Barometers are essential scientific instruments used to measure air pressure, which is the force exerted by the atmosphere on objects at or near the Earth’s surface. Air pressure plays a critical role in weather forecasting, aviation, and meteorology in general. Barometer A mercury barometer A barometer is an instrument used to measure air pressure. The barometer measures air pressure in various kinds of units including hectopascals (hPa) and millibars. An aneroid barometer There are various types of barometers such as the water barometer, aneroid barometer, and the mercury barometer. A barometer is a scientific instrument designed to measure barometric pressure. Barometers as we know them date back to 1643 when the Italian inventor Evangelista Torricelli measured air pressure using a glass tube filled with mercury and open on its downward-pointing end. A mercury barometer is an instrument used to measure atmospheric pressure in a certain location and has a vertical glass tube closed at the top sitting in an open mercury-filled basin at the bottom.
