An instrument for determining the weight or pressure of the atmosphere, and hence for judging of the probable changes of weather, or for ascertaining the height of any ascent
An instrument, often using a column of mercury, for measuring atmospheric pressure Traditionally a falling barometer measurement meant an approaching storm
instrument that measures atmospheric pressure Bermuda High: a subtropical anticyclone that occurs over the North Atlantic Ocean biosphere: the zone between the earth and the atmosphere in which most life forms reside black frost: when vegetation is frozen on the inside during a frost in which there is no moisture A black frost will almost always kill the plant boiling point: The temperature at which a substance will change from a liquid state to a gas state The boiling point of water is 100°C and 212°F
An instrument used to measure air pressure The international standard of measurement is the kilopascal although millibars and inches of mercury are also commonly used
If something is a barometer of a particular situation, it indicates how things are changing or how things are likely to develop. In past presidential elections, Missouri has been a barometer of the rest of the country. Device used to measure atmospheric pressure. Because atmospheric pressure changes with distance above or below sea level, a barometer can also be used to measure altitude. In the mercury barometer, atmospheric pressure balances a column of mercury, the height of which can be precisely measured. Normal atmospheric pressure is about 14.7 lb per square inch, equivalent to 30 in. (760 mm) of mercury. Other liquids can be used in barometers, but mercury is the most common because of its great density. An aneroid barometer indicates pressure on a dial using a needle that is mechanically linked to a partially evacuated chamber, which responds to pressure changes
An instrument used to measure atmospheric pressure A standard mercury barometer has a glass column about 30 inches long, closed at one end, with a mercury-filled reservoir Mercury in the tube adjusts until the weight of the mercury column balances the atmospheric force exerted on the reservoir High atmospheric pressure forces the mercury higher in the column Low pressure allows the mercury to drop to a lower level in the column An aneroid barometer uses a small, flexible metal box called an aneroid cell The box is tightly sealed after some of the air is removed, so that small changes in external air pressure cause the cell to expand or contract