As a result, atmospheric pressure is created. History of the discovery of atmospheric pressure

Atmospheric pressure is one of the most important climatic characteristics that affect weather conditions and people. It promotes the formation of cyclones and anticyclones, provokes the development of cardiovascular diseases in humans. Evidence that air has weight was obtained back in the 17th century, since then the process of studying its fluctuations is one of the central for weather forecasters.

What is the atmosphere?

The word "atmosphere" is of Greek origin, literally it is translated as "steam" and "ball". This is the gas shell around the planet, which rotates with it and forms a single whole cosmic body. It extends from the earth's crust, penetrating the hydrosphere, and ends with an exosphere, gradually flowing into interplanetary space.

The atmosphere of the planet is the most important element of the planet, ensuring the possibility of life on Earth. It contains the oxygen necessary for a person, the weather indicators depend on it. The boundaries of the atmosphere are very conventional. It is generally believed that they begin at a distance of about 1000 kilometers from the surface of the earth and then at a distance of another 300 kilometers smoothly pass into interplanetary space. According to the theories held by NASA, this gas shell ends at an altitude of about 100 kilometers.

It arose as a result of volcanic eruptions and evaporation of substances in the cosmic bodies that fell on the planet. Today, the Earth's atmosphere consists of nitrogen, oxygen, argon and other gases.

History of the discovery of atmospheric pressure

Until the 17th century, mankind did not think about whether the air has mass. There was also no idea what atmospheric pressure was. However, when the Duke of Tuscany decided to equip the famous Florentine gardens with fountains, his project failed miserably. The height of the water column did not exceed 10 meters, which contradicted all ideas about the laws of nature at that time. It is here that the history of the discovery of atmospheric pressure begins.

A student of Galileo, an Italian physicist and mathematician Evangeline Torricelli, studied the phenomenon. Using experiments on a heavier element, mercury, a few years later he managed to prove the presence of weight in the air. He first created a vacuum in the laboratory and developed the first barometer. Torricelli was a glass tube filled with mercury, in which, under the influence of pressure, there was such a quantity of substance that would equalize the pressure of the atmosphere. For mercury, the height of the column was 760 mm. For water - 10.3 meters, this is the height, which rose fountains in the gardens of Florence. It was he who discovered for mankind what is atmospheric pressure and how it affects human life. Airless space in the tube was named in his honor "Torricelli emptiness."

Why and why atmospheric pressure is created

One of the key tools of meteorology is the study of the motion and movement of air masses. Due to this, one can get an idea of what causes atmospheric pressure. Once it was proven that the air has weight, it became clear that it, like any other body on the planet, is affected by gravity. This is the cause of the emergence of pressure, when under the influence of gravity is the atmosphere. Atmospheric pressure can fluctuate due to differences in the mass of air in different areas.

Where there is more air, it is higher. In rarefied space, a decrease in atmospheric pressure is observed. The reason for the change in the mass of air lies in its temperature. It is heated not from the rays of the Sun, but from the surface of the Earth. When heated, air becomes lighter and rises, while cooled air masses descend, creating a constant, continuous movement of air masses. Each of these streams has a different atmospheric pressure, which provokes the appearance of winds on the surface of our planet.

Weather effects

Atmospheric pressure is one of the key terms in meteorology. Weather on the Earth is formed due to the impact of cyclones and anticyclones, which are formed under the influence of pressure drops in the gas shell of the planet. For anticyclones are characterized by high rates (up to 800 mm Hg and above) and low speed, while cyclones are areas with lower rates and high speed. Tornadoes, hurricanes, tornadoes are also formed due to sudden changes in atmospheric pressure - within the tornado it falls rapidly, reaching 560 mm Hg.

The movement of air leads to a change in weather conditions. Winds that arise between regions with different pressure levels overtake cyclones and anticyclones, which creates an atmospheric pressure that forms certain weather conditions. These movements are rarely systematic, and they are very difficult to predict. In areas where elevated and lower atmospheric pressure collide, a change in climatic conditions occurs.

Standard metrics

The average level under ideal conditions is 760 mm Hg. The pressure level varies with altitude: in lowlands or areas below sea level, the pressure will be higher, at a height where the air is sparse, on the contrary, its indicators decrease by 1 mm of mercury with each kilometer.

Low atmospheric pressure

It decreases with increasing altitude because of the distance from the surface of the Earth. In the first case, this process is explained by a decrease in the effect of gravitational forces.

Heating from the Earth, the gases that make up the air expand, their mass becomes lighter, and they rise to higher layers of the atmosphere. The movement occurs until the neighboring air masses are less dense, then the air is spreading to the sides, and the pressure is equalized.

Traditional areas with lower atmospheric pressure are the tropics. A reduced pressure is always observed in the equatorial territories. However, zones with an increased and decreased index are distributed unevenly above the Earth: in one geographic latitude there may be areas with different levels.

Elevated atmospheric pressure

The highest level on Earth is observed at the South and North Poles. This is explained by the fact that the air above the cold surface becomes cold and dense, its mass increases, therefore, it attracts gravity more strongly to the surface. It descends, and the space above it is filled with warmer air masses, which creates atmospheric pressure with an elevated level.

Effects on humans

Normal indicators, characteristic for the area where a person lives, should not have any effect on his state of health. At the same time, atmospheric pressure and life on Earth are inextricably linked. Its change - increase or decrease - can provoke the development of cardiovascular diseases in people with high blood pressure. A person can experience pain in the region of the heart, attacks of an unjustified headache, working capacity decreases.

For people suffering from respiratory diseases, anticyclones, which bring increased pressure, can become dangerous. The air descends and becomes denser, the concentration of harmful substances increases.

During fluctuations in atmospheric pressure, immunity is reduced in people, the level of leukocytes in the blood, therefore it is not recommended to load the body physically or intellectually on such days.