The logic of nature is the most accessible and most useful logic for children.

Konstantin Dmitrievich Ushinsky(03.03.1823–03.01.1871) - Russian teacher, founder of scientific pedagogy in Russia.

BIOPHYSICS: JET MOTION IN LIVING NATURE

I invite readers of the green pages to look into the fascinating world of biophysics and get to know the main principles of jet propulsion in wildlife. Today on the program: jellyfish cornermouth- the largest jellyfish in the Black Sea, scallops, enterprising rocker dragonfly larva, amazing the squid with its unrivaled jet engine and wonderful illustrations performed by a Soviet biologist and animal artist Kondakov Nikolai Nikolaevich.

A number of animals move in nature using the principle of jet propulsion, for example, jellyfish, scallops, dragonfly larvae, squid, octopus, cuttlefish... Let's get to know some of them better ;-)

The jet method of movement of jellyfish

Jellyfish are one of the most ancient and numerous predators on our planet! The body of a jellyfish is 98% water and is largely composed of hydrated connective tissue - mesoglea functioning like a skeleton. The basis of mesoglea is the protein collagen. The gelatinous and transparent body of the jellyfish is shaped like a bell or an umbrella (a few millimeters in diameter up to 2.5 m). Most jellyfish move in a reactive way, pushing water out of the umbrella cavity.

Jellyfish Cornerata(Rhizostomae), order of coelenterate animals of the scyphoid class. Jellyfish ( up to 65 cm in diameter) lacking marginal tentacles. The edges of the mouth are elongated into oral lobes with numerous folds that grow together to form many secondary oral openings. Touching the mouth blades may cause painful burns caused by the action of stinging cells. About 80 species; They live mainly in tropical, less often in temperate seas. In Russia - 2 types: Rhizostoma pulmo common in the Black and Azov Seas, Rhopilema asamushi found in the Sea of ​​Japan.

Jet escape of sea clams scallops

Sea shells scallops, usually lying calmly on the bottom, when their main enemy approaches them - a delightfully slow, but extremely insidious predator - starfish- they sharply squeeze the doors of their sink, forcefully pushing water out of it. Thus using jet propulsion principle, they emerge and, continuing to open and close the shell, can swim a considerable distance. If for some reason the scallop does not have time to escape with its jet flight, the starfish wraps its arms around it, opens the shell and eats it...

Scallop(Pecten), a genus of marine invertebrates of the class of bivalve mollusks (Bivalvia). The scallop shell is rounded with a straight hinge edge. Its surface is covered with radial ribs diverging from the top. The shell valves are closed by one strong muscle. Pecten maximus, Flexopecten glaber live in the Black Sea; in the Seas of Japan and Okhotsk – Mizuhopecten yessoensis ( up to 17 cm in diameter).

Rocker dragonfly larva jet pump

Temperament Rocker dragonfly larvae, or eshny(Aeshna sp.) is no less predatory than its winged relatives. She lives for two and sometimes four years in the underwater kingdom, crawling along the rocky bottom, tracking down small aquatic inhabitants, happily including fairly large-sized tadpoles and fry in her diet. In moments of danger, the larva of the rocker dragonfly takes off and swims forward with jerks, driven by the work of the remarkable jet pump. Taking water into the hindgut and then abruptly throwing it out, the larva jumps forward, driven by the recoil force. Thus using jet propulsion principle, the larva of the rocker dragonfly with confident jerks and jerks hides from the threat pursuing it.

Reactive impulses of the nervous “freeway” of squids

In all the above cases (principles of jet propulsion of jellyfish, scallops, rocker dragonfly larvae), shocks and jerks are separated from each other by significant periods of time, therefore high speed of movement is not achieved. To increase the speed of movement, in other words, number of reactive impulses per unit time, necessary increased nerve conduction which stimulate muscle contraction, servicing a living jet engine. Such large conductivity is possible with a large nerve diameter.

