Air Pressure Facts
Air Pressure can be defined as the continuous pounding of billions of air molecules as they zoom about. The earth is covered in a layer of air. This layer is not evenly distributed around the globe. Air is light but at ground level huge pressure can be exerted. It pushes in all the directions with a force of more than 1 kg per square cm. It can vary from place to place and time to time depending on the Sun’s heat. The unit of measuring air pressure is millibars and the device used for measurement is known as barometer. The normal air pressure at sea level ranges from 800 mb to 1050 mb.
Quick Facts: –
- The first ever barometer was invented by Evangelista Toricelli in 1644.
- On weather maps, air pressure is shown with line called isobars. These lines join places of equal pressure together.
- Zones with high pressure are called anticyclones and zones with low pressure are known as cyclones or depressions.
- Changes in air pressure help to predict the local weather.
- Steadily high air pressure indicates clear weather and a fall in air pressure shows stormy weather.
- Air Pressure is low at higher altitudes because there layer of air is thinner as compared to lower places.
- Breathing is difficult on high peaks because the air pressure is low and oxygen present in the air is more difficult to be absorbed in the blood.
- On a weather map ‘H’ shows relatively high air pressure and ‘L’ shows low air pressure.
- Generally, high pressure is associated with fair weather and low pressure is associated with unsettled and stormy weather.