High pressure in nature. What atmospheric pressure is considered normal for humans? Normal atmospheric pressure for regions of Russia in mm of mercury
Goals and objectives: to continue the formation of knowledge and ideas about the atmosphere; discuss new concepts and definitions with students; consider the types, magnitude, reasons for changes and methods of measuring At. D.; prove to students the existence of At. D.; show integration with biology - barometer plants; develop the ability to generalize, highlight the main thing, draw analogies, identify cause-and-effect relationships; to introduce geographical terms, to form a conscious discipline.
Lesson format:
conversation, demonstration of experience proving the existence of At. D (sheet of paper and glass of water). Solving practical problems in At. D.Lesson type:
explanation of new material.Equipment:
aneroid barometer, glass of water, sheet of paper, textbook, atlas for 6th grade.Terms and concepts:
At. D., normal pressure, mercury barometer, aneroid barometer. Evangelist Torricelli is explanatory, illustrative, reproductive, problematic.DURING THE CLASSES
1. Organizational moment.
2. New topic after practical work.
Every substance has its own weight and mass, and even air. Air exerts pressure on all objects it comes into contact with, for example, an experiment with a glass of water and a sheet of paper.
The mass of 1 m 3 of air above sea level is 1 kg 300 g
If we take a column of air from the earth's surface to the upper boundary of the atmosphere, it turns out that on 1 cm 2 of the surface, the air presses with the same force as a weight weighing 1 kg 33 g (1 m 2 = 10,000 cm 2 x 1.33 = 13 300 kg (13 t 300 kg)
Let's try to calculate the pressure exerted by the atmosphere on your palm.
Palm area is 60 cm 2 x 1.33 kg = 79.8 kg
Guys, why don’t we or other living organisms feel the pressure that puts pressure on us? (Because it is balanced by the internal pressure that exists inside the human body). Here we come to the definition - Atmospheric pressure is the force with which air presses on the earth's surface and all objects located on it ( write it down in your notebook).
Who measured and established what atmospheric pressure is?
In the 17th century The Italian scientist E. Torricelli proved that atmospheric pressure exists.
He conducted the following experiment: He took a tube 1 m high, sealed it at one end and poured in mercury (this is a liquid poisonous metal Hg), turned the tube over into a bowl of mercury and opened it, part of the mercury poured out, and some remained in the tube. If Atm. D. weakens, then the mercury will pour out a little more; if it increases, the column of mercury will rise.
What prevented the mercury from pouring out completely? (Air pressure puts pressure on the mercury in the cup and prevents the mercury from spilling out) as the experiment with a glass of water showed.
Now let's turn to the textbook, page 144
It has been established that normal Atm. D. is 760 mm Hg. at sea level at parallel 45° (Fig. 72) write it down in your notebook.
How is Atm measured? D.?
Barometer (mercury) from the Greek baros - weight, metreo - measure. It is used at all meteorological stations, where in addition a barograph is also installed.
An aneroid (without liquid) is a box from which air has been pumped out. If the pressure increases, the box contracts; if it decreases, the box expands; the arrow shows the change in its volume.
If Atm. D. goes down - then it’s to (to rain)
If it rises, then it’s to 
(to clear weather)
But how does atmospheric pressure change?
Let's look at Fig. again. 72
Conclusion: it means pressure will decrease with altitude. And after how many meters?
With altitude, the air becomes less dense, the oxygen in it decreases, and it becomes more difficult to breathe. Therefore, when a person climbs the mountains already at an altitude of 300 m, he begins to feel bad - shortness of breath, dizziness, and nosebleeds appear.
Every 10.5 m Atm. D. decreases by 1 mm Hg. Art.
Atmospheric pressure also varies with temperature. Warm air is lighter (expands) - Atm.D. – low; cold air is heavier (compressed) Atm. D. – high.
In nature, there are plants that can sense changes in Atm.D. and predict the weather (clover, violet, adonis, field bindweed, white water lily - “Entertaining biology” p. 83; take flower reproductions from your biology teacher).
Where can you use the material you are currently studying in class? (Students' answers).
3. Consolidation
Question No. 2.
a) cold weather – Atm increases. D.
b) warm weather - Atm decreases. D.
Question No. 5. The height of Kazan according to the atlas is 200 m; latitude 54.5° N Do you need to find out what pressure is in Kazan? 200 m / 10.5 m = 19.04 mm; 760 mm – 19.04 =741 mm Hg.
Problem: At the foot of a mountain at an altitude of 2300 m above ocean level, the air pressure is 756 mm, and at the top of the mountain at the same time it is 720 mm. Determine the relative and absolute height of the mountain?
