Which measuring instrument was invented by the Italian physicist and mathematician Evangelista Torricelli in 1643?
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The mercury barometer is a fundamental scientific instrument invented in 1643 by the Italian physicist and mathematician Evangelista Torricelli. This invention marked a major advance in the understanding of atmospheric pressure and paved the way for modern meteorology. Torricelli, a pupil of Galileo, was seeking to explain the phenomenon of the impossibility of pumping water above a certain height, a limit that no one was capable of crossing at the time. This question led him to experiment not with water, but with mercury, a much denser liquid.
The device he devised consisted of a long glass tube closed at one end, filled with mercury, then turned upside down into a bowl also filled with mercury. Once turned upside down, some of the mercury flowed into the bowl, but a column remained suspended in the tube, leaving a vacuum above it. This void was later dubbed the “Torricelli void”. He observed that the height of the mercury column in the tube was constant, at around 76 centimetres at sea level. He concluded that this height reflected the pressure exerted by the atmosphere on the bowl, which kept the column in suspension. Torricelli had thus proved that air has a weight, and that the earth’s atmosphere exerts a measurable pressure.
One of the revolutionary aspects of the invention of the mercury barometer was the idea that a vacuum could exist under natural conditions, a concept that contradicted the Aristotelian thinking still dominant at the time. Torricelli declared “we live at the bottom of an ocean of air”. This phrase sums up his realization that the earth’s atmosphere acts like a fluid that weighs down everything it covers.
Use of the mercury barometer quickly spread among European scientists. It became an essential instrument in meteorological studies, enabling changes in weather to be predicted thanks to variations in atmospheric pressure. A fall in the height of mercury in the tube generally indicates atmospheric depression, often synonymous with bad weather, while a rise heralds more stable weather. The mercury barometer was used for several centuries in meteorological observatories, before being gradually replaced in the 20th century by more compact, mercury-free aneroid barometers.
Technically speaking, the measurement scale of a mercury barometer is generally expressed in millimeters of mercury (mmHg) or hectopascals (hPa). Normal pressure at sea level is around 760 mmHg, or 1013 hPa. This unit is still used today in certain medical fields, notably to measure blood pressure.
The invention of the mercury barometer also had repercussions in other fields of physics and engineering. It led to a better understanding of the laws of gases, inspiring researchers such as Blaise Pascal, who confirmed Torricelli’s discoveries by conducting experiments at altitude, and Robert Boyle, who developed the law of gas compression.
The invention of the mercury barometer by Evangelista Torricelli in 1643 was a major milestone in the history of science. This instrument demonstrated the reality of atmospheric pressure and vacuum, while providing mankind with an essential tool for observing, predicting and better understanding the behavior of the earth’s atmosphere. Thanks to this invention, Torricelli is today recognized as one of the founders of modern meteorological science.
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Which measuring instrument was invented by the Italian physicist and mathematician Evangelista Torricelli in 1643?
Answer
The mercury barometer, invented by Torricelli in 1643, is an instrument that measures atmospheric pressure using a column of mercury in a sealed tube.