It is known that Squids have the largest nerve fibers in the animal world. On average, they reach a diameter of 1 mm - 50 times larger than that of most mammals - and they conduct excitation at a speed 25 m/s. And a three-meter squid dosidicus(it lives off the coast of Chile) the thickness of the nerves is fantastically large - 18 mm. Nerves are thick like ropes! Brain signals - the triggers of contractions - rush along the squid's nervous "freeway" at the speed of a car - 90 km/h.

Thanks to squids, research into the vital functions of nerves advanced rapidly at the beginning of the 20th century. "And who knows, writes British naturalist Frank Lane, Maybe there are now people who owe it to the squid for the fact that their nervous system is in a normal state..."

The speed and maneuverability of the squid is also explained by its excellent hydrodynamic forms animal body, why squid and nicknamed “living torpedo”.

Squid(Teuthoidea), suborder of cephalopods of the order Decapods. The size is usually 0.25-0.5 m, but some species are largest invertebrate animals(squids of the genus Architeuthis reach 18 m, including the length of the tentacles).
The body of squids is elongated, pointed at the back, and torpedo-shaped, which determines their high speed of movement as in water ( up to 70 km/h), and in the air (squids can jump out of the water to a height up to 7 m).

Squid Jet Engine

Jet propulsion, now used in torpedoes, aircraft, missiles and space shells, is also characteristic of cephalopods - octopuses, cuttlefish, squids. Of greatest interest to technicians and biophysicists is squid jet engine. Notice how simply, with what minimal use of material, nature solved this complex and still unsurpassed task;-)

In essence, the squid has two fundamentally different engines ( rice. 1a). When moving slowly, it uses a large diamond-shaped fin, which periodically bends in the form of a running wave along the body. The squid uses a jet engine to launch itself quickly.. The basis of this engine is the mantle - muscle tissue. It surrounds the mollusk’s body on all sides, making up almost half the volume of its body, and forms a kind of reservoir - mantle cavity - the “combustion chamber” of a living rocket, into which water is periodically sucked in. The mantle cavity contains the gills and internal organs of the squid ( rice. 1b).

With a jet swimming method the animal sucks water through a wide open mantle gap into the mantle cavity from the boundary layer. The mantle gap is tightly “fastened” with special “cufflinks-buttons” after the “combustion chamber” of a living engine is filled with sea water. The mantle gap is located near the middle of the squid's body, where it is thickest. The force causing the movement of the animal is created by throwing a stream of water through a narrow funnel, which is located on the abdominal surface of the squid. This funnel, or siphon, is "nozzle" of a living jet engine.

The engine “nozzle” is equipped with a special valve and the muscles can turn it. By changing the angle of installation of the funnel-nozzle ( rice. 1c), the squid swims equally well, both forward and backward (if it swims backward, the funnel is extended along the body, and the valve is pressed against its wall and does not interfere with the water stream flowing from the mantle cavity; when the squid needs to move forward, the free end of the funnel elongates somewhat and bends in the vertical plane, its outlet collapses and the valve takes a curved position). Jet shocks and the absorption of water into the mantle cavity follow one after another with elusive speed, and the squid rushes like a rocket in the blue of the ocean.

Squid and its jet engine - Figure 1

1a) squid – a living torpedo; 1b) squid jet engine; 1c) the position of the nozzle and its valve when the squid moves back and forth.

The animal spends a fraction of a second taking water in and pushing it out. By sucking water into the mantle cavity in the aft part of the body during periods of slow movements due to inertia, the squid thereby carries out suction of the boundary layer, thus preventing the flow from stalling during an unsteady flow regime. By increasing the portions of ejected water and increasing the contraction of the mantle, the squid easily increases its speed of movement.

The squid jet engine is very economical, thanks to which he can reach speed 70 km/h; some researchers believe that even 150 km/h!

