What causes atmospheric pressure. Atmospheric pressure and hypertension

Air, surrounding the earth, has a mass, and despite the fact that the mass of the atmosphere is about a million times less than the mass of the Earth (the total mass of the atmosphere is 5.2 * 10 21 g, and 1 m 3 of air earth's surface weighs 1.033 kg), this mass of air exerts pressure on all objects located on the earth's surface. The force exerted by air on the earth's surface is called atmospheric pressure.

A column of 15 tons of air presses on each of us. Such pressure can crush all living things. Why don't we feel it? This is explained by the fact that the pressure inside our body is equal to atmospheric pressure.

Thus, internal and external pressure are balanced.

Barometer

Atmospheric pressure is measured in millimeters of mercury (mmHg). To determine it, they use a special device - a barometer (from the Greek baros - gravity, weight and metreo - I measure). There are mercury and non-liquid barometers.

Liquid-free barometers are called aneroid barometers(from the Greek a - a negative particle, nerys - water, i.e. acting without the help of a liquid) (Fig. 1).

Rice. 1. Aneroid barometer: 1 - metal box; 2 - spring; 3 - transmission mechanism; 4 - arrow pointer; 5 - scale

normal atmospheric pressure

For normal Atmosphere pressure conventionally accepted air pressure at sea level at a latitude of 45 ° and at a temperature of 0 °C. In this case, the atmosphere presses on every 1 cm 2 of the earth's surface with a force of 1.033 kg, and the mass of this air is balanced by a mercury column 760 mm high.

The Torricelli Experience

The value of 760 mm was first obtained in 1644. Evangelista Torricelli(1608-1647) and Vincenzo Viviani(1622-1703) - students of the brilliant Italian scientist Galileo Galilei.

E. Torricelli soldered a long glass tube with divisions from one end, filled it with mercury and lowered it into a cup with mercury (this is how the first mercury barometer was invented, which was called the Torricelli tube). The level of mercury in the tube dropped as some of the mercury spilled into the cup and settled at 760 millimeters. A void formed above the column of mercury, which was called Torricelli's void(Fig. 2).

E. Torricelli believed that the pressure of the atmosphere on the surface of the mercury in the cup is balanced by the weight of the mercury column in the tube. The height of this column above sea level is 760 mm Hg. Art.

Rice. 2. Torricelli experience

1 Pa = 10 -5 bar; 1 bar = 0.98 atm.

High and low atmospheric pressure

Air pressure on our planet can vary widely. If the air pressure is greater than 760 mm Hg. Art., then it is considered increased less - lowered.

Since the air becomes more and more rarefied with ascent, atmospheric pressure decreases (in the troposphere, on average, 1 mm for every 10.5 m of ascent). Therefore, for territories located at different heights above sea level, the average value of atmospheric pressure will be different. For example, Moscow lies at an altitude of 120 m above sea level, so the average atmospheric pressure for it is 748 mm Hg. Art.

Atmospheric pressure rises twice during the day (morning and evening) and falls twice (after noon and after midnight). These changes are associated with the change and movement of air. During the year on the continents, the maximum pressure is observed in winter, when the air is supercooled and compacted, and the minimum pressure is observed in summer.

The distribution of atmospheric pressure over the earth's surface has a pronounced zonal character. This is due to uneven heating of the earth's surface, and consequently, a change in pressure.

On the globe three belts are distinguished with a predominance of low atmospheric pressure (minimums) and four belts with a predominance of high pressure (maximums).

In the equatorial latitudes, the surface of the Earth warms up strongly. The heated air expands, becomes lighter and therefore rises. As a result, low atmospheric pressure is established near the earth's surface near the equator.

At the poles, under the influence of low temperatures, the air becomes heavier and sinks. Therefore, at the poles, atmospheric pressure is increased by 60-65 ° compared to latitudes.

In the high layers of the atmosphere, on the contrary, over hot areas the pressure is high (although lower than at the Earth's surface), and over cold areas it is low.

General scheme distribution of atmospheric pressure is as follows (Fig. 3): along the equator there is a belt low pressure; at 30-40 ° latitude of both hemispheres - high pressure belts; 60-70 ° latitude - low pressure zones; in the polar regions - areas of high pressure.

As a result of the fact that in the temperate latitudes of the Northern Hemisphere in winter the atmospheric pressure over the continents greatly increases, the low pressure belt is interrupted. It persists only over the oceans in the form of closed areas of low pressure - the Icelandic and Aleutian lows. Over the continents, on the contrary, winter maxima are formed: Asian and North American.

Rice. 3. General scheme of distribution of atmospheric pressure

In summer, in the temperate latitudes of the Northern Hemisphere, the low atmospheric pressure belt is restored. A huge area of low atmospheric pressure centered in tropical latitudes - the Asian Low - is forming over Asia.

