How Does a Barometer Work?
In a barometer which is of mercury type,the weight of a column of mercury is made to balance the pressure of the atmosphere over a mercury trough.These mercury barometers consist of a glass of tube of uniform cross section and length of about 33 inches.The glass tube is closed at one end and filled with mercury.This tube is inverted vertically with its lower end open and dipping into a cistern of mercury(mercury trough).In one type of mercury barometer, this cistern is fixed(requiring only one setting while taking the reading) and in another type this can be raised or lowered in order to make contact with a setting index,requiring double settings while taking readings. .Barometers without using any liquid are also used.They are known as aneroid barometer.In aneroid barometers,the vertical movements of the upper lid of a closed partially-evacuted aluminium (or made of an alloy of beryllium and copper)capsule are calibrated to read atmospheric pressure directly.This capsule undergoes cha
A barometer is an instrument that measures air pressure. It uses mercury, which reacts to air pressure just as it reacts to temperature in a thermometer, by rising or falling in a glass tube. Perhaps you’re wondering why it is important to know something about air pressure. The answer is that it is an important aid to scientists
