Air pressure - the history of discovery

Everyone knows that the surface of the Earth is surrounded by a layer of air. It is located from the surface of the planet for tens and hundreds of kilometers up. But the amazing properties of the air near the surface of the Earth are extremely interesting. The air around us is so weightless, transparent and invisible that people did not immediately realize that it has a permanent effect on all life.

This was first noticed in 1640. The reason was a non-working fountain on the terrace of the palace of the Duke of Tuscany. The water could not be lifted to any significant height. An explanation of this phenomenon suggested Torricelli. It was suggested to them that there is an air pressure that affects everything on the surface of the Earth. To confirm his thoughts, he took a glass tube, one end of which was sealed, and filled it with mercury. Then the free end of the tube Torricelli placed in a flat vessel with mercury.

Mercury in the tank dropped, its height above the surface of the bowl was 760 millimeters. For the first time it was proved that there is pressure of the atmosphere, and barometric pressure was measured. It is measured in millimeters of mercury. Because The mercury column was the first device of this type, the pressure thus measured is called barometric. The result is explained simply - the air presses on the surface with a force equal to the weight of the mercury column at a height of 760 millimeters.

These conclusions were confirmed by the French scientist Pascal. He suggested that the air pressure depends on the height above the ground. The higher, the pressure should be less. His measurements he conducted with tubes filled with water. They were taken to the mountain, and an experiment was conducted there. The result fully confirmed the assumption of Pascal - the level of water rise in the tube at the top of the mountain was less than on the surface.

If you are so deeply immersed in the history of the discovery of atmospheric pressure, then it is necessary to recall the experience, conducted in 1654 in Magdeburg by the German scientist Otto von Guericke. He took two hemispheres, connected them together and pumped air out of the internal volume. Two teams of horses, each of them pulled in their direction, could not tear the hemisphere apart. Here is the force of their compressed air pressure.

This experience can be considered a decisive confirmation of the assumption of the presence of atmospheric pressure. In the future, scientists were engaged in the study of the atmosphere itself and the influence of barometric pressure on the human and animal organism. Do not forget about the study of the weather and its relationship with atmospheric pressure. Pressure measurements were carried out at different altitudes, in different areas, regularities and relationships of air pressure with natural phenomena

Now, to measure the pressure, not a mercury tube is used, but a special barometer-aneroid. Its basis, the air pressure sensor, is a metal box with a corrugated surface, to which is attached an arrow indicating the scale of the device air pressure. Such a device is in itself much more compact than a mercury barometer and can be used under heavy expeditionary conditions.

It should be noted that the discovery and further study of atmospheric pressure played a huge role in the study and understanding of many processes occurring on Earth. Changes in weather, cyclones and anticyclones, the effect of weather on the human body is largely due to a change in atmospheric pressure. So our current knowledge about the world and health is based on the discoveries of ingenious medieval scientists.

Here the history of the origin and study of such a concept as air pressure was considered. The descriptions of the experiments performed to confirm a new theory for that time were described, and how the air pressure was measured.