressure arose inside the sealed fuselage. On the ground, the external pressure and the pressure in the fuselage were the same. In other words, during each flight, the body parts were subjected to tensile loads due to an increase in excess pressure from zero to 0.6 atm and a decrease in it again to zero. As a result, a crack appeared and developed in the metal of the fuselage, and the body collapsed.
After these disasters, an entry appeared in the standards requiring the safety of the aircraft to be ensured due to fatigue. British and Soviet engineers followed the path of the so-called safe resource. It consists in the fact that the fuselage, wing and empennage are loaded with cyclic loads, repeatedly simulating flight conditions, until the elements of the aircraft are destroyed. The resulting resource, that is, the number of flights that the aircraft could make in real conditions, is reduced several times (at least three). And this reduced service life is considered safe, that is, during flights within the safe service life, no fatigue cracks should occur in the structure.
The Americans used a different approach, called the principle of safe destruction. It better corresponds to real situations - after all, cracks inevitably arise in structural elements, and if the aircraft does not collapse in their presence, then it has sufficient operational survivability. For testing, an artificial crack up to 0.5 m long was created in the fuselage, and cracks up to 0.3 m long were created on the wings and tested with a single static load. As further experience has shown, this approach is more effective.
In the USSR, standards based on the principle of a safe resource were in effect until 1972, until we learned a cruel lesson - an An-10A plane, whose safe resource had not yet been exhausted, crashed near Kharkov. The investigation showed that the plane crashed due to the formation of so-called multifocal cracks in the wing, which were not detected. In the fateful flight, the cracks connected, and the wing folded like a butterfly. And then TsAGI developed new standards based on our and foreign experience, which took into account factors of both endurance and survivability. The standards specified what kind of cracks could occur and what residual strength of the structure should be ensured.
The next changes to the standards appeared in 1977 after the tragic death of the Boeing 707 aircraft, which, by the way, was designed in accordance with the principles of safe destruction. A fatigue crack appeared in the tail of the aircraft, which, as in the case of our lost aircraft, could not be detected in time. The standards had to be supplemented with several points regulating the procedure and frequency of inspections to look for cracks, as well as requiring that new structures be inspectable, that is, the ability to inspect all places where cracks can form, or check them using non-destructive testing methods. The new survivability standards were called the damage tolerance principle.
Theorists did not stand aside either. Based on linear fracture mechanics, it is now possible to predict the development of fatigue damage with sufficient accuracy and for a long period.
In addition to developing safety standards, the task of strength specialists also includes testing samples of materials, panels and full-scale structures for compliance with these standards. The first tests began to be carried out even before the war. Then A.N. Tupolev and his colleagues tested the plane for strength in this way: they climbed onto the wing, lifted weights there and looked to see if it would break. Now, of course, everything is entrusted to machines. When testing full-scale aircraft, constant or variable loads are applied to various points of the airframe (there can be up to 150 such points in total) using hydraulic cylinders, simulating those that arise in flight. The test bench equipment allows you to quickly change load values and reproduce a multi-hour flight in a matter of minutes. Nevertheless, the period of endurance testing reaches up to three years - after all, the estimated service life of the aircraft reaches 25-30 years, and taking into account the safety factor, it is necessary to reproduce flights for 50 years or more.
The fuselage is subjected to separate tests. To protect yourself from the fate of “Comets”, the pressure in it is periodically raised and again lowered to external pressure. This is a complex procedure because you have to work with a real life-size fuselage. Initially, the entire fuselage was immersed in a hydraulic basin. The fact is that in air, fatigue failure occurred like an explosion, with the scattering of numerous fragments that could injure personnel and damage the building and equipment. Now we have learned how to organize tests in a regular laboratory: strong bands are installed on the fuselage in increments of about 1 m, which hold the structural elements in place when destroyed.
Now there is great interest in the use of composite materials in aviation, the density of which is almost half that of aluminum alloys. True, they are fragile and susceptible to moisture. But the “pros” significantly outweigh the “cons,” and, having at their disposal test facilities and climate chambers that allow testing various structural elements of the aircraft being designed for strength and endurance, TsAGI specialists confirmed this.
In addition, it is reported that composites with “self-healing” cracks have already been created abroad. As soon as one of the numerous sensors detects damage, electrical voltage is applied to this place, the material softens from heating and the crack is healed.
TsAGI testing equipment is also used to help related industries. For example, the institute is currently testing concrete sleepers for railways and composite overlays for butt jointing of rails.
Another important area of work for our specialists is increasing the service life of old aircraft. The standard service life of machines designed in the 60s and 70s of the last century was 15-20 years. However, new aircraft are expensive, and not all Russian and foreign airlines have the funds to purchase them. TsAGI studies the operating experience of each type of aircraft and, together with the design bureau and the State Research Institute of Civil Aviation, works to extend their service life and increase the service life of new aircraft, taking into account safety requirements.
Over decades of activity, TsAGI strength engineers have accumulated a wealth of experience in ensuring the safety and reliability of aircraft, and it helps them develop standards and recommendations that allow them to increase the service life of designed and used aircraft by 2-3 times. Our specialists were directly involved in the creation of the Il-96, Tu-204 and Tu-334 aircraft, and the giant An-124. And now the strength characteristics of medium-range aircraft of the new MC-21 family, which are already being called machines of the 21st century, are being studied.