756 mm – 720 mm = 36 mm x 10.5 m = 478 m (relative height)
478 m + 200 m = 678 m (absolute height)
Figure No. 1
Problem: If the pressure at the foot of the mountain is 760 mm, then what will the pressure be at an altitude of 336 m?
336 m / 10.5 m = 32 mm;
760 mm – 32 mm = 728 mm Hg.
4. Homework:§ 38 question No. 3; No. 4
About a third of our planet's population reacts sensitively to environmental changes. Most of all, a person’s well-being is influenced by atmospheric pressure - the attraction of air masses to the Earth. What atmospheric pressure is considered normal for a person depends on the area in which he spends the vast majority of the time. Everyone will find their familiar conditions comfortable.
What is atmospheric pressure
The planet is surrounded by an air mass, which, under the influence of gravity, presses on any object, including the human body. The force is called atmospheric pressure. Each square meter is pressed by a column of air weighing approximately 100,000 kg. Atmospheric pressure is measured using a special device - a barometer. It is measured in pascals, millimeters of mercury, millibars, hectopascals, atmospheres.
The normal atmospheric pressure is 760 mm Hg. Art., or 101 325 Pa. The discovery of the phenomenon belongs to the famous physicist Blaise Pascal. The scientist formulated a law: at the same distance from the center of the earth (it doesn’t matter, in the air, at the bottom of a reservoir), the absolute pressure will be the same. He was the first to propose measuring heights using the barometric alignment method.
Atmospheric pressure standards by region
It is impossible to find out what atmospheric pressure is considered normal for a healthy person - there is no definite answer. The impact varies across different regions of the globe. Within a relatively small area, this value can vary noticeably. For example, in Central Asia, slightly elevated numbers are considered standard (on average 715-730 mm Hg). For central Russia, normal atmospheric pressure is 730-770 mm Hg. Art.
Indicators are related to the elevation of the surface above sea level, wind direction, humidity and ambient temperature. Warm air weighs less than cold air. Over an area of high temperature or humidity, the compression of the atmosphere is always less. People living in high mountain areas are not sensitive to such barometer readings. Their body was formed under these conditions, and all organs underwent appropriate adaptation.
How pressure affects people
The ideal value is 760 mmHg. Art. What awaits when the mercury column fluctuates:
- A change in optimal indicators (up to 10 mm/h) already leads to a deterioration in well-being.
- With a sharp increase or decrease (on average by 1 mm/h), even healthy people experience a significant deterioration in well-being. Headache, nausea, and loss of performance appear.
Meteor dependence
A person’s sensitivity to weather conditions – wind changes, geomagnetic storms – is called weather dependence. The influence of atmospheric pressure has not yet been fully studied. It is known that when weather conditions change, internal tension is created inside the vessels and cavities of the body. Meteorological dependence can be expressed:
- irritability;
- pain of various localization;
- exacerbation of chronic diseases;
- general deterioration of health;
- problems with blood vessels.
In most cases, people with the following diseases suffer from weather dependence:
- respiratory tract diseases;
- hypo- and hypertension.
Reaction to high blood pressure
A decrease in barometer readings by at least 10 units (770 mm Hg and below) has a negative impact on health. People with long-standing diseases of the cardiovascular and digestive systems are especially affected by weather changes. On such days, doctors recommend reducing physical activity, spending less time on the street, and not abusing heavy foods and alcohol. Among the main reactions:
- feeling of congestion in the ear canals;
- decrease in the number of leukocytes in the blood;
- decreased activity of intestinal motility;
- dysfunction of the cardiovascular system;
- poor ability to concentrate.
Reaction to low atmospheric pressure
A decrease in atmospheric compression to 740 mm or less causes opposite shifts in the body. The basis of all unfavorable changes is oxygen starvation. A rarefied air is created, a low percentage of oxygen molecules: it becomes harder to breathe. They arise.
Atmospheric pressure is the force with which the air around us presses on the earth's surface. The first person to measure it was Galileo Galilei's student Evangelista Torricelli. In 1643, together with his colleague Vincenzo Viviani, he conducted a simple experiment.
Torricelli experience
How was he able to determine atmospheric pressure? Taking a meter-long tube sealed at one end, Torricelli poured mercury into it, closed the hole with his finger and, turning it over, lowered it into a bowl also filled with mercury. At the same time, some of the mercury poured out of the tube. The mercury stopped at 760 mm. from the surface level of the mercury in the bowl.