Engineers have already created engine similar to a squid jet engine: This water cannon, operating using a conventional gasoline or diesel engine. Why squid jet engine still attracts the attention of engineers and is the object of careful research by biophysicists? To work underwater, it is convenient to have a device that operates without access to atmospheric air. The creative search of engineers is aimed at creating a design hydrojet engine, similar air-jet…

Based on materials from wonderful books:
“Biophysics in physics lessons” Cecilia Bunimovna Katz,
And "Primates of the Sea" Igor Ivanovich Akimushkina

Kondakov Nikolay Nikolaevich (1908–1999) – Soviet biologist, animal artist, Candidate of Biological Sciences. His main contribution to biological science was his drawings of various representatives of the fauna. These illustrations were included in many publications, such as Great Soviet Encyclopedia, Red Book of the USSR, in animal atlases and teaching aids.

Akimushkin Igor Ivanovich (01.05.1929–01.01.1993) – Soviet biologist, writer and popularizer of biology, author of popular science books about animal life. Laureate of the All-Union Society "Knowledge" award. Member of the USSR Writers' Union. The most famous publication of Igor Akimushkin is a six-volume book "Animal world".

The materials in this article will be useful to apply not only in physics lessons And biology, but also in extracurricular activities.
Biophysical material is extremely beneficial for mobilizing the attention of students, for turning abstract formulations into something concrete and close, affecting not only the intellectual, but also the emotional sphere.

Literature:
§ Katz Ts.B. Biophysics in physics lessons

§ § Akimushkin I.I. Primates of the sea
Moscow: Mysl Publishing House, 1974
§ Tarasov L.V. Physics in nature
Moscow: Prosveshchenie Publishing House, 1988

Jet motion in nature and technology is a very common phenomenon. In nature, it occurs when one part of the body separates at a certain speed from some other part. In this case, the reactive force appears without the interaction of this organism with external bodies.

In order to understand what we are talking about, it is best to look at examples. in nature and technology are numerous. We will first talk about how animals use it, and then how it is used in technology.

Jellyfish, dragonfly larvae, plankton and mollusks

Many people, while swimming in the sea, came across jellyfish. In the Black Sea, in any case, there are plenty of them. However, not everyone realized that jellyfish move using jet propulsion. The same method is used by dragonfly larvae, as well as some representatives of marine plankton. The efficiency of invertebrate marine animals that use it is often much higher than that of technical inventions.

Many mollusks move in a way that interests us. Examples include cuttlefish, squid, and octopus. In particular, the scallop clam is able to move forward using a jet of water that is ejected from the shell when its valves are sharply compressed.

And these are just a few examples from the life of the animal world that can be cited to expand on the topic: “Jet propulsion in everyday life, nature and technology.”

How does a cuttlefish move?

The cuttlefish is also very interesting in this regard. Like many cephalopods, it moves in water using the following mechanism. Through a special funnel located in front of the body, as well as through a side slit, the cuttlefish takes water into its gill cavity. Then she vigorously throws it through the funnel. The cuttlefish directs the funnel tube back or to the side. The movement can be carried out in different directions.

The method that the salpa uses

The method that the salpa uses is also curious. This is the name of a sea animal that has a transparent body. When moving, the salpa draws in water using the front opening. The water ends up in a wide cavity, and gills are located diagonally inside it. The hole closes when the salpa takes a large sip of water. Its transverse and longitudinal muscles contract, compressing the entire body of the animal. Water is pushed out through the rear hole. The animal moves forward due to the reaction of the flowing jet.

Squids - "living torpedoes"

The greatest interest is, perhaps, the jet engine that the squid has. This animal is considered the largest representative of invertebrates, living at great ocean depths. In jet navigation, squids have achieved real perfection. Even the body of these animals resembles a rocket in its external shape. Or rather, this rocket copies the squid, since it is the squid that has the undisputed primacy in this matter. If it needs to move slowly, the animal uses a large diamond-shaped fin for this, which bends from time to time. If a quick throw is needed, a jet engine comes to the rescue.

The mollusk's body is surrounded on all sides by a mantle - muscle tissue. Almost half of the total volume of the animal’s body is the volume of its cavity. The squid uses the mantle cavity to move by sucking water inside it. Then he sharply throws out the collected stream of water through a narrow nozzle. As a result of this, it pushes backwards at high speed. At the same time, the squid folds all 10 tentacles into a knot above its head in order to acquire a streamlined shape. The nozzle contains a special valve, and the animal's muscles can turn it. Thus, the direction of movement changes.

