What is an aneroid barometer?

Barometer is a device for measuring atmospheric pressure. The air pressure is affected by weather systems and also changes with altitude, with decreasing height increasing, as the air is gradually pushing. Therefore, the barometer can be used to estimate the altitude or to provide information that helps to predict the weather. The aneroid barometer is based on a flexible metal compartment or membrane containing air at a reduced pressure attached to the needle that points to a calibrated circular scale. When the air pressure increases, it pushes the membrane inside and when it decreases, the membrane moves out; These movements determine the position of the needles on the scale, indicating the pressure. It was invented by the Italian physicist and mathematician evangelist Torricelli around 1645 and relied on the pressure on the pressure of the air pushes down the liquid and push it on the vertical tube. It was soon found that mercury - the hardest liquid available - was the most suitable liquid and this type is known as mercury baromEtr. Although the barometers of mercury are very accurate, they are expensive, bulky, require careful treatment and are not very portable.

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Anerooid barometer was invented in the 40s of the 20th century by French scientist Lucien Vidia. This type of barometer can be small and lightweight, suitable for household use and some types can even be transmitted - for example, as an altimeter for an altitude of altitude based on air pressure. Another advantage of the aneroid barometer is that it can be easily adapted to the design of the barograph, where the needle is a pen that monitors the line on the role of paper and provides a continuous record of pressure changes over time. Among the disadvantages of aneroid barometers are that they are less accurate than the barometers of mercury and are subject to gradual changes in the sensitivity of the diaphragm, so they need to recalibrate regularly, usually every one to two years.

Calibration of annestoid barometer is usually in the millbarS, which is a commonly accepted unit of air pressure, but can be in hektopascads that are equivalent. Although other factors should be taken into account, usually the pressure indicator of dry, calm weather and reduced pressure indicator of rain and wind is usually increased. For this reason, in addition to normal calibration, aneroid barometers in the home often have a rough description of the expected weather, for example "turbulent", "rain", "changes", "fair" to "fine". Anerooid barometers for home use can be ornamental, as well as functional and antique aneroid barometers are often valuable and sought after.