How to calculate atmospheric pressure at altitude. Atmospheric pressure at different altitudes

Dizziness;
Drowsiness;
Apathy, lethargy;
Joint pain;
Anxiety, fear;
Gastrointestinal dysfunction;

Low physical activity;
Presence of diseases;
Decline of immunity;
Deterioration of the central nervous system;
Weak blood vessels;
Age;
Ecological situation;
Climate.

Increased heart rate;
Weakness;
Tinnitus;
Facial redness;

Low atmospheric pressure

Dizziness;
Drowsiness;
Pain in the head;
Loss of strength.

Increased breathing;
Heart rate acceleration;
Pain in the head;
Attack of suffocation;
Nosebleeds.

Meteopathy

1. The concept of atmospheric pressure and its measurement. The air is very light, but it exerts significant pressure on the earth's surface. The weight of air creates atmospheric pressure.

Air exerts pressure on all objects. To verify this, do the following experiment. Pour a full glass of water and cover it with a piece of paper. Press the paper against the edges of the glass with your palm and quickly turn it over. Remove your palm from the leaf and you will see that the water does not pour out of the glass because the air pressure presses the leaf to the edges of the glass and holds the water.

Atmospheric pressure - the force with which air presses on the earth's surface and on all objects located on it. For every square centimeter of the earth's surface, air exerts a pressure of 1.033 kilograms - i.e. 1.033 kg/cm2.

Barometers are used to measure atmospheric pressure. There are mercury barometers and metal ones. The latter is called an aneroid. In a mercury barometer (Fig. 17), a glass tube with mercury sealed at the top is lowered with its open end into a bowl of mercury; there is an airless space above the surface of the mercury in the tube. The change in atmospheric pressure on the surface of the mercury in the bowl causes the column of mercury to rise or fall. The amount of atmospheric pressure is determined by altitude mercury in the tube.

The main part of the aneroid barometer (Fig. 18) is a metal box, devoid of air and very sensitive to changes in atmospheric pressure. When the pressure decreases, the box expands, and when the pressure increases, it contracts. Changes in the box using a simple device are transmitted to the arrow, which shows the atmospheric pressure on the scale. The scale is divided according to the mercury barometer.

If we imagine a column of air from the surface of the Earth to upper layers atmosphere, then the weight of such an air column will be equal to weight a column of mercury 760 mm high. This pressure is called normal atmospheric pressure. This is the air pressure at parallel 45° at a temperature of 0°C at sea level. If the height of the column is more than 760 mm, then the pressure is increased, less - decreased. Atmospheric pressure is measured in millimeters of mercury (mmHg).

2. Change in atmospheric pressure. Atmospheric pressure changes continuously due to changes in air temperature and its movement. When air is heated, its volume increases, density and weight decrease. Because of this, atmospheric pressure decreases. The denser the air, the heavier it is, and the greater the atmospheric pressure. During the day it increases twice (morning and evening) and decreases twice (after noon and after midnight). Pressure increases where there is more air and decreases where air leaves. Main reason movement of air - its heating and cooling from earth's surface. These fluctuations are especially pronounced at low latitudes. (What atmospheric pressure will be observed over land and over water at night?) During the year, the highest pressure in winter months, and the smallest in summer. (Explain this pressure distribution.) These changes are most pronounced in middle and high latitudes and weakest in low latitudes.

Atmospheric pressure decreases with altitude. Why is this happening? The change in pressure is caused by a decrease in the height of the air column that presses on the earth's surface. In addition, as altitude increases, air density decreases and pressure drops. At an altitude of about 5 km, atmospheric pressure decreases by half compared to normal pressure at sea level, at an altitude of 15 km - 8 times less, 20 km - 18 times.

Near the earth's surface it decreases by approximately 10 mm of mercury per 100 m of rise (Fig. 19).

At an altitude of 3000 m, a person begins to feel unwell and signs of altitude sickness appear: shortness of breath, dizziness. Above 4000 m, nosebleeds may occur, as small blood vessels rupture, and loss of consciousness is possible. This happens because with altitude the air becomes rarefied, and both the amount of oxygen in it and the atmospheric pressure decrease. The human body is not adapted to such conditions.

On the earth's surface, pressure is distributed unevenly. The air gets very hot near the equator (Why?), and the atmospheric pressure is low throughout the year. In the polar regions, the air is cold and dense, and the atmospheric pressure is high. (Why?)

? Test yourself

PracticallyAnde tasks

*At the foot of the mountain the air pressure is 740 mmHg. Art., at the top 340 mm Hg. Art. Calculate the height of the mountain.

*Calculate the force with which air presses on a person’s palm if its area is approximately 100 cm2.

*Determine the atmospheric pressure at an altitude of 200 m, 400 m, 1000 m, if at sea level it is 760 mm Hg. Art.

This is interesting

The highest atmospheric pressure is about 816 mm. Hg - registered in Russia, in the Siberian city of Turukhansk. The lowest (at sea level) atmospheric pressure recorded in the Japan region during the passage of Hurricane Nancy - about 641 mm Hg.

Competition of experts

Surface human body on average is 1.5 m2. This means that the air exerts a pressure of 15 tons on each of us. Such pressure can crush all living things. Why don't we feel it?

If the weather changes, patients with hypertension also feel unwell. Let's consider how atmospheric pressure affects hypertensive and weather-sensitive people.

Weather dependent and healthy people

Healthy people do not feel any changes in the weather. People who are weather dependent experience the following symptoms:

Dizziness;
Drowsiness;
Apathy, lethargy;
Joint pain;
Anxiety, fear;
Gastrointestinal dysfunction;
Fluctuations in blood pressure.

Often, health worsens in the fall, when there is an exacerbation of colds and chronic diseases. In the absence of any pathologies, meteosensitivity manifests itself as malaise.

Unlike healthy people, weather-dependent people react not only to fluctuations in atmospheric pressure, but also to increased humidity, sudden cold or warming. The reasons for this are often:

Low physical activity;
Presence of diseases;
Decline of immunity;
Deterioration of the central nervous system;
Weak blood vessels;
Age;
Ecological situation;
Climate.

As a result, the body's ability to quickly adapt to changes deteriorates. weather conditions.

High barometric pressure and hypertension

If the atmospheric pressure is high (above 760 mm Hg), there is no wind and precipitation, they speak of the onset of an anticyclone. There are no sudden temperature changes during this period. The amount of harmful impurities in the air increases.

Anticyclone has a negative effect on hypertensive patients. An increase in atmospheric pressure leads to an increase in blood pressure. Performance decreases, pulsation and pain in the head, and heart pain appear. Other symptoms of the negative influence of the anticyclone:

Increased heart rate;
Weakness;
Tinnitus;
Facial redness;
Flashing "flies" before the eyes.

The number of white blood cells in the blood decreases, which increases the risk of developing infections.

Elderly people with chronic cardiovascular diseases are especially susceptible to the effects of the anticyclone.. With an increase in atmospheric pressure, the likelihood of a complication of hypertension - a crisis - increases, especially if the blood pressure rises to 220/120 mm Hg. Art. Other dangerous complications may develop (embolism, thrombosis, coma).

Low atmospheric pressure

Low atmospheric pressure also has a bad effect on patients with hypertension - a cyclone. It is characterized by cloudy weather, precipitation, and high humidity. Air pressure drops below 750 mm Hg. Art. The cyclone has the following effect on the body: breathing becomes more frequent, the pulse quickens, however, the force of the heart beat is reduced. Some people experience shortness of breath.

When air pressure is low, blood pressure also drops. Considering that hypertensive patients take medications to lower blood pressure, the cyclone has a bad effect on their well-being. The following symptoms appear:

Dizziness;
Drowsiness;
Pain in the head;
Loss of strength.

In some cases, there is a deterioration in the functioning of the gastrointestinal tract.

When atmospheric pressure increases, patients with hypertension and weather-sensitive people should avoid active physical activity. We need to rest more. A low-calorie diet containing increased amounts of fruit is recommended.

Even “advanced” hypertension can be cured at home, without surgery or hospitals. Just remember once a day...

