Which instrument is used to measure atmospheric pressure?

The instrument specifically designed to measure atmospheric pressure is the barometer. Barometers work by detecting changes in atmospheric pressure, which can indicate weather changes. They typically use a column of mercury or an aneroid system to record pressure variations.

Thermometers measure temperature, while altimeters gauge altitude based on atmospheric pressure differences, primarily in aviation. Venturi meters measure fluid flow rates rather than atmospheric pressure. Thus, the barometer is the appropriate choice for measuring atmospheric pressure, directly linking changes in air pressure to weather conditions and helping meteorologists predict weather patterns.