# Air pressure law

Atmospheric pressure
Air pressure is defined as the weight of the air column that starts from the Earth's surface to the last layer of the Earth's atmosphere, which affects the unit area. This makes the altitude or drop below sea level the most important value of atmospheric pressure. Which is constructed from the point of contact with the surface of the earth down to the last layers of the atmosphere, and the concept of pressure from the general concepts that are not related to the pressure of the atmosphere alone, there is pressure resulting from the existence of the layers of the ground, there is known as pressure of liquids, The law of atmospheric pressure, in this article will be discussed About air pressure law.

Air pressure law
The air pressure law aims at finding the weight of the air column on the unit of space at a given point. Here is some information about atmospheric pressure law and some of the conclusions of this physical law:

The air pressure is obtained by dividing the weight of the air column at a certain point on the unit of area at that point, so the atmospheric pressure law is as follows:

Air pressure: Air / space column weight
The air pressure law expresses the symbols by: Z = S / A, and from this physical law, the following can be inferred:

The unit of measurement of atmospheric pressure according to the law above and according to the system of units of global measurement is Newton / square meter, this physical unit is called Pascal.
Pascal is defined as the pressure resulting from a force of 1 Newton affecting an area of ​​1 square meter.
The atmospheric pressure law can infer some factors that affect the value of atmospheric pressure at a given point. This can be summarized as follows:
The air pressure is directly proportional to the force that expresses the weight of the air column on the unit of area, so that the amount of air pressure increases as the weight of the air column on the unit of area increases. As the weight of the air column depends on the length of the air column where its mass increases, The elevation of the point at which the atmospheric pressure value is measured or decreased affects the value of the atmospheric pressure. The lower the point of the sea, the longer the column of air increases the atmospheric pressure.
The air pressure is inversely proportional to the surface area. The lower the surface area where the weight of the air column is mounted, the greater the atmospheric pressure.
Atmospheric pressure measurement
There are some devices in which the value of atmospheric pressure can be measured at a specific point. The reading of these devices represents the weight of the air column on the unit of area at that point, by the following:

Mercury Barometric: This device is in the form of a glass tube containing mercury, and is calculated by calculating atmospheric pressure at a point.
Barometer: This device is called Barometer Arinoid, and it was developed because it is easier to use than the mercurial barometer. It is characterized as easy to carry. It consists of a metal box containing low pressure air. It measures the value of atmospheric pressure through a specific indicator that gives the value of atmospheric pressure At the point.