Impressive squid speed

It must be said that the squid engine is very economical. The speed that it is capable of reaching can reach 60-70 km/h. Some researchers even believe that it can reach up to 150 km/h. As you can see, the squid is not called the “living torpedo” for nothing. It can turn in the desired direction, bending its tentacles folded in a bundle down, up, left or right.

How does a squid control movement?

Since the steering wheel is very large compared to the size of the animal itself, only a slight movement of the steering wheel is sufficient for the squid to easily avoid a collision with an obstacle, even moving at maximum speed. If you turn it sharply, the animal will immediately rush in the opposite direction. The squid bends the end of the funnel back and, as a result, can slide head first. If he bends it to the right, he will be thrown to the left by the jet thrust. However, when it is necessary to swim quickly, the funnel is always located directly between the tentacles. In this case, the animal rushes tail first, like the running of a fast-moving crayfish if it had the agility of a racer.

When there is no need to rush, cuttlefish and squid swim, undulating with their fins. Miniature waves run across them from front to back. Squid and cuttlefish glide gracefully. They only push themselves from time to time with a stream of water that shoots out from under their mantle. The individual shocks that the mollusk receives during the eruption of jets of water are clearly visible at such moments.

Flying squid

Some cephalopods are capable of accelerating up to 55 km/h. It seems that no one has made direct measurements, but we can give such a figure based on the range and speed of flying squids. It turns out that there are such people. The Stenoteuthis squid is the best pilot of all mollusks. English sailors call it a flying squid (flying squid). This animal, the photo of which is presented above, is small in size, about the size of a herring. It chases fish so quickly that it often jumps out of the water, skimming like an arrow over its surface. He also uses this trick when he is in danger from predators - mackerel and tuna. Having developed maximum jet thrust in the water, the squid launches into the air and then flies more than 50 meters above the waves. When it flies, it is so high that frequent flying squids end up on the decks of ships. A height of 4-5 meters is by no means a record for them. Sometimes flying squids fly even higher.

Dr. Rees, a mollusk researcher from Great Britain, in his scientific article described a representative of these animals, whose body length was only 16 cm. However, he was able to fly a fair distance through the air, after which he landed on the bridge of a yacht. And the height of this bridge was almost 7 meters!

There are times when a ship is attacked by many flying squids at once. Trebius Niger, an ancient writer, once told a sad story about a ship that seemed unable to withstand the weight of these sea animals and sank. Interestingly, squids are able to take off even without acceleration.

Flying octopuses

Octopuses also have the ability to fly. Jean Verani, a French naturalist, watched one of them speed up in his aquarium and then suddenly jump out of the water. The animal described an arc of about 5 meters in the air and then plopped down into the aquarium. The octopus, gaining the speed necessary for the jump, moved not only thanks to jet thrust. It also paddled with its tentacles. Octopuses are baggy, so they swim worse than squids, but at critical moments these animals can give a head start to the best sprinters. California Aquarium workers wanted to take a photo of an octopus attacking a crab. However, the octopus, rushing at its prey, developed such a speed that the photographs, even when using a special mode, turned out to be blurry. This means that the throw lasted only a fraction of a second!

However, octopuses usually swim quite slowly. Scientist Joseph Seinl, who studied the migrations of octopuses, found that the octopus, whose size is 0.5 m, swims at an average speed of about 15 km/h. Each jet of water that he throws out of the funnel moves him forward (more precisely, backward, since he swims backwards) by about 2-2.5 m.

"Squirting cucumber"

Reactive movement in nature and technology can be considered using examples from the plant world to illustrate it. One of the most famous is the ripened fruits of the so-called They bounce off the stalk at the slightest touch. Then, from the resulting hole, a special sticky liquid containing the seeds is ejected with great force. The cucumber itself flies in the opposite direction at a distance of up to 12 m.

