Fauzan Khattak

X-rays

DEFINITION An X-ray is an invisible, highly penetrating electromagnetic radiation of much shorter wavelength (higher frequency) than visible light. The wavelength range for X-rays is from about 10⁻⁸ m to about 10⁻¹¹ m; the corresponding frequency range is from about 3 × 10¹⁶ Hz to about 3 × 10¹⁹ Hz. Photographs made with X-rays are …

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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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Anion

DEFINITION An anion is a monoatomic or polyatomic species having one or more elementary charges of the electron[1]. DISCOVERY The English scientist Michael Faraday discovered[2] the anion in 1834 while analysing the electrochemical properties of electrolytic solutions. In an effort to create an electrochemical nomenclature, he says in his 1834 publication, “Finally, I require a …

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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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Fibrinogen

DEFINITION Fibrinogen is a protein in the blood plasma that is essential for the coagulation of blood and is converted to fibrin by the action of thrombin in the presence of ionised calcium[1]. It is also called “coagulation factor I”. DISCOVERY The Swedish physiologist Olof Hammarsten discovered[2] fibrinogen in 1877 after researching what substances in …

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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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