Information about General Conference On Weights And Measures
The General Conference on Weights and Measures is the English name of the Conférence générale des poids et mesures (CGPM, never GCWM). It is one of the three organizations established to maintain the International System of Units (SI) under the terms of the Convention du Mètre (Metre Convention) of 1875. It meets in Paris every four to six years. In 2002 the CGPM represented 51 member states and ten further associate members. As of 2005, the number of associates has grown to 17.[1]
The carat is a unit of mass used for measuring gems and pearls, and is exactly 200 milligrams.
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CGPM Meetings
| 1st (1889) | kilogram defined as mass of the international prototype kilogram (IPK) made of platinum-iridium and kept at the International Bureau of Weights and Measures (Bureau international des poids et mesures), Sèvres, France. International prototype metre sanctioned. |
| 2nd (1897) | No resolutions were passed by the 2nd CGPM. |
| 3rd (1901) | litre redefined as volume of 1 kg of water. Clarified that kilograms are units of mass, "standard weight" defined, standard acceleration of gravity defined endorsing use of grams force and making them well-defined. |
| 4th (1907) | carat = 200 mg adopted. |
| 5th (1913) | International Temperature Scale proposed. |
| 6th (1921) | Metre Convention revised. |
| 7th (1927) | Consultative Committee for Electricity (CCE) created. |
| 8th (1933) | need for absolute electrical unit identified. |
| 9th (1948) | ampere, bar, coulomb, farad, henry, joule, newton, ohm, volt, watt, weber defined. Chose degree Celsius from among the three names then in use. l (lowercase L) adopted as symbol for litre. Both the comma and dot on a line are accepted as decimal marker symbols. Symbols for the stere and second changed [1]. The universal return to the Long Scale numbering system was proposed but not adopted. |
| 10th (1954) | kelvin, standard atmosphere defined. International System of Units (metre, kilogram, second, ampere, kelvin, candela) began. |
| 11th (1960) | metre redefined in terms of wavelengths of light. Units: hertz, lumen, lux, tesla adopted. New metric system given the official symbol SI for Système International d'Unités, the "modernized metric system". Prefixes pico-, nano-, micro-, mega-, giga- and tera- confirmed. |
| 12th (1964) | original definition of litre = 1 dm³ restored. atto- and femto- prefixes. |
| 13th (1967) | second redefined as duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom at a temperature of 0 K. Degree Kelvin renamed kelvin. Candela redefined. |
| 14th (1971) | new SI base unit mole defined. pascal, siemens approved. |
| 15th (1975) | peta- and exa- prefixes. gray and becquerel radiological units. |
| 16th (1979) | candela, sievert defined. Both l and L provisionally allowed as symbols for litre. |
| 17th (1983) | metre redefined in terms of the speed of light, but keeps same length. |
| 18th (1987) | conventional values adopted for Josephson constant, KJ, and von Klitzing constant, RK, preparing the way for alternative definitions of the ampere and kilogram. |
| 19th (1991) | new prefixes yocto-, zepto-, zetta- and yotta-. |
| 20th (1995) | SI supplementary units (radian and steradian) become derived units. |
| 21st (1999) | new SI derived unit, the katal = mole per second, for the expression of catalytic activity. |
| 22nd (2003) | a comma or a dot on a line are reaffirmed as decimal marker symbols, and not as grouping symbols in order to facilitate reading; "neither dots nor commas are ever inserted in the spaces between groups". Comma remains the preferred decimal separator " ... , some international bodies, including some international standards organizations, specify the decimal marker to be the comma on the line in all languages, ..." [2]. |
| 23nd (2007) |
See also
- International Bureau of Weights and Measures (BIPM)
- International Committee for Weights and Measures
- Institute for Reference Materials and Measurements (IRMM)
- National Institute of Standards and Technology (NIST)
References
Si, si, or SI may refer to (all SI unless otherwise stated):
In language:
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In language:
- One of two Italian words:
- sì (accented) for "yes"
- si
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The Convention du Mètre of May 20, 1875 is an international treaty that established three organizations to oversee the keeping of metric standards. It is written in French, and called in English the Metre Convention, or, in the United States, the
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18th century - 19th century - 20th century
1840s 1850s 1860s - 1870s - 1880s 1890s 1900s
1872 1873 1874 - 1875 - 1876 1877 1878
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Subjects: Archaeology - Architecture -
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1840s 1850s 1860s - 1870s - 1880s 1890s 1900s
1872 1873 1874 - 1875 - 1876 1877 1878
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Subjects: Archaeology - Architecture -
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Ville de Paris
City flag City coat of arms
Motto: Fluctuat nec mergitur
(Latin: "Tossed by the waves, she does not sink")
The Eiffel Tower in Paris, as seen from the esplanade du Trocadéro.
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City flag City coat of arms
Motto: Fluctuat nec mergitur
(Latin: "Tossed by the waves, she does not sink")
The Eiffel Tower in Paris, as seen from the esplanade du Trocadéro.
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20th century - 21st century - 22nd century
1970s 1980s 1990s - 2000s - 2010s 2020s 2030s
1999 2000 2001 - 2002 - 2003 2004 2005
2002 by topic:
News by month
Jan - Feb - Mar - Apr - May - Jun
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1970s 1980s 1990s - 2000s - 2010s 2020s 2030s
1999 2000 2001 - 2002 - 2003 2004 2005
2002 by topic:
News by month
Jan - Feb - Mar - Apr - May - Jun
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20th century - 21st century - 22nd century
1970s 1980s 1990s - 2000s - 2010s 2020s 2030s
2002 2003 2004 - 2005 - 2006 2007 2008
2005 by topic:
News by month
Jan - Feb - Mar - Apr - May - Jun
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1970s 1980s 1990s - 2000s - 2010s 2020s 2030s
2002 2003 2004 - 2005 - 2006 2007 2008
2005 by topic:
News by month
Jan - Feb - Mar - Apr - May - Jun
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19th century - 20th century
1850s 1860s 1870s - 1880s - 1890s 1900s 1910s
1886 1887 1888 - 1889 - 1890 1891 1892
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1850s 1860s 1870s - 1880s - 1890s 1900s 1910s
1886 1887 1888 - 1889 - 1890 1891 1892
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kilogram or kilogramme (symbol: kg) is the SI base unit of mass. The kilogram is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.
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4, 5, 6
(mildly basic oxide)
Electronegativity 2.28 (scale Pauling)
Ionization energies 1st: 870 kJ/mol
2nd: 1791 kJ/mol
Atomic radius 135 pm
Atomic radius (calc.
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(mildly basic oxide)
Electronegativity 2.28 (scale Pauling)
Ionization energies 1st: 870 kJ/mol
2nd: 1791 kJ/mol
Atomic radius 135 pm
Atomic radius (calc.
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4, 6
(mildly basic oxide)
Electronegativity 2.20 (scale Pauling)
Ionization energies 1st: 880 kJ/mol
2nd: 1600 kJ/mol
Atomic radius 135 pm
Atomic radius (calc.
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(mildly basic oxide)
Electronegativity 2.20 (scale Pauling)
Ionization energies 1st: 880 kJ/mol
2nd: 1600 kJ/mol
Atomic radius 135 pm
Atomic radius (calc.
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The International Bureau of Weights and Measures is the English translation of the name of the Bureau international des poids et mesures (BIPM), a standards organisation, one of the three organisations established to maintain the International System of Units (SI)
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Commune of
Sèvres
Vue de Pont de Sèvres, by Henri Rousseau (1908)
Location
Paris and inner ring départements
Coordinates
Administration
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Sèvres
Vue de Pont de Sèvres, by Henri Rousseau (1908)
Location
Paris and inner ring départements
Coordinates
Administration
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18th century - 19th century - 20th century
1860s 1870s 1880s - 1890s - 1900s 1910s 1920s
1894 1895 1896 - 1897 - 1898 1899 1900
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Subjects: Archaeology - Architecture -
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1860s 1870s 1880s - 1890s - 1900s 1910s 1920s
1894 1895 1896 - 1897 - 1898 1899 1900
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19th century - 20th century - 21st century
1870s 1880s 1890s - 1900s - 1910s 1920s 1930s
1898 1899 1900 - 1901 - 1902 1903 1904
Year 1901 (MCMI
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1870s 1880s 1890s - 1900s - 1910s 1920s 1930s
1898 1899 1900 - 1901 - 1902 1903 1904
Year 1901 (MCMI
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The litre or liter (see spelling differences) is a unit of volume. There are two official symbols, namely the Latin letter L both in lower and upper case: l and L.