It is interesting that the result of the experiment did not depend on the diameter, inclination or even shape of the tube - the mercury always stopped at the same level. However, if the weather suddenly changed (and the atmospheric pressure fell or increased), the mercury column fell or rose a few millimeters.
Since then, atmospheric pressure has been measured in millimeters of mercury, and pressure is 760 mm. rt. Art. is considered equal to 1 atmosphere and is called normal pressure. This is how the first barometer was created - a device for measuring atmospheric pressure.
Other ways to measure atmospheric pressure
Mercury is not the only liquid that can be used to measure atmospheric pressure. Many scientists at different times built water barometers, but since water is much lighter than mercury, their tubes rose to a height of up to 10 m. In addition, water turned into ice already at 0 ° C, which created certain inconveniences.
Modern mercury barometers use Torricelli's principle, but are somewhat more complicated. For example, a siphon barometer is a long glass tube bent into a siphon and filled with mercury. The long end of the tube is sealed, the short end is open. A small weight floats on the open surface of mercury, balanced by a counterweight. When atmospheric pressure changes, the mercury moves, dragging the float with it, which, in turn, sets in motion the counterweight connected to the arrow.
Mercury barometers are used in stationary laboratories and at meteorological stations. They are very accurate, but rather cumbersome, so at home or in the field, atmospheric pressure is measured using a liquid-free barometer or aneroid barometer.
How does an aneroid barometer work?
In a liquid-free barometer, fluctuations in atmospheric pressure are sensed by a small round metal box with rarefied air inside. The aneroid box has a thin corrugated membrane wall, which is pulled back by a small spring. The membrane bends outward when atmospheric pressure drops and presses inward when it rises. These movements cause deviations of the arrow moving along a special scale. The scale of an aneroid barometer is aligned with a mercury barometer, but it is still considered a less accurate instrument, since over time the spring and membrane lose their elasticity.
Man is far from being the king of nature, but rather its child, an integral part of the universe. We live in a world where everything is strictly interconnected and subordinated to a single system.
Everyone knows that the Earth is surrounded by a dense air mass, which is commonly called the atmosphere. And any object, including the human body, is “pressed” by an air column having a certain weight. Scientists have experimentally established that every square centimeter of the human body is exposed to atmospheric pressure weighing 1.033 kilograms. And if you carry out simple mathematical calculations, it turns out that the average person is under pressure of 15,550 kg.
The weight is colossal, but, fortunately, completely imperceptible. This may be due to the presence of dissolved oxygen in human blood.
What is the effect of atmospheric pressure on humans? Let's talk a little more about this.
Atmospheric pressure standard
Doctors, when talking about what atmospheric pressure is considered normal, indicate a range of 750....760 mmHg. Such a scatter is quite acceptable, since the planet’s topography is not perfectly flat.
Meteor dependence
Doctors say that some people's bodies are able to adapt to any conditions. They don’t even care about such serious tests as long-distance flights by plane from one climate zone to another.
At the same time, others, without leaving their apartment, feel the approach of changes in the weather. This can manifest itself in the form of severe headaches, unexplained weakness, or constantly wet palms, for example. Such people are more often diagnosed with diseases of the blood vessels and endocrine system.
It is especially difficult when atmospheric pressure makes a sharp jump in a short time. According to statistics, the majority of people whose bodies react so violently to changes in atmospheric pressure are women living in large cities. Unfortunately, the harsh rhythm of life, overcrowding, and the environment are not the best companions for health.
If desired, you can get rid of addiction. You just need to show persistence and consistency. Everyone knows the methods. These are the basics of a healthy lifestyle: hardening, swimming, walking and running, healthy eating, adequate sleep, eliminating bad habits, weight loss.
How does our body react to increased atmospheric pressure?
Atmospheric pressure (normal for humans) is ideally 760 mmHg. But this figure is very rarely maintained.
As a result of the increase in pressure in the atmosphere, clear weather sets in and there are no sudden changes in humidity and air temperature. The body of hypertensive and allergic patients actively reacts to such changes.
In city conditions, in calm weather, gas pollution naturally makes itself felt. The first to feel this are patients who have problems with the respiratory organs.
An increase in atmospheric pressure also affects the immune system. Specifically, this is expressed in a decrease in leukocytes in the blood. A weakened body will not easily cope with infections.
Doctors advise:
Start your day with light morning exercises. Take a contrast shower. For breakfast, give preference to foods high in potassium (cottage cheese, raisins, dried apricots, bananas). Don't indulge in large meals. Don't overeat. This day is not the best for great physical effort and expression of emotions. When you come home, rest for an hour, do routine household chores, and go to bed earlier than usual.
