Inventions

Thiele tube

DEFINITION The Thiele tube is a type of laboratory glassware designed to determine the melting point of a substance[1]. INVENTION The German chemist Friedrich Karl Johannes Thiele invented[2] the tube that bears his name in 1905 in order to accurately determine the melting points of substances. In his publication[2], he states that heating the tube …

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Kjeldahl flask

DEFINITION The Kjeldahl flask is a small pear-shaped flask with a long neck that is primarily used in the Kjeldahl method[1]. INVENTION The Danish chemist Johan Gustav Christoffer Thorsager Kjeldahl invented[2] the flask that bears his name in 1888 in order to facilitate a method (the Kjeldahl method) that he invented in 1883. Here is …

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Erlenmeyer flask

DEFINITION The Erlenmeyer flask (also known as the conical flask or titration flask) is a conical laboratory flask with a broad bottom and a narrow neck[1]. INVENTION The German chemist Richard August Carl Emil Erlenmeyer invented[2] the conical flask that bears his name in 1857 in an effort to make activities involving laboratory chemicals more …

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Wheelbarrow

DEFINITION A wheelbarrow is a small, hand-pushed vehicle with a single wheel and axle between the front ends of two shafts that support a boxlike body and serve as handles at the rear[1]. INVENTION The wheelbarrow was invented[2] in China circa 118. Here is a Han dynasty-era brick[3] showing a wheelbarrow being used: Here is …

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Voltaic pile

DEFINITION The voltaic pile is an early form of primary battery, consisting of alternate pairs of dissimilar metal discs with moistened pads between pairs[1]. It was the first electrochemical battery that could continuously provide an electric current to a circuit. INVENTION The Italian scientist Alessandro Giuseppe Antonio Anastasio Volta invented[2] the voltaic pile in 1800 …

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Mercury sphygmomanometer

DEFINITION The mercury sphygmomanometer is an instrument for determining arterial blood pressure indirectly by using a column of mercury to indicate the pressure[1]. INVENTION The Austrian physician Samuel Siegfried Karl von Basch invented[2] the mercury sphygmomanometer in 1881 while experimenting with ways to make blood pressure measurement more convenient and accurate. Here is an animation …

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Sphygmograph

DEFINITION A sphygmograph is an instrument consisting of a lever, the short end of which rests on the radial artery at the wrist, and the long end being provided with a stylet that records on a moving ribbon of paper the movements, form, and force of the arterial pulse[1]. INVENTION The German physiologist Karl von …

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Calorimeter

DEFINITION A calorimeter is an apparatus for measuring heat quantities generated in or emitted by materials in processes such as chemical reactions, changes of state, or formation of solutions[1]. INVENTION The French scientists Antoine-Laurent de Lavoisier and Pierre-Simon Laplace invented[2] the calorimeter in 1780 to research the amount of heat released or absorbed by various …

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