Law of conservation of momentum

You should definitely talk about it when considering jet motion in nature and technology. Knowledge of the law of conservation of momentum allows us to change, in particular, our own speed of movement if we are in open space. For example, you are sitting in a boat and you have several stones with you. If you throw them in a certain direction, the boat will move in the opposite direction. This law also applies in outer space. However, for this purpose they use

What other examples of jet propulsion can be noted in nature and technology? Very well illustrated with the example of a gun.

As you know, a shot from it is always accompanied by recoil. Let's say the weight of the bullet was equal to the weight of the gun. In this case, they would fly apart at the same speed. Recoil occurs because a reactive force is created, since there is a thrown mass. Thanks to this force, movement is ensured both in airless space and in the air. The greater the speed and mass of the flowing gases, the greater the recoil force that our shoulder feels. Accordingly, the stronger the reaction of the gun, the higher the reaction force.

Dreams of flying into space

Jet propulsion in nature and technology has been a source of new ideas for scientists for many years. For many centuries, humanity has dreamed of flying into space. The use of jet propulsion in nature and technology, it must be assumed, has by no means exhausted itself.

And it all started with a dream. Science fiction writers several centuries ago offered us various means of how to achieve this desired goal. In the 17th century, Cyrano de Bergerac, a French writer, created a story about a flight to the moon. His hero reached the Earth's satellite using an iron cart. He constantly threw a strong magnet over this structure. The cart, being attracted to him, rose higher and higher above the Earth. Eventually she reached the moon. Another famous character, Baron Munchausen, climbed to the moon using a bean stalk.

Of course, at that time little was known about how the use of jet propulsion in nature and technology could make life easier. But the flight of fancy certainly opened up new horizons.

On the way to an outstanding discovery

In China at the end of the 1st millennium AD. e. invented jet propulsion to power rockets. The latter were simply bamboo tubes that were filled with gunpowder. These rockets were launched for fun. The jet engine was used in one of the first automobile designs. This idea belonged to Newton.

N.I. also thought about how jet motion arises in nature and technology. Kibalchich. This is a Russian revolutionary, the author of the first project of a jet aircraft, which is intended for human flight. The revolutionary, unfortunately, was executed on April 3, 1881. Kibalchich was accused of participating in the assassination attempt on Alexander II. Already in prison, while awaiting execution of the death sentence, he continued to study such an interesting phenomenon as jet motion in nature and technology, which occurs when part of an object is separated. As a result of these researches, he developed his project. Kibalchich wrote that this idea supports him in his position. He is ready to calmly face his death, knowing that such an important discovery will not die with him.

Implementation of the idea of ​​space flight

The manifestation of jet propulsion in nature and technology continued to be studied by K. E. Tsiolkovsky (his photo is presented above). At the beginning of the 20th century, this great Russian scientist proposed the idea of ​​​​using rockets for space flights. His article on this issue appeared in 1903. It presented a mathematical equation that became the most important for astronautics. It is known in our time as the “Tsiolkovsky formula”. This equation described the motion of a body having variable mass. In his further works, he presented a diagram of a rocket engine running on liquid fuel. Tsiolkovsky, studying the use of jet propulsion in nature and technology, developed a multi-stage rocket design. He also came up with the idea of ​​​​the possibility of creating entire space cities in low-Earth orbit. These are the discoveries the scientist came to while studying jet propulsion in nature and technology. Rockets, as Tsiolkovsky showed, are the only devices that can overcome a rocket. He defined it as a mechanism with a jet engine that uses the fuel and oxidizer located on it. This device transforms the chemical energy of the fuel, which becomes the kinetic energy of the gas jet. The rocket itself begins to move in the opposite direction.

Finally, scientists, having studied the reactive movement of bodies in nature and technology, moved on to practice. A large-scale task lay ahead to realize the long-standing dream of humanity. And a group of Soviet scientists, led by Academician S.P. Korolev, coped with it. She realized Tsiolkovsky's idea. The first artificial satellite of our planet was launched in the USSR on October 4, 1957. Naturally, a rocket was used.