Low atmospheric pressure and well-being
Low atmospheric pressure, how much is it? To answer the question, we can conditionally say if the barometer readings are lower than 750 mmHg. But it all depends on the region of residence. In particular, for Moscow the figures are 748-749 mmHg. are the norm.
Among the first to feel this deviation from the norm are “heart patients” and those who have intracranial pressure. They complain of general weakness, frequent migraines, lack of oxygen, shortness of breath, and pain in the intestines.
Doctors advise:
Normalize your blood pressure. Reduce physical activity. Add ten minutes of rest to every working hour. Drink fluids more often, preferring green tea with honey. Drink morning coffee. Take herbal tinctures indicated for heart patients. Relax in the evenings under a contrast shower. Go to bed earlier than usual.
How changes in humidity affect the body
Low air humidity of 30–40 percent is not beneficial. It irritates the nasal mucosa. Asthmatics and allergy sufferers are the first to feel this deviation. In this case, moisturizing the mucous membrane of the nasopharynx with a slightly salted aqueous solution can help.
Frequent precipitation naturally increases air humidity to 70 - 90 percent. This also has a negative impact on health.
High air humidity can cause exacerbation of chronic kidney and joint diseases.
Doctors advise:
Change the climate to a dry one if possible. Reduce the time you spend outside in wet weather. Go out for a walk in warm clothes. Remember the vitamins
Atmospheric pressure and temperature
The optimal temperature for a person in a room is no higher than +18. This is especially true in the bedroom.
How does the mutual influence of atmospheric pressure and oxygen develop?
In the event of an increase in air temperature and a simultaneous decrease in atmospheric pressure, people with cardiovascular and respiratory diseases suffer.
If the temperature decreases and the atmospheric pressure increases, it becomes worse for hypertensive patients, asthmatics and those who have problems with the stomach and genitourinary system.
In the event of a sharp and repeated temperature fluctuation, the body produces an unacceptably large amount of histamine, the main trigger of allergies.
Good to know
Now you know what normal atmospheric pressure is for a person. This is 760 mmHg, but the barometer records such indicators very rarely.
It is also important to remember that the change in atmospheric pressure with altitude (at the same time it rapidly decreases) occurs quite sharply. It is precisely because of this difference that a person climbing a mountain very quickly can lose consciousness.
In Russia, atmospheric pressure is measured in mmHg. But the international system accepts pascals as a unit of measurement. In this case, normal atmospheric pressure in pascals will be equal to 100 kPa. If we convert our 760 mmHg. in pascals, then the normal atmospheric pressure in pascals for our country will be 101.3 kPa.
For normal atmospheric pressure, it is customary to take the air pressure at sea level at a latitude of 45 degrees at a temperature of 0°C. Under these ideal conditions, the column of air presses on each area with the same force as a column of mercury 760 mm high. This figure is an indicator of normal atmospheric pressure.
Atmospheric pressure depends on the altitude of the area above sea level. At higher elevations, the indicators may differ from ideal, but they will also be considered the norm.
Atmospheric pressure standards in different regions
As altitude increases, atmospheric pressure decreases. So, at an altitude of five kilometers, pressure indicators will be approximately two times less than below.Due to the location of Moscow on a hill, the normal pressure level here is considered to be 747-748 mm column. In St. Petersburg, normal pressure is 753-755 mm Hg. This difference is explained by the fact that the city on the Neva is located lower than Moscow. In some areas of St. Petersburg you can find a pressure norm of an ideal 760 mm Hg. For Vladivostok, normal pressure is 761 mmHg. And in the mountains of Tibet – 413 mmHg.
Impact of atmospheric pressure on people
A person gets used to everything. Even if normal pressure readings are low compared to the ideal 760 mmHg, but are the norm for the area, people will.A person’s well-being is affected by sharp fluctuations in atmospheric pressure, i.e. decrease or increase in pressure by at least 1 mmHg within three hours
When pressure decreases, a lack of oxygen occurs in a person’s blood, hypoxia of body cells develops, and the heartbeat increases. Headaches appear. There are difficulties with the respiratory system. Due to poor blood supply, a person may experience pain in the joints and numbness in the fingers.
Increased pressure leads to an excess of oxygen in the blood and tissues of the body. The tone of blood vessels increases, which leads to their spasms. As a result, the body's blood circulation is disrupted. Visual disturbances may occur in the form of spots before the eyes, dizziness, and nausea. A sharp increase in pressure to large values can lead to rupture of the eardrum.