If the anticyclone is accompanied by heat, it is also necessary to avoid physical activity. If possible, you should be in an air-conditioned room. A low-calorie diet will be relevant. Increase the amount of potassium-rich foods in your diet.

Read also: What are the complications of hypertension?

To normalize blood pressure at low atmospheric pressure, doctors recommend increasing the volume of fluid consumed. Drink water, infusions medicinal herbs. It is necessary to reduce physical activity and rest more.

Sound sleep helps a lot. In the morning, you can have a cup of caffeinated drink. During the day you need to measure your blood pressure several times.

Effect of pressure and temperature changes

Changes in air temperature can also cause many health problems for hypertensive patients. During the period of an anticyclone, combined with heat, the risk of cerebral hemorrhages and heart damage increases significantly.

Due to high temperature and high humidity the oxygen content in the air decreases. This weather has a particularly bad effect on older people.

The dependence of blood pressure on atmospheric pressure is not so strong when heat is combined with low humidity and normal or slightly increased air pressure.

However, in some cases, such weather conditions cause blood thickening. This increases the risk of blood clots and the development of heart attacks and strokes.

The well-being of hypertensive patients will worsen if the atmospheric pressure rises simultaneously with a sharp drop in temperature environment. With high humidity and strong wind, hypothermia (hypothermia) develops. Excitation of the sympathetic nervous system causes a decrease in heat transfer and an increase in heat production.

The reduction in heat transfer is caused by a decrease in body temperature due to vasospasm. The process helps to increase the body's thermal resistance. To protect the extremities and facial skin from hypothermia, the blood vessels located in these parts of the body narrow.

Change in atmospheric pressure with altitude

As you know, the higher you are from sea level, the lower the air density and the lower the atmospheric pressure. At an altitude of 5 km it decreases by about 2 r. The influence of air pressure on the blood pressure of a person located high above sea level (for example, in the mountains) is manifested by the following symptoms:

Increased breathing;
Heart rate acceleration;
Pain in the head;
Attack of suffocation;
Nosebleeds.

Read also: What are the dangers of high eye pressure?

At the core negative impact low blood pressure air there is oxygen starvation, when the body receives less oxygen. Subsequently, adaptation occurs, and health becomes normal.

A person who permanently lives in such an area does not feel the effects of low atmospheric pressure. You should know that in hypertensive patients, when rising to altitude (for example, during flights), blood pressure can change sharply, which threatens loss of consciousness.

Underground and water air pressure is increased. Its effect on blood pressure is directly proportional to the distance to which it must be descended.

The following symptoms appear: breathing becomes deep and rare, heart rate decreases, but only slightly. Slightly numb skin, mucous membranes become dry.

The body is hypertensive, like ordinary person, adapts better to changes in atmospheric pressure if they occur slowly.

Much more severe symptoms develop due to a sharp change: increase (compression) and decrease (decompression). Miners and divers work in conditions of high atmospheric pressure.

They go down and up underground (underwater) through sluices, where the pressure increases/decreases gradually. At increased atmospheric pressure, gases contained in the air dissolve in the blood. This process is called "saturation". During decompression, they leave the blood (desaturation).

If a person descends to a great depth underground or under water in violation of the sluice regime, the body will become oversaturated with nitrogen. Caisson disease will develop, in which gas bubbles penetrate into the vessels, causing multiple embolisms.

The first symptoms of the pathology of the disease are muscle and joint pain. In severe cases, the eardrums burst, dizziness occurs, and labyrinthine nystagmus develops. Caisson disease is sometimes fatal.

Meteopathy

Meteopathy is the body's negative reaction to weather changes. Symptoms range from mild malaise to severe myocardial dysfunction, which can cause irreversible tissue damage.

The intensity and duration of manifestations of meteoropathy depend on age, body composition, and the presence of chronic diseases. For some, the ailments continue for up to 7 days. According to medical statistics, 70% of people with chronic illnesses and 20% of healthy people have meteopathy.

The reaction to weather changes depends on the degree of sensitivity of the body. The first (initial) stage (or meteosensitivity) is characterized by a slight deterioration in well-being, which is not confirmed by clinical studies.

The second degree is called meteodependence, it is accompanied by changes in blood pressure and heart rate. Meteopathy is the most severe third degree.

With hypertension combined with weather dependence, the cause of deterioration in well-being can be not only fluctuations in atmospheric pressure, but also other environmental changes. Such patients need to pay attention to weather conditions and weather forecasts. This will allow you to take the measures recommended by your doctor in a timely manner.

The cardiovascular system can often fail Significant Impact Changing weather conditions affect people's health and well-being. Meteopaths can be not only sick people, but also healthy people. Let's look at the different types of dependence on weather conditions, who suffers, and at what atmospheric pressure the headache occurs. In addition, we will find out what measures will help prevent the deterioration of well-being due to weather dependence.

joint pain;
unreasonable anxiety;
decreased performance;
depression;
weakness of the body;
deterioration of the gastrointestinal tract;

Atmospheric pressure is the force with which an air column exerts an impact on 1 cm2 of surface. The normal level of atmospheric pressure is 760 mm Hg. Art. Even minimal deviations from this value in one direction can lead to a deterioration in well-being. The following symptoms may appear:

headache and dizziness;
joint pain;
unreasonable anxiety;
decreased performance;
depression;
weakness of the body;
deterioration of the gastrointestinal tract;
difficulty breathing, shortness of breath.

headache and dizziness;
joint pain;
unreasonable anxiety;
decreased performance;
depression;
weakness of the body;
deterioration of the gastrointestinal tract;
difficulty breathing, shortness of breath.

Changes in atmospheric pressure can be caused by a number of reasons. Let's look at them in more detail:

Cyclones, during which the atmospheric pressure decreases, there is an increase in air temperature, cloudiness, and maybe rain. Scientists have proven the influence of atmospheric pressure on human blood pressure. Particularly affected at this time are hypotensive patients, as well as those who have vascular pathologies and work disorders. respiratory system. They lack oxygen and become short of breath. A person with high intracranial pressure has a headache when the atmospheric pressure is low.
Anticyclones, when the weather is clear outside. In this case, the atmospheric pressure, on the contrary, increases. With anticyclone, allergy sufferers and asthmatics suffer. Hypertensive patients experience headaches at high atmospheric pressure.
High or low humidity causes the most inconvenience to allergy sufferers and people with respiratory problems.
Air temperature. The most comfortable indicator for a person is +16 ... +18 Co, since in this mode the air is most saturated with oxygen. When the temperature rises, people with heart and vascular diseases suffer.

The following degrees of dependence on atmospheric pressure are distinguished:

first (mild) – slight malaise, anxiety, irritability appears, and performance decreases;
second (medium) – changes occur in the body’s functioning: blood pressure changes, heart rate becomes erratic, and the content of leukocytes in the blood increases;
third (severe) – requires treatment and can lead to temporary disability.

The following degrees of dependence on atmospheric pressure are distinguished:

first (mild) – slight malaise, anxiety, irritability appears, and performance decreases;
second (medium) – changes occur in the body’s functioning: blood pressure changes, heart rate becomes erratic, and the content of leukocytes in the blood increases;
third (severe) – requires treatment and can lead to temporary disability.

Scientists distinguish the following types of weather dependence:

cerebral – the appearance of headaches, dizziness, tinnitus;
cardiac – the occurrence of painful sensations in the heart, disturbances in heart rhythm, increased breathing, sensations of lack of air;
mixed - combines the symptoms of the first two types;
asthenoneurotic – the appearance of weakness, irritability, depression, decreased performance;
uncertain – a feeling of general weakness of the body, pain in the joints, lethargy.

The more abruptly the weather changes, the stronger the human body’s reaction will be. Even healthy people get headaches when atmospheric pressure changes.

The human body most often reacts to changing weather conditions with the appearance of a headache. This is due to the fact that when atmospheric pressure decreases, the vessels expand. With an increase, on the contrary, a narrowing occurs. That is, you can clearly trace the influence of atmospheric pressure on a person’s blood pressure.

The human brain has special baroreceptors. Their function is to detect changes in blood pressure and prepare the body for changes in weather. In healthy people, this happens unnoticed, but with minor deviations from the norm, symptoms of weather dependence begin to appear.