Yu. A. Gagarin (pictured above) was the man who had the honor of being the first to fly in outer space. This important event for the world took place on April 12, 1961. Gagarin flew around the entire globe on the Vostok satellite. The USSR was the first state whose rockets reached the Moon, flew around it and photographed the side invisible from Earth. In addition, it was the Russians who visited Venus for the first time. They brought scientific instruments to the surface of this planet. American astronaut Neil Armstrong is the first person to walk on the surface of the Moon. He landed on it on July 20, 1969. In 1986, Vega 1 and Vega 2 (ships belonging to the USSR) explored at close range Halley's Comet, which approaches the Sun only once every 76 years. Space exploration continues...

As you can see, physics is a very important and useful science. Jet propulsion in nature and technology is just one of the interesting issues that are discussed in it. And the achievements of this science are very, very significant.

How jet propulsion is used in nature and technology these days

In physics, particularly important discoveries have been made in the last few centuries. While nature remains virtually unchanged, technology is developing at a rapid pace. Nowadays, the principle of jet propulsion is widely used not only by various animals and plants, but also in astronautics and aviation. In outer space there is no medium that a body could use to interact in order to change the magnitude and direction of its speed. That is why only rockets can be used to fly in airless space.

Today, jet propulsion is actively used in everyday life, nature and technology. It is no longer a mystery as it used to be. However, humanity should not stop there. New horizons are ahead. I would like to believe that the jet movement in nature and technology, briefly described in the article, will inspire someone to make new discoveries.

>>Physics: Jet propulsion

Newton's laws help explain a very important mechanical phenomenon - jet propulsion. This is the name given to the movement of a body that occurs when some part of it is separated from it at any speed.

Let's take, for example, a children's rubber ball, inflate it and release it. We will see that when the air begins to leave it in one direction, the ball itself will fly in the other. This is reactive movement.

Some representatives of the animal world move according to the principle of jet propulsion, such as squids and octopuses. Periodically throwing out the water they absorb, they are able to reach speeds of up to 60-70 km/h. Jellyfish, cuttlefish and some other animals move in a similar way.

Examples of jet propulsion can also be found in the plant world. For example, the ripened fruits of a “mad” cucumber, with the lightest touch, bounce off the stalk and from the hole formed at the site of the detached stalk, a bitter liquid with seeds is forcefully thrown out, while the cucumbers themselves fly off in the opposite direction.

The reactive motion that occurs when water is released can be observed in the following experiment. Pour water into a glass funnel connected to a rubber tube with an L-shaped tip (Fig. 20). We will see that when water begins to flow out of the tube, the tube itself will begin to move and deviate in the direction opposite to the direction of flow of water.

Flights are based on the principle of jet propulsion missiles. A modern space rocket is a very complex aircraft consisting of hundreds of thousands and millions of parts. The mass of the rocket is enormous. It consists of the mass of the working fluid (i.e., hot gases formed as a result of fuel combustion and emitted in the form of a jet stream) and the final or, as they say, “dry” mass of the rocket remaining after the working fluid is ejected from the rocket.

The “dry” mass of a rocket, in turn, consists of the mass of the structure (i.e., the shell of the rocket, its engines and control system) and the mass of the payload (i.e., scientific equipment, the body of the spacecraft launched into orbit, the crew and the system ship life support).

As the working fluid expires, the released tanks, excess parts of the shell, etc. begin to burden the rocket with unnecessary cargo, making it difficult to accelerate. Therefore, to achieve cosmic speeds, composite (or multi-stage) rockets are used (Fig. 21). At first, only the first stage 1 blocks work in such rockets. When the fuel reserves in them run out, they are separated and the second stage 2 is turned on; after the fuel in it is exhausted, it is also separated and the third stage 3 is turned on. The satellite or any other spacecraft located in the head of the rocket is covered with a head fairing 4, the streamlined shape of which helps to reduce air resistance when the rocket flies in the Earth's atmosphere.

When a jet of gas is ejected from a rocket at high speed, the rocket itself rushes in the opposite direction. Why is this happening?

According to Newton's third law, the force F with which the rocket acts on the working fluid is equal in magnitude and opposite in direction to the force F" with which the working fluid acts on the rocket body:
F" = F (12.1)
Force F" (which is called reactive force) accelerates the rocket.

