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World Metrology Day
World Metrology Day is an event occurring on 20 May celebrating the International System of Units. The date is the anniversary of the signing of the Metre Convention in 1875. Metrology is the study of measurement. The World Metrology Day project is currently realized jointly by the BIPM and the OIML. 2019 The 2019 Metrology Day is when the changes to the International System that were decided on in 2018 come into effect, among them the replacement of the international prototype of the kilogram with a redefinition based on the Planck Constant The Planck constant, or Planck's constant, is a fundamental physical constant of foundational importance in quantum mechanics. The constant gives the relationship between the energy of a photon and its frequency, and by the mass-energy equivale .... External linksWorldMetrologyDay.org– official website See also 2019 redefinition of SI base units References May observances Unofficial observances {{measurement-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Minor Secular Observances
Lists of holidays by various categorizations. Religious holidays Abrahamic holidays (Middle Eastern) Jewish holidays *Chag HaMatzot (Feast of Unleavened bread, Unleavened Bread – 7 days of consumption of matzo with wine and avoidance of leavened foods) *Hanukkah (Feast of Dedication; Also called the Festival of Lights – Commemoration of the rededication of the Jerusalem Temple) *Pesach (Passover – Deliverance of Jews from slavery in Egypt) **Lag BaOmer (A holiday celebrated on the 33rd day of the Counting of the Omer, which occurs on the 18th day of the Hebrew month of Iyar) *Purim (Feast of Lots – Deliverance of Jews in Persia from extermination by Haman) *Reishit Katzir (Feast of Bikkurim (First-fruits), Firstfruits – Collecting and waving of grain bundles (barley or wheat); Occurs during the 7 days of unleavened bread after the Sabbath) *Rosh Hashanah (Jewish New Year – First day of Tishrei every year) *Shabbat (The 7th Day Sabbath – The day of rest and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International System Of Units
The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. Established and maintained by the General Conference on Weights and Measures (CGPM), it is the only system of measurement with an official status in nearly every country in the world, employed in science, technology, industry, and everyday commerce. The SI comprises a coherent system of units of measurement starting with seven base units, which are the second (symbol s, the unit of time), metre (m, length), kilogram (kg, mass), ampere (A, electric current), kelvin (K, thermodynamic temperature), mole (mol, amount of substance), and candela (cd, luminous intensity). The system can accommodate coherent units for an unlimited number of additional quantities. These are called coherent derived units, which can always be represented as p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre Convention
The Metre Convention (french: link=no, Convention du Mètre), also known as the Treaty of the Metre, is an international treaty that was signed in Paris on 20 May 1875 by representatives of 17 nations (Argentina, Austria-Hungary, Belgium, Brazil, Denmark, France, Germany, Italy, Peru, Portugal, Russia, Spain, Sweden and Norway, Switzerland, Ottoman Empire, United States of America, and Venezuela). The treaty created the International Bureau of Weights and Measures (BIPM), an intergovernmental organization under the authority of the General Conference on Weights and Measures ( CGPM) and the supervision of the International Committee for Weights and Measures (CIPM), that coordinates international metrology and the development of the metric system. As well as founding the BIPM and laying down the way in which the activities of the BIPM should be financed and managed, the Metre Convention established a permanent organizational structure for member governments to act in common accord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metrology
Metrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in France when a length standard taken from a natural source was proposed. This led to the creation of the decimal-based metric system in 1795, establishing a set of standards for other types of measurements. Several other countries adopted the metric system between 1795 and 1875; to ensure conformity between the countries, the Bureau International des Poids et Mesures (BIPM) was established by the Metre Convention. This has evolved into the International System of Units (SI) as a result of a resolution at the 11th General Conference on Weights and Measures (CGPM) in 1960. Metrology is divided into three basic overlapping activities: * The definition of units of measurement * The realisation of these units of measurement in practice * Traceabi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BIPM
The International Bureau of Weights and Measures (french: Bureau international des poids et mesures, BIPM) is an intergovernmental organisation, through which its 59 member-states act together on measurement standards in four areas: chemistry, ionising radiation, physical metrology, and coordinated universal time. It is based in Saint-Cloud, Paris, France. The organisation has been referred to as IBWM (from its name in English) in older literature. Structure The BIPM is supervised by the International Committee for Weights and Measures (french: Comité international des poids et mesures, CIPM), a committee of eighteen members that meet normally in two sessions per year, which is in turn overseen by the General Conference on Weights and Measures (french: Conférence générale des poids et mesures, CGPM) that meets in Paris usually once every four years, consisting of delegates of the governments of the Member States and observers from the Associates of the CGPM. These organs ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OIML
The International Organization of Legal Metrology (french: Organisation Internationale de Métrologie Légale - OIML), is an intergovernmental organization, intergovernmental organisation that was created in 1955 to promote the global harmonisation of the legal metrology procedures that underpin and facilitate international trade. Such harmonisation ensures that certification of measuring devices in one country is compatible with certification in another, thereby facilitating trade in the measuring devices and in products that rely on the measuring devices. Such products include Weighing scale, weighing devices, Taximeter, taxi meters, speedometers, agricultural measuring devices such as Moisture meter, cereal moisture meters, health related devices such as Exhaust gas, exhaust measurements and Alcohol by volume, alcohol content of drinks. Since its establishment, the OIML has developed a number of guidelines to assist its Members, particularly developing nations, to draw up approp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Prototype Of The Kilogram
The International Prototype of the Kilogram (referred to by metrologists as the IPK or Le Grand K; sometimes called the '' ur-kilogram,'' or ''urkilogram,'' particularly by German-language authors writing in English) is an object that was used to define the magnitude of the mass of the kilogram from 1889, when it replaced the Kilogramme des Archives, until 2019, when it was replaced by a new definition of the kilogram based on physical constants. During that time, the IPK and its duplicates were used to calibrate all other kilogram mass standards on Earth. The IPK is a roughly golfball-sized object made of a platinum alloy known as "Pt10Ir", which is 90% platinum and 10% iridium (by mass) and is machined into a right-circular cylinder with height equal to its diameter of about 39 millimetres to reduce its surface area. The addition of 10% iridium improved upon the all-platinum Kilogramme des Archives by greatly increasing hardness while still retaining platinum's many vir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redefinition Of SI Base Units
In 2019, four of the seven SI base units specified in the International System of Quantities were redefined in terms of natural physical constants, rather than human artifacts such as the standard kilogram. Effective 20 May 2019, the 144th anniversary of the Metre Convention, the kilogram, ampere, kelvin, and mole are now defined by setting exact numerical values, when expressed in SI units, for the Planck constant ('), the elementary electric charge ('), the Boltzmann constant (), and the Avogadro constant (), respectively. The second, metre, and candela had previously been redefined using physical constants. The four new definitions aimed to improve the SI without changing the value of any units, ensuring continuity with existing measurements. In November 2018, the 26th General Conference on Weights and Measures (CGPM) unanimously approved these changes, The conference ran from 13–16 November and the vote on the redefinition was scheduled for the last day. Kazakhstan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planck Constant
The Planck constant, or Planck's constant, is a fundamental physical constant of foundational importance in quantum mechanics. The constant gives the relationship between the energy of a photon and its frequency, and by the mass-energy equivalence, the relationship between mass and frequency. Specifically, a photon's energy is equal to its frequency multiplied by the Planck constant. The constant is generally denoted by h. The reduced Planck constant, or Dirac constant, equal to the constant divided by 2 \pi, is denoted by \hbar. In metrology it is used, together with other constants, to define the kilogram, the SI unit of mass. The SI units are defined in such a way that, when the Planck constant is expressed in SI units, it has the exact value The constant was first postulated by Max Planck in 1900 as part of a solution to the ultraviolet catastrophe. At the end of the 19th century, accurate measurements of the spectrum of black body radiation existed, but the distribut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2019 Redefinition Of SI Base Units
In 2019, four of the seven SI base units specified in the International System of Quantities were redefined in terms of natural physical constants, rather than human artifacts such as the standard kilogram. Effective 20 May 2019, the 144th anniversary of the Metre Convention, the kilogram, ampere, kelvin, and mole are now defined by setting exact numerical values, when expressed in SI units, for the Planck constant ('), the elementary electric charge ('), the Boltzmann constant (), and the Avogadro constant (), respectively. The second, metre, and candela had previously been redefined using physical constants. The four new definitions aimed to improve the SI without changing the value of any units, ensuring continuity with existing measurements. In November 2018, the 26th General Conference on Weights and Measures (CGPM) unanimously approved these changes, The conference ran from 13–16 November and the vote on the redefinition was scheduled for the last day. Kazakhstan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
May Observances
May is the fifth month of the year in the Julian and Gregorian calendars and is the third of seven months to have a length of 31 days. May is a month of spring in the Northern Hemisphere, and autumn in the Southern Hemisphere. Therefore, May in the Southern Hemisphere is the seasonal equivalent of November in the Northern Hemisphere and vice versa. Late May typically marks the start of the summer vacation season in the United States (Memorial Day) and Canada (Victoria Day) that ends on Labor Day, the first Monday of September. May (in Latin, ''Maius'') was named for the Greek goddess Maia, who was identified with the Roman era goddess of fertility, Bona Dea, whose festival was held in May. Conversely, the Roman poet Ovid provides a second etymology, in which he says that the month of May is named for the ''maiores,'' Latin for "elders," and that the following month (June) is named for the ''iuniores,'' or "young people" (''Fasti VI.88''). Eta Aquariids meteor shower appea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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