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Edwin Herbert Hall
Edwin Herbert Hall (November 7, 1855 – November 20, 1938) was an American physicist, who discovered the eponymous Hall effect. Hall conducted thermoelectric research and also wrote numerous physics textbooks and laboratory manuals. Biography Hall was born in Gorham, Maine, U.S. Hall did his undergraduate work at Bowdoin College, Brunswick, Maine, graduating in 1875. He was the principal of Gould Academy in 1875–1876 and the principal of Brunswick High School in 1876–1877. He did his graduate schooling and research, and earned his Ph.D. degree (1880), at the Johns Hopkins University where his seminal experiments were performed. The Hall effect was discovered by Hall in 1879, while working on his doctoral thesis in Physics under the supervision of Henry Augustus Rowland. Hall's experiments consisted of exposing thin gold leaf (and, later, using various other materials) on a glass plate and tapping off the gold leaf at points down its length. The effect is a potential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorham, Maine
Gorham is a town in Cumberland County, Maine, United States. The population was 18,336 at the 2020 United States Census. In addition to its urban village center known as Gorham Village or simply "the Village," the town encompasses a number of smaller, unincorporated villages and hamlets with distinct historical identities, including South Gorham, West Gorham, Little Falls, White Rock, and North Gorham. Gorham is home to one of the three campuses of the University of Southern Maine. In 2013, Gorham was voted second-best town in Maine after Hampden by a financial website. Gorham is part of the Portland– South Portland–Biddeford, Maine metropolitan statistical area. Initially named Narragansett Number 7, the village was renamed Gorhamtown Plantation in honor of the famous New England Ranger John Gorham I, the great grandfather of John Gorham 4th. History First called Narragansett Number 7 was one of seven townships granted by the Massachusetts General Court to soldiers (or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current (electricity)
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In an electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons. The SI unit of electric current is the ampere, or ''amp'', which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit. Electric current is measured using a device called an ammeter. Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers. In ordinary conduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Phenomena Named After People
This is a list of scientific phenomena and concepts named after people (eponymous phenomena). For other lists of eponyms, see eponym. A * Abderhalden–Fauser reaction – Emil Abderhalden and August Fauser (1856–1938) * Abney effect – William de Wiveleslie Abney * Abrikosov lattice – Alexei Alexeyevich Abrikosov * Aharonov–Bohm effect – Yakir Aharonov and David Bohm * Alfvén wave – Hannes Olof Gösta Alfvén * Alhazen's problem – Alhazen * Allais effect – Maurice Allais * Allee effect – Warder Clyde Allee * Amdahl's law, a.k.a. Amdahl's argument – Gene Amdahl * Ampère's law – André-Marie Ampère * Anderson–Higgs mechanism (a.k.a. Higgs mechanism) – Peter Higgs and Philip Warren Anderson * Anderson–Darling test – Theodore Wilbur Anderson and Donald A. Darling * Andreev reflection – Alexander F. Andreev * Apgar score – Virginia Apgar * Arago spot – Dominique François Jean Arago * Michaelis–Arbuzov reaction – Aleksandr Ermin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Smith (chemist)
Prof Alexander Smith FRSE LLD (11 September 1865 – 8 September 1922) was a Scottish chemist, who spent his working life teaching in the universities of America. Biography He was born at 4 Nelson Street in Edinburgh's New Town, the son of Isabella (née Carter) and Alexander W. Smith, a music teacher. His paternal grandfather was the sculptor Alexander Smith. The family moved to 4 West Castle Road in the Merchiston district while he was young. He was educated at Edinburgh Collegiate School. He studied sciences (later specialising in chemistry) at the University of Edinburgh. He was taught mathematics by George Chrystal, physics by Peter Guthrie Tait and chemistry by Alexander Crum Brown. He graduated BSc in 1886. During his university years he showed a keen interest in astronomy and published four papers on the subject. He went to Germany in 1886 for further postgraduate studies and gained his doctorate at the University of Munich under Prof Rainer Ludwig Claisen in Baeyer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joseph Young Bergen
Joseph Young Bergen (February 22, 1851 – October 10, 1917) was an American botanist. Career Bergen was born in Red Beach, Maine. He graduated in 1872 from Antioch College, and was for a time successively a member of the Ohio Geological Survey and professor of natural sciences at Lombard College. In 1883, he became principal of the Peabody, Massachusetts high school and subsequently an instructor at the English High School of Boston (1889-1901). He was elected a Fellow of the American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ... in 1915. Family He married his fellow Antioch College graduate Fanny Dickerson on the 28 June 1876. They would write ''A Primer of Darwinism and Organic Evolution'' together, published in 1890. Fanny published numerous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, quantum field theory, quantum technology, and quantum information science. Classical physics, the collection of theories that existed before the advent of quantum mechanics, describes many aspects of nature at an ordinary (macroscopic) scale, but is not sufficient for describing them at small (atomic and subatomic) scales. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large (macroscopic) scale. Quantum mechanics differs from classical physics in that energy, momentum, angular momentum, and other quantities of a bound system are restricted to discrete values ( quantization); objects have characteristics of both particles and waves (wave–particle duality); and there are limits to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Hall Effect