Submitted by readers from Internet sites

Online library with textbooks and books, lesson plans for 8th grade physics, download physics tests, books and textbooks according to the 8th grade physics calendar planning

Today, most people, of course, primarily associate jet propulsion with the latest scientific and technical developments. From physics textbooks we know that by “reactive” we mean movement that occurs as a result of the separation of any part of it from an object (body). Man wanted to rise into the sky to the stars, he wanted to fly, but he was able to realize his dream only with the advent of jet aircraft and stepped spaceships, capable of traveling over vast distances, accelerating to supersonic speeds, thanks to the modern jet engines installed on them. Designers and engineers were developing the possibility of using jet propulsion in engines. Science fiction writers also did not stand aside, offering the most incredible ideas and ways to achieve this goal. Surprisingly, this principle of movement is widespread in wildlife. Just look around, you can notice the inhabitants of the seas and land, among which there are plants, the basis of whose movement is the reactive principle.

Story

Even in ancient times, scientists studied and analyzed with interest the phenomena associated with jet motion in nature. One of the first to theoretically substantiate and describe its essence was Heron, a mechanic and theorist of Ancient Greece, who invented the first steam engine, named after him. The Chinese were able to find practical applications for the reactive method. They were the first, taking as a basis the method of movement of cuttlefish and octopuses, to invent rockets back in the 13th century. They were used in fireworks, making a great impression, and also as signal flares, and possibly military missiles that were used as rocket artillery. Over time, this technology came to Europe.

The pioneer of modern times was N. Kibalchich, who came up with a design for a prototype aircraft with a jet engine. He was an outstanding inventor and a convinced revolutionary, for which he was imprisoned. It was while in prison that he made history by creating his project. After his execution for active revolutionary activities and speaking out against the monarchy, his invention was forgotten on the archive shelves. After some time, K. Tsiolkovsky was able to improve Kibalchich’s ideas, proving the possibility of exploring outer space through the reactive propulsion of spaceships.

Later, during the Great Patriotic War, the famous Katyushas, ​​field rocket artillery systems, appeared. This is the affectionate name people informally called for the powerful installations used by the USSR forces. It is not known for certain why the weapon received this name. The reason for this was either the popularity of Blanter’s song, or the letter “K” on the body of the mortar. Over time, front-line soldiers began to give nicknames to other weapons, thus creating a new tradition. The Germans called this combat missile launcher the “Stalinist organ” for its appearance, which resembled a musical instrument and the piercing sound that came from the launching missiles.

Vegetable world

Representatives of the fauna also use the laws of jet propulsion. Most of the plants that have these properties are annuals and young perennials: thorny carp, common spadefoot spadefoot, impatiens heartwood, two-cut pikulnik, three-veined meringia.

The prickly cucumber, also known as the crazy cucumber, belongs to the pumpkin family. This plant reaches large sizes, has a thick root with a rough stem and large leaves. It grows in Central Asia, the Mediterranean, the Caucasus, and is quite common in the south of Russia and Ukraine. Inside the fruit, during the period of seed ripening, it is transformed into mucus, which, under the influence of temperatures, begins to ferment and release gas. Closer to ripening, the pressure inside the fruit can reach 8 atmospheres. Then, with a light touch, the fruit breaks away from the base and the seeds with liquid fly out of the fruit at a speed of 10 m/s. Due to its ability to shoot 12 m in length, the plant was called the “ladies pistol”.

Impatiens heartwood is a widespread annual species. It is found, as a rule, in shady forests, along the banks of rivers. Once in the northeastern part of North America and South Africa, it successfully took root. Touch-me-not is propagated by seeds. The seeds of the impatiens are small, weighing no more than 5 mg, which are thrown at a distance of 90 cm. Thanks to this method of seed dispersal, the plant got its name.

Animal world

Jet propulsion - interesting facts about the animal world. In cephalopods, jet propulsion occurs through water exhaled through a siphon, which usually tapers to a small opening to obtain maximum expiratory flow. Water passes through the gills before exhalation, fulfilling the dual purpose of breathing and movement. Sea hares, also known as gastropods, use similar means of locomotion, but without the complex neurological apparatus of cephalopods, they move more clumsily.

