What do we use to measure atmospheric pressure?

A barometer is used to measure atmospheric pressure, which is the force exerted onto a surface by the weight of the air above that surface in the atmosphere. Barometers can be constructed using different principles, such as mercury or aneroid mechanisms. A mercury barometer measures atmospheric pressure based on the height of mercury displaced in a glass column due to air pressure, while an aneroid barometer uses a sealed, flexible metal box that expands or contracts with changes in atmospheric pressure.

Understanding how atmospheric pressure influences weather patterns, altitude measurements, and various physical phenomena is critical in fields like meteorology and physiology. While a manometer is designed for measuring the pressure of gases in a closed system rather than directly measuring atmospheric pressure, thermometers measure temperature and spirometers assess lung function. Therefore, their functions are distinct from that of a barometer, which is specifically intended for atmospheric pressure.