The quantum Hall effect (or integer quantum Hall effect) is a quantized version of the Hall effect which is observed in two-dimensional electron systems subjected to low temperatures and strong magnetic fields, in which the Hall resistance exhibits steps that take on the quantized values : R_ = \frac = \frac , where is the Hall voltage, is the channel current, is the elementary charge and is Planck's constant. The divisor can take on either integer () or fractional () values. Here, is roughly but not exactly equal to the filling factor of Landau levels. The quantum Hall effect is referred to as the integer or fractional quantum Hall effect depending on whether is an integer or fraction, respectively. The striking feature of the integer quantum Hall effect is the persistence of the quantization (i.e. the Hall plateau) as the electron density is varied. Since the electron density remains constant when the Fermi level is in a clean spectral gap, this situation corresp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called ''centigrade''), the Fahrenheit scale (°F), and the Kelvin scale (K), the latter being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero, i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in the third law of thermodynamics. It would be impossible to extract energy as heat from a body at that temperature. Temperature is important in all fields of natur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hall-effect Thruster
In spacecraft propulsion, a Hall-effect thruster (HET) is a type of ion thruster in which the propellant is accelerated by an electric field. Hall-effect thrusters (based on the discovery by Edwin Hall) are sometimes referred to as Hall thrusters or Hall-current thrusters. Hall effect, Hall-effect thrusters use a magnetic field to limit the electrons' axial motion and then use them to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume. The Hall-effect thruster is classed as a moderate specific impulse (1,600s) space propulsion technology and has benefited from considerable theoretical and experimental research since the 1960s. Hall thrusters operate on a variety of propellants, the most common being xenon and krypton. Other propellants of interest include argon, bismuth, iodine, magnesium, zinc and adamantane. Hall thrusters are able to accelerate their exhaust to effective exhaust velocity, speeds between 10 and 80 k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rumford Chair Of Physics
The Rumford Chair of Physics (originally the Rumford Chair and Lectureship on the Application of Science to the Useful Arts) is an endowed professorship established at Harvard University in 1816 under the will of Benjamin Thompson, Count Rumford. Endowment Specifically, an initial annuity of $1000 (with reversion of certain further substantial annuities) was bequeathed “for the purpose of founding a new institution and professorship, in order to teach by regular courses of academical and public lectures, accompanied with proper experiments, the utility of the physical and mathematical sciences for the improvement of the useful arts, and for the extension of the industry, prosperity, happiness, and well-being of society.” The centrality of “useful” knowledge, in contradistinction to the classical tradition then dominant at Harvard, was further emphasised by a stipulation that the professorship was to be held outside of the philosophy department. History The first incu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Trowbridge (physicist)
John Trowbridge (August 5, 1843 – February 18, 1923) was an American physicist, noted for his research into electricity and magnetism, and for his innovations in scientific education. Early life Born into a long-established New England family, John Trowbridge could trace his roots in Massachusetts and Connecticut back to the early seventeenth century. His father, John Howe Trowbridge, was a graduate of Harvard Medical School, but did not pursue a professional career, having inherited a sufficient fortune to finance a life of ease. Evidently this state of affairs did not last, however, and the younger Trowbridge would later recount that he was obliged to support himself in youth by monetising his talents as a painter. Also an accomplished pianist and writer, a career in arts and letters seemingly beckoned, but pragmatic considerations led him ultimately to pursuit of the sciences. Academic career Trowbridge studied physics at the Lawrence Scientific School of Harvard Univers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Professor
Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who professes". Professors are usually experts in their field and teachers of the highest rank. In most systems of List of academic ranks, academic ranks, "professor" as an unqualified title refers only to the most senior academic position, sometimes informally known as "full professor". In some countries and institutions, the word "professor" is also used in titles of lower ranks such as associate professor and assistant professor; this is particularly the case in the United States, where the unqualified word is also used colloquially to refer to associate and assistant professors as well. This usage would be considered incorrect among other academic communities. However, the otherwise unqualified title "Professor" designated with a capital let ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