In tropical latitudes, the continents are always hotter than the oceans, and the pressure over them is lower. Thus, over the oceans throughout the year there are maxima: North Atlantic (Azores), North Pacific, South Atlantic, South Pacific and South Indian.

The lines that climate map connecting points of equal atmospheric pressure are called isobars(from the Greek isos - equal and baros - heaviness, weight).

The closer the isobars are to each other, the faster atmospheric pressure changes over distance. The amount of change in atmospheric pressure per unit distance (100 km) is called pressure gradient.

The formation of atmospheric pressure belts near the earth's surface is influenced by the uneven distribution solar heat and the rotation of the earth. Depending on the season, both hemispheres of the Earth are heated by the Sun in different ways. This causes some movement of atmospheric pressure belts: in summer - to the north, in winter - to the south.

The number of weather-sensitive people is growing all the time. The height of the mercury column now predicts how the day will go, what mood and well-being a person will have. But initially it was believed that atmospheric pressure affects only the weather. Let's figure out what low and high atmospheric pressure is, and whether it can really affect our lives so much.

What is atmospheric pressure

If you take general definition, then this is a value that shows the force with which a column of air presses, starting from the upper boundary of the atmospheric layer, onto the earth or water surface.

Above 762 mm Hg is high atmospheric pressure, and below 758 mm, respectively, the maximum pressure at sea level is recorded - 808.7 mm and the minimum - 684 mm.

What does atmospheric pressure depend on?

First of all, the pressure changes due to uneven heating of the air above. Features of landscape zones, the rotation of the Earth, the difference in heat capacity and reflective abilities of the water and earth surfaces - all this affects in this case. As a result, cyclones and anticyclones are formed, which shape the weather.

Cyclones are relatively fast moving eddies with reduced atmospheric pressure. In summer they bring rain and coolness, in winter - snow and thaw, but at the same time always - strong winds and cloudy weather.

Anticyclones are slow moving areas characterized by high atmospheric pressure. In summer they create hot windless weather, and in winter - frosty and clear.

On a global scale, atmospheric pressure changes uniformly from the equator to the poles. The areas of the lowest pressure are the region of the equator and 60-65 degrees south and northern latitude. And the highest - 30-35 degrees of latitude and both poles. In addition, over cold continents every winter there is a stable high atmospheric pressure.

Atmospheric pressure also varies with the time of day. Its peaks are at 9-10 o'clock and 21-22 o'clock, and the recessions occur at 3-4 o'clock in the morning and 15-16 o'clock.

They may have chest pains, jumps in blood pressure, exacerbation of angina, migraine, tachycardia.

What will help with high atmospheric pressure

If weather forecasters predict the onset of an anticyclone and an increase in pressure, then weather-sensitive people should prepare in advance - try to reduce physical activity and consult a doctor to prescribe special medications.

High atmospheric pressure very often entails or prolonged heat. And air temperature affects health several times stronger than pressure. So it's better to take care of yourself and try not to go out once again to the street, while the apartment should have a comfortable temperature.

In any case, there is no need to panic, so as not to get the effect of self-hypnosis. An interesting fact is that people using elevators are exposed to changes in atmospheric pressure several times a day, but their health does not suffer from this simply because the elevator is a common occurrence. Take care of yourself!

Pressure (atmospheric) is a physical quantity expressing the force with which they press air masses the earth and everything on it. For each region, the indicators of the mercury column are different, since they are influenced by altitude, air humidity and temperature of air masses.

The human body adapts to the pressure values in the living climatic zone. If there is a change in the indicator up or down (moving to another region, changing weather, traveling to the mountains), then deviations from the norm can cause a disturbance in well-being.

The earth is surrounded by an atmosphere, which consists of several layers and performs protective functions.(protects from harmful radiation, maintains the desired composition in the air, and also keeps all living and non-living substances on the planet by applying pressure).

To determine the value of atmospheric pressure, several units are used (mm Hg, Pascals, millibars). The essence of these indicators is to display the magnitude of the pressure exerted by the atmosphere on a certain area of the surface. A person does not feel atmospheric pressure (at normal levels), since it is balanced by the fluid inside the body.

Atmospheric pressure standards in different regions of Russia

Mercury column pressure (the norm depends on climate zone) varies from region where the indicator is measured. A person adapts to the value where he lives. Therefore, when you change your place of residence with other climatic conditions, there is often a deterioration in well-being.

Atmospheric pressure indicators in mm Hg. Art. in large regions of Russia:

Region names	Average indicators for the year	Maximum deviations
Izhevsk	747	753
Leningradsky	755	762
Moscow	748	755
Permian	745	751
Seaside	755	766
Rostov	741	748
Samara	753	760
Sverdlovsk	738	755
Tula	747	755
Tyumen	771	775
Chelyabinsk	741	756
Yaroslavsky	736	758

Depending on the season of the year, the pressure indicator may change up or down.

