Difference between revisions of "Realization"
Physchim62 (talk | contribs) (Created page with 'In metrology, the '''realization''' of a measurement unit or a measurement scale is the practical method by which the unit can be measured (or the scale put into prac…') |
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| − | In [[metrology]], the '''realization''' of a [[measurement unit]] or a [[measurement scale]] is the practical method by which the unit can be measured (or the scale put into practice). The realization of a unit or of a scale creates one or more '''measurement standards''' against which an unknown [[physical quantity]] of the same kind can be compared.<ref name="VIM">{{VIM3rd|pages=46–47}}.</ref> | + | In [[metrology]], the '''realization''' (or '''embodiment''') of a [[measurement unit]] or a [[measurement scale]] is the practical method by which the unit can be measured (or the scale put into practice). The realization of a unit or of a scale creates one or more '''measurement standards''' against which an unknown [[physical quantity]] of the same kind can be compared.<ref name="VIM">{{VIM3rd|pages=46–47}}.</ref> |
There are three general methods of realizing a unit or a scale. The first and most obvious is simply to follow the definition of the unit or scale, for example by measuring the [[distance]] travelled by [[light]] in [[vacuum]] in {{frac|299,792,458}} of a [[second]] to realize the [[metre]]. The second method is to use a physical phenomenon which is accepted to be equivalent to the definition, for example realizing the metre by laser [[interferometry]] with a measured [[frequency]] of light. The third method is to have a physical standard, for example the now-obsolete [[International Prototype Metre]].<ref name="VIM"/> | There are three general methods of realizing a unit or a scale. The first and most obvious is simply to follow the definition of the unit or scale, for example by measuring the [[distance]] travelled by [[light]] in [[vacuum]] in {{frac|299,792,458}} of a [[second]] to realize the [[metre]]. The second method is to use a physical phenomenon which is accepted to be equivalent to the definition, for example realizing the metre by laser [[interferometry]] with a measured [[frequency]] of light. The third method is to have a physical standard, for example the now-obsolete [[International Prototype Metre]].<ref name="VIM"/> | ||
Revision as of 14:40, 29 July 2010
In metrology, the realization (or embodiment) of a measurement unit or a measurement scale is the practical method by which the unit can be measured (or the scale put into practice). The realization of a unit or of a scale creates one or more measurement standards against which an unknown physical quantity of the same kind can be compared.[1]
There are three general methods of realizing a unit or a scale. The first and most obvious is simply to follow the definition of the unit or scale, for example by measuring the distance travelled by light in vacuum in 1⁄299,792,458 of a second to realize the metre. The second method is to use a physical phenomenon which is accepted to be equivalent to the definition, for example realizing the metre by laser interferometry with a measured frequency of light. The third method is to have a physical standard, for example the now-obsolete International Prototype Metre.[1]
References
- ↑ 1.0 1.1 International vocabulary of metrology — Basic and general concepts and associated terms (VIM), 3rd ed.; International Bureau of Weights and Measures: Sèvres, France, 2008; pp 46–47, <http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf>.
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