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Wilhelm Hallwachs
Wilhelm Ludwig Franz Hallwachs (9 July 1859 – 20 June 1922) was a German physicist. Life and career Early years Hallwachs was born in 1859 in Darmstadt to Ludwig and Emilie Hallwachs. His father was a high ranking public official ( Geheimer Staatsrat) with the Ministry of the Interior and Justice of the Grand Duchy of Hesse, then part of the German Confederation. Career From 1878 Hallwachs studied physics, most of his time at the University of Strasbourg, then part of Germany he also did one year at the University of Berlin. At last he was an assistant to August Kundt at Strasbourg where he was awarded a doctorate in 1893. Hallwachs moved on to become an assistant to Friedrich Kohlrausch at the University of Würzburg where he stayed there from 1884 until 1886. In 1886, he went to Leipzig where he habilitated with Gustav Heinrich Wiedemann until 1888. After that he followed Friedrich Kohlrausch in Strasbourg. Hallwachs became a professor at the Dresden University of T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darmstadt
Darmstadt () is a city in the States of Germany, state of Hesse in Germany, located in the southern part of the Frankfurt Rhine Main Area, Rhine-Main-Area (Frankfurt Metropolitan Region). Darmstadt has around 160,000 inhabitants, making it the fourth largest city in the state of Hesse after Frankfurt am Main, Wiesbaden, and Kassel. Darmstadt holds the official title "City of Science" (german: link=no, Wissenschaftsstadt) as it is a major centre of scientific institutions, universities, and high-technology companies. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the European Space Operations Centre (ESOC) are located in Darmstadt, as well as Gesellschaft für Schwerionenforschung, GSI Centre for Heavy Ion Research, where several chemical elements such as bohrium (1981), meitnerium (1982), hassium (1984), darmstadtium (1994), roentgenium (1994), and copernicium (1996) were discovered. The existence of the following elements were also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friedrich Kohlrausch (physicist)
Friedrich Wilhelm Georg Kohlrausch (14 October 1840 – 17 January 1910) was a German physicist who investigated the conductive properties of electrolytes and contributed to knowledge of their behaviour. He also investigated elasticity, thermoelasticity, and thermal conduction as well as magnetic and electrical precision measurements. Nowadays, Friedrich Kohlrausch is classed as one of the most important experimental physicists. His early work helped to extend the absolute system of Carl Friedrich Gauss and Wilhelm Weber to include electrical and magnetic measuring units. Biography Education Son of Rudolf Kohlrausch, Friedrich Wilhelm Georg Kohlrausch was born on October 14, 1840, in Rinteln, Germany. After studying physics at Erlangen and Göttingen, Friedrich Kohlrausch completed his doctorate in Göttingen. Teaching After a two-year work as a lecturer in Frankfurt, Kohlrausch was appointed a professor of physics at the University of Göttingen (1866–70). During 1870 Koh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1859 Births
Events January–March * January 21 – José Mariano Salas (1797–1867) becomes Conservative interim President of Mexico. * January 24 ( O. S.) – Wallachia and Moldavia are united under Alexandru Ioan Cuza (Romania since 1866, final unification takes place on December 1, 1918; Transylvania and other regions are still missing at that time). * January 28 – The city of Olympia is incorporated in the Washington Territory of the United States of America. * February 2 – Miguel Miramón (1832–1867) becomes Conservative interim President of Mexico. * February 4 – German scholar Constantin von Tischendorf rediscovers the ''Codex Sinaiticus'', a 4th-century uncial manuscript of the Greek Bible, in Saint Catherine's Monastery on the foot of Mount Sinai, in the Khedivate of Egypt. * February 14 – Oregon is admitted as the 33rd U.S. state. * February 12 – The Mekteb-i Mülkiye School is founded in the Ottoman Empire. * February 17 – French naval forces under Char ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1922 Deaths
Nineteen or 19 may refer to: * 19 (number), the natural number following 18 and preceding 20 * one of the years 19 BC, AD 19, 1919, 2019 Films * ''19'' (film), a 2001 Japanese film * ''Nineteen'' (film), a 1987 science fiction film Music * 19 (band), a Japanese pop music duo Albums * ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * ''Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * ''XIX'' (EP), a 2019 EP by 1the9 Songs * "19" (song), a 1985 song by British musician Paul Hardcastle. * "Nineteen", a song by Bad4Good from the 1992 album '' Refugee'' * "Nineteen", a song by Karma to Burn from the 2001 album ''Almost Heathen''. * "Nineteen" (song), a 2007 song by American singer Billy Ray Cyrus. * "Nineteen", a song by Tegan and Sara from the 2007 album '' The Con''. * "XIX" (song), a 2014 song by Slipk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientists From Hesse
A scientist is a person who conducts scientific research to advance knowledge in an area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosophical study of nature called natural philosophy, a precursor of natural science. Though Thales (circa 624-545 BC) was arguably the first scientist for describing how cosmic events may be seen as natural, not necessarily caused by gods,Frank N. Magill''The Ancient World: Dictionary of World Biography'', Volume 1 Routledge, 2003 it was not until the 19th century that the term ''scientist'' came into regular use after it was coined by the theologian, philosopher, and historian of science William Whewell in 1833. In modern times, many scientists have advanced degrees in an area of science and pursue careers in various sectors of the economy such as academia, industry, government, and nonprofit environments.'''' History The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Solar Cells
In the 19th century, it was observed that the sunlight striking certain materials generates detectable electric current – the photoelectric effect. This discovery laid the foundation for solar cells. Solar cells have gone on to be used in many applications. They have historically been used in situations where electrical power from the grid was unavailable. As the invention was brought out it made solar cells as a prominent utilization for power generation for satellites. Satellites orbit the Earth, thus making solar cells a prominent source for power generation through the sunlight falling on them. Solar cells are commonly used in satellites in today's times. 1800s * 1839 - Edmond Becquerel observes the photovoltaic effect via an electrode in a conductive solution exposed to light. * 1873 - Willoughby Smith finds that selenium shows photoconductivity. * 1874 - James Clerk Maxwell writes to fellow mathematician Peter Tait of his observation that light affects the conductivity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectric Effect
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid state and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission. The experimental results disagree with classical electromagnetism, which predicts that continuous light waves transfer energy to electrons, which would then be emitted when they accumulate enough energy. An alteration in the intensity of light would theoretically change the kinetic energy of the emitted electrons, with sufficiently dim light resulting in a delayed emission. The experimental results instead show that electrons are dislodged only when the light exceeds a certain frequency—regardless of the light's intensity or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrons
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron's mass is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum ( spin) of a half-integer value, expressed in units of the reduced Planck constant, . Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: They can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionization, ionize atoms, it can cause chemical reactions and causes many substances to glow or fluorescence, fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Hertz
Heinrich Rudolf Hertz ( ; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's Maxwell's equations, equations of electromagnetism. The unit of frequency, cycle per second, was named the "hertz" in his honor.IEC History . Iec.ch. Biography Heinrich Rudolf Hertz was born in 1857 in Hamburg, then a sovereign state of the German Confederation, into a prosperous and cultured Hanseatic (class), Hanseatic family. His father was Gustav Ferdinand Hertz. His mother was Anna Elisabeth Pfefferkorn. While studying at the Gelehrtenschule des Johanneums in Hamburg, Hertz showed an aptitude for sciences as well as languages, learning Arabic. He studied sciences and engineering in th ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Würzburg
Würzburg (; Main-Franconian: ) is a city in the region of Franconia in the north of the German state of Bavaria. Würzburg is the administrative seat of the ''Regierungsbezirk'' Lower Franconia. It spans the banks of the Main River. Würzburg is situated approximately east-southeast of Frankfurt am Main and approximately west-northwest of Nuremberg (). The population (as of 2019) is approximately 130,000 residents. The administration of the ''Landkreis Würzburg'' ( district of Würzburg) is also located in the town. The regional dialect is East Franconian. History Early and medieval history A Bronze Age (Urnfield culture) refuge castle, the Celtic Segodunum,Koch, John T. (2020)CELTO-GERMANIC Later Prehistory and Post-Proto-Indo-European vocabulary in the North and West p. 131 and later a Roman fort, stood on the hill known as the Leistenberg, the site of the present Fortress Marienberg. The former Celtic territory was settled by the Alamanni in the 4th or 5th century ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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