Variability of air pressure depending on the height of the relief and other conditions

When measuring the pressure indicator, the influence of the main factors should be taken into account:

height above sea level. When you are at the same point according to geographical parameters, but at different heights, the pressure value will change in the following directions - when rising above sea level, the pressure will decrease, and when lowered, it will increase;
temperature indicator. When the temperature is above 0 degrees, atmospheric pressure will decrease. At temperatures below 0 degrees, atmospheric pressure will increase;
humidity level. The increased liquid content in the air causes an increase in pressure. In dry weather, the pressure indicator drops.

The article provides the norm of the pressure of the mercury column.

Therefore, in the summer at night (when the temperature drops and humidity increases), the pressure indicator increases. The main reason for the change in indicators is the change in air density from the influence of these parameters.

Normal human air column pressure in mmHg and pascals

The pressure of the mercury column (the norm is measured at sea level in Paris at an air temperature of 15 degrees) in 760 mmHg Art. or 101.3 kPa is the standard of a normal indicator. But given value is conditional when comparing its impact on the human condition. Since the body adapts to the indicator that prevails during the year in the region of human residence.

The effect of changes in atmospheric pressure on people

The human body adapts to the pressure indicator that prevails in a given climatic zone. As a result, systems and organs function in a normal rhythm.

But when the value changes, a restructuring occurs in the body, which is accompanied by the following deviations:

headaches in the temples, dizziness and fainting;
rapid decline in strength;
increased irritability due to headaches and fatigue;
depression or anxiety for no reason;
deterioration in breathing (lack of air);
violation of the rhythm of heart contractions and pain in the region of the heart;
decrease / increase in blood pressure;
deterioration of vision and “flies” before the eyes due to increased intraocular pressure;
violation of blood circulation, accompanied by numbness of the limbs;
pain in the joints. Caused by impaired blood supply;
nausea and loss of appetite;
noise and buzzing in the ears;
violation of the activity of the digestive tract;
deterioration in attention;
drowsiness.

Deterioration of well-being is noted with changes in atmospheric pressure from 5 units.

Daily fluctuations of 1-2 divisions do not affect the functioning of the body. Changes develop as a result of a violation of the movement of fluid in the body, which leads to a malfunction of all systems and a slowdown in metabolism. If these deviations in the body occur in a person even with small changes in the pressure indicator and regularly, then meteorological dependence is diagnosed.

At-risk groups

Pressure (atmospheric) can cause a disturbance even in healthy people if the mercury column rises or falls by more than 3 bars within 1-3 hours. After the return of atmospheric pressure to normal, the state of health stabilizes.

The diagnosis of meteorological dependence is diagnosed more often in the following groups of people:

men and women of advanced age. Their body can no longer quickly adapt to changes in atmospheric pressure;
women during childbearing. During this period, the forces of the body are aimed at maintaining pregnancy and developing the fetus. As a result, pregnant women feel even small pressure drops;
children up to 3-5 years old. Their body is just learning to respond to weather changes;
teenagers during the restructuring of hormones. During this period, the body is sensitive not only to pressure fluctuations, the psycho-emotional balance is disturbed and the immune system is weakened;
climax period. The body again undergoes hormonal changes and is sensitive to any changes inside and out;
people with kidney disease. This disease causes a violation of the water composition in the body, which causes increased sensitivity to pressure fluctuations;
allergies and asthmatics. Meteorological dependence is caused by a decrease in immunity;
patients with diseases of the cardiovascular system and suffering from changes in blood pressure;
people with chronic pathologies of the musculoskeletal system;
patients with psychological disorders;
people with chronic ENT diseases.

People living in large cities with poor environmental conditions are more susceptible to pressure drops than residents of rural areas.

Symptoms of disorders of well-being

The pressure of the mercury column (the norm for each person is individual) can be increased or decreased, which causes different symptoms in weather-dependent people.

Description of signs depending on the change in the pressure indicator:

With an anticyclone. weather phenomenon characterized by a change from normal atmospheric pressure to elevated pressure.	During a cyclone, the atmospheric pressure changes from normal to low.
Pain in the region of the heart	There is a lack of oxygen, accompanied by shortness of breath and the release of red blood cells (the phenomenon is dangerous for the formation of blood clots)
Increased heart rate	The number of heartbeats increases, but the force of impact decreases
strong headache with a feeling of pulse in the temples, dizziness	Headaches may be unbearable
Increased fatigue and general malaise	Rapid fatigue and general weakness (feeling of "cotton legs")
A rush of blood to the face, which causes a feeling of heat and redness	Deterioration in the quality of vision
An increase in blood pressure, may be accompanied by nosebleeds	Sensation of noise and buzzing in the ears
Decrease in the number of leukocytes in the blood, which is dangerous for colds and other infectious diseases or exacerbation of chronic pathologies	Exacerbation of joint diseases and numbness of the extremities
Increase in perspiration	Lowering blood pressure
Feeling ringing in the ears	Increased intracranial pressure
Loss of sharpness of vision	Violation of the activity of the digestive tract, accompanied by flatulence
Bowel dysfunction (constipation)	The appearance of swelling of the limbs

