What device measures atmospheric pressure?

A barometer is the device specifically designed to measure atmospheric pressure. It operates based on the principle that changes in air pressure can be detected by measuring the height of a column of mercury or using a more modern digital sensor. Barometers come in two main types: mercury barometers, which utilize mercury in a glass tube to measure pressure, and aneroid barometers, which use a small, flexible metal box that expands and contracts with changes in pressure.

Measuring atmospheric pressure is essential for weather prediction and understanding weather patterns, as pressure changes can indicate upcoming weather changes. A decrease in atmospheric pressure often signals stormy weather, while an increase generally suggests fair weather.

The other options have different functions: a weather balloon is used for collecting data about the atmosphere at various altitudes, an anemometer measures wind speed, and Doppler radar is primarily used for detecting precipitation and monitoring storm systems. Each of these devices plays a crucial role in meteorology but does not serve the purpose of measuring atmospheric pressure like a barometer does.