barometr

Barometr, also spelled barometer in English, is an instrument for measuring atmospheric pressure. It has been central to meteorology and weather forecasting and is widely used in aviation, navigation, and scientific research. Barometers come in several designs; the oldest and most famous is the mercury barometer, which measures air pressure by the height of a mercury column balanced against the atmospheric force. A common modern alternative is the aneroid barometer, which uses a sealed flexible metal chamber that expands or contracts with pressure and translates that motion into a dial reading. Digital barometers employ electronic sensors, such as MEMS or capacitive devices, to measure pressure and transmit readings electronically.

Principle and units: Atmospheric pressure is the force per unit area exerted by the column of air above a location. Readings are typically reported in hectopascals (hPa) or millibars (mb), with 1 hPa equal to 1 mb; standard sea-level pressure is about 1013.25 hPa. Some contexts use inches of mercury (inHg) or bars. Barometric pressure tends to regulate daily weather patterns: low-pressure systems are often associated with storms, while high-pressure systems correlate with fair weather. Pressure decreases with altitude, making barometers useful for altitude estimation and, in aviation, for altimetry.

History: The barometer was developed in the 17th century, with Evangelista Torricelli’s mercury barometer (1643) as a landmark. Blaise Pascal demonstrated that pressure decreases with altitude. The 19th century saw the rise of aneroid barometers, enabling portable, liquid-free measurements. In modern times, digital sensors are common in weather stations, smartphones, and aircraft instruments, often integrated with other data sources for forecasting and navigation.