With a change in pressure in any direction, an exacerbation of chronic pathologies occurs.

health hazard

A change in atmospheric pressure is dangerous for weather-sensitive people, as well as a sharp change in it (quick diving to depth, climbing mountains or a sharp increase / decrease in pressure) for ordinary people.

Possible complications from fluctuations in atmospheric pressure:

violation of psychological balance in an irreversible direction (schizophrenia, depression, psychosis);
development of a stroke due to increased intracranial pressure;
the development of a heart attack in people with heart pathologies;
irreversible mental impairment due to lack of oxygen;
the development of asthma due to impaired oxygen metabolism and bronchial activity;
the formation of blood clots with subsequent blockage of blood vessels;
as a result of a decrease in immunity, infection with a dangerous infection with the development of subsequent complications;
deterioration of the condition of blood vessels with the likelihood of developing varicose veins or their rupture;
irreversible changes in the quality of vision and hearing. Perhaps to complete blindness and deafness.

Fainting is also dangerous, since the result of a fall from loss of consciousness can be fatal.

How to protect yourself from pressure drops for weather dependent people?

Hg pressure ( normal rate can sharply change to increased or decreased during the day several times) cannot be corrected, therefore people who depend on weather conditions are advised to adhere to the following rules:

be examined by a specialist. Examination by a doctor will reveal additional causes of the body's sensitivity to changes in atmospheric pressure (hidden chronic pathologies, hormonal imbalance, or a general weakening of the immune system);
undergo treatment. Timely stop the exacerbation of chronic diseases under the supervision of a specialist;
weather forecast tracking or purchase a home barometer. This method will allow you to prepare in advance for the approaching atmospheric pressure drops and take preventive measures;
provide a good night's rest. Night sleep should be at least 8 hours. It is also recommended to get up no later than 7 am and go to bed before 10 am. Good sleep will allow the body to fully recover and it is easier to endure a decrease / increase in pressure;
follow a nutritious diet. Food should be varied and contain enough vitamins and minerals. Good nutrition will strengthen the immune system and respond less to fluctuations in atmospheric pressure. Also, heavy and junk food should be excluded from the menu, do not overeat before going to bed and avoid long breaks between meals. This will avoid the development of pathologies in the digestive tract or exacerbation of chronic diseases that contribute to a decrease in immunity;
realize daily walks outdoors (any weather). Fresh air normalizes metabolic processes in the body, increases the amount of oxygen in the blood and strengthens the immune system;
perform daily physical activity. In the presence of diseases that limit physical activity, a set of exercises is compiled in the exercise therapy room under the supervision of a specialist. Classes allow you to normalize the activity of the cardiovascular system, activate blood circulation and the functioning of the joints. As a result, the symptoms from fluctuations in atmospheric pressure will be less pronounced;
adjust the schedule. If possible, then for the period of the cyclone or anticyclone, postpone physical and mental work and devote more time to rest;
take a contrast shower in the morning. The procedure allows you to normalize the state of blood vessels, activates metabolic processes and strengthens the immune system;
use vitamin complexes and immunomodulators. These drugs allow you to further activate the body's defenses. The funds are especially recommended for busy people who do not have the opportunity to take daily walks, physical activity and other methods to strengthen immunity;
to refuse from bad habits. Nicotine and alcohol have a negative state on the vessels, organs of the gastrointestinal tract and exacerbate the deterioration during the period of atmospheric pressure drops;
taking medication. In the presence of chronic diseases, prepare the necessary medicines (ointments for joint pain, pills for headaches or means to lower / increase pressure). The type of drugs depends on the type of disease, and are prescribed by a doctor;
take sedatives. During the period of pressure fluctuations, it is required to take sedative medications and drink soothing herbal decoctions. They are involved in the normalization of pressure, eliminate nervous strain and help relieve symptoms from pressure drops.

Additionally (after consulting a doctor), you can pre-purchase the following medicines, prescribed for an increase / decrease in atmospheric pressure.

