What is the atmospheric pressure?

The correct value of atmospheric pressure is1.01325×105pa.

This is the data calculated by professional researchers, and everyone should have been exposed to it in physics class.

The international system unit of air pressure is Pascal, abbreviated as Pa, and the symbol is PA. In meteorology, people usually use kilopascals (kPa) or hectopascals (hpa) as units.

Discovery and application

1640 10 Torricelli, assistant of Torricelli Galileo, realized that the weight of air in the atmosphere exerted pressure on the mercury in the basin, and this force pressed the mercury into the glass tube. The weight of mercury in the glass tube should be exactly equal to the weight of mercury exerted by the atmosphere on the basin.

When the weight of the atmosphere changes, the pressure it exerts on the basin will increase or decrease, thus causing the mercury column in the glass tube to rise or fall. Weather changes will inevitably cause changes in the weight of the atmosphere. Torricelli discovered atmospheric pressure and found a way to measure and study it.

Torricelli's discovery was the beginning of a formal study of weather and atmosphere, which made us understand the atmosphere and laid the foundation for Newton and other scientists to study gravity. At the same time, this new discovery made Torricelli create the concept of vacuum and invented the basic instrument of meteorological research-barometer.

Application of atmospheric pressure: press the plastic hook with suction cup on a very flat wall and it can be used to hang things; Piston and centrifugal pump can pump water from the lower part to the higher part; Squeeze the air out of the pen tube, and then let go to suck the ink into the pen tube; Cooking food in a pressure cooker is easy; There is a small hole on the lid of the teapot, which can easily pour out the water; There are also high-pressure boilers, agricultural sprayers, drinking water through straws, and using syringe needles for liquid medicine, all of which are related to atmospheric pressure.