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What is barometer?

What is barometer ?

  • A barometer measures atmospheric pressure. The air in the atmosphere exerts a force called pressure that constantly changes due to moving weather systems. Therefore, in conjunction with other meteorological instruments, a barometer helps to predict clear or rainy weather. In 1643, Evangelista Torricelli invented the first barometer. He figured that if he had a vacuum, an airless space, he could compare the ever-present atmospheric pressure with zero pressure. So he placed a vacuum contained in a glass tube on top of a larger container of mercury. The air presses down on the mercury's exposed surface and pushes it up into the tube. The higher the mercury level, the greater the air pressure. Originally, the units of air pressure were just millimeters of mercury. People could finally measure the force of air. Since the advent of "Torricelli's tube," others developed the aneroid barometer that works without liquid. In this instrument, a flexible metal accordion box that resembles a bellows is partially squeezed to a medium pressure. Then, if air pressure rises, the bellows contract because the air inside them takes up less volume. An aneroid barometer often connects to a recording device, together forming a barograph. A pen moves against a rotating cylinder whenever the bellows moves, and thus creates a visual aid to the pattern of falling and rising air pressure. The barograph remains a basic instrument of modern meteorology. Used in conjunction with a thermometer, a barometer can make general weather predictions. While weather is very complex, storms more or less follow certain patterns of high and low pressure systems. In simplified terms, a rising barometer means wind, frost, or clear skies, while a falling barometer indicates coming storms. A steady barometer might mean precipitation or sun. Weather forecasters look at the relative change at different places, taking into account how air pressure changes with elevation. Some home hobbyist barometers still convert units to inches or millimeters of mercury, whether or not mercury is present. The International Meteorological Society has declared the universal unit of pressure to be the hectopascal. For example, 1016 hectopascals equals 30 inches of mercury (762.1 mm).

  • Answer:

    A barometer is an meteorological. instrument which shows the pressure exerted by the wing in a given place. the air pressure is responsible for the movement of air, rain and the direction of air. the air moves from the low pressure area to low pressure area, and hence the flow of air.

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it is the device used to measure positive pressure

SATISH K

a device to messure the atmospheric pressure the normal amospheric pressure is 764 toores

aasaf_burnout

it is use to measure the atmospheric pressure at sea level

pushpa

A device used to measure atmospheric pressure basically mercury barometers have been used since a long time mercury barometers consist of a long tube with one end closed and the other end dipped in a mercury filled tumbler open to the atmosphere.change in air pressure causes the mercury level to rise. This pressure is known as the atmospheric pressure and is measured in mm of mercury, besides this dial type pressure gauges are also used which consist of a round tube open to the pressure source which is connected to rack and pinion type mechanism on which the dial pin rests and rotates showing the pressure value on the indicator. This device measures pressure in the standard unit of bar. Avery important device for industrial as well as research use.

ratish n

Barometer (bərŏm'ətər) , instrument for measuring atmospheric pressure. It was invented in 1643 by the Italian scientist Evangelista Torricelli, who used a column of water in a tube 34 ft (10.4 m) long. This inconvenient water column was soon replaced by mercury, which is denser than water and requires a tube about 3 ft (0.9 m) long. The mercurial barometer consists of a glass tube, sealed at one end and filled with pure mercury. After being heated to expel the air, it is inverted in a small cup of mercury called the cistern. The mercury in the tube sinks slightly, creating above it a vacuum (the Torricellian vacuum). Atmospheric pressure on the surface of the mercury in the cistern supports the column in the tube, which varies in height with variations in atmospheric pressure and hence with changes in elevation, generally decreasing with increases in height above sea level. Standard sea-level pressure is 14.7 lb per sq in. (1,030 grams per sq cm), which is equivalent to a column of mercury 29.92 in. (760 mm) in height; the decrease with elevation is approximately 1 in. (2.5 cm) for every 900 ft (270 m) of ascent. In weather forecasting, barometric readings are usually measured on electronically controlled instruments often tied to computers. The results are plotted on base maps so that analyses of weather-producing pressure systems can be made. At a given location a storm is generally anticipated when the barometer is falling rapidly; when the barometer is rising, fair weather may usually be expected. The aneroid barometer is a metallic box so made that when the air has been partially removed from the box the surface depresses or expands with variation of air pressure on it; this motion is transmitted by a train of levers to a pointer which shows the pressure on a graduated scale. A barograph is a self-recording aneroid barometer; an altimeter is often an aneroid barometer used to calculate altitude..

questresolved

the instrument used to measure air pressure is also called barometer.

tawseef khan

barometer is a device used to measure atmospheric pressure.

Rose

an instrument used for measuring atmospheric pressure

chilly

hey u only wrote what the answer is.thanq fo da answer

sallie

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