Barometer

A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. The measurements taken by barometers can be used to forecast short-term changes in weather, as pressure patterns are closely linked to weather conditions. There are two primary types of barometers: mercury barometers and aneroid barometers. A mercury barometer uses a column of liquid mercury that rises or falls in response to changes in air pressure. An aneroid barometer, on the other hand, uses a small, flexible metal box called an aneroid cell that expands or contracts with changes in pressure. Changes in atmospheric pressure can indicate incoming weather changes, for instance, falling pressure often signals that a storm is coming, while rising pressure suggests good weather.