Some knightfish have also developed jet propulsion, forcing water over their gills to complement fin movement.

In dragonfly larvae, reactive force is achieved by displacing water from a specialized cavity in the body. Scallops and cardids, siphonophores, tunics (such as salps) and some jellyfish also use jet propulsion.

Most of the time, scallops lie quietly on the bottom, but if danger arises, they quickly close the valves of their shells, so they push out the water. This behavior mechanism also speaks of the use of the principle of reactive movement. Thanks to it, scallops can float up and move over long distances using the opening-closing technique of the shell.

The squid also uses this method, absorbs water, and then pushes it through the funnel with great force and moves at a speed of at least 70 km/h. By collecting the tentacles into one knot, the squid's body forms a streamlined shape. Using this squid engine as a basis, engineers designed a water cannon. The water in it is sucked into the chamber and then thrown out through the nozzle. Thus, the ship is directed in the opposite direction from the ejected jet.

Compared to squids, salps use the most efficient engines, spending an order of magnitude less energy than squids. Moving, the salpa releases water into the hole in the front, and then enters the wide cavity where the gills are stretched. After a sip, the hole closes, and with the help of contracting longitudinal and transverse muscles that compress the body, water is released through the hole at the back.

The most unusual of all locomotion mechanisms is the common cat. Marcel Despres suggested that a body is capable of moving and changing its position even with the help of internal forces alone (without pushing off or relying on anything), from which it could be concluded that Newton’s laws may be erroneous. The proof of his assumption could be a cat that fell from a height. If she falls upside down, she will still land on all her paws; this has already become a kind of axiom. Having photographed the cat’s movement in detail, we were able to see from the frames everything that it did in the air. We saw her move her paw, which caused a response from her body, turning in the other direction relative to the movement of her paw. Acting according to Newton's laws, the cat landed successfully.

In animals, everything happens at the level of instinct; humans, in turn, do it consciously. Professional swimmers, having jumped from the tower, manage to turn around three times in the air, and having managed to stop the rotation, straighten up strictly vertically and dive into the water. The same principle applies to aerial circus gymnasts.

No matter how much people try to surpass nature by improving the inventions it has created, we still have not yet achieved that technological perfection when airplanes could repeat the actions of a dragonfly: hover in the air, instantly back up or move to the side. And all this happens at high speed. Perhaps a little more time will pass and airplanes, thanks to adjustments to the aerodynamics and jet capabilities of dragonflies, will be able to make sharp turns and become less susceptible to external conditions. Having looked at nature, man can still improve a lot for the benefit of technical progress.

The principle of jet propulsion is that this type of movement occurs when a part of it is separated from the body at a certain speed. A classic example of jet propulsion is the movement of a rocket. The peculiarities of this movement include the fact that the body receives acceleration without interaction with other bodies. Thus, the movement of a rocket occurs due to a change in its mass. The mass of the rocket decreases due to the outflow of gases that occur during fuel combustion. Consider the motion of a rocket. Let us assume that the mass of the rocket is equal to , and its speed at the moment of time is . After time, the mass of the rocket decreases by an amount and becomes equal to: , the speed of the rocket becomes equal to .

Then the change in momentum over time can be represented as:

where is the speed of gas flow relative to the rocket. If we accept that is a small quantity of higher order in comparison with the others, then we get:

When external forces () act on the system, we represent the change in momentum as:

We equate the right sides of formulas (2) and (3), we get:

where the expression is called the reactive force. Moreover, if the directions of the vectors are opposite, then the rocket accelerates, otherwise it decelerates. Equation (4) is called the equation of motion of a body of variable mass. It is often written in the form (equation of I.V. Meshchersky):

The idea of ​​using reactive force was proposed back in the 19th century. Later K.E. Tsiolkovsky put forward the theory of rocket motion and formulated the foundations of the theory of a liquid jet engine. If we assume that no external forces act on the rocket, then formula (4) will take the form: