A coward not only doesn't play hockey, a coward doesn't fly into space. Of course, because the profession of an astronaut requires incredible willpower, responsibility, remarkable human courage and, of course, ingenuity. Space itself is interesting. Outside the stratosphere, there is a great many interesting things that have been shared with us by astronauts, scientists and researchers for decades, and therefore they have accumulated enough to be able to tell you about them.

16 sunrises in one day

In Earth orbit, sunsets and sunrises alternate every hour and a half, which is why astronauts are able to see as many as 16 sunrises in one day. But this mode knocks down biorhythms and does not allow you to sleep peacefully. Therefore, the cosmonauts conditionally live according to the Earth's Greenwich Mean Time, alternating rises and lights out. By the way, scientists have revealed an unexpected fact: the absence of gravity reduces snoring.

Radiation flare

Astronauts sometimes observe unusual flashes of light in their eyes. As it turned out in practice, this is not light at all, but nothing more than cosmic radiation, only the brain recognizes it as a flash. Such flashes are extremely harmful to the eyes, so subsequently astronauts often acquire eye diseases.

Growth

In the absence of gravity, the human spine lengthens, and an astronaut can even grow by 5-8 centimeters. Unfortunately, this growth can lead to back and nervous system complications.

Hygiene

It's no secret that astronauts have hygiene problems. Any liquid in space, due to the lack of gravity, rolls up into a ball and flies randomly in space. Therefore, astronauts have to wipe themselves with special wet sponges and napkins, as well as use an individual hygiene kit. But shaving remains according to earthly traditions, but one has to be very careful, because any tiny hair can get into the eye or get into the equipment, and this is fraught with catastrophic consequences.

"Precise Landing"

The operation of a toilet in space is also not an easy task. Astronauts even have to work out the “precision landing” technique on special simulators while still on Earth, and all in order to “land” exactly in the center.

"Second birth"

In the absence of gravity, muscles atrophy from insufficient exercise. To combat this, for example, the ISS crew has to exercise hard for 2.5 hours a day. But this does not guarantee the absence of muscle degradation. So, upon returning home, the astronauts feel a complete weakness in the area of ​​​​the arms, legs and in general the whole body, they become like babies, and therefore their return to Earth is called their “second birth”.

astronauts don't cry

Indeed, if an astronaut suddenly decides to unload emotionally and cry or watch a sad movie, nothing will come of it. Tears instantly curl right in the eyes and cause itching, burning and other unpleasant sensations.

"Homecoming"

After returning to Earth, astronauts go through a period of some adaptation, because they have already learned that all objects fly, and therefore it is not surprising that everything falls out of their hands every now and then.

Interesting facts about space people

Humankind has the most daring and far-reaching expectations of space exploration. People who devote themselves to this cause are doomed to fame and are forced to bear serious responsibility. Designers, engineers, cosmonauts and other specialists, without whom progress in this area is impossible, are people who look far into the future. Colossal physical and psychological stress is an integral part of their daily work. After all, no matter how insignificant on the scale of the Universe the success of each of them would seem, for humanity this is a huge breakthrough. Get to know these wonderful people and this selection offers.

The force of gravity is an integral part of our life, although we perceive it as something ordinary. I. Newton, thanks to an apple that fell on his head, developed this theory, but gravity is something more.
Before Newton, scientists such as Kepler, Descartes, Epicurus and others also philosophized about the existence of such a force. But, by and large, they believed that there are two attractions: heavenly (in space) and earthly (on the surface of the planet). Isaac Newton went a little further, he connected these two concepts. In addition, the legend that he was walking in the garden and an apple fell on him is actually fiction and just a beautiful story.

Gravity is the force of attraction between objects in proportion to their mass. Obi-Wan Kenobi in the world-famous movie mentioned that “the power is around us and penetrates us. She holds the galaxy together." However, if good and evil act according to the dual principle, then the force of attraction only attracts objects to each other, but does not repel them. Gravity is around us. This is the force that keeps the planet in the shape of a sphere, it does not allow us to break away from the surface. Gravity also holds our atmosphere around it and prevents it from floating in space. Below are some interesting facts about the force of gravity.

Many believe that astronauts on the space station and fans of extreme entertainment at speed experience "zero" gravity, i.e. for some time they are not subject to gravity at all. In fact, this is a fundamentally wrong statement, because. they tend to descend at the same speed as the object in which they are located.

The force of gravity acts equally on all objects, regardless of their weight. For example, if two cinder blocks of the same parameters, but different in weight, are dropped from a height, they will touch the surface of the earth together. The additional speed of an object that is lighter in mass is offset by the inertia of a heavier object.

It turns out that the greater the weight of the cosmic body, the heavier the objects on it. This means that the same person who weighs fifty kilograms on our planet would weigh twice as much on Saturn.
The force of gravity on a planet is determined by its size. For example, on Mars, the force of gravity is much less than on our planet. This fact negatively affects the human body, so a person cannot stay on this planet for a long time.
Jupiter is neither a planet nor a star. It has enough gravitational force to gain the necessary weight and become a full-fledged star, a heavenly body, but its field is too weak and cannot start the process of transforming the planet.

Interesting fact! In the absence of the force of gravity, i.e. in a state of weightlessness, all liquids take the form of a ball. You will not be able to wash your hands or pour water from vessel to vessel. Therefore, in order to feel comfortable in space, astronauts get used to it for a long time. Even sleep is unusual for them, because. they sleep in bags that are attached to the walls of the ship. In addition, astronauts have a harder time sleeping, because the phases of sleep and wakefulness of a person depend on sunsets and sunrises, and in space only 90 minutes pass between these two processes, i.e. There are 8 cycles per day.

Many people think that there is no gravitational force in space. Actually this is a false statement. The force of gravity is almost everywhere, but it acts with different strengths. As you know, the gravitational force between 2 bodies is inversely proportional to the distance between them and proportional to the product of their weight. Due to the fact that the earth's radius is slightly less than the height of the orbit of the international space station (by about 10 percent), therefore, the force of attraction there is less and tends to zero.

The flame in the absence of gravity also behaves differently than we are used to. This is because on Earth, during combustion, air saturated with carbon dioxide rises, while making room for oxygen to enter. Under weightlessness, there is no such air change, so over time, all the oxygen around the fire burns out, and the combustion process stops. Due to the lack of air convection in space, not only the flame suffers, but also the person, because during his immobility, oxygen also does not circulate around and ends. For such situations, spacecraft compartments are provided with fans for artificial air circulation.

According to the theory of scientists, it is the force of gravity that plays a role in determining the height of mountains on Earth. Thus, for our planet, the maximum height of the mountains will be a distance of no more than 15 kilometers. For example, if the Sun were to become a neural luminary, then its powerful gravity would not allow such a phenomenon as mountains to appear, in principle.

It turns out that the force of gravity in the center of the Earth would act on objects (if it were possible to place them there) differently than on the surface of the planet. In the core of the planet, objects would be pulled simultaneously on all four sides, which, in principle, is similar to the situation in a state of weightlessness.

Gravity affects not only objects, but also affects many calculations and factors. It turns out that its potential has a significant impact on the timing. Relatively recently, physicists from Denmark proved that the center of our planet is younger than its surface. The lower the gravity, the slower the time. According to hypothetical measurements, the age of the core and crust of celestial bodies differ significantly from each other in favor of their center.

We all know, and have previously mentioned that the presence of force itself on Earth was discovered by the scientist Newton in the 17th century. But few people know that in fact he described only a part of this force. For many years, scientists have tried to refine this theory. Another well-known genius stated that the force of gravity is just a curvature of time-space created by the mass of this object. That scientist was Einstein, and it wasn't until the 20th century that he got closer to unraveling this phenomenon. But in fact, gravity still holds many mysteries that are beyond our control at the moment and in the future have yet to be unraveled.

Sleeping in an upright position, a shower without water and a haircut with a vacuum cleaner. We tell how the life of astronauts differs from the earthly one.

1. Astronauts don't change their clothes for a long time.

They don't wash things on the ISS because there is no water in space. Because of this, astronauts wear the same thing for a long time: socks for a week, jacket and pants for about a month. If they changed their clothes more often, they would take up too much space. But this does not mean that astronauts go around dirty: the air on the ISS is cleaner and hygiene is tougher than on Earth, so clothes get dirty more slowly.

In addition, scientists are developing space underwear with an antimicrobial coating to keep clothes fresher longer. It is not so simple: underwear should not irritate the skin and cause dysbacteriosis, which kills beneficial bacteria on human skin.

2. It's uncomfortable to cry in space.

In weightlessness, nothing makes tears run down your cheeks. Instead, they accumulate in a ball around the eyeball and burn the eyes. The more tears, the larger the water ball, which, as it were, stuck to the eye and does not flow anywhere. To get rid of the discomfort, you need to wipe the tear with a towel or handkerchief.

In space, tears irritate the eyes, although nature intended to moisturize and protect. This happens because under the influence of low gravity, the chemical composition of fluids in the body changes. In addition, in weightlessness, a person has a feeling of dry eyes, and tears provoke a very contrasting, and therefore unpleasant sensation.

3. Astronauts don't just eat out of tubes.

Contrary to popular misconception, it is possible to eat fruit, berries and cakes in natural form in orbit. The official menu of Russian cosmonauts consists of 250 items, and if a cargo ship is sent to the ISS, they can order something fresh.

Ordinary salt and pepper are not available to astronauts: if you salt or pepper a dish in zero gravity, the spices will scatter and get into your eyes. Therefore, liquid saline and seasonings are used - mustard and ketchup are especially popular. Ketchup and Maheev sauces are supplied to the ISS for Russian cosmonauts. According to the director of Essen Production AG, Leonid Baryshev, who owns the Maheev trademark, exactly the same ketchup is delivered into orbit as in stores. The company did not create a special line of products for food on board: ordinary sauces from the supermarket successfully passed all quality tests. Therefore, if you eat ketchup or mustard "Maheev", you can feel like an astronaut.

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4. You can sleep in space upright and even upside down

In order not to fly around the ship during sleep, astronauts rest in special sleeping modules. These are vertical and horizontal sleeping bags attached to the wall. The sleeping modules are arranged in this way because in space it's the same as sleeping: there is no floor and ceiling, bottom and top, so you can even rest upside down. Often, astronauts assume the fetal position, which is most natural in low gravity.

In addition, astronauts have to sleep under a fan. It circulates air with the correct oxygen content and prevents a person from suffocating from the carbon dioxide exhaled during sleep. The fan works loudly: the noise reaches 65 dB. That's why astronauts use earplugs.

5. The skin on the heels becomes smooth, but this is dangerous.

To move in weightlessness, you do not need to walk. Therefore, the rough skin on the heels softens and exfoliates. Because of this, astronauts have to be very careful when removing their socks so that dead skin cells do not scatter everywhere, risking getting into someone's eye or clogging equipment.

6. Astronauts don't shower.

On the ISS, no one takes a shower in the usual sense of the word. Astronauts wipe their skin with a damp towel to save water and time. If you really want, you can squeeze a drop of water and liquid soap directly onto the skin - the liquid bubbles will stick to it. Then you need to mix them very slowly right on the skin and rub over the body so that they do not separate and fly away. Very little water is spent at the station, because in orbit even shampoo is indelible - after soaping, the hair is simply wiped with a towel.

7. Astronauts cut their hair with scissors and a vacuum cleaner

The crew is at the station for several months, so sometimes you have to cut your hair right in space. To do this, the astronauts use scissors connected to a vacuum tube that sucks up the hairs, preventing them from flying around the cabin of the spacecraft. Electric shavers work on the same principle, sucking up shaved hairs.

8. Astronauts train to go to the toilet on Earth

There is no escape from daily visits to the toilet, even in orbit. To make the process as comfortable as possible, it was equipped with belts. The visitor secures himself in a comfortable position and sits down. But it's not that simple. Due to the fact that water is not used for draining in space, astronauts have to train on Earth in order not to miss in weightlessness and avoid annoying mistakes.

9 Space Bloating Is A Serious Problem

In space, food that causes bloating is banned. Not only because a lover of extravagant food will annoy colleagues with an unpleasant smell, but also because of the danger to life. Methane and hydrogen produced by the human body are explosive gases.

10. In zero gravity, you must definitely play sports.

In weightlessness, it is much easier for the heart to pump blood around the body. This is dangerous, because over time, from a lack of load, it can greatly weaken. To stay in shape, astronauts devote 2.5 hours to sports every day. To do this, the spacecraft has simulators: a treadmill, a bicycle ergonometer and a simulator that simulates gravity. Regular physical activity also helps to avoid atrophy of the leg muscles, because they are hardly used in space.

Space life seems very strange. But the human body quickly adapts to life in weightlessness. Returning to Earth, many astronauts drop objects and break dishes, getting used to the fact that things are floating in the air.

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Weightlessness is not gibberish-hahanki ... Giggle-hahonki will begin when your inquisitive peanut, a little burr and "mumble", asks you about it. No matter how much you have to blush ... After all, they are like that - our today's Pochemuchki. How to tell a child in simple words about complex processes and phenomena that we cannot show in ordinary life? Only through comparisons and understandable analogies. We tell you how.

pikabu.ru

So, it's decided. We're flying into space! But insidious weightlessness awaits us there, so we will learn more about it, because knowledge is power!

Everything that we are used to on Earth, in a state of weightlessness, is completely different: people and objects “float” in space, it is almost impossible to touch your nose with your finger, to dance a waltz or show your favorite football trick is generally on the verge of fantasy. You laugh when you look at how the astronauts are trying to make the usual movements in zero gravity.

IMAGINE… Imagine that you are in a cold pool, and even upside down. You seem to understand everything, but you can't do anything. Astronauts in a state of weightlessness feel about the same.

LIFE EXPERIENCE: Invite the child to close their eyes and touch the tip of their nose with their finger. Difficult? And what about astronauts?
While bathing in the bath, offer to catch a small object underwater.
In the children's park, while jumping on a trampoline with elastic bands, you can also feel something like a state of weightlessness for a split second.
You can experience the state of weightlessness if you jump.
We experience weightlessness when swinging on a swing: at the moment when they froze for a second before changing direction and falling down.
We experience weightlessness aboard a ship, bobbing on the waves.

www.novate.ru

If something floated out of the hands directly into space - write wasted!

TRICKY QUESTION: Why are there many "satellites" around the Earth in the form of ballpoint pens, all kinds of bolts and wrenches?

Expert's ANSWER: To then once he dropped it all, forgetting about weightlessness and the fact that the force of gravity in space does not work!

The law of gravity is described in great detail in the video of the Academy of Entertaining Sciences.

Slobs in space have a hard time! Weightlessness can play a cruel joke with them. Threw pajamas anywhere - chase her for half a day. But that's not the worst!

IMAGINE… Imagine that you decide to have a snack in space.

Once, during a flight to the moon, I tried to open my favorite Rastishka curd. Oh, what happened ... He stretched out into a thin thread, then strayed into droplets and puddles, and then just stuck to my ear, as if something wet had been thrown at me. In general, it's good that the quick-witted Belka and Strelka captured tubes prepared from the Earth. Otherwise, we would have to sit hungry in space. But now I have - a magnet glowing in the dark, where on the reverse side is useful information about what weightlessness is.

And in space it is strictly forbidden to crumble! Therefore, real astronauts observe the children's rule: "Eat everything to the last crumb!" Otherwise, you will not end up in trouble!

TRICKY QUESTION: Why is it impossible to crumble in space?

Expert's ANSWER: The crumbs can scatter and get into the eyes or nose - this is very dangerous! Do you remember about the insidious weightlessness ...

I hope you have already understood that there is no place for Sloppy and Nehochuh in space: you need to observe and keep order.

Flying pajamas, scattered pens and tools, garbage are a potential danger for astronauts, therefore, since we are already flying to the moon, we need to be Ryakhs and Chukhs, i.e. observe the rules of hygiene and take into account the peculiarities of life in a state of weightlessness.

To be honest, washing and washing hands turns into an exciting activity in space. Water in weightlessness does not pour and does not flow, but, imagine, it is smeared! He squeezed a ball of water out of the tube, smeared it on his face - and swam further, washed himself, it is considered. How about brushing your teeth? It's a total adventure!

Well, if you were an ace on Earth in these matters, then it will be easy for you in space. And if not? Oh, you'll have to sweat, I don't envy you.

TRICKY QUESTION: Why can't you cry in space?

If in life you are a Reva-cow, they won’t take you into space for sure. More precisely, they will take something, but you simply won’t be able to roar in space! You can not even try - in vain.

Expert's ANSWER: Tears in space do not flow, but are collected in a "puddle" around the eyeball.

TRICKY QUESTION: How do astronauts sleep and what do they dream about?

What do you think astronauts dream about? The roar of the spaceport and the green grass near the house? Personally, I think they are dreaming of a comfortable earthly bed...

www.voprosy-kak-i-pochemu.ru

In conditions of weightlessness, it is not so easy to fall asleep, especially at first. It seems that you are falling down all the time, your arms are dangling in free flight, and your legs are dancing on their own. In order to somehow pacify your body, you have to climb into a sleeping bag and fasten your belts to the walls or ceiling of the ship.

The second problem is the constant noise of the fans that provide fresh air. The noise is as if a tram rumbles under the windows! But the problem is solved simply - ear plugs.

“There were a lot of dreams. In space, dreams are exactly the same as on Earth. As your eyes close in space, your body relaxes and your hands release the book. But without gravity, your head doesn't fall and you don't flinch when you realize you've dozed off. If you wake up, your book will float where you left it."
Former astronaut Clayton Anderson

Due to weightlessness in space, there is no need for a pillow and a blanket: astronauts do not use them. By the way, there is a big fat plus for astronauts in zero gravity - they don't snore! That's where happiness is: the neighbor will definitely not wake you up.

Here they are, all the “charms” of cosmic life: eat your own sweets from a tube and sleep upside down like a space bat in diapers. Now you can go to the moon! Download and go on a space journey with Dino!

MINISTRY OF EDUCATION AND SCIENCE OF THE RUSSIAN FEDERATION

MUNICIPAL EDUCATIONAL INSTITUTION

SECONDARY EDUCATIONAL SCHOOL №4

name

ON PHYSICS ON THE TOPIC:

WEIGHTLESSNESS

Work completed:

10 "B" class Khlusova Anastasia

Supervisor:

Physics teacher

Introduction

The phenomenon of weightlessness has always aroused my interest. Still, every person wants to fly, and weightlessness is something close to the state of flight. Before starting the research, I only knew that weightlessness is a condition that is observed in space, on a spacecraft, in which all objects fly, and astronauts cannot stand on their feet, as on Earth.

Weightlessness is more of a problem for astronautics than an unusual phenomenon. During a flight in a spacecraft, health problems may arise, and after landing, astronauts must be re-learned to walk and stand. Thus, it is very important to know what weightlessness is and how it affects the well-being of people traveling in outer space. As a result, it is necessary to solve this problem by creating programs to reduce the risk of adverse effects of weightlessness on the body.

The purpose of my work is to give the concept of weightlessness in a complex form (i.e., consider it from different angles), to note the relevance of this concept not only in the study of outer space, the negative impact on humans, but also in the framework of the possibility of using technology on Earth, invented to reduce this impact; carrying out some technological processes that are difficult or impossible to implement in terrestrial conditions.

The objectives of this abstract:

1) Understand the mechanism of occurrence of this phenomenon;

2) Describe this mechanism mathematically and physically;

3) Tell interesting facts about weightlessness;

4) To understand how the state of weightlessness affects the health of people in the spacecraft, at the station, etc., that is, to look at weightlessness from a biological and medical point of view;

5) Process the material, arrange it according to generally accepted rules;

6) Create a presentation based on the processed material.

The sources that I used in the process of writing an essay are textbooks, encyclopedias, the Internet.

Chapter 1. Body weight and weightlessness

1.1. Body weight

In technology and everyday life, the concept of body weight is widely used.

body weight called the total elastic force acting in the presence of gravity on all supports, suspensions.

Body weight P, that is, the force with which the body acts on the support, and the elastic force FY, with which the support acts on the body (Fig. 1), in accordance with Newton's third law, are equal in absolute value and opposite in direction: P = - Fu

If the body is at rest on a horizontal surface or moves uniformly and only the gravity force FT and the elastic force FY from the side of the support act on it, then the equality follows from the equality of the vector sum of these forces to zero: FT = - FY.

https://pandia.ru/text/78/040/images/image005_5.png" width="22" height="12">.png" width="22" height="12"> With accelerated body movement and support weight P will be different from the gravity FT.

According to Newton's second law, when a body of mass m moves under the action of gravity FT and elastic force Fy with acceleration a, the equality FT + FY = ma is fulfilled.

https://pandia.ru/text/78/040/images/image016_2.png" width="22" height="12">.png" width="22" height="12">.png" width= "22" height="12">.png" width="22" height="12">.png" width="22" height="12">From the equations P = - Fy and FT + Fy = ma : P \u003d FТ - ma \u003d mg - ma, or P \u003d m (g - a).

https://pandia.ru/text/78/040/images/image026_1.png" width="21" height="12"> Let's consider the case of elevator movement when acceleration a is directed vertically downwards. If the coordinate axis OY (Fig. 2) point vertically down, then the vectors P, g and a turn out to be parallel to the OY axis, and their projections are positive; then the equation P = m(g - a) will take the form: Py = m(gY - aY).

Since the projections are positive and parallel to the coordinate axis, they can be replaced by modules of vectors: P = m(g - a).

The weight of a body in which the direction of acceleration of free and fall and acceleration are the same is less than the weight of a body at rest.

1.2. The weight of a body moving with acceleration

Speaking about the weight of a body in a rapidly moving elevator, three cases are considered (except for the case of rest or uniform motion):

1) https://pandia.ru/text/78/040/images/image029_1.png" width="21" height="12">The elevator moves with upward acceleration (overloads, body weight is greater than gravity, P =mg+ma);

2) https://pandia.ru/text/78/040/images/image029_1.png" width="21" height="12">The elevator moves with downward acceleration (weight decreases, body weight is less than gravity, P=mg-ma);

3) The elevator is falling (weightlessness, body weight is zero, P=0).

These three cases do not qualitatively exhaust all situations. It makes sense to consider the 4th case, so that the analysis is complete. (Indeed, in the second case it is assumed that a< g. Третий случай есть частный для второго при a = g. Случай a >g left unconsidered.) To do this, you can ask the students a question that at first surprises them : “How should the elevator move so that a person can walk on the ceiling?” Students quickly “guess” that the elevator must move way down with acceleration big g. Indeed: with an increase in the acceleration of the elevator down, in accordance with the formula P=mg-ma, the body weight will decrease. When the acceleration a becomes equal to g, the weight becomes zero. If you continue to increase the acceleration, then we can assume that the weight of the body will change direction.

After that, you can depict the body weight vector in the figure:

You can solve this problem in the reverse formulation: “What will be the weight of the body in an elevator moving down with an acceleration a > g?” This task is a little more difficult, because students need to overcome the inertia of thinking and swap “up” and “down”.

There may be an objection that the 4th case is not considered in textbooks because it does not occur in practice. But the fall of the elevator is also found only in problems, but, nevertheless, it is considered, because it is convenient and useful.

Movement with acceleration directed downwards or upwards is observed not only in an elevator or a rocket, but also during the movement of an aircraft performing aerobatics, as well as when a body moves along a convex or concave bridge. The considered 4th case corresponds to the movement along the “dead loop”. At its upper point, the acceleration (centripetal) is directed downward, the reaction force of the support is downward, and the weight of the body is upward.

Let's imagine a situation: an astronaut has left the ship into space and with the help of an individual rocket engine takes a walk around the neighborhood. Returning, he somewhat overexposed the engine on, approached the ship with an excess of speed and hit his knee on it. Will he hurt?

- It won't be: after all, in weightlessness an astronaut is lighter than a feather, - such an answer can be heard.

The answer is wrong. When you fell off the fence on Earth, you too were in a state of weightlessness. For when you hit the earth's surface, you felt a noticeable overload, the greater, the harder the place on which you fell, and the greater was your speed at the moment of contact with the ground.

Weightlessness and weightiness have nothing to do with impact. Mass and speed are important here, not weight.

And yet, the astronaut will not be as hurt when he hits the ship as you do when hitting the ground (ceteris paribus: the same masses, relative velocities and the same hardness of the obstacles). The mass of the ship is much less than the mass of the Earth. Therefore, upon impact with the ship, a noticeable part of the kinetic energy of the astronaut will be converted into the kinetic energy of the ship, and less deformation will remain. The ship will acquire additional speed, and the astronaut's pain sensation will not be so strong.

1.3. Weightlessness

If the body, together with the support, falls freely, then a = g, then from the formula

P = m(g – a) it follows that P = 0.

The disappearance of the weight during the movement of the support with the acceleration of free fall only under the action of gravity is called weightlessness.

There are two types of weightlessness.

The weight loss that occurs at a great distance from celestial bodies due to the weakening of attraction is called static weightlessness. And the state in which a person is during a flight in orbit is dynamic weightlessness.

They appear exactly the same. Human feelings are the same. But the reasons are different.

Astronauts in flight deal only with dynamic weightlessness.

The expression "dynamic weightlessness" means: "weightlessness arising from motion."

We feel the Earth's pull only when we resist it. Only when we "refuse" to fall. And as soon as we “agreed” to fall, the feeling of heaviness instantly disappears.

Imagine - you are walking with a dog, holding it on a strap. The dog rushed somewhere, pulled on the strap. You feel the pull on the strap—the “pull” of the dog—only while you resist. And if you run after the dog, the strap will sag and the feeling of attraction will disappear.

The same is true with the attraction of the Earth.

The plane is flying. In the cockpit, two paratroopers prepared to jump. The earth is pulling them down. And yet they resist. They put their feet on the floor of the plane. They feel the attraction of the Earth - the soles of their feet are pressed to the floor with force. They feel their weight. "The strap is tight."

But here they agreed to follow where the Earth pulls them. We stood on the edge of the hatch and jumped down. "Strap slack." The feeling of gravity of the Earth immediately disappeared. They became weightless.

One can imagine a continuation of this story.

Simultaneously with the paratroopers, a large empty box was dropped from the plane. And now they are flying side by side, at the same speed, somersaulting in the air, two people who did not open their parachutes, and an empty box.

One man reached out, grabbed a box flying nearby, opened the door in it and pulled himself inside.

Now, out of two people, one flies outside the box and the other flies inside the box.

They will feel completely different.

The one that flies outside sees and feels that it is rapidly flying down. The wind whistles in his ears. The approaching Earth is visible in the distance.

And the one that flies inside the box closed the door and began, pushing off the walls, to “float” along the box. It seems to him that the box is quietly standing on the Earth, and he, having lost weight, floats through the air, like a fish in an aquarium.

Strictly speaking, there is no difference between the two skydivers. Both are flying towards the Earth with the same speed. But one would say, "I'm flying," and the other, "I'm floating on the spot." The thing is that one is guided by the Earth, and the other by the box in which it flies.

This is exactly how the state of dynamic weightlessness arises in the cockpit of a spacecraft.

At first glance, this may seem incomprehensible. It would seem that the spacecraft flies parallel to the Earth, like an airplane. And in a horizontally flying plane, there is no weightlessness. But we know that the spaceship-satellite is constantly falling. It looks much more like a box dropped from an airplane than an airplane.

Dynamic weightlessness sometimes occurs on Earth as well. Weightless, for example, swimmers-divers flying into the water from a tower. Weightless for a few seconds skiers during ski jumping. Parachutists falling like a stone are weightless until they open their parachutes. For training astronauts for thirty to forty seconds create weightlessness in an airplane. To do this, the pilot makes a "slide". He accelerates the plane, soars steeply obliquely upwards and turns off the engine. The plane starts flying by inertia, like a stone thrown by hand. At first it rises a little, then describes an arc, turning down. Dive to Earth. All this time, the aircraft is in a state of free fall. And all this time, real weightlessness reigns in his cockpit. Then the pilot turns on the engine again and carefully brings the aircraft out of the dive into normal level flight. When the motor is turned on, weightlessness immediately disappears.

In a state of weightlessness, gravity forces act on all particles of a body in a state of weightlessness, but there are no external forces applied to the surface of the body (for example, support reactions) that could cause mutual pressures of particles on each other. A similar phenomenon is observed for bodies located in an artificial satellite of the Earth (or in a spaceship); these bodies and all their particles, having received, together with the satellite, the corresponding initial speed, move under the influence of gravitational forces along their orbits with equal accelerations, as free, without exerting mutual pressure on each other, that is, they are in a state of weightlessness. Like a body in an elevator, they are affected by the force of gravity, but there are no external forces applied to the surfaces of the bodies that could cause mutual pressures of the bodies or their particles on each other.

In general, a body under the action of external forces will be in a state of weightlessness if: a) the acting external forces are only mass (gravitational forces); b) the field of these body forces is locally homogeneous, that is, the field forces impart to all particles of the body in each of its positions identical in magnitude and direction of acceleration; c) the initial velocities of all particles of the body are the same in modulus and direction (the body moves forward). Thus, any body, the dimensions of which are small compared to the Earth's radius, making free translational motion in the Earth's gravitational field, will, in the absence of other external forces, be in a state of weightlessness. The result will be similar for the motion in the gravitational field of any other celestial bodies.

Due to the significant difference between the conditions of weightlessness and terrestrial conditions, in which devices and assemblies of artificial Earth satellites, spacecraft and their launch vehicles are created and debugged, the problem of weightlessness occupies an important place among other problems of astronautics. This is most significant for systems having tanks partially filled with liquid. These include propulsion systems with liquid-propellant rocket engines (liquid-propellant engines), designed for repeated activation in space flight conditions. Under weightless conditions, the liquid can occupy an arbitrary position in the tank, thereby disrupting the normal functioning of the system (for example, the supply of components from fuel tanks). Therefore, to ensure the launch of liquid propulsion systems in weightless conditions, the following are used: separation of the liquid and gaseous phases in fuel tanks using elastic separators; fixing a part of the liquid at the intake device of grid systems (Agena rocket stage); creating short-term overloads (artificial "weight") before turning on the main propulsion system with the help of auxiliary rocket engines, etc. The use of special techniques is also necessary for separating the liquid and gaseous phases under weightless conditions in a number of units of the life support system, in the fuel elements of the power supply system (for example, collection of condensate with a system of porous wicks, separation of the liquid phase with a centrifuge). Spacecraft mechanisms (for opening solar panels, antennas, for docking, etc.) are designed to work in weightless conditions.

Weightlessness can be used to implement some technological processes that are difficult or impossible to implement under terrestrial conditions (for example, obtaining composite materials with a uniform structure throughout the volume, obtaining bodies of an exact spherical shape from molten material due to surface tension forces, etc.). For the first time, an experiment on welding various materials under weightless vacuum conditions was carried out during the flight of the Soviet spacecraft Soyuz-6 (1969). A number of technological experiments (on welding, studying the flow and crystallization of molten materials, etc.) were carried out on the American Skylab orbital station (1973).

Scientists conduct various experiments in space, they set up experiments, but they have little idea of ​​the final result of these actions. But if any experiment gave a certain result, then for a long time you have to check it in order to ultimately explain and apply the knowledge gained in practice.

Below are descriptions of some experiments and interesting news about weightlessness, which are still to be worked on.

1.4. It is interesting

1.4.1. Flame in weightlessness

On Earth, due to gravity, convection currents arise, which determine the shape of the flame. They raise hot soot particles that emit visible light. Because of this, we see the flame. In weightlessness, there are no convection currents, soot particles do not rise, and the candle flame takes on a spherical shape. Since the candle material is a mixture of saturated hydrocarbons, they release hydrogen when burned, which burns with a blue flame. Scientists are trying to understand how and why fire spreads in zero gravity. The study of a flame under weightless conditions is necessary for assessing the fire resistance of a spacecraft and for developing special fire-extinguishing means. So you can ensure the safety of astronauts and vehicles.

1.4.2. The vibration of the liquid accelerates its boiling in weightlessness

In weightlessness, boiling becomes a much slower process. However, as French physicists have discovered, the vibration of a liquid can cause it to boil violently. This result has implications for the space industry.

Each of us has repeatedly observed the phase transition of a liquid into a gas under the influence of high temperature, that is, in other words, the boiling process. Vapor bubbles, breaking away from the heat source, rush upward, and a new portion of liquid enters in their place. As a result, boiling is accompanied by active mixing of the liquid, which greatly increases the rate of its transformation into vapor.

The key role in this turbulent process is played by the Archimedes force acting on the bubble, which, in turn, exists due to gravity. In conditions of weightlessness, there is no weight, there is no concept of "heavier" and "lighter", and therefore the bubbles of heated steam will not float anywhere. A layer of steam forms around the heating element, which prevents the transfer of heat to the entire volume of the liquid. For this reason, the boiling of liquids in weightlessness (but at the same pressure, and not at all in a vacuum!) will proceed in a completely different way than on Earth. A detailed understanding of this process is essential for the successful operation of spacecraft carrying tons of liquid propellant.

To understand this process, it is very important to understand what physical phenomena can accelerate boiling in weightlessness. A recent article by French physicists describes the results of an experimental study of how high frequency vibrations affect the boiling rate.

As a working substance, the researchers chose liquid hydrogen - the lightest rocket fuel. The state of weightlessness was created artificially, with the help of a strong inhomogeneous magnetic field, which just compensated for the force of gravity (read about magnetic levitation in our article Magnetic superconductivity: levitation in liquid oxygen). The temperature and pressure of the sample were chosen so that the phase transition occurred as slowly as possible and all its features could be seen.

The main result of the experiments of French physicists is that, under weightless conditions, vibration accelerates the transformation of liquid into vapor. Under the influence of vibration inside a slightly superheated liquid, a “volumetric ripple” appears: a network of small, fractions of a millimeter in size, vapor bubbles in the liquid. At first, these bubbles grow slowly, but after 1-2 seconds from the start of exposure, the whole process accelerates sharply: the liquid literally boils.

According to the authors, there are two reasons for this behavior. First, while the vapor bubbles are small, the viscosity of the liquid, as it were, “holds” them in place, preventing them from quickly approaching each other. For large bubbles, the viscosity fades into the background, and their merging and further growth becomes more intense. The second reason lies in the very essence of the mathematical laws governing the movement of fluids. These laws are non-linear, which means that external vibrations not only cause the liquid to “shake finely”, but also generate large-scale flows in it. It is these currents, having accelerated, that effectively mix the working volume and lead to an acceleration of the process.

The authors of the work emphasize that the phenomenon they discovered is not only of applied, but also of purely scientific interest. In their experiments, the complex hydrodynamic flows accompanying the evolution of the bubble network run in parallel with the phase transition itself. Both of these phenomena support and reinforce each other, leading to extreme fluid instability even in zero gravity.

Boiling water on Earth and in zero gravity (image from nasa.gov)

So, having understood the causes of weightlessness and the features of this phenomenon, we can proceed to the question of its influence on the human body.

Chapter 2Man and weightlessness

We are accustomed to our own gravity. We are accustomed to the fact that all the objects around us have weight. We don't represent anything else. Not only our life passed in conditions of weightiness. The entire history of life on Earth proceeded in the same conditions. The gravity of the earth has never vanished in millions of years. Therefore, all organisms living on our planet have long adapted to supporting their own weight.

Already in the most ancient times, bones formed in the body of animals, which became supports for their body. Without bones, animals under the influence of earthly gravity would “spread” along the ground, like a soft jellyfish taken out of the water onto the shore.

All our muscles have adapted over millions of years to move our body, overcoming the gravity of the Earth.

And inside our body everything is adapted to the conditions of gravity. The heart has powerful muscles, designed to continuously pump several kilograms of blood. And if down, into the legs, it still flows easily, then up, into the head, it must be applied with force. All our internal organs are suspended on strong ligaments. If they weren’t there, the insides would “roll” down, huddle together there.

Due to constant weightiness, we have developed a special organ, the vestibular apparatus, located deep in the head, behind the ear. It allows us to feel which side the Earth is from us, where the “up” is and where the “down” is.

The vestibular apparatus is a small cavity filled with fluid. They contain tiny stones. When a person stands upright, the pebbles lie at the bottom of the cavity. If a person lies down, the pebbles will roll and lie on the side wall. The human brain senses this. And a person, even with his eyes closed, will immediately tell where the bottom is.

So, everything in man is adapted to the conditions in which he lives on the surface of the planet Earth.

And what are the conditions of human life in such a peculiar state as weightlessness?

It is especially important to take into account the peculiarity of weightlessness during the flight of manned spacecraft: the conditions of a person's life in a state of weightlessness differ sharply from the usual terrestrial ones, which causes a change in a number of his vital functions. Thus, weightlessness puts the central nervous system and receptors of many analyzer systems (vestibular apparatus, muscular-articular apparatus, blood vessels) in unusual conditions of functioning. Therefore, weightlessness is considered as a specific integral stimulus that affects the human and animal organism during the entire orbital flight. The response to this stimulus is adaptive processes in physiological systems; the degree of their manifestation depends on the duration of weightlessness and, to a much lesser extent, on the individual characteristics of the organism.

The adverse effect of weightlessness on the human body in flight can be prevented or limited by various means and methods (muscle training, muscle electrical stimulation, negative pressure applied to the lower half of the body, pharmacological and other means). In a flight lasting about 2 months (the second crew at the American Skylab station, 1973), a high preventive effect was achieved mainly due to the physical training of the cosmonauts. High-intensity work, which caused an increase in heart rate up to 150-170 beats per minute, was performed on a bicycle ergometer for 1 hour a day. Restoration of the function of blood circulation and respiration occurred 5 days after landing. Metabolic changes, static-kinetic and vestibular disorders were weakly expressed.

An effective means is likely to be the creation of an artificial "gravity" on board the spacecraft, which can be obtained, for example, by making the station in the form of a large rotating (that is, not moving forward) wheel and placing work rooms on its "rim". Due to the rotation of the "rim" of the body in it, they will be pressed against its surface, which will play the role of the "floor", and the reaction of the "floor" applied to the surfaces of the bodies will create artificial "gravity". The creation of artificial "gravity" on spacecraft can ensure the prevention of the adverse effect of weightlessness on the organisms of animals and humans.

To solve a number of theoretical and practical problems of space medicine, laboratory methods for modeling weightlessness are widely used, including the limitation of muscle activity, depriving a person of his usual support along the vertical axis of the body, reducing hydrostatic blood pressure, which is achieved by staying a person in a horizontal position or at an angle (the head is lower legs), prolonged continuous bed rest or immersion of a person for several hours or days in a liquid (so-called immersion) medium.

Weightlessness conditions disrupt the ability to correctly assess the size of objects and distances to them, which prevents astronauts from navigating in the surrounding space and can lead to accidents during space flights, according to an article by French scientists published in the journal Acta Astronautica. To date, a lot of evidence has been accumulated that cosmonauts' mistakes in determining distances do not occur by chance. Often distant objects appear closer to them than they really are. Scientists from the French National Center for Scientific Research conducted an experimental test of the ability to estimate distances in conditions of artificially created weightlessness when an aircraft is flying in a parabola. In this case, weightlessness lasts a very short period - about 20 seconds. Volunteers were shown an unfinished image of a cube with the help of special glasses and asked to complete the correct geometric figure. Under ordinary gravity, the subjects drew all sides equal, but during weightlessness they failed to perform the test correctly. According to scientists, this experiment shows that weightlessness, and not long-term adaptation to it, should be considered as an important factor that distorts perception.

2.1. Study of the problems of life in space

The book "Skylab Orbital Station", written back in 1977 by the leading American experts in astronautics Professor E. Stuhlinger and Dr. L. Bellew, the scientific supervisors of the Skylab program implemented by NASA, tells about the research carried out at the orbital station

the influence exerted by the surrounding outer space on the capabilities of the crew members. The biomedical research program covered the following four areas: medical experiments involved in-depth studies of those physiological effects and the period of their action that were observed during previous flights.

Biological experiments included the study of fundamental biological processes that can be affected by weightlessness conditions.

Biotechnical experiments were aimed at developing the efficiency of man-machine systems when working in space and at improving the technique of using bioequipment. Here are some research topics:

study of salt balance;

biological studies of body fluids;

study of changes in bone tissue;

creation of negative pressure on the lower body in flight;

Obtaining vector cardiograms;

· cytogenetic blood tests;

Immunity research;

Investigation of changes in blood volume and life expectancy of red blood cells;

studies of the metabolism of red blood cells;

study of special hematological effects;

· study of the cycle of sleep and wakefulness in space flight conditions;

filming of astronauts during certain work operations;

measurement of metabolic rate;

measurement of the astronaut's body weight in space flight conditions;

· studies of the effect of weightlessness on living cells and human tissues. (Attachment 1)

Large scientific and practical material has been accumulated by Russian scientists and cosmonauts.

Is it possible to operate on people in zero gravity? At first glance, this question seems incredible, but, in fact, a lot is possible in our world!

This showed that scientists were able to move from experiments, which often had some flaws and required improvement, to real discoveries and were able to prove in practice that it is possible to operate on a person in zero gravity!

2.2. Operation in space

French doctors led by Professor Dominique Martin from Bordeaux performed the world's first surgical operation in zero gravity. The experiment was carried out on board the A-300 airliner in a specially equipped module. It was attended by three surgeons and two anesthesiologists, who were to remove a fatty tumor on the arm of a volunteer patient, 46-year-old Philippe Sancho, under conditions.

As Professor Marten said, the task of the physicians was not to demonstrate technical achievements, but to test the feasibility of the operation under conditions of weightlessness. "We have simulated a situation that corresponds to the conditions of outer space, and now we know that a person can be operated on in outer space without serious complications," the surgeon added. According to him, the operation to remove the tumor took a total of less than 10 minutes. The three-hour flight regime on board the A-300 was designed in such a way that during this time the state of weightlessness was created 32 times, with each phase lasting about 20 seconds. "If we were continuously in a state of weightlessness for two hours, we would be able to operate on appendicitis," said Professor Marten.

The next stage of the experiment, which is planned to be carried out in about a year, will be a surgical operation, which will have to be carried out by a medical robot controlled by commands from a ground base.

2.3. Application of space developments on Earth

We move less and less and more and more like astronauts floating in zero gravity. In any case, we experience all the disadvantages of a decrease in motor activity that cosmonauts suffer from in full. For those who work in orbit, scientists have come up with a lot of ways to counter them. On Earth, as it has recently become clear, some of these inventions are getting back on their feet even those who have never walked at all. “In space and on Earth, the factors of influence are similar, so the methods of counteracting the effects developing in weightlessness turned out to be applicable in everyday life,” says Inessa Benediktovna KOZLOVSKAYA, head of the department of sensorimotor physiology and prevention at the Institute of Biomedical Problems. - A decrease in motor activity (hypokinesia) is becoming a leading factor in the life of our society: we stop moving. One American researcher monitored daily muscle activity in people of various professions and in animals. It turned out that our activity compared to the activity of any living creature (rats, cats, dogs, monkeys) is less than two orders of magnitude.

We are on the verge of a hypokinetic disease, a disease of deep detraining, the most striking expression of which we saw in cosmonauts in 1970. After returning from a 17-day flight, they really could not stand up or move, it was difficult for them even to breathe, because the respiratory muscles had detrained too.

“We simulated the effect of weightlessness on Earth using dry immersion,” says Irina SAENKO, Senior Researcher, Head of the Clinical Physiology Department of the State Scientific Center of the Russian Federation, Institute of Biomedical Problems, Russian Academy of Sciences. - To do this, a thin waterproof film is placed in a pool of water with a size significantly larger than the surface of the water, and the person is immersed in the water, being separated from it. At the same time, he loses his support, and we see how immediately motor disorders begin to develop: the posture and coordination of motor acts suffer. He stands unsteadily, walks badly and awkwardly, performs precise operations with difficulty. To prevent these disorders, it was proposed to stimulate the support zones of the feet by applying a load approximately equal to that which occurs on Earth when standing and walking.

In addition, other effective methods of treating people in terrestrial conditions are used, for example, the Penguin suit began to be introduced into terrestrial medicine in 1992 (it has been used in space for more than 20 years), high-frequency and high-intensity electrical stimulation for the treatment of children with cerebral palsy and people who lie for a long time due to illness.

So, the second and last chapter of the essay has come to an end. After presenting all the material, I would like to proceed to the conclusion.

CONCLUSION

So, in conclusion of my work, I would like to once again recall the main provisions of the abstract, which reveal the essence of the topic:

1) Weightlessness occurs when the body falls freely together with the support, i.e., the acceleration of the body and the support is equal to the acceleration of free fall;

2) There are two types of weightlessness: static and dynamic;

3) Weightlessness can be used to implement some technological processes that are difficult or impossible to implement under terrestrial conditions;

4) The study of flames under weightless conditions is necessary to assess the fire resistance of a spacecraft and to develop special fire extinguishing means;

5) A detailed understanding of the process of liquid boiling in space is extremely important for the successful operation of spacecraft carrying tons of liquid fuel on board;

6) The effect of weightlessness on the body is negative, as it causes a change in a number of its vital functions. This can be corrected by creating artificial gravity on the spacecraft, limiting the astronauts' muscle activity, etc.

7) A person can be operated on in outer space, under conditions of weightlessness. This was proved by French doctors led by Professor Dominique Martin from Bordeaux.

Thus, one can find a lot of different information about weightlessness, but I think that in my work the material is presented in sufficient detail, since it is considered from two different points of view: physical and medical. Also in the abstract are descriptions of some experiments that scientists conducted in weightlessness. This, in my opinion, gives a visual representation of weightlessness, the mechanism of its occurrence, the features of this phenomenon, and the effect on the body. Two points of view on the phenomenon of weightlessness - physical and medical - are complementary, since medicine is impossible without physics!

Literature

1) Great Soviet Encyclopedia (in 30 volumes). Ch. ed. . Ed.3. M., "Soviet Encyclopedia", 1974.

2) Kabardin: Reference materials: Textbook for students. - 3rd ed. - M .: Education, 1991. - 367 p.

3), In orbit - a spaceship. - M .: Pedagogy, 1980

4) Makovetsky to the root! Collection of curious problems and questions. - M.: Nauka, 1979

5) Chandaeva and man. -M.: JSC "Aspect Press", 1994

6) Belyu L., Stulinger E. Orbital station "Skylab". USA, 1973. (Abridged translation from English). Ed. Doctor of Physics and Mathematics Sciences. M., "Engineering", 1977 - Access mode: http://epizodsspace. *****/bibl/skylab/obl. html

7) Dyubankova O. Space medicine does not reach the Earth *****/online/health/511/03_01

8) Ivanov I. Vibration of a liquid accelerates its boiling in weightlessness. Website: Elements. Science news. Access mode - http://*****/news/164820?page

9) Klushantsev P. House in orbit: Stories about orbital stations. - L .: Det. lit., 1975. - P.25-28. Per. in email view. Yu. Zubakin, 2007- Access mode: (http://www. *****, http://epizodsspace. *****/bibl/Klusantsev/dom-na-orb75/Klushantsev_04. htm)

10) People can be operated on in space. French doctors performed the first surgical operation in zero gravity. Website of the Russian newspaper. RIA News. – Access mode: http://www. *****/2006/09/28/nevesomost-anons. html

11) Flame in weightlessness. Moshkov Library. – Access mode: http://*****/tp/nr/pn. htm

12) Scientists have determined why weightlessness is dangerous. Newspaper-24. – Access mode: RIA Novosti http://24.ua/news/show/id/66415.htm

APPENDIX

Attachment 1

https://pandia.ru/text/78/040/images/image038_0.jpg" width="265" height="188 src=">

Rice. 2. Device for determining the mass of samples in weightlessness:
1 - elastic cover

https://pandia.ru/text/78/040/images/image040.jpg" width="426" height="327 src=">

Rice. 4. Operation with the LBNP spacecraft on board the Skylab station (figure)

https://pandia.ru/text/78/040/images/image042.jpg" width="185" height="201">

Rice. 6. Body weight measurement

https://pandia.ru/text/78/040/images/image044.jpg" width="242" height="455 src=">

Rice. 8. Studying sleep and reactions during sleep astronauts

Rice. 9. Study of the metabolic characteristics of an astronaut during experiments on a bicycle ergometer:
1 - bicycle ergometer; 2 - metabolic analyzer: 3 - mouthpiece; 4 - hose; 5 - probe for temperature measurement; 6 - electrodes