With an anticyclone		When the cyclone
For headache relief	Paracetamol	Painkillers and tonics	caffetamin
	Analgin		Askofen
	ibuprofen		Citramon
To normalize the activity of nerve cells	Persen	To normalize pressure	Heptamine
	Sedariston		Apilak
	Novopassit		Dopamine
To normalize the activity of the joints	Voltaren gel	To normalize breathing	Ketoprofen
	Fastum gel		Intal
	Nurofen gel		Cromolyn

The normal indicator of pressure is 760 mm Hg. Art. But depending on climate zone value changes up or down. A person adapts to the indicator that prevails in the region of residence. Importantly, a sharp increase or decrease in the mercury column is the main cause of sudden drops in blood pressure.

Video about atmospheric pressure and its effect on humans

How weather affects a person:

A fragment of the program "Live healthy" about pressure and weather:

The Earth's atmosphere contains in its composition various gases, the main of which are oxygen and nitrogen. From the Earth, it rises to a height of up to 9000 km. Thus, the atmosphere is the protector of the planet. Oxygen and nitrogen give life to all life on Earth. Atmospheric pressure has a strong effect on our planet. Specialists claim, What on human account for pressure V 16 tons. However, due to the fact that inside a person the pressure is balanced with atmospheric pressure, he does not feel such global changes.

Atmospheric pressure measurement

According to generally accepted standards, it is customary to take millimeters of mercury as a unit for measuring pressure. In short - mm. rt. Art. To determine the use of an instrument called a barometer. Barometers are divided into mercury and non-liquid. The second - are called aneroid barometers. The barometer is represented by a glass tube, which is sealed on one side. Mercury is placed inside this tube. During the experiment, the open end of the tube is lowered into a vessel not completely filled with mercury. As the pressure rises or falls, the mercury in the tube begins to rise, and vice versa. The official unit for measurement is Pascal.

Important! The kilopascal or kPa is the SI unit of mechanical stress pressure. The megapascal or MPa is a metric unit of measure. If we translate these units, we get that 1 MPa is equal to 1000 KPa.

Atmospheric pressure norm

Atmospheric forcing is considered normal when the air pressure is at sea level at latitude 45°. The temperature indicator is 0 degrees Celsius. In 1644, thanks to Evangelista Torrencelli and Vincenzo Viviani, a value of 760 mm was obtained. It is worth noting that these discoverers were students of . A person feels most comfortable with standard values of 750-760 mm. rt. Art.However, these readings may not be completely accurate for all regions over a full year.

Increasing and decreasing pressure

Atmospheric impact increases when the air pressure exceeds the norm of 760 mm. rt. Art. Otherwise, it decreases.Within 24 hours in the morning and in the evening, the value of the pressure increases significantly.Low atmospheric exposure occurs in the afternoon and after midnight. These changes are due to the fact that there is a temperature drop and air movement. On Earth, there are 3 belts where low atmospheric pressure prevails, and 4 belts with high. Due to the fact that the heat from the Sun and the rotation of the Earth is uneven, belts of atmospheric pressure are formed on the globe. During the year, the Sun heats the hemispheres of the Earth differently. Heating varies depending on what time of the year in a particular period.

Important! Experts have identified a decline in atmospheric impact in Moscow, which is 727 mm. rt. Art. In 2015, there was an abnormal pressure in Moscow equal to 778 mm. rt. Art. Plus, Moscow is located on the border of a vast cyclone, the central region of which is located over Latvia.

Influence on a person. Anticyclone

An anticyclone is an increase in barometric pressure.During such periods, there is no significant wind on the street, sunny weather prevails, the temperature is not characterized by sudden changes. The humidity level remains normal. The anticyclone has a bad effect on human health. The change in pressure has an adverse effect, especially on people with allergies, asthmatics and those who have increased arterial pressure. A person has a headache during an anticyclone, and he is also tormented by heart pains. It is believed that during such periods performance decreases, malaise appears. Depending on the height of the anticyclone, there is an effective or ineffective protection of the body from diseases.

Important! In order to more easily endure the anticyclone, experts recommend alternately pouring hot and cold water in the shower, eat more fruits that contain potassium, do light gymnastics. To improve immune function and nervous system it is necessary for a certain time to forget about serious matters that can undermine health. On such days, a person suffering from negative symptoms should devote more time to rest to recuperate.

Cyclone

A cyclone is a period when the atmospheric effect decreases. The temperature rises during a cyclone, it becomes cloudy, humidity and precipitation increase, as well as during an anticyclone. During a cyclone, some groups of people cannot easily endure the change in weather and pressure. Cyclone is poorly tolerated by people who have problems with respiratory functions, low blood pressure, as well as those who have problems with the cardiovascular system. A cyclone reduces the amount of oxygenas a result of which it becomes difficult to breathe, shortness of breath appears. Patients complain of weakness. There is an increase in cerebral circulation, as a result of which a person is tormented by a migraine. No matter how many symptoms, experts advise drinking plenty of water, taking a contrast shower. It is also necessary that a person sleeps well. In the morning, your favorite cup of coffee will not interfere. Despite the fact that the current pressure is known - low or high, it is necessary to drink tincture of lemongrass and ginseng.

