Air pressure

Air pressure is the force exerted by the weight of air on any surface in its contact. It is a fundamental concept in the fields of atmospheric science, meteorology, and physics.

Definition

Air pressure is defined as the force per unit area exerted against a surface by the weight of the air above that surface. It is usually measured in pascals (Pa), which is equivalent to newtons per square meter (N/m²).

Measurement

The measurement of air pressure is performed using an instrument known as a barometer. The two main types of barometers are the mercury barometer and the aneroid barometer. The mercury barometer uses a column of mercury to measure pressure, while the aneroid barometer uses a small, flexible metal box called an aneroid cell.

Factors affecting air pressure

Air pressure is affected by several factors, including altitude, temperature, and humidity. At higher altitudes, there is less air above a surface, so the air pressure is lower. Temperature can also affect air pressure, as warmer air is less dense and exerts less pressure than cooler air. Humidity can also influence air pressure, as moist air is less dense than dry air.

Effects of air pressure

Air pressure has a significant impact on weather and climate. Changes in air pressure can result in various weather phenomena, such as wind, storms, and cyclones. In addition, air pressure is also crucial in the operation of many devices, such as tires, hydraulic presses, and aircraft.

See also

• Atmospheric pressure
• Barometer
• Meteorology
• Pascal (unit)