Most people get headaches when their air pressure is too low or too high. What to do in this case? The best solution in the presence of weather dependence is healthy sleep, putting your lifestyle in order and maximizing the body’s ability to adapt. In particular, you need:

Quitting bad habits.
Minimizing tea and coffee consumption.
Hardening, contrast shower.
Formation of a normal daily routine and adherence to a good sleep schedule.
Reducing stress.
Moderate physical activity, breathing exercises.
Walking on fresh air(can be combined with physical therapy).
The use of adaptogens, such as ginseng, eleutherococcus, lemongrass tincture.
Taking courses of multivitamins.
Healthy and nutritious nutrition. It is advisable to consume more foods containing vitamin C, potassium, iron and calcium. Fish, vegetables and dairy products are recommended. Hypertensive patients should not consume salt.

Weather dependence can manifest itself with many symptoms. However, one of the most frequent manifestations the influence of weather on the body is a pain in the head. It can be observed both when atmospheric pressure increases and decreases. In these two cases, the impact is felt by different categories of people. When pressure increases, hypertensive people suffer more from headaches, and when pressure decreases, hypotensive people suffer more from headaches. For them, weather changes can lead to serious consequences, including heart attack and stroke.

Why do you get headaches at high atmospheric pressure? This is explained by the fact that the blood vessels dilate. Blood pressure increases, heart rate increases, and tinnitus appears.

If a person has a headache at high atmospheric pressure, you need to pay close attention to your condition. This is necessary, since there is a high risk of hypertensive crisis, stroke and heart attack, coma, thrombosis, embolism.

High atmospheric pressure, headache... What to do? When such a situation arises, it is necessary to limit physical activity, take a contrast shower, drink more fluids, cook low-calorie foods (eat more fruits and vegetables), and try not to go outside in the heat, but stay in a cool room.

Thus, it is observed negative influence high atmospheric pressure on the vessels of the head. In addition, the load on the heart and the entire cardiovascular system increases. Therefore, if it becomes known about an increase in atmospheric pressure, you need to prepare for this in advance by postponing all non-essential matters and providing the body with a rest from stress.

Why do headaches appear at low atmospheric pressure? This is explained by the fact that the blood vessels narrow. Blood pressure decreases and pulse weakens. Breathing becomes difficult. Intracranial pressure increases, which contributes to spasm and headache. Hypotonic people mostly suffer. This can lead to serious consequences. For a hypotensive person in this situation, the danger lies in the onset of a hypertensive crisis and coma.

Low atmospheric pressure, headaches... What to do? In this case, it is recommended to get enough sleep, consume more water, drink coffee or tea in the morning, and also take a contrast shower.

So, a decrease in atmospheric pressure for hypotensive people is fraught with headaches and can lead to disruptions in the functioning of body systems. Therefore, such people are advised to regularly harden themselves, give up bad habits, and normalize their lifestyle as much as possible.

Summarizing all of the above, we can draw the following conclusion: an increase or decrease in atmospheric pressure has a negative effect on the human body. In particular, the nervous system suffers, hormonal background and the circulatory system. Mainly hypertensive and hypotensive people, allergy sufferers, heart patients, diabetics, and asthmatics are susceptible to weather dependence. But sometimes healthy people also become meteoropaths. Moreover, women sense weather changes better than men. To the question about what atmospheric pressure a headache occurs at, we can answer that at any pressure other than ideal. Joints are also sensitive to weather changes.

Weather dependence cannot be treated; it is impossible to completely get rid of it. However, timely prevention of diseases and normalization of lifestyle will minimize the occurrence of painful reactions to any sudden changes in weather.

All bodies in the Universe tend to attract each other. Large and massive ones have more high strength attraction compared to small ones. This law is also inherent in our planet.

The Earth attracts to itself any objects that are located on it, including the gas shell surrounding it - the atmosphere. Although air is much lighter than the planet, it has heavy weight and presses on everything that is on the earth's surface. This creates atmospheric pressure.

Atmospheric pressure refers to the hydrostatic pressure of the gas shell on the Earth and objects located on it. On different heights and in different parts of the world it has different indicators, but at sea level the standard is considered to be 760 mm of mercury.

This means that a column of air weighing 1.033 kg exerts pressure on a square centimeter of any surface. Accordingly, on square meter there is a pressure of more than 10 tons.

People learned about the existence of atmospheric pressure only in the 17th century. In 1638, the Tuscan Duke decided to embellish his gardens in Florence beautiful fountains, but unexpectedly discovered that the water in the constructed structures did not rise above 10.3 meters.

Deciding to find out the reason for this phenomenon, he turned for help to the Italian mathematician Torricelli, who, through experiments and analysis, determined that air has weight.

Atmospheric pressure is one of the most important parameters of the gas shell of the Earth. Since it varies in different places, a special device is used to measure it - a barometer. An ordinary household appliance is a metal box with a corrugated base, in which there is no air at all.

When pressure increases, this box contracts, and when pressure decreases, on the contrary, it expands. Along with the movement of the barometer, a spring attached to it moves, which affects the needle on the scale.

On weather stations liquid barometers are used. In them, pressure is measured by the height of a mercury column enclosed in a glass tube.

Since atmospheric pressure is created by overlying layers of gas, it changes as altitude increases. It can be influenced by both air density and the height of the air column itself. In addition, pressure varies depending on the location on our planet, since different areas of the Earth are located at different altitudes above sea level.

From time to time, slowly moving areas of high or low pressure are created above the earth's surface. In the first case they are called anticyclones, in the second - cyclones. On average, sea level pressure readings range from 641 to 816 mmHg, although tornadoes can drop as low as 560 mmHg inside.

The distribution of atmospheric pressure across the Earth is uneven, which is associated, first of all, with the movement of air and its ability to create so-called baric vortices.

In the northern hemisphere, clockwise rotation of the air leads to the formation of downward air currents (anticyclones), which bring clear or partly cloudy weather to a specific area. complete absence rain and wind.

If the air rotates counterclockwise, then rising vortices are formed above the ground, characteristic of cyclones, with heavy precipitation, heavy winds, and thunderstorms. IN southern hemisphere Cyclones move clockwise, anticyclones move counterclockwise.

Each person is pressed by an air column weighing from 15 to 18 tons. In other situations, such a weight could crush all living things, but the pressure inside our body is equal to atmospheric pressure, so when normal indicators at 760 mm Hg we do not experience any discomfort.

If the atmospheric pressure is higher or lower than normal, some people (especially the elderly or sick) feel unwell, have headaches, and note an exacerbation of chronic diseases.

Most often, a person experiences unpleasant sensations at high altitudes (for example, in the mountains), since in such areas the air pressure is lower than at sea level.

The human body is very sensitive to changes in atmospheric pressure (especially during periods of its fluctuation). Low or high atmospheric pressure disrupts some individual functions body, which leads to poor health or even the need to take medications.

Pressure that reaches levels exceeding 755 mm Hg is considered elevated. This increase in atmospheric pressure primarily affects people prone to mental illness, as well as asthma. People with various heart pathologies also feel uncomfortable. This is especially evident at the moment when atmospheric pressure jumps occur quite sharply.

In people suffering from hypotension, when atmospheric pressure increases, blood pressure also increases. If a person is healthy, in such a situation in the atmosphere, only his upper systolic pressure increases, and if a person is hypertensive, his blood pressure decreases with an increase in atmospheric pressure.

At low atmospheric pressure, the partial pressure of oxygen decreases. In human arterial blood, the tension of this gas noticeably decreases, which stimulates special receptors in the carotid arteries. The impulse from them is transmitted to the brain, resulting in rapid breathing. Thanks to enhanced pulmonary ventilation, the human body is able to be fully supplied with oxygen at altitude (when climbing mountains).

The general performance of a person at low atmospheric pressure is reduced by the following two factors: increased activity of the respiratory muscles, which requires the provision of additional oxygen, and leaching carbon dioxide from the body. A large number of people with low atmospheric pressure experience problems with some physiological functions, which leads to oxygen starvation of tissues and manifests itself in the form of shortness of breath, nausea, nosebleeds, suffocation, pain and changes in the sense of smell or taste, as well as arrhythmic heart function.

How does atmospheric pressure affect blood pressure?

Headache.
Nosebleed.
Nausea, attacks of vomiting.
Joint and muscle pain.
Sleep disorders.
Psycho-emotional disorders.

As altitude changes, significant changes in temperature and pressure can be observed. The terrain can greatly influence the formation of a mountain climate.

It is customary to distinguish between mountain and alpine climates. The first is typical for altitudes less than 3000-4000 m, the second - for more high levels. It should be noted that climatic conditions on high, vast plateaus differ significantly from conditions on mountain slopes, in valleys or on individual peaks. Of course, they also differ from climatic conditions, characteristic of a free atmosphere over the plains. Humidity, atmospheric pressure, precipitation and temperature change quite strongly with altitude.

As altitude increases, air density and atmospheric pressure decrease, and the content of dust and water vapor in the air decreases, which significantly increases its transparency for solar radiation, its intensity increases significantly compared to the plains. As a result, the sky appears bluer and denser, and light levels increase. On average, atmospheric pressure decreases by 1 mmHg for every 12 meters of ascent, but specific indicators always depend on the terrain and temperature. The higher the temperature, the slower the pressure decreases as it rises. Untrained people begin to experience discomfort due to low pressure already at an altitude of 3000 m.

With altitude in the troposphere, the air temperature also drops. Moreover, it depends not only on the altitude of the area, but also on the exposure of the slopes - on the northern slopes, where the influx of radiation is not so large, the temperature is usually noticeably lower than on the southern ones. At significant altitudes (in high-mountain climates), firn fields and glaciers influence the temperature. Firn fields are areas of special granular perennial snow (or even a transitional stage between snow and ice) that form above the snow line in the mountains.

In internal areas mountain ranges in winter time Stagnation of cooled air may occur. This often leads to temperature inversions, i.e. temperature increases as altitude increases.

The amount of precipitation in the mountains increases with altitude up to a certain level. It depends on the exposure of the slopes. Largest quantity precipitation can be observed on those slopes that face the main winds, this amount further increases if the prevailing winds carry moisture-containing air masses. On leeward slopes, the increase in precipitation as you ascend is not as noticeable.

Most scientists agree that the optimal temperature for normal human well-being is from +18 to +21 degrees, when relative humidity air does not exceed 40-60%. When these parameters change, the body reacts by changing blood pressure, which is especially noticeable by people with hypertension or hypotension.

Weather fluctuations with a significant change in temperature conditions, when the differences are more than 8 degrees Celsius within one day, negatively affect people with unstable blood pressure.

With a significant increase

temperature vessels

They expand sharply so that blood circulates faster and cools the body. The heart begins to beat much faster. All this leads to a sharp change in blood pressure. U

hypertensive patients

if there is insufficient compensation for the disease, a sharp jump may occur, which will lead to a hypertensive crisis.

Hypotonic people feel dizzy when the air temperature rises, but at the same time

heartbeat

becomes much faster, which somewhat improves well-being, especially if hypotension occurs against the background of bradycardia.

A decrease in air temperature leads to constriction of blood vessels,

pressure

decreases somewhat, but against the background of this there may be a severe headache, since vasoconstriction can lead to spasm. With hypotension, blood pressure can drop to critical levels.

As the weather becomes stable, the autonomic nervous system adapts to temperature conditions, well-being stabilizes in persons who do not have serious health conditions.

Patients with chronic diseases in case of strong changes in air temperature and atmospheric pressure, you should especially carefully monitor your health, measure your blood pressure more often using

tonometer take

prescribed by a doctor

drugs

If in the background

the usual dose of pharmaceuticals, unstable blood pressure is still observed, you need to consult a doctor to review the tactics

or changes in doses of prescribed medications.

how the air temperature is changing in 2017

Temperature (t) and pressure (P) are two interrelated physical quantities. This relationship manifests itself in all three states of matter. Most natural phenomena depend on fluctuations in these quantities.

A very close relationship can be found between fluid temperature and atmospheric pressure. Inside any liquid there are many small air bubbles that have their own internal pressure. When heated, these bubbles evaporate saturated steam from the surrounding fluid. All this continues until the internal pressure becomes equal to the external (atmospheric) pressure. Then the bubbles cannot stand it and burst - a process called boiling occurs.

A similar process occurs in solids during melting or during the reverse process - crystallization. Solid consists of crystalline

Which can be destroyed when atoms move away from each other. The pressure, increasing, acts in the opposite direction - it presses the atoms towards each other. Accordingly, in order for the body to melt,

more is needed

energy and temperature rises.

The Clapeyron-Mendeleev equation describes the temperature dependence

from pressure

in gas. The formula looks like this: PV = nRT. P – gas pressure in the vessel. Since n and R are constant values, it becomes clear that pressure is directly proportional to temperature (at V=const). This means that the higher P, the higher t. This process is due to the fact that when heated, the intermolecular space increases, and the molecules begin to move quickly in a chaotic order, which means they hit each other more often.

vessel walls

Which contains gas. Temperature in the Clapeyron-Mendeleev equation is usually measured in degrees Kelvin.

There is a concept of standard temperature and pressure: temperature is -273° Kelvin (or 0 °C), and pressure is 760 mm

mercury

Please note

Ice has a high specific heat capacity, equal to 335 kJ/kg. Therefore, to melt it, you need to spend a lot of thermal energy. For comparison: the same amount of energy can heat water to 80 °C.

The decrease in air pressure with increasing altitude is known scientific fact substantiating large number phenomena associated with low pressure at high altitudes above sea level.

You will need

7th grade physics textbook, molecular physics textbook, barometer.

Read in a physics textbook

definition of the concept of pressure. Regardless of what type of pressure is considered, it is equal to the force acting on a unit area. Thus, than more strength, acting on a certain area, so more value pressure. If we're talking about about air pressure, the force in question is the gravity of air particles.

Note that each layer of air in the atmosphere makes its own contribution to the air pressure of the layers below. It turns out that with increasing altitude above sea level, the number of layers pressing on the lower part of the atmosphere increases. Thus, as the distance to the ground increases, the force of gravity acting on the air in the lower parts of the atmosphere increases. This leads to the fact that the layer of air located near the surface of the earth experiences the pressure of all the upper layers, and the layer located closer to the upper boundary of the atmosphere does not experience such pressure. Accordingly, the air in the lower layers of the atmosphere has a much higher pressure than the air in the upper layers.

Remember how the pressure of a liquid depends on the depth of immersion in the liquid. The law that describes this pattern is called Pascal's law. He states that the pressure of a liquid increases linearly with increasing depth of immersion in it. Thus, the tendency for pressure to decrease with increasing height is also observed in liquid if the height is measured from the bottom of the container.

Note that the physics of increasing pressure in a liquid with increasing depth is the same as in air. The lower the layers of liquid lie, the more they have to support the weight of the upper layers. Therefore, in the lower layers of the liquid the pressure is greater than in the upper ones. However, if in a liquid the pattern of pressure increase is linear, then in air this is not the case. This is justified by the fact that the liquid is not compressible. The compressibility of air leads to the fact that the dependence of pressure on the altitude above sea level becomes exponential.

Remember from the course of molecular kinetic theory ideal gas that a similar exponential dependence is inherent in the distribution of particle concentrations in the Earth’s gravitational field, which was identified by Boltzmann. The Boltzmann distribution, in fact, is directly related to the phenomenon of a decrease in air pressure, since this decrease leads to the fact that the concentration of particles decreases with height.

A person spends his life, as a rule, at an altitude of the Earth's surface, which is close to sea level. The body in such a situation experiences pressure surrounding atmosphere. The normal pressure value is considered to be 760 mmHg, also called “one atmosphere”. The pressure we experience externally is balanced by internal pressure. In this regard, the human body does not feel the heaviness of the atmosphere.

Atmospheric pressure can change throughout the day. Its performance also depends on the season. But, as a rule, such pressure surges occur within no more than twenty to thirty millimeters of mercury.

Such fluctuations are not noticeable to the body healthy person. But in persons suffering hypertension, rheumatism and other diseases, these changes can cause disturbances in the functioning of the body and a deterioration in overall well-being.

A person can feel low atmospheric pressure when he is on a mountain and takes off on an airplane. The main physiological factor of altitude is reduced atmospheric pressure and, as a result, reduced partial pressure of oxygen.

The body reacts to low atmospheric pressure, first of all, by increasing breathing. Oxygen at altitude is discharged. This causes excitation of the chemoreceptors of the carotid arteries, and it is transmitted to the medulla oblongata to the center, which is responsible for increasing breathing. Thanks to this process, the pulmonary ventilation of a person who experiences low atmospheric pressure increases within the required limits and the body receives a sufficient amount of oxygen.

An important physiological mechanism that is triggered by low atmospheric pressure is considered to be an increase in the activity of the organs responsible for hematopoiesis. This mechanism manifests itself in an increase in the amount of hemoglobin and red blood cells in the blood. In this mode, the body is able to transport more oxygen.

Boiling is the process of vaporization, that is, the transition of a substance from liquid state into a gaseous state. It differs from evaporation by a much greater speed and rapid flow. Any pure liquid boils at a certain temperature. However, depending on the external pressure and impurities, the temperature boiling may change significantly.

You will need

- flask;
- test liquid;
- cork or rubber stopper;
- laboratory thermometer;
- curved tube.

As a simple device for determining temperature

boiling

You can use a flask with a capacity of about 250–500 milliliters with a round bottom and a wide neck. Pour the test product into it

liquid

(preferably within 20-25%

from volume

vessel), plug the neck with a cork or rubber stopper with two holes. Insert into one of the holes

laboratory thermometer, in the other - a curved tube that plays the role of a safety

for vapor removal.

If you have to determine temperature boiling clean liquid - the tip of the thermometer should be close to it, but not touching it. If you need to measure temperature boiling solution - the tip should be in the liquid.

What heat source can be used to heat a flask with liquid? This could be a water or sand bath, an electric stove, or a gas burner. The choice depends on the properties of the liquid and its expected temperature boiling.

Immediately after the process begins

boiling

Write it down

temperature

Which is shown by the mercury column of the thermometer. Monitor the thermometer readings for at least 15 minutes, recording readings every few minutes at regular intervals. For example, measurements were taken immediately after the 1st, 3rd, 5th, 7th, 9th, 11th, 13th and 15th

experience. There were 8 of them in total. After

graduation

experience, calculate the arithmetic mean

temperature boiling

according to the formula: tcp = (t1 + t2 +…+t8)/8.

At the same time, it is necessary to take into account important point. In all physical, chemical, technical reference books

temperature indicators boiling liquids

given at normal atmospheric pressure (760 mmHg). It follows from this that simultaneously with measuring the temperature, it is necessary to measure

atmospheric

pressure and make the necessary adjustments to the calculations. Exactly the same amendments are given

in tables

temperatures

boiling

for a wide variety of liquids.

How will the boiling point of water change in 2017?

How temperature and atmospheric pressure change in the mountains

When your head starts to hurt before a thunderstorm, and every cell of your body feels the approach of rain, you begin to think that this is old age. In fact, this is how millions of people react to changing weather. globe.

This process is called weather dependence. The first factor that directly affects well-being is the close relationship between atmospheric and blood pressure.

Atmospheric pressure is a physical quantity. It is characterized by the action of force air masses per unit surface. Its magnitude is variable and depends on the altitude of the area above sea level, geographical latitude and is related to the weather. Normal atmospheric pressure is 760 mmHg. It is with this value that a person experiences the most comfortable state of health.

A deviation of the barometer needle by 10 mm in one direction or another is sensitive to humans. And pressure drops occur for several reasons.

In summer, when the air warms up, the pressure on the mainland drops to its minimum values. IN winter period, due to the heavy and cold air, the barometer needle reaches its maximum value.

In the morning and in the evenings, the pressure usually rises slightly, and in the afternoon and midnight it becomes lower.

Atmospheric pressure also has a pronounced zonal character. The globe is divided into areas with a predominance of high and low pressure. This happens because the Earth's surface warms up unevenly.

At the equator, where the land is very hot, warm air rises and areas of low pressure are formed. Closer to the poles, cold, heavy air descends to the ground and presses on the surface. Accordingly, a zone is formed here high pressure.

Let's remember the geography course for high school. As you gain altitude, the air becomes thinner and the pressure decreases. Every twelve meters of ascent reduces the barometer reading by 1 mmHg. But at high altitudes the patterns are different.

See the table for how air temperature and pressure change with altitude.

0	15	760
500	11.8	716
1000	8.5	674
2000	2	596
3000	-4.5	525
4000	-11	462
5000	-17.5	405

This means that if you climb Mount Belukha (4,506 m), from the foot to the top, the temperature will drop by 30°C and the pressure will drop by 330 mm Hg. This is why high-altitude hypoxia, oxygen starvation, or miner's disease occurs in the mountains!

A person is designed in such a way that over time he gets used to new conditions. Stable weather has established itself - all body systems work without failures, the dependence of blood pressure on atmospheric pressure is minimal, the condition is normalized. And during periods of change of cyclones and anticyclones, the body fails to quickly switch to a new mode of operation, health worsens, blood pressure may change, and blood pressure may jump.

Arterial, or blood pressure, is the pressure of blood on the walls of blood vessels - veins, arteries, capillaries. It is responsible for the uninterrupted movement of blood through all vessels of the body, and directly depends on the atmospheric one.

People with chronic heart disease and cardiovascular system(perhaps the most common disease is hypertension).

Also at risk are:

Patients with neurological disorders and nervous exhaustion;
Allergy sufferers and people with autoimmune diseases;
Patients with mental disorders, obsessive fears and anxiety;
People suffering from lesions of the articular apparatus.

A cyclone is an area with low atmospheric pressure. The thermometer drops to 738-742 mm. rt. Art. The amount of oxygen in the air decreases.

In addition, low atmospheric pressure is distinguished by the following symptoms:

Increased humidity and air temperature,
Cloudiness,
Precipitation in the form of rain or snow.

People with diseases of the respiratory system, cardiovascular system and hypotension suffer from such weather changes. Under the influence of a cyclone, they experience weakness, lack of oxygen, difficulty breathing, and shortness of breath.

Some weather-sensitive people experience increased intracranial pressure, headaches, and gastrointestinal disorders.

How does a cyclone affect people with low blood pressure? When atmospheric pressure decreases, blood pressure also becomes lower, the blood is less saturated with oxygen, resulting in headaches, weakness, a feeling of lack of air, and a desire to sleep. Oxygen starvation can lead to hypotensive crisis and coma.

We'll tell you what to do at low atmospheric pressure. Hypotonic patients need to monitor their blood pressure during a cyclone. It is believed that pressure from 130/90 mmHg, elevated for hypotensive patients, may be accompanied by symptoms of a hypertensive crisis.

Therefore, you need to drink more fluids and get enough sleep. In the morning you can drink a cup of strong coffee or 50 g of cognac. To prevent weather dependence, you need to harden the body, take vitamin complexes that strengthen the nervous system, tincture of ginseng or eleutherococcus.

When an anticyclone approaches, the barometer needles creep up to the level of 770-780 mm Hg. The weather changes: it becomes clear, sunny, and a light breeze blows. The amount of industrial pollutants harmful to health is increasing in the air.

High blood pressure is not dangerous for hypotensive patients.

But if it increases, then allergy sufferers, asthmatics, and hypertensives experience negative manifestations:

Headaches and heartaches,
Decreased performance,
Increased heart rate,
Redness of the face and skin,
Flickering of flies before the eyes,
Increased blood pressure.

Also, the number of leukocytes in the blood decreases, which means a person becomes vulnerable to disease. With blood pressure 220/120 mm Hg. there is a high risk of developing hypertensive crisis, thrombosis, embolism, coma.

To alleviate the condition, doctors advise patients with blood pressure above normal to perform gymnastics exercises, arrange contrasting water procedures, and eat vegetables and fruits containing potassium. These are: peaches, apricots, apples, Brussels sprouts and cauliflower, spinach.

You should also avoid strenuous physical activity and try to get more rest.. As the air temperature rises, drink more liquid: clean drinking water, tea, juices, fruit drinks.

Is it possible to reduce weather sensitivity?

It is possible to reduce weather dependence if you follow simple but effective recommendations from doctors.

The advice is banal, keep a daily routine. Go to bed early, sleep at least 9 hours. This is especially true on days when the weather changes.
Before bed drink a glass of mint or chamomile tea. It's calming.
Do a light warm-up in the morning, stretch, massage your feet.
After gymnastics take a contrast shower.
Be positive. Remember that a person cannot influence the increase or decrease in atmospheric pressure, but it is within our power to help the body cope with its fluctuations.

Resume: weather dependence is typical for patients with pathologies of the heart and blood vessels, as well as for older people suffering from a bunch of diseases. People with allergies, asthmatics, and hypertension are at risk. The most dangerous for weather-sensitive people are sudden changes in atmospheric pressure. Saves from discomfort hardening of the body and healthy image life.

ATMOSPHERIC PRESSURE

Since air has mass and weight, it exerts pressure on the surface in contact with it. It is calculated that a column of air with a height from sea level to the upper boundary of the atmosphere presses on a 1 cm area with the same force as a weight of 1 kg 33 g. Man and all other living organisms do not feel this pressure, since it is balanced by their internal air pressure. When climbing in the mountains, already at an altitude of 3000 m, a person begins to feel unwell: shortness of breath and dizziness appear. At an altitude of more than 4000 m, a nose may bleed, as blood vessels rupture, and sometimes a person even loses consciousness. All this happens because atmospheric pressure decreases with altitude, the air becomes rarefied, the amount of oxygen in it decreases, but a person’s internal pressure does not change. Therefore, in airplanes flying at high altitudes, the cabins are hermetically sealed, and they are artificially maintained at the same air pressure as at the surface of the Earth. Pressure is measured using a special device - a barometer - in mm of mercury.

It has been established that at sea level at parallel 45° with an air temperature of 0°C, atmospheric pressure is close to the pressure produced by a column of mercury 760 mm high. The air pressure under such conditions is called normal atmospheric pressure. If the pressure indicator is greater, then it is considered increased, if less, it is considered decreased. When climbing mountains, for every 10.5 m, the pressure decreases by approximately 1 mmHg. Knowing how pressure changes, you can use a barometer to calculate the altitude of a place.

Pressure changes not only with altitude. It depends on the air temperature and the influence of air masses. Cyclones lower atmospheric pressure, and anticyclones increase it.

First, let's remember the physics course high school, which explains why and how atmospheric pressure changes with altitude. The higher the area is above sea level, the lower the pressure there. It is very simple to explain: atmospheric pressure indicates the force with which a column of air presses on everything that is on the surface of the Earth. Naturally, the higher you rise, the lower the height of the air column, its mass and the pressure exerted will be.

In addition, at altitude the air is rarefied; it contains a much smaller number of gas molecules, which also immediately affects the mass. And we must not forget that with increasing altitude, the air is cleared of toxic impurities, exhaust gases and other “delights”, as a result of which its density decreases and atmospheric pressure indicators drop.

Studies have shown that the dependence of atmospheric pressure on altitude differs as follows: an increase of ten meters causes a decrease in the parameter by one unit. As long as the altitude of the area does not exceed five hundred meters above sea level, changes in the pressure of the air column are practically not felt, but if you rise five kilometers, the values will be half the optimal ones. The strength of the pressure exerted by the air also depends on the temperature, which decreases greatly when rising to a higher altitude.

For blood pressure levels and general condition In the human body, the value of not only atmospheric pressure, but also partial pressure, which depends on the concentration of oxygen in the air, is very important. In proportion to the decrease in air pressure, the partial pressure of oxygen also decreases, which leads to an insufficient supply of this essential element to the cells and tissues of the body and the development of hypoxia. This is explained by the fact that the diffusion of oxygen into the blood and its subsequent transportation to the internal organs occurs due to the difference in the partial pressure of the blood and pulmonary alveoli, and when rising to a high altitude, the difference in these readings becomes significantly smaller.

How does altitude affect a person's well-being?

Main negative factor The main effect on the human body at altitude is the lack of oxygen. It is as a result of hypoxia that acute disorders of the heart and blood vessels, increased blood pressure, digestive disorders and a number of other pathologies develop.

Hypertensive patients and people prone to pressure surges should not climb high into the mountains and it is advisable not to take long flights. They will also have to forget about professional mountaineering and mountain tourism.

The severity of the changes occurring in the body made it possible to distinguish several altitude zones:

Up to one and a half to two kilometers above sea level is a relatively safe zone in which there are no special changes in the functioning of the body and the state of vitality. important systems. Deterioration in well-being, decreased activity and endurance are observed very rarely.
From two to four kilometers - the body tries to cope with the oxygen deficiency on its own, thanks to increased breathing and taking deep breaths. Heavy physical work exercise, which requires the consumption of a large volume of oxygen, is difficult to perform, but light exercise is well tolerated for several hours.
From four to five and a half kilometers - the state of health noticeably worsens, performing physical work is difficult. Psycho-emotional disorders appear in the form of high spirits, euphoria, and inappropriate actions. When staying at such a height for a long time, headaches, a feeling of heaviness in the head, problems with concentration, and lethargy occur.
From five and a half to eight kilometers - it is impossible to do physical work, the condition worsens sharply, and the percentage of loss of consciousness is high.
Above eight kilometers - at this altitude a person is able to maintain consciousness for a maximum of several minutes, after which deep fainting and death follows.

For metabolic processes to occur in the body, oxygen is necessary, the deficiency of which at altitude leads to the development of altitude sickness. The main symptoms of the disorder are:

Headache.
Increased breathing, shortness of breath, lack of air.
Nosebleed.
Nausea, attacks of vomiting.
Joint and muscle pain.
Sleep disorders.
Psycho-emotional disorders.

At high altitudes, the body begins to experience a lack of oxygen, as a result of which the functioning of the heart and blood vessels is disrupted, arterial and intracranial pressure increases, and vital signs fail. internal organs. To successfully overcome hypoxia, you need to include nuts, bananas, chocolate, cereals, and fruit juices in your diet.

Effect of altitude on blood pressure levels

When rising to a high altitude, a decrease in atmospheric pressure and thin air cause an increase in heart rate and an increase in blood pressure. However, with a further increase in altitude, blood pressure levels begin to decrease. A decrease in the oxygen content in the air to critical values causes depression of cardiac activity and a noticeable decrease in pressure in the arteries, while in the venous vessels the levels increase. As a result, a person develops arrhythmia and cyanosis.

Not long ago, a group of Italian researchers decided for the first time to study in detail how altitude affects blood pressure levels. To conduct research, an expedition to Everest was organized, during which the participants’ pressure readings were determined every twenty minutes. During the hike, an increase in blood pressure during ascent was confirmed: the results showed that the systolic value increased by fifteen, and the diastolic value by ten units. It was noted that the maximum blood pressure values were determined at night. The effect of antihypertensive drugs at different altitudes was also studied. It turned out that the drug under study effectively helped at an altitude of up to three and a half kilometers, and when rising above five and a half it became absolutely useless.

Atmospheric pressure is the force of pressure of an air column per unit area. It is calculated in kilograms per 1 cm 2 of surface, but since previously it was measured only with mercury manometers, it is conventionally accepted to express this value in millimeters of mercury (mmHg). Normal atmospheric pressure is 760 mmHg. Art., or 1.033 kg/cm 2, which is considered to be one atmosphere (1 ata).

When performing certain types of work, it is sometimes necessary to work at high or low atmospheric pressure, and these deviations from the norm are sometimes within significant limits (from 0.15-0.2 ata to 5-6 ata or more).

The effect of low atmospheric pressure on the body

As you rise to altitude, atmospheric pressure decreases: the higher you are above sea level, the lower the atmospheric pressure. So, at an altitude of 1000 m above sea level it is equal to 734 mm Hg. Art., 2000 m - 569 mm, 3000 m -526 mm, and at an altitude of 15000 m - 90 mm Hg. Art.

With reduced atmospheric pressure, there is increased and deepening of breathing, increased heart rate (their strength is weaker), a slight drop in blood pressure, and changes in the blood are also observed in the form of an increase in the number of red blood cells.

The adverse effect of low atmospheric pressure on the body is based on oxygen starvation. It is due to the fact that with a decrease in atmospheric pressure, the partial pressure of oxygen also decreases, therefore, with the normal functioning of the respiratory and circulatory organs, less oxygen enters the body. As a result, the blood is not sufficiently saturated with oxygen and does not fully deliver it to organs and tissues, which leads to oxygen starvation (anoxemia). Such changes occur more severely when rapid decline atmospheric pressure, which happens during rapid takeoffs to high altitudes, when working on high-speed lifting mechanisms (cable cars, etc.). Rapidly developing oxygen starvation affects brain cells, which causes dizziness, nausea, sometimes vomiting, loss of coordination of movements, decreased memory, drowsiness; a reduction in oxidative processes in muscle cells due to lack of oxygen is expressed in muscle weakness and rapid fatigue.

Practice shows that climbing to an altitude of more than 4500 m, where the atmospheric pressure is below 430 mm Hg, is difficult to tolerate without oxygen supply for breathing, and at an altitude of 8000 m (pressure 277 mm Hg) a person loses consciousness.

Blood, like any other liquid, upon contact with a gaseous medium (in this case in the alveoli of the lungs) dissolves certain part gases - the higher their partial pressure, the greater the saturation of the blood with these gases. When atmospheric pressure decreases, partial pressure changes components air and, in particular, its main components - nitrogen (78%) and oxygen (21%); As a result, these gases begin to be released from the blood until the partial pressure equalizes. During a rapid decrease in atmospheric pressure, the release of gases, especially nitrogen, from the blood is so great that they do not have time to be removed through the respiratory system and accumulate in the blood vessels in the form of small bubbles. These gas bubbles can stretch tissue (even to the point of small tears), causing acute pain, and in some cases form gas clots in small vessels, impeding blood circulation.

The complex of physiological and pathological changes, arising as a result of a decrease in atmospheric pressure, is called altitude sickness, since these changes are usually associated with an increase in altitude.

Preventing altitude sickness

One of the widespread and effective measures to combat altitude sickness is the supply of oxygen for breathing when ascending to high altitudes (over 4500 m). Almost all modern aircraft flying at high altitudes, and especially spaceships, are equipped with sealed cabins, where, regardless of the altitude and atmospheric pressure outside, the pressure is maintained constant at a level that fully ensures the normal condition of the flight crew and passengers. This is one of the radical solutions to this issue.

When performing physical and intense mental work in conditions of low atmospheric pressure, it is necessary to take into account the relatively rapid onset of fatigue, therefore periodic breaks should be provided, and in some cases, a shortened working day.

To work in conditions of low atmospheric pressure, the physically strongest persons, absolutely healthy, mainly men aged 20 - 30 years, should be selected. When selecting flight personnel, mandatory testing is required for the so-called altitude qualification tests in special chambers with reduced pressure.

Training and hardening play an important role in the prevention of altitude sickness. It is necessary to play sports, systematically perform one or another physical work. The diet of those working at low atmospheric pressure should be high-calorie, varied and rich in vitamins and mineral salts.

Useful information:

You will need

mercury barometer or aneroid barometer. And if you need to continuously take pressure readings, you should use a barograph.

Instructions

Mercury usually shows atmospheric pressure in millimeters of mercury. Just look at the level in the flask on the scale - and that’s the atmospheric pressure in your room. As a rule, this value is 760±20 mmHg. If you need to know the pressure, then use a simple translation system: 1 mmHg. = 133.3 Pa. For example, 760 mmHg. = 133.3*760 Pa = 101308 Pa. This pressure is considered normal at sea level at 15°C.

Taking pressure readings from the barograph scale is also very simple. This device is based on the action of an aneroid box, which changes. If the pressure increases, the walls of this box bend inward; if the pressure decreases, the walls straighten. This whole system is connected to a pointer, and you just need to see what value the pointer shows on the instrument scale. Don't be alarmed if the scale is in units such as hPa - this is a hectopascal: 1 hPa = 100 Pa. And to convert to the more familiar mm.Hg. just use the equality from the previous paragraph.

And you can find the atmospheric pressure at a certain altitude even without using a device, if you know the pressure at sea level. All you need is some math skills. Use this formula: P=P0 * e^(-Mgh/RT). In this formula: P is the desired pressure at height h;
P0 is the pressure at sea level in ;
M is molar, equal to 0.029 kg/mol;
g – earth’s acceleration due to gravity, approximately equal to 9.81 m/s²;
R is the universal gas constant, taken as 8.31 J/mol K;
T – air temperature in Kelvin (to convert from °C to K, use the formula
T = t + 273, where t is temperature °C);
h is the altitude above sea level where we find the pressure, measured in meters.

Useful advice

As you can see, you don't even have to be in a specific place to measure atmospheric pressure. It can be easily calculated. Look at the last formula - the higher we rise above the ground, the lower the atmospheric pressure will be. And already at an altitude of 4000 meters, water will boil at a temperature not of 100°C, as we are used to, but at about 85°C, since the pressure there is not 100,500 Pa, but about 60,000 Pa. Therefore, the cooking process at this altitude becomes longer.

Sources:

how to find atmospheric pressure

Determined by availability own weight the air that makes up the Earth's atmosphere. This atmosphere presses on its surface and the objects on it. At the same time, an average-sized person is pressed by a load equivalent to 15 tons! But since the air inside the body presses with the same force, we do not feel this load.

You will need

Mercury barometer, aneroid barometer, ruler

Instructions

Atmospheric barometer. The simplest and most effective devices include mercury. It consists of a vessel filled with mercury and a 1 m long tube sealed on one side. Fill the tube with mercury and lower it into a vessel, in which some amount of this substance should also remain. After this it will drop somewhat. Carefully measure the height of the mercury column above the liquid level in . The pressure of this column of mercury will be equal to the pressure. The normal atmospheric pressure is 760 mmHg.

To convert pressure in mmHg to International Pascals, use the coefficient 133.3. Simply multiply the atmospheric pressure in mmHg by this.

Another way to measure atmospheric pressure is with an aneroid barometer. Inside it there is a metal box with corrugated walls to increase the area of contact of air with its surface. The air has been pumped out of it, so it contracts when atmospheric pressure increases and expands again when it decreases.

This metal box is, in fact, called an aneroid. A mechanism is attached to it that transmits its movement to a pointer with a scale, which is graduated in mm of mercury and kilopascals. It is used to determine the atmospheric pressure at each moment in time at a given point. It is a known fact that atmospheric pressure changes with the observer's altitude above sea level. For example, in a deep mine it increases, and in high mountain– decreases.

If the atmospheric pressure at sea level is known, it can be calculated. To do this, raise the exponent (2.72) to a power, to calculate which multiply the numbers 0.029 and 9.81, multiply the result by the height of the rise or fall of the body. Divide the resulting value by the number 8.31 and the air temperature in Kelvin. Place a minus sign in front of the exponent. Multiply the exponent raised to the resulting power by the pressure value at sea level P=P0 e^(-0.029 9.81 h/8.31 T).

Sources:

atmospheric pressure translation

Air pressure at the same point on the earth's surface does not remain constant, but varies depending on various processes occurring in the atmosphere. “Normal” atmospheric pressure is conventionally considered to be a pressure equal to 760 mmHg, i.e. one (physical) atmosphere (§154).

Air pressure at sea level in all parts of the globe is close to one atmosphere on average. As we rise up from sea level, we will notice that the air pressure decreases; its density decreases accordingly: the air becomes more and more rarefied. If you open a vessel at the top of a mountain that was tightly sealed in the valley, then some of the air will come out of it. On the contrary, a container sealed at the top will allow some air to enter if it is opened at the foot of the mountain. At an altitude of about 6 km, the pressure and density of air decrease by approximately half.

Each altitude corresponds to a certain air pressure; Therefore, by measuring (for example, using an aneroid) the pressure at a given point on the top of a mountain or in the basket of a balloon and knowing how atmospheric pressure changes with height, one can determine the height of the mountain or the height of the balloon. The sensitivity of a conventional aneroid is so great that the indicator needle moves noticeably if you raise the aneroid by 2-3 m. When going up or down the stairs with an aneroid in your hands, it is easy to notice a gradual change in pressure. It is convenient to carry out such an experiment on the escalator of a metro station. The aneroid is often calibrated directly to the height. Then the position of the arrow indicates the height at which the device is located. Such aneroids are called altimeters (Fig. 295). They are supplied to airplanes; they allow the pilot to determine his flight altitude.

Rice. 295. Aircraft altimeter. The long hand counts hundreds of meters, the short hand counts kilometers. The head allows you to bring the zero of the dial under the arrow on the surface of the Earth before starting the flight

The decrease in air pressure during ascent is explained in the same way as the decrease in pressure in the depths of the sea during ascent from the bottom to the surface. Air at sea level is compressed by the weight of the Earth's entire atmosphere, while higher layers of the atmosphere are compressed by the weight of only the air that lies above these layers. In general, the change in pressure from point to point in the atmosphere or in any other gas under the influence of gravity obeys the same laws as pressure in a liquid: the pressure is the same at all points of the horizontal plane; when moving from bottom to top, the pressure decreases by the weight of the air column, the height of which is equal to the height of the transition, and the cross-sectional area is equal to unity.

Rice. 296. Plotting a graph of pressure decreasing with height. The right side shows columns of air of the same thickness, taken at different heights. The columns are more densely shaded compressed air having high density

However, due to the high compressibility of gases, the overall picture of pressure distribution over height in the atmosphere turns out to be completely different than for liquids. In fact, let's plot the decrease in air pressure with height. We will plot altitudes, etc., above some level (for example, above sea level) along the ordinate axis, and pressure along the abscissa axis (Fig. 296). We will climb up the steps of the height. To find the pressure on the next step, you need to subtract from the pressure on the previous step the weight of the air column at height equal to . But as altitude increases, air density decreases. Therefore, the decrease in pressure that occurs when ascending to the next step will be less, the higher the step is located. Thus, as you rise upward, the pressure will decrease unevenly: at low altitude, where the air density is greater, the pressure decreases quickly; the higher it is, the lower the air density and the slower the pressure decreases.

In our reasoning, we assumed that the pressure in the entire layer of thickness is the same; Therefore, we got a stepped (dashed) line on the graph. But, of course, the decrease in density when ascending to some a certain height occurs not in spurts, but continuously; therefore, in reality the graph looks like a smooth line (solid line on the graph). Thus, in contrast to the linear pressure graph for liquids, the law of decreasing pressure in the atmosphere is depicted by a curved line.

For small air volumes (room, balloon) it is enough to use a small section of the graph; in this case, the curved section can be replaced without much error by a straight section, as for a liquid. In fact, with a small change in altitude, the air density changes insignificantly.

Rice. 297. Graphs of pressure changes with height for different gases

If there is a certain volume of any gas other than air, then the pressure in it also decreases from bottom to top. For each gas, you can construct a corresponding graph. It is clear that at the same pressure below, the pressure of heavy gases will decrease with height faster than the pressure of light gases, since a column of heavy gas weighs more than a column of light gas of the same height.

In Fig. 297 such graphs were constructed for several gases. The graphs are built for a small height interval, so they look like straight lines.

175. 1. An L-shaped tube, the long elbow of which is open, is filled with hydrogen (Fig. 298). Where will the rubber film covering the short elbow of the tube be bent?

Rice. 298. For exercise 175.1

Caused by the weight of air. 1 m³ of air weighs 1.033 kg. For every meter of the earth's surface there is an air pressure of 10033 kg. This refers to a column of air from sea level to the upper atmosphere. If we compare it with a column of water, the diameter of the latter would have a height of only 10 meters. That is, atmospheric pressure is created by its own air mass. The amount of atmospheric pressure per unit area corresponds to the mass of the air column located above it. As a result of an increase in air in this column, pressure increases, and as air decreases, a decrease occurs. Normal atmospheric pressure is considered to be air pressure at t 0°C at sea level at a latitude of 45°. In this case, the atmosphere presses with a force of 1.033 kg for every 1 cm² of earth's area. The mass of this air is balanced by a column of mercury 760 mm high. Atmospheric pressure is measured using this relationship. It is measured in millimeters of mercury or millibars (mb), as well as in hectopascals. 1mb = 0.75 mm Hg, 1 hPa = 1 mm.

Measuring atmospheric pressure.

measured using barometers. They come in two types.

1. A mercury barometer is a glass tube that is sealed at the top and the open end is immersed in a metal bowl with mercury. A scale indicating the change in pressure is attached next to the tube. The mercury is acted upon by air pressure, which balances the column of mercury in the glass tube with its weight. The height of the mercury column changes with pressure changes.

2. A metal barometer or aneroid is a corrugated metal box that is hermetically sealed. Inside this box there is rarefied air. The change in pressure causes the walls of the box to vibrate, pushing in or out. These vibrations by a system of levers cause the arrow to move along a graduated scale.

Recording barometers or barographs are designed to record changes atmospheric pressure. The pen picks up the vibration of the walls of the aneroid box and draws a line on the tape of the drum, which rotates around its axis.

What is the atmospheric pressure?

Atmospheric pressure on the globe varies widely. Its minimum value - 641.3 mm Hg or 854 mb was recorded over Pacific Ocean in Hurricane Nancy, and the maximum was 815.85 mm Hg. or 1087 MB in Turukhansk in winter.

Air pressure on the earth's surface changes with altitude. Average atmospheric pressure value above sea level - 1013 mb or 760 mm Hg. The higher the altitude, the lower the atmospheric pressure, as the air becomes increasingly rarefied. In the lower layer of the troposphere to a height of 10 m it decreases by 1 mmHg. for every 10 m or 1 mb for every 8 meters. At an altitude of 5 km it is 2 times less, at 15 km - 8 times, 20 km - 18 times.

Due to air movement, temperature changes, seasonal changes atmospheric pressure constantly changing. Twice a day, in the morning and in the evening, it increases and decreases the same number of times, after midnight and after noon. During the year, due to cold and compacted air, atmospheric pressure is at its maximum in winter and at its minimum in summer.

Constantly changing and distributed across the earth's surface zonally. This occurs due to uneven heating of the earth's surface by the Sun. The change in pressure is affected by the movement of air. Where there is more air, the pressure is high, and where the air leaves - low. The air, having warmed up from the surface, rises and the pressure on the surface decreases. At altitude, the air begins to cool, becomes denser and sinks to nearby cold areas. There the atmospheric pressure increases. Consequently, the change in pressure is caused by the movement of air as a result of its heating and cooling from the earth's surface.

Atmospheric pressure in equatorial zone constantly reduced, and in tropical latitudes - increased. This happens due to constant high temperatures air at the equator. The heated air rises and moves towards the tropics. In the Arctic and Antarctic, the surface of the earth is always cold and the atmospheric pressure is high. It is caused by air that comes from temperate latitudes. In turn, in temperate latitudes due to the outflow of air, a zone of low pressure is formed. Thus, there are two belts on Earth atmospheric pressure- low and high. Decreased at the equator and in two temperate latitudes. Raised on two tropical and two polar. They may shift slightly depending on the time of year following the Sun towards the summer hemisphere.

Polar high pressure belts exist all year round, however, in summer they contract and in winter, on the contrary, they expand. All year round, areas of low pressure persist near the Equator and in the southern hemisphere in temperate latitudes. In the northern hemisphere, things happen differently. In temperate latitudes northern hemisphere the pressure over the continents increases greatly and the low pressure field seems to “break”: it persists only over the oceans in the form of closed areas low atmospheric pressure- Icelandic and Aleutian minimums. Over the continents, where the pressure has noticeably increased, winter maximums form: Asian (Siberian) and North American (Canadian). In summer, the low pressure field in the temperate latitudes of the northern hemisphere is restored. At the same time, a vast area of low pressure is formed over Asia. This is the Asian low.

In the belt increased atmospheric pressure- in the tropics - the continents heat up more than the oceans and the pressure above them is lower. Because of this, subtropical highs are distinguished over the oceans: