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G. J. Stoney
George Johnstone Stoney FRS (15 February 1826 – 5 July 1911) was an Irish physicist. He is most famous for introducing the term ''electron'' as the "fundamental unit quantity of electricity". He had introduced the concept, though not the word, as early as 1874, initially naming it "electrine", and the word itself came in 1891. He published around 75 scientific papers during his lifetime. Education and employment Stoney was born at Oakley Park, near Birr, County Offaly, in the Irish Midlands, the son of George Stoney (1792–) and Anne Blood (1801–1883). The Stoney family is an old-established Anglo-Irish family. He attended Trinity College Dublin, graduating with a B.A. degree in 1848. From 1848 to 1852 he worked as an astronomy assistant to William Parsons, 3rd Earl of Rosse at Birr Castle, County Offaly, where Parsons had built the world's largest telescope, the 72-inch Leviathan of Parsonstown. Simultaneously Stoney continued to study physics and mathematics and was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birr, County Offaly
Birr (; ga, Biorra, meaning "plain of water") is a town in County Offaly, Ireland. Between 1620 and 1899 it was called Parsonstown, after the Parsons family who were local landowners and hereditary Earls of Rosse. Birr is a designated Irish ''Heritage Town'' with a carefully preserved Georgian heritage. Birr itself has graceful wide streets and elegant buildings. Many of the houses in John's Place and Oxmantown Mall have exquisite fanlight windows of the Georgian period. The town is known for Birr Castle and gardens, home of the Parsons family, and also site of the Leviathan of Parsonstown, the largest telescope in the world for over 70 years, and a large modern radio telescope. Access and transport The town is situated near the meeting of the Camcor and Little Brosna rivers, the latter flowing on into the River Shannon near Victoria Lock. The Ormond Flying Club has been in operation at Birr Airfield for over 30 years. The area has been linked with aviation for s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leviathan Of Parsonstown
Leviathan of Parsonstown, or Rosse six-foot telescope, is a historic reflecting telescope of aperture, which was the largest telescope in the world from 1845 until the construction of the Hooker Telescope in California in 1917. The Rosse six-foot telescope was built by William Parsons, 3rd Earl of Rosse on his estate, Birr Castle, at Parsonstown (now Birr in Ireland). Design and construction Parsons improved the techniques of casting, grinding and polishing large telescope mirrors from speculum metal, and constructed steam-powered grinding machines for parabolic mirrors. His mirror of 1839 was cast in smaller pieces and then fitted together before grinding and polishing; its 1840 successor was cast in a single piece. In 1842, Parsons cast his first mirror, but it took another five casts before he had two ground and polished mirrors. Speculum mirrors tarnished rapidly; with two mirrors, one could be used in the telescope while the other was being re-polished. The telescope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coulomb Constant
The Coulomb constant, the electric force constant, or the electrostatic constant (denoted , or ) is a proportionality constant in electrostatics equations. In SI base units it is equal to .Derived from ''k''e = 1/(4''πε''0) – It was named after the French physicist Charles-Augustin de Coulomb (1736–1806) who introduced Coulomb's law. Value of the constant The Coulomb constant is the constant of proportionality in Coulomb's law, :\mathbf = k_\text\frac\mathbf_r where is a unit vector in the -direction. In SI: : k_\text = \frac, where \varepsilon_0 is the vacuum permittivity. This formula can be derived from Gauss's law, Gauss' law, : Taking this integral for a sphere, radius , centered on a point charge, the electric field points radially outwards and is normal to a differential Differential (infinitesimal), surface element on the sphere with constant magnitude for all points on the sphere. : Noting that for some test charge , :\begin \mathbf &= \frac\frac\m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newtonian Constant Of Gravitation
The gravitational constant (also known as the universal gravitational constant, the Newtonian constant of gravitation, or the Cavendish gravitational constant), denoted by the capital letter , is an empirical physical constant involved in the calculation of gravitational effects in Sir Isaac Newton's law of universal gravitation and in Albert Einstein's theory of general relativity. In Newton's law, it is the proportionality constant connecting the gravitational force between two bodies with the product of their masses and the inverse square of their distance. In the Einstein field equations, it quantifies the relation between the geometry of spacetime and the energy–momentum tensor (also referred to as the stress–energy tensor). The measured value of the constant is known with some certainty to four significant digits. In SI units, its value is approximately The modern notation of Newton's law involving was introduced in the 1890s by C. V. Boys. The first im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Of Light
The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space. All forms of electromagnetic radiation, including visible light, travel at the speed of light. For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and very sensitive measurements, their finite speed has noticeable effects. Starlight viewed on Earth left the stars many years ago, allowing humans to study the history of the universe by viewing distant objects. When communicating with distant space probes, it can take minutes to hours for signals to travel from Earth to the spacecraft and vice versa. In computing, the speed of light fixes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elementary Charge
The elementary charge, usually denoted by is the electric charge carried by a single proton or, equivalently, the magnitude of the negative electric charge carried by a single electron, which has charge −1 . This elementary charge is a fundamental physical constant. In the SI system of units, the value of the elementary charge is exactly defined as e = coulombs, or 160.2176634 zeptocoulombs (zC). Since the 2019 redefinition of SI base units, the seven SI base units are defined by seven fundamental physical constants, of which the elementary charge is one. In the centimetre–gram–second system of units (CGS), the corresponding quantity is . Robert A. Millikan and Harvey Fletcher's oil drop experiment first directly measured the magnitude of the elementary charge in 1909, differing from the modern accepted value by just 0.6%. Under assumptions of the then-disputed atomic theory, the elementary charge had also been indirectly inferred to ~3% accuracy f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal charter by King Charles II as The Royal Society and is the oldest continuously existing scientific academy in the world. The society is governed by its Council, which is chaired by the Society's President, according to a set of statutes and standing orders. The members of Council and the President are elected from and by its Fellows, the basic members of the society, who are themselves elected by existing Fellows. , there are about 1,700 fellows, allowed to use the postnominal title FRS (Fellow of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fellow Of The Royal Society
Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural knowledge, including mathematics, engineering science, and medical science". Fellowship of the Society, the oldest known scientific academy in continuous existence, is a significant honour. It has been awarded to many eminent scientists throughout history, including Isaac Newton (1672), Michael Faraday (1824), Charles Darwin (1839), Ernest Rutherford (1903), Srinivasa Ramanujan (1918), Albert Einstein (1921), Paul Dirac (1930), Winston Churchill (1941), Subrahmanyan Chandrasekhar (1944), Dorothy Hodgkin (1947), Alan Turing (1951), Lise Meitner (1955) and Francis Crick (1959). More recently, fellowship has been awarded to Stephen Hawking (1974), David Attenborough (1983), Tim Hunt (1991), Elizabeth Blackburn (1992), Tim Berners-Lee (2001), Venki Ramakrishn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Museum, London
The Science Museum is a major museum on Exhibition Road in South Kensington, London. It was founded in 1857 and is one of the city's major tourist attractions, attracting 3.3 million visitors annually in 2019. Like other publicly funded national museums in the United Kingdom, the Science Museum does not charge visitors for admission, although visitors are requested to make a donation if they are able. Temporary exhibitions may incur an admission fee. It is one of the five museums in the Science Museum Group. Founding and history The museum was founded in 1857 under Bennet Woodcroft from the collection of the Royal Society of Arts and surplus items from the Great Exhibition as part of the South Kensington Museum, together with what is now the Victoria and Albert Museum. It included a collection of machinery which became the ''Museum of Patents'' in 1858, and the ''Patent Office Museum'' in 1863. This collection contained many of the most famous exhibits of what is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliostat
A heliostat (from '' helios'', the Greek word for ''sun'', and ''stat'', as in stationary) is a device that includes a mirror, usually a plane mirror, which turns so as to keep reflecting sunlight toward a predetermined target, compensating for the sun's apparent motions in the sky. The target may be a physical object, distant from the heliostat, or a direction in space. To do this, the reflective surface of the mirror is kept perpendicular to the bisector of the angle between the directions of the sun and the target as seen from the mirror. In almost every case, the target is stationary relative to the heliostat, so the light is reflected in a fixed direction. According to contemporary sources the heliostata, as it was called at first, was invented by Willem 's Gravesande (1688–1742). Other contenders are Giovanni Alfonso Borelli (1608–1679) and Daniel Gabriel Fahrenheit (1686–1736). A Heliostat designed by George Johnstone Storey is in the Science Museum Group co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecule
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (molecule), water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Association For The Advancement Of Science
The British Science Association (BSA) is a charity and learned society founded in 1831 to aid in the promotion and development of science. Until 2009 it was known as the British Association for the Advancement of Science (BA). The current Chief Executive is Katherine Mathieson. The BSA's mission is to get more people engaged in the field of science by coordinating, delivering, and overseeing different projects that are suited to achieve these goals. The BSA "envisions a society in which a diverse group of people can learn and apply the sciences in which they learn." and is managed by a professional staff located at their Head Office in the Wellcome Wolfson Building. The BSA offers a wide variety of activities and events that both recognize and encourage people to be involved in science. These include the British Science Festival, British Science Week, the CREST Awards, Huxley Summit, Media Fellowships Scheme, along with regional and local events. History Foundation The Ass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
