What is the atmospheric pressure at sea level, Pa?

The sea level pressure is 10 1325Pa. The earth's atmosphere can be divided into five layers: troposphere, stratosphere, mesosphere, thermosphere and outer layer. Among them, the troposphere is the lowest layer of our life, with a height of about 8- 18 km. At this altitude, the atmospheric pressure gradually decreases with the elevation.

The earth is a planet that rotates, and its rotation speed is about 1670 km per hour. Due to the rotation of the earth, the air near the equator will be affected by Coriolis force, which will make the air in these areas flow eastward. The air near the polar regions will be affected by inertial force, which will make the air in these areas flow westward.

In this circulation system, the air near the equator is pushed by Coriolis force and flows eastward, and finally flows into the polar high pressure area. The polar air cannot flow eastward because of inertia force, so it can only be forced to rise. In this way, the equatorial region formed a low pressure area, while the polar region formed a high pressure area.

The cause of atmospheric pressure is mainly related to the gravity of the earth and the thermal motion of air molecules.

The earth is a huge celestial body, and its mass is far greater than that of other planets and satellites. So the earth's attraction to the surrounding objects is very strong. This gravity acts on all objects on the earth, including our bodies, buildings, airplanes and so on. When an object is attracted by the earth, it will be subjected to a downward pressure, which is atmospheric pressure.

The thermal movement of air molecules is also one of the causes of atmospheric pressure. Air is made up of a large number of molecules, which are constantly moving irregularly. When the air is heated, the movement speed of molecules will be accelerated, thus expanding the air; On the contrary, when the air gets cold, the movement speed of molecules will slow down, thus causing the air to contract.

The atmospheric pressure on the earth's surface is also affected by altitude. With the increase of height, the thickness of the atmosphere will also increase. Because the density of the atmosphere decreases with the increase of altitude, the attraction of the atmosphere to ground objects at high altitude is relatively small, which leads to the decrease of atmospheric pressure.

The causes of atmospheric pressure mainly include the gravity of the earth and the thermal motion of air molecules. These two factors work together to make the atmosphere on the earth exert certain pressure and provide necessary support for our daily life.