|
Eugen Goldstein
Eugen Goldstein (; 5 September 1850 – 25 December 1930) was a German physicist. He was an early investigator of discharge tubes, the discoverer of anode rays or canal rays, later identified as positive ions in the gas phase including the hydrogen ion. He was the great uncle of the violinists Mikhail Goldstein and Boris Goldstein. Life Goldstein was born in 1850 at Gleiwitz Upper Silesia, now known as Gliwice, Poland, to a Jewish family. He studied at Breslau and later, under Helmholtz, in Berlin. Goldstein worked at the Berlin Observatory from 1878 to 1890 but spent most of his career at the Potsdam Observatory, where he became head of the astrophysical section in 1927. He died in 1930 and was buried in the Weißensee Cemetery in Berlin. Work In the mid-nineteenth century, Julius Plücker investigated the light emitted in discharge tubes (Crookes tubes) and the influence of magnetic fields on the glow. Later, in 1869, Johann Wilhelm Hittorf studied discharge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gleiwitz
Gliwice (; german: Gleiwitz) is a city in Upper Silesia, in southern Poland. The city is located in the Silesian Highlands, on the Kłodnica river (a tributary of the Oder River, Oder). It lies approximately 25 km west from Katowice, the regional capital of the Silesian Voivodeship. Gliwice is the westernmost city of the Metropolitan Association of Upper Silesia and Dąbrowa Basin, Upper Silesian metropolis, a conurbation of 2.0 million people, and is the third-largest city of this area, with 175,102 permanent residents as of 2021. It also lies within the larger Upper Silesian metropolitan area which has a population of about 5.3 million people and spans across most of eastern Upper Silesia, western Lesser Poland and the Moravian-Silesian Region in the Czech Republic. Gliwice is bordered by three other cities and towns of the metropolitan area: Zabrze, Knurów and Pyskowice. It is one of the major college towns in Poland, thanks to the Silesian University of Technology, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliwice
Gliwice (; german: Gleiwitz) is a city in Upper Silesia, in southern Poland. The city is located in the Silesian Highlands, on the Kłodnica river (a tributary of the Oder). It lies approximately 25 km west from Katowice, the regional capital of the Silesian Voivodeship. Gliwice is the westernmost city of the Upper Silesian metropolis, a conurbation of 2.0 million people, and is the third-largest city of this area, with 175,102 permanent residents as of 2021. It also lies within the larger Upper Silesian metropolitan area which has a population of about 5.3 million people and spans across most of eastern Upper Silesia, western Lesser Poland and the Moravian-Silesian Region in the Czech Republic. Gliwice is bordered by three other cities and towns of the metropolitan area: Zabrze, Knurów and Pyskowice. It is one of the major college towns in Poland, thanks to the Silesian University of Technology, which was founded in 1945 by academics of Lwów University of Technology. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Effect
The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession. The reason for the Doppler effect is that when the source of the waves is moving towards the observer, each successive wave crest is emitted from a position closer to the observer than the crest of the previous wave. Therefore, each wave takes slightly less time to reach the observer than the previous wave. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
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 wavele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathode Ray
Cathode rays or electron beam (e-beam) are streams of electrons observed in discharge tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow, due to electrons emitted from the cathode (the electrode connected to the negative terminal of the voltage supply). They were first observed in 1859 by German physicist Julius Plücker and Johann Wilhelm Hittorf, and were named in 1876 by Eugen Goldstein ''Kathodenstrahlen'', or cathode rays. In 1897, British physicist J. J. Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, which was later named the ''electron''. Cathode-ray tubes (CRTs) use a focused beam of electrons deflected by electric or magnetic fields to render an image on a screen. Description Cathode rays are so named because they are emitted by the negative electrode, or cathode, in a vacuum tube. To release electrons into the tube, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after. Fluorescence has many practical applications, including mineralogy, gemology, medicine, chemical sensors (fluorescence spectroscopy), fluorescent labelling, dyes, biological detectors, cosmic-ray detection, vacu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials depending on the type of battery. The electrophore, invented by Johan Wilcke, was an early version of an electrode used to study static electricity. Anode and cathode in electrochemical cells Electrodes are an essential part of any battery. The first electrochemical battery made was devised by Alessandro Volta and was aptly named the Voltaic cell. This battery consisted of a stack of copper and zinc electrodes separated by brine-soaked paper disks. Due to fluctuation in the voltage provided by the voltaic cell it wasn't very practical. The first practical battery was invented in 1839 and named the Daniell cell after John Frederic Daniell. Still making use of the zinc–copper electrode combination. Since then many more batteries have be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Wilhelm Hittorf
