Jet propulsion in nature briefly. Jet propulsion in nature and technology. Jet propulsion in physics

Jet propulsion in nature and technology

ABSTRACT ON PHYSICS

Jet motion - the motion that occurs when a part of it separates from the body at a certain speed.

The reactive force arises without any interaction with external bodies.

Application jet propulsion in nature

Many of us in our lives have met while swimming in the sea with jellyfish. In any case, there are enough of them in the Black Sea. But few people thought that jellyfish also use jet propulsion to move around. In addition, this is how dragonfly larvae and some types of marine plankton move. And often the efficiency of marine invertebrates when using jet propulsion is much higher than that of technical inventions.

Jet propulsion is used by many mollusks - octopuses, squids, cuttlefish. For example, a sea scallop mollusk moves forward due to the reactive force of a jet of water ejected from the shell during a sharp compression of its valves.

Octopus

Cuttlefish

The cuttlefish, like most cephalopods, moves in the water in the following way. She takes water into the gill cavity through a lateral slit and a special funnel in front of the body, and then vigorously throws a stream of water through the funnel. The cuttlefish directs the tube of the funnel to the side or back and, rapidly squeezing water out of it, can move in different sides.

Salpa is a marine animal with a transparent body; when moving, it takes water through the front opening, and the water enters a wide cavity, inside which the gills are stretched diagonally. As soon as the animal takes a large sip of water, the hole closes. Then the longitudinal and transverse muscles of the salpa contract, the whole body contracts, and water is pushed out through the rear opening. The reaction of the outflowing jet pushes the salpa forward.

Of greatest interest is the squid jet engine. Squid is the largest invertebrate inhabitant of the ocean depths. Squids have reached the highest level of excellence in jet navigation. They even have a body with its external forms that copies a rocket (or, better, a rocket copies a squid, since it has an indisputable priority in this matter). When moving slowly, the squid uses a large diamond-shaped fin, which periodically bends. For a quick throw, he uses a jet engine. Muscular tissue - the mantle surrounds the body of the mollusk from all sides, the volume of its cavity is almost half the volume of the body of the squid. The animal sucks water into the mantle cavity, and then abruptly ejects a jet of water through a narrow nozzle and moves backward with high speed. In this case, all ten squid tentacles are collected in a knot above the head, and it takes on a streamlined shape. The nozzle is equipped with a special valve, and the muscles can turn it, changing the direction of movement. The squid engine is very economical, it is able to reach speeds of up to 60 - 70 km / h. (Some researchers believe that even up to 150 km / h!) It is not for nothing that the squid is called a “living torpedo”. Bending the tentacles folded in a bundle to the right, left, up or down, the squid turns in one direction or another. Since such a steering wheel is very large in comparison with the animal itself, its slight movement is enough for the squid, even at full speed, to easily dodge a collision with an obstacle. A sharp turn of the steering wheel - and the swimmer rushes already in reverse side. Now he has bent the end of the funnel back and is now sliding head first. He arched it to the right - and the jet thrust threw him to the left. But when you need to swim fast, the funnel always sticks out right between the tentacles, and the squid rushes with its tail forward, as a cancer would run - a runner endowed with the agility of a horse.

If there is no need to hurry, squids and cuttlefish swim, undulating their fins - miniature waves run through them from front to back, and the animal gracefully glides, occasionally pushing itself also with a jet of water thrown out from under the mantle. Then the individual shocks that the mollusk receives at the time of the eruption of water jets are clearly visible. Some cephalopods can reach speeds of up to fifty-five kilometers per hour. No one seems to have made direct measurements, but this can be judged by the speed and range of flying squids. And such, it turns out, there are talents in the relatives of the octopuses! The best pilot among molluscs is the squid stenoteuthis. English sailors call it - flying squid ("flying squid"). This is a small animal the size of a herring. He pursues fish with such swiftness that he often jumps out of the water, rushing over its surface like an arrow. He also resorts to this trick to save his life from predators - tuna and mackerel. Having developed maximum jet thrust in the water, the pilot squid takes off into the air and flies over the waves for more than fifty meters. The apogee of the flight of a living rocket lies so high above the water that flying squids often fall on the decks of ocean-going ships. Four or five meters is not a record height to which squids rise into the sky. Sometimes they fly even higher.

The English shellfish researcher Dr. Rees described in a scientific article a squid (only 16 centimeters long), which, having flown a fair distance through the air, fell on the bridge of the yacht, which towered almost seven meters above the water.

It happens that many flying squids fall on the ship in a sparkling cascade. The ancient writer Trebius Niger once told a sad story about a ship that allegedly even sank under the weight of flying squid that fell on its deck. Squids can take off without acceleration.

Octopuses can also fly. The French naturalist Jean Verany saw an ordinary octopus speed up in an aquarium and suddenly jump out of the water backwards. Describing in the air an arc about five meters long, he plopped back into the aquarium. Gaining speed for a jump, the octopus moved not only due to jet thrust, but also rowed with tentacles.
Baggy octopuses swim, of course, worse than squids, but in critical moments they can show a record class for the best sprinters. California Aquarium staff tried to photograph an octopus attacking a crab. The octopus rushed at prey with such speed that on the film, even when shooting at the highest speeds, there were always lubricants. So, the throw lasted hundredths of a second! Usually octopuses swim relatively slowly. Joseph Signl, who studied octopus migration, calculated that a half-meter octopus swims through the sea at an average speed of about fifteen kilometers per hour. Each jet of water thrown out of the funnel pushes it forward (or rather, back, as the octopus swims backwards) two to two and a half meters.

Jet motion can also be found in the plant world. For example, the ripened fruits of the “mad cucumber” at the slightest touch bounce off the stalk, and a sticky liquid with seeds is ejected with force from the hole formed. The cucumber itself flies in the opposite direction up to 12 m.

Knowing the law of conservation of momentum, you can change your own speed of movement in open space. If you are in a boat and you have some heavy rocks, then throwing rocks in a certain direction will move you in the opposite direction. The same will happen in outer space, but jet engines are used for this.

Everyone knows that a shot from a gun is accompanied by recoil. If the weight of the bullet were equal to the weight of the gun, they would fly apart at the same speed. Recoil occurs because the discarded mass of gases creates a reactive force, due to which movement can be ensured both in air and in airless space. And the greater the mass and speed of the outflowing gases, the greater the recoil force felt by our shoulder, the stronger the reaction of the gun, the greater the reactive force.

The use of jet propulsion in technology

For many centuries, mankind has dreamed of space flights. Science fiction writers have proposed a variety of means to achieve this goal. In the 17th century, a story appeared by the French writer Cyrano de Bergerac about a flight to the moon. The hero of this story got to the moon in an iron wagon, over which he constantly threw a strong magnet. Attracted to him, the wagon rose higher and higher above the Earth until it reached the Moon. And Baron Munchausen said that he climbed to the moon on the stalk of a bean.

At the end of the first millennium of our era, jet propulsion was invented in China, which powered rockets - bamboo tubes filled with gunpowder, they were also used as fun. One of the first car projects was also with jet engine and this project belonged to Newton

The author of the world's first project of a jet aircraft designed for human flight was the Russian revolutionary N.I. Kibalchich. He was executed on April 3, 1881 for participating in the assassination attempt on Emperor Alexander II. He developed his project in prison after the death sentence. Kibalchich wrote: “While in prison, a few days before my death, I am writing this project. I believe in the feasibility of my idea, and this belief supports me in my terrible position ... I will calmly face death, knowing that my idea will not die with me.

The idea of ​​using rockets for space flights was proposed at the beginning of our century by the Russian scientist Konstantin Eduardovich Tsiolkovsky. In 1903, an article by a teacher of the Kaluga gymnasium K.E. Tsiolkovsky "Research of world spaces by jet devices". This work contained the most important mathematical equation for astronautics, now known as the “Tsiolkovsky formula”, which described the motion of a body of variable mass. Subsequently, he developed a scheme for a rocket engine on liquid fuel, proposed a multi-stage rocket design, expressed the idea of ​​​​the possibility of creating entire space cities in near-Earth orbit. He showed that the only apparatus capable of overcoming gravity is a rocket, i.e. an apparatus with a jet engine using fuel and an oxidizer located on the apparatus itself.

A jet engine is an engine that converts the chemical energy of the fuel into the kinetic energy of a gas jet, while the engine acquires speed in the opposite direction.

The idea of ​​K.E. Tsiolkovsky was carried out by Soviet scientists under the guidance of Academician Sergei Pavlovich Korolev. The first artificial Earth satellite in history was launched by a rocket in the Soviet Union on October 4, 1957.

The principle of jet propulsion is widely practical use in aviation and astronautics. In outer space there is no medium with which the body could interact and thereby change the direction and modulus of its velocity, therefore only jet engines can be used for space flights. aircrafts, i.e. rockets.

Rocket device

Rocket motion is based on the law of conservation of momentum. If at some point in time a body is thrown from the rocket, then it will acquire the same momentum, but directed in the opposite direction

In any rocket, regardless of its design, there is always a shell and fuel with an oxidizer. The shell of the rocket includes a payload (in this case it is spaceship), instrument compartment and engine (combustion chamber, pumps, etc.).

The main mass of the rocket is fuel with an oxidizer (the oxidizer is needed to keep the fuel burning, since there is no oxygen in space).

Fuel and oxidizer are pumped into the combustion chamber. The fuel, when burned, turns into a gas of high temperature and high pressure. Due to the large pressure difference in the combustion chamber and in outer space, the gases from the combustion chamber rush out in a powerful jet through a specially shaped bell, called a nozzle. The purpose of the nozzle is to increase the speed of the jet.

Before a rocket launches, its momentum is zero. As a result of the interaction of the gas in the combustion chamber and all other parts of the rocket, the gas escaping through the nozzle receives some impulse. Then the rocket is a closed system, and its total momentum must be equal to zero after launch. Therefore, the shell of the rocket, whatever is in it, receives an impulse equal in absolute value to the impulse of the gas, but opposite in direction.

The most massive part of the rocket, designed to launch and accelerate the entire rocket, is called the first stage. When the first massive stage of a multi-stage rocket exhausts all fuel reserves during acceleration, it separates. Further acceleration is continued by the second, less massive stage, and to the speed previously achieved with the help of the first stage, it adds some more speed, and then separates. The third stage continues to increase its speed to the required value and delivers the payload into orbit.

The first person to fly in outer space was a citizen Soviet Union Yuri Alekseyevich Gagarin. April 12, 1961 He circled the globe on the Vostok satellite ship

Soviet rockets were the first to reach the Moon, circled the Moon and photographed its invisible side from the Earth, were the first to reach the planet Venus and delivered scientific instruments to its surface. In 1986, two Soviet spacecraft "Vega-1" and "Vega-2" studied Halley's Comet at close range, approaching the Sun once every 76 years.

At best, require correction ... "R. Feynman Even a brief review of the history of the development of technology shows the amazing fact of an avalanche-like development modern science and technology throughout the history of all mankind. If the transition of man from stone tools to metal took about 2 million years; improvement of the wheel from a solid wooden one to a wheel having a hub, ...

Which is lost in the mists of time, was, is and will always be the focus of domestic science and culture: and will always be open in the cultural and scientific movement to the whole world. " * "Moscow in the history of science and technology" - this is the name research project(Head S.S. Ilizarov), carried out by the Institute of the History of Natural Science and Technology. S.I. Vavilov of the Russian Academy of Sciences with the support of...

The results of their many years of work in various areas physical optics. It laid the foundations for a new direction in optics, which the scientist called microoptics. Vavilov gave great attention questions of the philosophy of natural science and the history of science. He is credited with the development, publication and promotion of the scientific heritage of M. V. Lomonosov, V. V. Petrov and L. Euler. The scientist headed the Commission on the history of...

The use of jet propulsion in nature Many of us in our lives have met while swimming in the sea with jellyfish. But few people thought that jellyfish also use jet propulsion to move around. And often the efficiency of marine invertebrates when using jet propulsion is much higher than that of techno inventions.

Cuttlefish Cuttlefish, like most cephalopods, moves in the water in the following way. She takes water into the gill cavity through a lateral slit and a special funnel in front of the body, and then vigorously throws a stream of water through the funnel. The cuttlefish directs the funnel tube to the side or back and, rapidly squeezing water out of it, can move in different directions.

Squid The squid is the largest invertebrate inhabitant of the ocean depths. It moves according to the principle of jet propulsion, absorbing water into itself, and then pushing it with great force through a special hole - a "funnel", and at high speed (about 70 km / h) moves back in jolts. In this case, all ten tentacles of the squid are collected in a knot above the head and it acquires a streamlined shape.

Flying squid This is a small animal about the size of a herring. He pursues fish with such swiftness that he often jumps out of the water, rushing over its surface like an arrow. Having developed maximum jet thrust in the water, the pilot squid takes off into the air and flies over the waves for more than fifty meters. The apogee of the flight of a living rocket lies so high above the water that flying squids often fall on the decks of ocean-going ships. Four or five meters is not a record height to which squids rise into the sky. Sometimes they fly even higher.

Octopus Octopuses can also fly. The French naturalist Jean Verany saw an ordinary octopus speed up in an aquarium and suddenly jump out of the water backwards. Describing in the air an arc about five meters long, he plopped back into the aquarium. Gaining speed for a jump, the octopus moved not only due to jet thrust, but also rowed with tentacles.

Crazy Cucumber In the southern countries (and here on the Black Sea coast too) a plant called "Crazy Cucumber" grows. One has only to lightly touch the ripe fruit, similar to a cucumber, as it bounces off the stalk, and liquid with seeds flies out of the fruit at a speed of up to 10 m / s through the hole formed. Shoots a mad cucumber (otherwise it is called a "lady's pistol") more than 12 m.

slide 2

Application of jet propulsion in nature

Many of us in our lives have met while swimming in the sea with jellyfish. But few people thought that jellyfish also use jet propulsion to move around. And often the efficiency of marine invertebrates when using jet propulsion is much higher than that of technical inventions.

slide 3

Jet propulsion is used by many mollusks - octopuses, squids, cuttlefish.

slide 4

Cuttlefish

The cuttlefish, like most cephalopods, moves in the water in the following way. She takes water into the gill cavity through a lateral slit and a special funnel in front of the body, and then vigorously throws a stream of water through the funnel. The cuttlefish directs the funnel tube to the side or back and, rapidly squeezing water out of it, can move in different directions.

slide 5

Squid

Squids have reached the highest level of excellence in jet navigation. They even have a body that copies a rocket with its external forms (or better, a rocket copies a squid, since it has an indisputable priority in this matter)

slide 6

Squid is the largest invertebrate inhabitant of the ocean depths. It moves according to the principle of jet propulsion, absorbing water into itself, and then pushing it with great force through a special hole - a "funnel", and at high speed (about 70 km / h) moves back in jolts. In this case, all ten tentacles of the squid are collected in a knot above the head and it acquires a streamlined shape.

Slide 7

flying squid

This is a small animal the size of a herring. He pursues fish with such swiftness that he often jumps out of the water, rushing over its surface like an arrow. Having developed maximum jet thrust in the water, the pilot squid takes off into the air and flies over the waves for more than fifty meters. The apogee of the flight of a living rocket lies so high above the water that flying squids often fall on the decks of ocean-going ships. Four or five meters is not a record height to which squids rise into the sky. Sometimes they fly even higher.

Slide 8

Octopus

Octopuses can also fly. The French naturalist Jean Verany saw an ordinary octopus speed up in an aquarium and suddenly jump out of the water backwards. Describing in the air an arc about five meters long, he plopped back into the aquarium. Gaining speed for a jump, the octopus moved not only due to jet thrust, but also rowed with tentacles.

Multi-ton spaceships soar into the sky, and transparent, gelatinous jellyfish, cuttlefish and octopuses deftly maneuver in the sea waters - what do they have in common? It turns out that in both cases, the principle of jet propulsion is used to move. It is this topic that our today's article is devoted to.

Let's look into history

Most The first reliable information about rockets dates back to the 13th century. They were used by Indians, Chinese, Arabs and Europeans in combat operations as military and signal weapons. Then followed centuries of almost complete oblivion of these devices.

In Russia, the idea of ​​using a jet engine was revived thanks to the work of the Narodnaya Volya revolutionary Nikolai Kibalchich. Sitting in the royal dungeons, he developed Russian project jet engine and aircraft for people. Kibalchich was executed, and for many years his project was gathering dust in the archives of the tsarist secret police.

The main ideas, drawings and calculations of this talented and courageous person were further developed in the works of K. E. Tsiolkovsky, who proposed using them for interplanetary communications. From 1903 to 1914, he published a number of works, where he convincingly proves the possibility of using jet propulsion to explore outer space and substantiates the feasibility of using multi-stage rockets.

Many scientific developments of Tsiolkovsky are still used in rocket science.

biological missiles

How did it come about the idea of ​​moving by pushing off your own jet stream? Perhaps, closely watching the marine life, the inhabitants of the coastal zones noticed how this happens in the animal world.

For example, scallop moves due to the reactive force of the water jet ejected from the shell during the rapid compression of its valves. But he will never keep up with the fastest swimmers - squids.

Their rocket-like bodies rush tail forward, throwing out stored water from a special funnel. move according to the same principle, squeezing out water by contracting their transparent dome.

Nature endowed a "jet engine" and a plant called "squirting cucumber". When its fruits are fully ripe, in response to the slightest touch, it shoots out gluten with seeds. The fetus itself is thrown in the opposite direction at a distance of up to 12 m!

Neither marine life, neither plants know the physical laws underlying this mode of locomotion. We'll try to figure this out.

Physical foundations of the principle of jet propulsion

Let's start with a simple experiment. Inflate a rubber ball and, without tying, we will let go into free flight. The rapid movement of the ball will continue as long as the stream of air flowing from it is strong enough.

To explain the results of this experience, we should turn to the third law, which states that two bodies interact with forces equal in magnitude and opposite in direction. Therefore, the force with which the ball acts on the jets of air escaping from it is equal to the force with which the air repels the ball from itself.

Let's transfer this reasoning to the rocket. These devices at great speed throw out some of their mass, as a result of which they themselves receive acceleration in the opposite direction.

From a physics point of view, this the process is clearly explained by the law of conservation of momentum. Momentum is the product of the body's mass and its velocity (mv) While the rocket is at rest, its velocity and momentum are zero. If a jet stream is ejected from it, then the remaining part, according to the law of conservation of momentum, must acquire such a speed that the total momentum is still equal to zero.

Let's look at the formulas:

m g v g + m p v p =0;

m g v g \u003d - m p v p,

where m g v g the momentum created by the jet of gases, m p v p the momentum received by the rocket.

The minus sign shows that the direction of movement of the rocket and the jet stream are opposite.

The device and principle of operation of a jet engine

In technology, jet engines propel aircraft, rockets, put into orbit spacecraft. Depending on the purpose, they have a different device. But each of them has a supply of fuel, a chamber for its combustion and a nozzle that accelerates the jet stream.

The interplanetary automatic stations are also equipped with an instrument compartment and cabins with a life support system for astronauts.

Modern space rockets are complex, multi-stage aircraft that use the latest achievements in engineering. After launch, the fuel in the lower stage burns first, after which it separates from the rocket, reducing it total weight and increasing speed.

Then the fuel is consumed in the second stage, and so on. Finally, the aircraft is brought to a given trajectory and begins its independent flight.

Let's dream a little

The great dreamer and scientist K. E. Tsiolkovsky gave future generations the confidence that jet engines will allow humanity to break out of the earth's atmosphere and rush into space. His prediction came true. The moon, and even distant comets, are successfully explored by spacecraft.

In astronautics, liquid propellant engines are used. Using petroleum products as fuel, but the speeds that can be obtained with their help are insufficient for very long-distance flights.

Perhaps you, our dear readers, will witness the flights of earthlings to other galaxies on vehicles with nuclear, thermonuclear or ion jet engines.

If this message was useful to you, I would be glad to see you

Jet propulsion in nature and technology

ABSTRACT ON PHYSICS

Jet propulsion- the movement that occurs when a part of it separates from the body at a certain speed.

The reactive force arises without any interaction with external bodies.

Application of jet propulsion in nature

Many of us in our lives have met while swimming in the sea with jellyfish. In any case, there are enough of them in the Black Sea. But few people thought that jellyfish also use jet propulsion to move around. In addition, this is how dragonfly larvae and some types of marine plankton move. And often the efficiency of marine invertebrates when using jet propulsion is much higher than that of technical inventions.

Jet propulsion is used by many mollusks - octopuses, squids, cuttlefish. For example, a sea scallop mollusk moves forward due to the reactive force of a jet of water ejected from the shell during a sharp compression of its valves.

Octopus

Cuttlefish

The cuttlefish, like most cephalopods, moves in the water in the following way. She takes water into the gill cavity through a lateral slit and a special funnel in front of the body, and then vigorously throws a stream of water through the funnel. The cuttlefish directs the funnel tube to the side or back and, rapidly squeezing water out of it, can move in different directions.

Salpa is a marine animal with a transparent body; when moving, it takes water through the front opening, and the water enters a wide cavity, inside which the gills are stretched diagonally. As soon as the animal takes a large sip of water, the hole closes. Then the longitudinal and transverse muscles of the salpa contract, the whole body contracts, and water is pushed out through the rear opening. The reaction of the outflowing jet pushes the salpa forward.

Of greatest interest is the squid jet engine. Squid is the largest invertebrate inhabitant of the ocean depths. Squids have reached the highest level of excellence in jet navigation. They even have a body with its external forms that copies a rocket (or, better, a rocket copies a squid, since it has an indisputable priority in this matter). When moving slowly, the squid uses a large diamond-shaped fin, which periodically bends. For a quick throw, he uses a jet engine. Muscular tissue - the mantle surrounds the body of the mollusk from all sides, the volume of its cavity is almost half the volume of the body of the squid. The animal sucks water into the mantle cavity, and then abruptly ejects a jet of water through a narrow nozzle and moves backward with high speed. In this case, all ten squid tentacles are collected in a knot above the head, and it takes on a streamlined shape. The nozzle is equipped with a special valve, and the muscles can turn it, changing the direction of movement. The squid engine is very economical, it is able to reach speeds of up to 60 - 70 km / h. (Some researchers believe that even up to 150 km / h!) It is not for nothing that the squid is called a “living torpedo”. Bending the tentacles folded in a bundle to the right, left, up or down, the squid turns in one direction or another. Since such a steering wheel is very large in comparison with the animal itself, its slight movement is enough for the squid, even at full speed, to easily dodge a collision with an obstacle. A sharp turn of the steering wheel - and the swimmer rushes in the opposite direction. Now he has bent the end of the funnel back and is now sliding head first. He arched it to the right - and the jet thrust threw him to the left. But when you need to swim fast, the funnel always sticks out right between the tentacles, and the squid rushes with its tail forward, as a cancer would run - a runner endowed with the agility of a horse.

If there is no need to hurry, squids and cuttlefish swim, undulating their fins - miniature waves run through them from front to back, and the animal gracefully glides, occasionally pushing itself also with a jet of water thrown out from under the mantle. Then the individual shocks that the mollusk receives at the time of the eruption of water jets are clearly visible. Some cephalopods can reach speeds of up to fifty-five kilometers per hour. No one seems to have made direct measurements, but this can be judged by the speed and range of flying squids. And such, it turns out, there are talents in the relatives of the octopuses! The best pilot among molluscs is the squid stenoteuthis. English sailors call it - flying squid ("flying squid"). This is a small animal the size of a herring. He pursues fish with such swiftness that he often jumps out of the water, rushing over its surface like an arrow. He also resorts to this trick to save his life from predators - tuna and mackerel. Having developed maximum jet thrust in the water, the pilot squid takes off into the air and flies over the waves for more than fifty meters. The apogee of the flight of a living rocket lies so high above the water that flying squids often fall on the decks of ocean-going ships. Four or five meters is not a record height to which squids rise into the sky. Sometimes they fly even higher.

The English shellfish researcher Dr. Rees described in a scientific article a squid (only 16 centimeters long), which, having flown a fair distance through the air, fell on the bridge of the yacht, which towered almost seven meters above the water.

It happens that many flying squids fall on the ship in a sparkling cascade. The ancient writer Trebius Niger once told a sad story about a ship that allegedly even sank under the weight of flying squid that fell on its deck. Squids can take off without acceleration.

Octopuses can also fly. The French naturalist Jean Verany saw an ordinary octopus speed up in an aquarium and suddenly jump out of the water backwards. Describing in the air an arc about five meters long, he plopped back into the aquarium. Gaining speed for a jump, the octopus moved not only due to jet thrust, but also rowed with tentacles.
Baggy octopuses swim, of course, worse than squids, but in critical moments they can show a record class for the best sprinters. California Aquarium staff tried to photograph an octopus attacking a crab. The octopus rushed at prey with such speed that on the film, even when shooting at the highest speeds, there were always lubricants. So, the throw lasted hundredths of a second! Usually octopuses swim relatively slowly. Joseph Signl, who studied octopus migration, calculated that a half-meter octopus swims through the sea at an average speed of about fifteen kilometers per hour. Each jet of water thrown out of the funnel pushes it forward (or rather, back, as the octopus swims backwards) two to two and a half meters.

Jet motion can also be found in the plant world. For example, the ripened fruits of the “mad cucumber” at the slightest touch bounce off the stalk, and a sticky liquid with seeds is ejected with force from the hole formed. The cucumber itself flies in the opposite direction up to 12 m.

Knowing the law of conservation of momentum, you can change your own speed of movement in open space. If you are in a boat and you have some heavy rocks, then throwing rocks in a certain direction will move you in the opposite direction. The same will happen in outer space, but jet engines are used for this.

Everyone knows that a shot from a gun is accompanied by recoil. If the weight of the bullet were equal to the weight of the gun, they would fly apart at the same speed. Recoil occurs because the discarded mass of gases creates a reactive force, due to which movement can be ensured both in air and in airless space. And the greater the mass and speed of the outflowing gases, the greater the recoil force felt by our shoulder, the stronger the reaction of the gun, the greater the reactive force.

The use of jet propulsion in technology

For many centuries, mankind has dreamed of space flights. Science fiction writers have proposed a variety of means to achieve this goal. In the 17th century, a story appeared by the French writer Cyrano de Bergerac about a flight to the moon. The hero of this story got to the moon in an iron wagon, over which he constantly threw a strong magnet. Attracted to him, the wagon rose higher and higher above the Earth until it reached the Moon. And Baron Munchausen said that he climbed to the moon on the stalk of a bean.

At the end of the first millennium of our era, jet propulsion was invented in China, which powered rockets - bamboo tubes filled with gunpowder, they were also used as fun. One of the first car projects was also with a jet engine and this project belonged to Newton

The author of the world's first project of a jet aircraft designed for human flight was the Russian revolutionary N.I. Kibalchich. He was executed on April 3, 1881 for participating in the assassination attempt on Emperor Alexander II. He developed his project in prison after the death sentence. Kibalchich wrote: “While in prison, a few days before my death, I am writing this project. I believe in the feasibility of my idea, and this belief supports me in my terrible position ... I will calmly face death, knowing that my idea will not die with me.

The idea of ​​using rockets for space flights was proposed at the beginning of our century by the Russian scientist Konstantin Eduardovich Tsiolkovsky. In 1903, an article by a teacher of the Kaluga gymnasium K.E. Tsiolkovsky "Research of world spaces by jet devices". This work contained the most important mathematical equation for astronautics, now known as the “Tsiolkovsky formula”, which described the motion of a body of variable mass. Subsequently, he developed a scheme for a liquid-fuel rocket engine, proposed a multi-stage rocket design, and expressed the idea of ​​the possibility of creating entire space cities in near-Earth orbit. He showed that the only apparatus capable of overcoming gravity is a rocket, i.e. an apparatus with a jet engine using fuel and an oxidizer located on the apparatus itself.

Jet engine- this is an engine that converts the chemical energy of the fuel into the kinetic energy of the gas jet, while the engine acquires speed in the opposite direction.

The idea of ​​K.E. Tsiolkovsky was carried out by Soviet scientists under the guidance of Academician Sergei Pavlovich Korolev. The first artificial Earth satellite in history was launched by a rocket in the Soviet Union on October 4, 1957.

The principle of jet propulsion finds wide practical application in aviation and astronautics. In outer space there is no medium with which the body could interact and thereby change the direction and modulus of its velocity; therefore, only jet aircraft, i.e., rockets, can be used for space flights.

Rocket device

Rocket motion is based on the law of conservation of momentum. If at some point in time a body is thrown from the rocket, then it will acquire the same momentum, but directed in the opposite direction

In any rocket, regardless of its design, there is always a shell and fuel with an oxidizer. The rocket shell includes a payload (in this case, a spacecraft), an instrument compartment and an engine (combustion chamber, pumps, etc.).

The main mass of the rocket is fuel with an oxidizer (the oxidizer is needed to keep the fuel burning, since there is no oxygen in space).

Fuel and oxidizer are pumped into the combustion chamber. Fuel, burning, turns into a gas of high temperature and high pressure. Due to the large pressure difference in the combustion chamber and in outer space, gases from the combustion chamber rush out in a powerful jet through a specially shaped bell called a nozzle. The purpose of the nozzle is to increase the speed of the jet.

Before a rocket launches, its momentum is zero. As a result of the interaction of the gas in the combustion chamber and all other parts of the rocket, the gas escaping through the nozzle receives some impulse. Then the rocket is a closed system, and its total momentum must be equal to zero after launch. Therefore, the shell of the rocket, whatever is in it, receives an impulse equal in absolute value to the impulse of the gas, but opposite in direction.

The most massive part of the rocket, designed to launch and accelerate the entire rocket, is called the first stage. When the first massive stage of a multi-stage rocket exhausts all fuel reserves during acceleration, it separates. Further acceleration is continued by the second, less massive stage, and to the speed previously achieved with the help of the first stage, it adds some more speed, and then separates. The third stage continues to increase its speed to the required value and delivers the payload into orbit.

The first person to fly in outer space was Yuri Alekseevich Gagarin, a citizen of the Soviet Union. April 12, 1961 He circled the globe on the Vostok satellite ship

Soviet rockets were the first to reach the Moon, circled the Moon and photographed its invisible side from the Earth, were the first to reach the planet Venus and delivered scientific instruments to its surface. In 1986, two Soviet spacecraft "Vega-1" and "Vega-2" studied Halley's Comet at close range, approaching the Sun once every 76 years.

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