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International Prototype Metre
During the French Revolution, the traditional units of measure were to be replaced by consistent measures based on natural phenomena. As a base unit of length, scientists had favoured the seconds pendulum (a pendulum with a half-period of one second) one century earlier, but this was rejected as it had been discovered that this length varied from place to place with local gravity. A new unit of length, the ''metre'' was introduced – defined as one ten-millionth of the shortest distance from the North Pole to the equator passing through Paris, assuming an Earth flattening of . Following the arc measurement of Delambre and Méchain, the historical French official standard of the metre was made available in the form of the , a platinum bar held in Paris. During the mid nineteenth century, following the American Revolution and independence of Latin America, the metre gained adoption in Americas, particularly in scientific usage, and it was officially established as an inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric Standards Rijksmuseum
Metric or metrical may refer to: Measuring * Metric system, an internationally adopted decimal system of measurement * An adjective indicating relation to measurement in general, or a noun describing a specific type of measurement Mathematics In mathematics, metric may refer to one of two related, but distinct concepts: * A function which measures distance between two points in a metric space * A metric tensor, in differential geometry, which allows defining lengths of curves, angles, and distances in a manifold Natural sciences * Metric tensor (general relativity), the fundamental object of study in general relativity, similar to the gravitational field in Newtonian physics * Senses related to measurement: ** Metric system, an internationally adopted decimal system of measurement ** Metric units, units related to a metric system ** International System of Units, or ''Système International'' (SI), the most widely used metric system * METRIC, a model that uses Landsat satell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standardisation
Standardization (American English) or standardisation (British English) is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments. Standardization can help maximize compatibility, interoperability, safety, repeatability, efficiency, and quality. It can also facilitate a normalization of formerly custom processes. In social sciences, including economics, the idea of ''standardization'' is close to the solution for a coordination problem, a situation in which all parties can realize mutual gains, but only by making mutually consistent decisions. Divergent national standards impose costs on consumers and can be a form of non-tariff trade barrier. History Early examples Standard weights and measures were developed by the Indus Valley civilization.Iwata, Shigeo (2008), "Weights and Measures in the Indus Valley", ''Encyclopaedia of the History of S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giovanni Battista Riccioli
Giovanni Battista Riccioli (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order. He is known, among other things, for his experiments with pendulums and with falling bodies, for his discussion of 126 arguments concerning the motion of the Earth, and for introducing the current scheme of lunar nomenclature. He is also widely known for discovering the first double star. He argued that the rotation of the Earth should reveal itself because on a rotating Earth, the ground moves at different speeds at different times. Biography Riccioli was born in Ferrara, Italy, Ferrara. He entered the Society of Jesus on 6 October 1614. After completing his novitiate, he began to study humanities in 1616, pursuing those studies first at Ferrara, and then at Piacenza. From 1620 to 1628 he studied philosophy and theology at the College of Parma. Parma Jesuits had developed a strong program of experimentation, such as with falling bodies. One of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pendulum
A pendulum is a device made of a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. When released, the restoring force acting on the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum and also to a slight degree on the amplitude, the width of the pendulum's swing. Pendulums were widely used in early mechanical clocks for timekeeping. The regular motion of pendulums was used for timekeeping and was the world's most accurate timekeeping technology until the 1930s. The pendulum clock invented by Christiaan Huygens in 1656 became the world's standard timekeeper, used in homes and offices for 270 years, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galileo
Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a polymath. He was born in the city of Pisa, then part of the Duchy of Florence. Galileo has been called the father of observational astronomy, modern-era classical physics, the scientific method, and modern science. Galileo studied speed and velocity, gravity and free fall, the principle of relativity, inertia, projectile motion and also worked in applied science and technology, describing the properties of the pendulum and " hydrostatic balances". He was one of the earliest Renaissance developers of the thermoscope and the inventor of various military compasses. With an improved telescope he built, he observed the stars of the Milky Way, the phases of Venus, the four largest satellites of Jupiter, Saturn's rings, lunar craters and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Revolution