Johann Wilhelm Hittorf (27 March 1824 – 28 November 1914) was a German physicist who was born in Bonn and died in Münster, Germany. Hittorf was the first to compute the electricity-carrying capacity of charged atoms and molecules (ions), an important factor in understanding electrochemical reactions. He formulated ion transport numbers and the first method for their measurements. He observed tubes with energy rays extending from a negative electrode. These rays produced a fluorescence when they hit the glass walls of the tubes. In 1876 the effect was named "cathode rays" by Eugen Goldstein. Hittorf's early investigations were on the allotropes of phosphorus and selenium. Between 1853 and 1859 his most important work was on ion movement caused by electric current. In 1853 Hittorf pointed out that some ions traveled more rapidly than others. This observation led to the concept of transport number, the fraction of the electric current carried by each ionic species. He meas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crookes Tube
A Crookes tube (also Crookes–Hittorf tube) is an early experimental electrical discharge tube, with partial vacuum, invented by English physicist William Crookes and others around 1869-1875, in which cathode rays, streams of electrons, were discovered. Developed from the earlier Geissler tube, the Crookes tube consists of a partially evacuated glass bulb of various shapes, with two metal electrodes, the cathode and the anode, one at either end. When a high voltage is applied between the electrodes, cathode rays (electrons) are projected in straight lines from the cathode. It was used by Crookes, Johann Hittorf, Julius Plücker, Eugen Goldstein, Heinrich Hertz, Philipp Lenard, Kristian Birkeland and others to discover the properties of cathode rays, culminating in J.J. Thomson's 1897 identification of cathode rays as negatively charged particles, which were later named ''electrons''. Crookes tubes are now used only for demonstrating cathode rays. Wilhelm Röntgen discovered X ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discharge Tubes
A gas-filled tube, also commonly known as a discharge tube or formerly as a Plücker tube, is an arrangement of electrodes in a gas within an insulating, temperature-resistant envelope. Gas-filled tubes exploit phenomena related to electric discharge in gases, and operate by ionizing the gas with an applied voltage sufficient to cause electrical conduction by the underlying phenomena of the Townsend discharge. A gas-discharge lamp is an electric light using a gas-filled tube; these include fluorescent lamps, metal-halide lamps, sodium-vapor lamps, and neon lights. Specialized gas-filled tubes such as krytrons, thyratrons, and ignitrons are used as switching devices in electric devices. The voltage required to initiate and sustain discharge is dependent on the pressure and composition of the fill gas and geometry of the tube. Although the envelope is typically glass, power tubes often use ceramics, and military tubes often use glass-lined metal. Both hot cathode and cold cath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julius Plücker
Julius Plücker (16 June 1801 – 22 May 1868) was a German mathematician and physicist. He made fundamental contributions to the field of analytical geometry and was a pioneer in the investigations of cathode rays that led eventually to the discovery of the electron. He also vastly extended the study of Lamé curves. Biography Early years Plücker was born at Elberfeld (now part of Wuppertal). After being educated at Düsseldorf and at the universities of Bonn, Heidelberg and Berlin he went to Paris in 1823, where he came under the influence of the great school of French geometers, whose founder, Gaspard Monge, had only recently died. In 1825 he returned to Bonn, and in 1828 was made professor of mathematics. In the same year he published the first volume of his ''Analytisch-geometrische Entwicklungen'', which introduced the method of "abridged notation". In 1831 he published the second volume, in which he clearly established on a firm and independent basis projective ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weißensee Cemetery
Weißensee (German: ''white lake'') may refer to: Places *Weissensee (Berlin), a district of Berlin *Weißensee, Thuringia, a town in Thuringia, Germany *Weissensee, Austria, a municipality in Carinthia, Austria *Weissensee (Carinthia), a lake in Carinthia, Austria * Weißensee (Füssen), a lake in Allgäu, Bavaria, Germany People * Friedrich Weissensee (c.1560–1622), German composer and Protestant minister Other *Weissensee, a song by Neu! from their eponymous first album *Weissensee, a song by Elder_(band) from their 2019 album The Gold & Silver Sessions *Weissensee (TV series) ''Weissensee'' is a German television series. The series is set in East Berlin between 1980 and 1990 and follows two families. Outline The plot follows the Kupfer family, who are well-connected within the communist regime. Hans Kupfer and his so ..., a German television series See also * White Lake (other) {{geodis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
