What is Barometer?
[[File:Prinzip Torricelli.jpg|thumb|upright|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 [[millibar]]s. [[File:Aneroid barometer.JPG|thumb|left|An aneroid barometer]] There are various types of ''barometers'' such as the [[water barometer]], [[aneroid barometer]], and the [[mercury barometer]]. The mercury barometer, the earliest barometer, was created by an [[Italy|Italian]] [[mathematician]] named [[Evangelista Torricelli]] in [[1643]]. They are used for measuring [[altitude]], or height above the ground, such as the height of a mountain, and they were often used to measure altitude aboard a [[hot air balloon]]. Barometers are also used in modern aviation as [[altimeter]]s. Miners sometimes use them to determine the depth of a mine. The most used purpose of the barometer is measuring air pressure. This helps meteorologists in predicting [[weather]]. A '''barograph''' is a device which records barometric readings on paper. {{Meteorological equipment}} {{sci-stub}} [[Category:Weather instruments]] [[Category:Measuring tools]]