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The experiment became a popular way to illustrate the principles of air pressure, and many smaller copies of the hemispheres were made, and are used to this day in science classes. Reenactments of von Guericke's experiment of 1654 are performed in locations around the world by the Otto von Guericke Society.
The experiment uses a simple barometer to measure the pressure of air, filling it with mercury up until 75% of the tube. Any air bubbles in the tube must be removed by inverting several times. After that, a clean mercury is filled once again until the tube is completely full. The barometer is then placed inverted on the dish full of mercury.
An aneroid barometer is an instrument used for measuring air pressure via a method that does not involve liquid. Invented in 1844 by French scientist Lucien Vidi, [23] the aneroid barometer uses a small, flexible metal box called an aneroid cell (capsule), which is made from an alloy of beryllium and copper. The evacuated capsule (or usually ...
He used linseed oil as the thermometric fluid. [6] 1701 — Ole Christensen Rømer made one of the first practical thermometers. As a temperature indicator it used red wine. (Rømer scale), The temperature scale used for his thermometer had 0 representing the temperature of a salt and ice mixture (at about 259 s).
masses of ions, used to identify chemical substances through their mass spectra measuring cup: liquid and dry goods measuring cylinder: volume measuring spoon: a spoon used to measure an amount of an ingredient, either liquid or dry megger: electrical insulation mercury barometer: Atmospheric pressure micrometer: small distances multimeter
A McLeod gauge is a scientific instrument used to measure very low pressures, down to 10 −6 Torr (0.133 mPa). It was invented in 1874 by Herbert McLeod (1841–1923). [1] McLeod gauges were once commonly found attached to equipment that operates under vacuum, such as a lyophilizer. Today, however, these gauges have largely been replaced by ...
The changing height of the mercury in the barometer was recorded on a continuously moving photosensitive surface. [5] By 1847, a sophisticated temperature-compensation mechanism was also employed. Ronalds’ barograph was utilised by the UK Meteorological Office for many years to assist in weather forecasting and the machines were supplied to ...
This procedure is followed in many experiments, including an experiment in which one experimentally determines the Ideal gas law constant R. The eudiometer is similar in structure to the meteorological barometer. Similarly, a eudiometer uses water to release gas into the eudiometer tube, converting the gas into a visible, measurable amount.