Importance of Atmospheric Pressure

There is people who think that scientific knowledge is far removed from everyday reality. This belief is completely uncertain, since scientific knowledge is present in all kinds of circumstances.

A good example is weather, as everyone cares what time will be tomorrow or if your vacation will coincide with a period of bad weather.

Variables and measurements of different types are studied within meteorology. nature and one of the most significant is atmospheric pressure.

fundamental principles

Our planet is surrounded by a layer of air known as the atmosphere. Its approximate thickness is 500 kilometers. Being an air mass, it has a certain weight that acts on the earth's surface. This mass produces a force that in turn generates a pressure, which is known as atmospheric pressure. In others words, is the force per unit area that the air exerts on the Earth's surface. This effect was discovered by the Italian scientist Evangelista Torricelli in the 17th century.

Mercury barometers are normally used to determine its value and the internationally accepted unit of pressure is the pascal, the bar, the atmosphere or the millimeter of mercury.

In the language of meteorology, high pressure areas produce anticyclones and low pressure areas generate storms.

High pressures occur when the air masses cool, the molecules are concentrated and the air is denser and heavier (as a consequence of all this, the air descends to the surface of the Earth and the air masses below it are compressed and this circumstance normally produces good time).

In contrast, the low pressure is accompanied by a warming in its air mass, the molecules separate and rise (this phenomenon produces clouds that usually cause precipitation). These zones are graphically represented on weather maps by lines, the isobars.

Absolute and relative atmospheric pressure

Pressure is always the force exerted by something divided by the surface area. The weight of the air mass that surrounds us exerts an atmospheric pressure. The air above us is equal to the weight of a 760-millimeter column of mercury.

The pressure of the atmosphere can be absolute or relative. In the first case, the measurement base is 0 and, therefore, as it is an absolute measurement below 0, there are no negative pressures but rather they are always positive (these measurements are used theoretically).

The pressure that the air exerts on the Earth is not absolute but relative and this pressure is measured through the manometers. This implies that the absolute pressure is the sum of the relative pressure and the atmospheric pressure.

Images: Fotolia – Artem, Alenaif