elohopeabarometreistä

Elohopeabarometreistä refers to instruments used to measure atmospheric pressure, commonly known as barometers, that utilize mercury as their fluid. These devices were the standard for barometric measurements for centuries due to mercury's distinct properties, such as its high density and visibility, which allow for precise readings.

The operation of a mercury barometer is based on Torricelli's principle. A long glass tube, sealed at one end, is filled with mercury and then inverted into a reservoir of mercury. The atmospheric pressure pushing down on the mercury in the reservoir supports a column of mercury within the tube. The height of this mercury column is directly proportional to the atmospheric pressure. A higher column indicates higher pressure, and a lower column indicates lower pressure.

While highly accurate, mercury barometers have significant drawbacks. Mercury is a toxic substance, posing health and environmental risks if the instrument breaks. This toxicity has led to a decline in their use and a preference for alternative barometer types, such as aneroid barometers, which use a sealed, flexible metal box instead of mercury. Despite these safety concerns, mercury barometers remain valuable for historical research and in certain scientific applications where their precision is paramount and containment measures are strictly enforced.