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Standard gravity, usually denoted by g0 or gn, is the nominal acceleration due to gravity at the Earth's surface at sea level. By definition it is equal to exactly 9.80665 m·s−2 (approx. 32.174 ft·s−2).
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19th century - 20th century - 21st century
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1904 1905 1906 - 1907 - 1908 1909 1910
Year 1907 (MCMVII
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1904 1905 1906 - 1907 - 1908 1909 1910
Year 1907 (MCMVII
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- For other uses of the word carat, see Carat.
The carat is a unit of mass used for measuring gems and pearls, and is exactly 200 milligrams.
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19th century - 20th century - 21st century
1880s 1890s 1900s - 1910s - 1920s 1930s 1940s
1910 1911 1912 - 1913 - 1914 1915 1916
Year 1913 (MCMXIII
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1910 1911 1912 - 1913 - 1914 1915 1916
Year 1913 (MCMXIII
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19th century - 20th century - 21st century
1890s 1900s 1910s - 1920s - 1930s 1940s 1950s
1918 1919 1920 - 1921 - 1922 1923 1924
Year 1921 (MCMXXI
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1918 1919 1920 - 1921 - 1922 1923 1924
Year 1921 (MCMXXI
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20th century - 21st century
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1924 1925 1926 - 1927 - 1928 1929 1930
Year 1927 (MCMXXVII
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1924 1925 1926 - 1927 - 1928 1929 1930
Year 1927 (MCMXXVII
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1900s 1910s 1920s - 1930s - 1940s 1950s 1960s
1930 1931 1932 - 1933 - 1934 1935 1936
Year 1933 (MCMXXXIII
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1930 1931 1932 - 1933 - 1934 1935 1936
Year 1933 (MCMXXXIII
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1910s 1920s 1930s - 1940s - 1950s 1960s 1970s
1945 1946 1947 - 1948 - 1949 1950 1951
Year 1948 (MCMXLVIII
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1910s 1920s 1930s - 1940s - 1950s 1960s 1970s
1945 1946 1947 - 1948 - 1949 1950 1951
Year 1948 (MCMXLVIII
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ampere, in practice often shortened to amp, (symbol: A) is a unit of electric current, or amount of electric charge per second. The ampere is an SI base unit, and is named after André-Marie Ampère, one of the main discoverers of electromagnetism.
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The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. They are not SI units, but they are accepted for use with the SI.
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The coulomb (symbol: C) is the SI unit of electric charge. It is named after Charles-Augustin de Coulomb.
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Definition
1 coulomb is the amount of electric charge transported by a current of 1 ampere in 1 second...... Click the link for more information.
farad (symbol: F) is the SI unit of capacitance. It is named after the British physicist Michael Faraday.
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Definition
The farad is defined as the amount of capacitance for which a potential difference of one volt results in a static charge of one coulomb...... Click the link for more information.
The henry (symbol: H) is the SI unit of inductance. It is named after Joseph Henry (1797-1878), the American scientist who discovered electromagnetic induction independently of and at about the same time as Michael Faraday (1791-1867) in England.
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The joule (IPA: [dʒuːl] or [dʒaʊl]) (symbol: J) is the SI unit of energy.
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The newton (symbol: N) is the SI derived unit of force, named after Sir Isaac Newton in recognition of his work on classical mechanics.
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Definition
A newton..... Click the link for more information.
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