Atmospheric pressure in the mountains

A person who wants to conquer high mountains knows that the hike can be dangerous. For example,an altitude of 3000 meters causes a decrease in performance, and at 6000 meters a person can hardly survive. This is explained by the fact that the pressure is halved, a person lacks oxygen, it is difficult for him to survive. However, it all depends on what climatic conditions there is a climber. If we take the humid maritime climate of Kamchatka, then a person will feel uncomfortable there already at an altitude of 1000 meters. Dry continental climate in the Himalayas allows the climber in most cases not to feel difficulties when climbing up to 5000 meters. Different heights and their influence:

5000 meters- there is a lack of oxygen, due to which the climber may lose consciousness.
6000 meters- the highest height for permanent human settlements.
8882 meters- height . Here, a person adapted to such a height can live for several hours. At this altitude, the boiling point will be +68 degrees Celsius.
13,500 meters- at about this height, a climber is able to survive by inhaling pure oxygen. This height is the maximum for survival without external protection.
20,000 meters- at this altitude, a person dies almost immediately if he is outside the pressurized cabin.

For more immersion in the topic of atmospheric pressure, we recommend watching the video:

Attention! The site administration site is not responsible for the content methodological developments, as well as for compliance with the development of the Federal State Educational Standard.

Participant: Vertushkin Ivan Aleksandrovich
Head: Vinogradova Elena Anatolyevna

Topic: "Atmospheric pressure"

Introduction

It's raining outside today. After the rain, air temperature decreased, humidity increased and atmospheric pressure decreased. Atmospheric pressure is one of the main factors that determine the state of weather and climate, so knowledge of atmospheric pressure is essential in weather forecasting. big practical value has the ability to measure atmospheric pressure. And it can be measured with special barometers. In liquid barometers, as the weather changes, the liquid column rises or falls.

Knowledge of atmospheric pressure is necessary in medicine, in technological processes, in the life of a person and all living organisms. There is a direct relationship between atmospheric pressure changes and weather changes. An increase or decrease in atmospheric pressure can be a sign of weather changes and affect a person's well-being.

Description of three interrelated physical phenomena from Everyday life:

Relationship between weather and atmospheric pressure.
Phenomena underlying the operation of instruments for measuring atmospheric pressure.

The relevance of the work

The relevance of the chosen topic lies in the fact that at all times people, thanks to their observations of the behavior of animals, could predict weather changes, natural disasters, to avoid human casualties.

The influence of atmospheric pressure on our body is inevitable, sudden changes in atmospheric pressure affect the well-being of a person, especially weather-dependent people suffer. Of course, we cannot reduce the impact of atmospheric pressure on human health, but we can help our own body. Correctly organize your day, distribute time between work and rest can help the ability to measure atmospheric pressure, knowledge folk signs, the use of homemade appliances.

Goal of the work: find out what role atmospheric pressure plays in a person's daily life.

Tasks:

Learn the history of atmospheric pressure measurement.
Determine if there is a relationship between weather and atmospheric pressure.
To study the types of instruments designed to measure atmospheric pressure, made by man.
Explore physical phenomena, underlying the operation of instruments for measuring atmospheric pressure.
The dependence of liquid pressure on the height of the liquid column in liquid barometers.

Research methods

Literature analysis.
Generalization of the received information.
Observations.

Field of study: Atmosphere pressure

Hypothesis: atmospheric pressure is important for humans .

Significance of work: the material of this work can be used in the classroom and in extracurricular activities, in the lives of my classmates, students of our school, all lovers of nature studies.

Work plan

I. Theoretical part(collection of information):

Review and analysis of literature.
Internet resources.

II. Practical part:

observations;
collection of weather information.

III. Final part:

Conclusions.
Presentation of the work.

History of atmospheric pressure measurement

We live at the bottom of a vast ocean of air called the atmosphere. All changes that occur in the atmosphere will certainly affect a person, his health, ways of life, because. man is an integral part of nature. Each of the factors that determine the weather: atmospheric pressure, temperature, humidity, ozone and oxygen content in the air, radioactivity, magnetic storms etc. has a direct or indirect effect on the well-being and health of a person. Let's take a look at atmospheric pressure.

Atmosphere pressure- this is the pressure of the atmosphere on all objects in it and the Earth's surface.

