Air pressure, also known as atmospheric pressure or barometric pressure, is the force exerted by the weight of the column of air above a specific area on the Earth's surface. It results from the gravitational pull acting on the atmospheric gases above that location
. Key points about air pressure:
- It is the weight of the air column extending from the Earth's surface up to the top of the atmosphere, acting on a unit area (e.g., one square meter)
- Air pressure decreases with increasing altitude because the column of air above becomes shorter and lighter
- It is measured in units such as pascals (Pa), hectopascals (hPa), millibars (mb), or atmospheres (atm), with standard sea-level pressure defined as approximately 101,325 Pa or 1 atm
- Instruments to measure air pressure include mercury barometers and aneroid barometers, which detect changes in atmospheric pressure by balancing or sensing the weight of the air column
- Air pressure influences weather patterns; areas of low pressure often bring clouds and rain due to rising air, while high pressure areas are associated with clearer, drier weather
In summary, air pressure is the force per unit area exerted by the atmosphere's mass above a point, varying with elevation and weather conditions, and is fundamental in meteorology and climate studies