The Scientific Revolution was a series of events that marked the emergence of History of science, modern science during the early modern period, when developments in History of mathematics#Mathematics during the Scientific Revolution, mathematics, History of physics#Scientific Revolution, physics, History of astronomy#Renaissance Period, astronomy, History of biology#Renaissance and early modern developments, biology (including History of anatomy, human anatomy) and History of chemistry#17th and 18th centuries: Early chemistry, chemistry transformed the views of society about nature.Galilei, Galileo (1974) ''Two New Sciences'', trans. Stillman Drake, (Madison: Univ. of Wisconsin Pr. pp. 217, 225, 296–67.Clagett, Marshall (1961) ''The Science of Mechanics in the Middle Ages''. Madison, Univ. of Wisconsin Pr. pp. 218–19, 252–55, 346, 409–16, 547, 576–78, 673–82#Hannam, Hannam, p. 342 The Scientific Revolution took place in Europe in the second half of the Renaissance pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Physics Teacher
''The Physics Teacher'' is a peer-reviewed academic journal published by AIP Publishing on behalf of the American Association of Physics Teachers covering the history and philosophy of physics, applied physics, physics education (curriculum developments, pedagogy, instructional lab equipment, etc.), and book reviews. It was established in 1963 and the current editor-in-chief is Gary White (George Washington University). Paul G. Hewitt is a regular contributor to The Physics Teacher. See also * ''American Journal of Physics The ''American Journal of Physics'' is a monthly, peer-reviewed scientific journal published by the American Association of Physics Teachers and the American Institute of Physics. The editor-in-chief is Beth Parks of Colgate University."Current ...'' * '' European Journal of Physics'' References External links * Monthly journals American Institute of Physics academic journals Academic journals established in 1963 English-language journals Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yard
The yard (symbol: yd) is an English units, English unit of length in both the British imperial units, imperial and US United States customary units, customary systems of measurement equalling 3 foot (unit), feet or 36 inches. Since 1959 it has been by international yard and pound, international agreement standardized as exactly 0.9144 Metre, meter. A distance of 1,760 yards is equal to 1 mile. The theoretical survey foot, US survey yard is very slightly longer. Name The term, ''yard'' derives from the Old English , etc., which was used for branches, staves and measuring rods. It is first attested in the late 7th century Ine of Wessex#Laws, laws of Ine of Wessex, wherein the "yard of land" mentioned is the virgate, yardland, an old English unit of tax assessment equal to hide (unit), hide. Around the same time the Lindisfarne Gospels account of the messengers from John the Baptist in the Gospel of Matthew used it for a branch swayed by the wind. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Of Light In Vacuum
The speed of light in vacuum, commonly denoted , is a universal physical constant exactly equal to ). It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time interval of second. The speed of light is the same for all observers, no matter their relative velocity. It is the upper limit for the speed at which information, matter, or energy 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 sensitive measurements, their finite speed has noticeable effects. Much starlight viewed on Earth is from the distant past, allowing humans to study the history of the universe by viewing distant objects. When communicating with distant space probes, it can take hours for signals to travel. In computing, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Of Light
The speed of light in vacuum, commonly denoted , is a universal physical constant exactly equal to ). It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time interval of second. The speed of light is invariant (physics), the same for all observers, no matter their relative velocity. It is the upper limit for the speed at which Information#Physics_and_determinacy, information, matter, or energy can travel through Space#Relativity, 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 sensitive measurements, their finite speed has noticeable effects. Much starlight viewed on Earth is from the distant past, allowing humans to study the history of the universe by viewing distant objects. When Data communication, comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Krypton-86
There are 34 known isotopes of krypton (36Kr) with atomic mass numbers from 67 to 103. Naturally occurring krypton is made of five stable isotopes and one () which is slightly radioactive with an extremely long half-life, plus traces of radioisotopes that are produced by cosmic rays in the atmosphere. List of isotopes , -id=Krypton-67 , rowspan=2, 67Kr , rowspan=2 style="text-align:right" , 36 , rowspan=2 style="text-align:right" , 31 , rowspan=2, 66.98331(46)# , rowspan=2, 7.4(29) ms , β+? (63%) , 67Br , rowspan=2, 3/2-# , rowspan=2, , rowspan=2, , - , 2p (37%) , 65Se , -id=Krypton-68 , rowspan=3, 68Kr , rowspan=3 style="text-align:right" , 36 , rowspan=3 style="text-align:right" , 32 , rowspan=3, 67.97249(54)# , rowspan=3, 21.6(33) ms , β+, p (>90%) , 67Se , rowspan=3, 0+ , rowspan=3, , rowspan=3, , - , β+? (98.7%) , 70Br , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β+, p (<1.3%) , 69Se , -id=Krypton-71 , row ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