In 1640, the Grand Duke of Tuscany decided to make a fountain on the terrace of his palace and ordered to bring water from a nearby lake using a suction pump. The invited Florentine craftsmen said this was not possible because the water had to be sucked up over 32 feet (over 10 meters). And why the water is not absorbed to such a height, they could not explain. The Duke asked the great Italian scientist Galileo Galilei to sort it out. Although the scientist was already old and sick and could not do experiments, he nevertheless suggested that the solution to the problem lies in determining the weight of air and its pressure on the water surface of the lake. Galileo's student Evangelista Torricelli took up the task of resolving this issue. To test the hypothesis of his teacher, he conducted his famous experiment. I filled a glass tube 1 m long, sealed at one end, completely with mercury, and tightly closing the open end of the tube, turned it over with this end into a cup with mercury. Some of the mercury spilled out of the tube, some remained. An airless space formed above the mercury. The atmosphere puts pressure on the mercury in the cup, the mercury in the tube also puts pressure on the mercury in the cup, since equilibrium has been established, these pressures are equal. To calculate the pressure of mercury in a tube means to calculate the pressure of the atmosphere. If atmospheric pressure rises or falls, then the column of mercury in the tube rises or falls accordingly. This is how the unit of measurement of atmospheric pressure appeared - mm. rt. Art. - millimeter of mercury. Watching the level of mercury in the tube, Torricelli noticed that the level changes, which means that it is not constant and depends on changes in the weather. If the pressure rises, the weather will be good: cold in winter, hot in summer. If the pressure drops sharply, it means that clouds are expected to appear and the air is saturated with moisture. The Torricelli tube with a ruler attached is the first instrument for measuring atmospheric pressure - a mercury barometer. (Annex 1)

Created barometers and other scientists: Robert Hooke, Robert Boyle, Emile Marriott. Water barometers were designed by the French scientist Blaise Pascal and the German burgomaster of the city of Magdeburg Otto von Guericke. The height of such a barometer was more than 10 meters.

Different units are used to measure pressure: mmHg, physical atmospheres, in the SI system - Pascals.

Relationship between weather and barometric pressure

In Jules Verne's novel The Fifteen-Year-Old Captain, the description of how to understand the readings of a barometer interested me.

“Captain Gul, a good meteorologist, taught him to read the barometer. We will briefly describe how to use this wonderful device.

When, after a long period of good weather, the barometer begins to fall sharply and continuously, it is a sure sign of rain. However, if good weather stood for a very long time, then the mercury column can fall for two or three days, and only after that there will be any noticeable changes in the atmosphere. In such cases, the more time passed between the beginning of the fall of the mercury column and the beginning of the rains, the longer it will stand rainy weather.

On the other hand, if during a long rainy period the barometer begins to rise slowly but steadily, good weather can be predicted with certainty. And the good weather will last the longer, the more time has passed between the beginning of the rise of the mercury column and the first clear day.

In both cases, the weather change that occurred immediately after the rise or fall of the mercury column is kept for a very short time.

If the barometer slowly but steadily rises for two or three days or longer, this portends good weather, even if all these days it rains without ceasing, and vice versa. But if the barometer rises slowly on rainy days, and immediately begins to fall when good weather sets in, the good weather will not last very long, and vice versa

In spring and autumn, a sharp drop in the barometer portends windy weather. In summer, in extreme heat, it predicts a thunderstorm. In winter, especially after prolonged frosts, a rapid drop in the mercury column indicates an upcoming change in wind direction, accompanied by a thaw and rain. On the contrary, an increase in the mercury column during prolonged frosts portends snowfall.

Frequent fluctuations in the level of the mercury column, either rising or falling, should by no means be considered as a sign of a long approach; period of dry or rainy weather. Only a gradual and slow fall or rise in the mercury column heralds the onset of a long period of stable weather.

When at the end of autumn, after a long period of winds and rains, the barometer begins to rise, this heralds the north wind in the onset of frost.

Here are the general conclusions that can be drawn from the readings of this valuable instrument. Dick Sand was very good at understanding the predictions of the barometer and was convinced many times how correct they were. Every day he consulted his barometer so as not to be taken by surprise by the change in the weather.

I made observations of weather changes and atmospheric pressure. And I was convinced that this dependence exists.

date	Temperature,°С	Precipitation,	Atmospheric pressure, mm Hg	Cloudiness

				Mainly cloudy

				Mainly cloudy
				Mainly cloudy
				Mainly cloudy
				Mainly cloudy




				Mainly cloudy

				Mainly cloudy

Atmospheric pressure instruments

For scientific and everyday purposes, you need to be able to measure atmospheric pressure. For this, there are special devices - barometers. Normal atmospheric pressure is the pressure at sea level at 15°C. It is equal to 760 mm Hg. Art. We know that with a change in altitude of 12 meters, atmospheric pressure changes by 1 mmHg. Art. Moreover, with an increase in altitude, atmospheric pressure decreases, and with a decrease, it increases.

The modern barometer is made liquid-free. It's called an aneroid barometer. Metal barometers are less accurate, but not as bulky and fragile.

is a very sensitive instrument. For example, going up to the last floor of a nine-story building, due to the difference in atmospheric pressure at different heights, we will find a decrease in atmospheric pressure by 2-3 mm Hg. Art.

A barometer can be used to determine the altitude of an aircraft. Such a barometer is called a barometric altimeter or altimeter. The idea of Pascal's experiment formed the basis for the design of the altimeter. It determines the height of the rise above sea level from changes in atmospheric pressure.

When observing the weather in meteorology, if it is necessary to register fluctuations in atmospheric pressure over a certain period of time, they use a recording device - barograph.

(Storm Glass) (stormglass, netherl. storm- "storm" and glass- “glass”) is a chemical or crystalline barometer, consisting of a glass flask or ampoule filled with an alcohol solution in which camphor, ammonia and potassium nitrate are dissolved in certain proportions.

This chemical barometer was actively used during his sea voyages by the English hydrographer and meteorologist, Vice Admiral Robert Fitzroy, who carefully described the behavior of the barometer, this description is still used. Therefore, stormglass is also called the "Fitzroy Barometer". In 1831–36, Fitzroy led an oceanographic expedition aboard the Beagle, which included Charles Darwin.

The barometer works as follows. The flask is hermetically sealed, but, nevertheless, the birth and disappearance of crystals constantly occurs in it. Depending on the upcoming weather changes, crystals form in the liquid various shapes. Stormglass is so sensitive that it can predict a sudden change in the weather 10 minutes in advance. The principle of operation has not received a complete scientific explanation. The barometer works better when near a window, especially in reinforced concrete houses, probably in this case the barometer is not so shielded.

Baroscope- a device for monitoring changes in atmospheric pressure. You can make a baroscope with your own hands. The following equipment is required to make a baroscope: 0.5 liter glass jar.

A piece of film from a balloon.
rubber ring.
Light arrow made of straw.
Arrow wire.
Vertical scale.
Instrument body.

Dependence of liquid pressure on the height of the liquid column in liquid barometers

When atmospheric pressure changes in liquid barometers, the height of the liquid column (water or mercury) changes: when the pressure decreases, it decreases, and when it increases, it increases. This means that there is a dependence of the height of the liquid column on atmospheric pressure. But the liquid itself presses on the bottom and walls of the vessel.

The French scientist B. Pascal in the middle of the 17th century empirically established a law called Pascal's law:

Pressure in a liquid or gas is transmitted equally in all directions and does not depend on the orientation of the area on which it acts.

To illustrate Pascal's law, the figure shows a small rectangular prism immersed in a liquid. If we assume that the density of the material of the prism is equal to the density of the liquid, then the prism must be in a state of indifferent equilibrium in the liquid. This means that the pressure forces acting on the edges of the prism must be balanced. This will happen only if the pressures, i.e., the forces acting per unit area of the surface of each face, are the same: p 1 = p 2 = p 3 = p.

The pressure of the liquid on the bottom or side walls of the vessel depends on the height of the liquid column. Force of pressure on the bottom of a cylindrical vessel of height h and base area S equal to the weight of the liquid column mg, Where m = ρ ghS is the mass of the liquid in the vessel, ρ is the density of the liquid. Hence p = ρ ghS / S

The same pressure at depth h in accordance with Pascal's law, the liquid also exerts on the side walls of the vessel. Liquid column pressure ρ gh called hydrostatic pressure.

In many devices that we encounter in life, the laws of liquid and gas pressure are used: communicating vessels, plumbing, hydraulic press, sluices, fountains, artesian wells, etc.

Conclusion

Atmospheric pressure is measured in order to be more likely to predict a possible change in the weather. There is a direct relationship between pressure changes and weather changes. An increase or decrease in atmospheric pressure can, with some probability, be a sign of a change in the weather. You need to know: if the pressure drops, then cloudy, rainy weather is expected, if it rises - dry weather, with a cold snap in winter. If the pressure drops very sharply, serious bad weather is possible: a storm, a severe thunderstorm or a storm.

Even in ancient times, doctors wrote about the effect of weather on the human body. In Tibetan medicine there is a mention: "pain in the joints increases in rainy time and during periods of high winds." The famous alchemist, physician Paracelsus noted: "He who has studied winds, lightning and weather knows the origin of diseases."

In order for a person to be comfortable, atmospheric pressure should be equal to 760 mm. rt. Art. If atmospheric pressure deviates, even by 10 mm, in one direction or another, a person feels uncomfortable and this may affect his state of health. Adverse phenomena are observed during changes in atmospheric pressure - increase (compression) and especially its decrease (decompression) to normal. The slower the change in pressure occurs, the better and without adverse consequences the human body adapts to it.

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