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Revision as of 16:38, 18 October 2006 by 12.159.70.178 (talk) (→History)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)- This article is about the unit of length. For other uses of metre or meter, see meter (disambiguation).
Template:Unit of length The metre, or meter (US), is a measure of length. It is the basic unit of length in the metric system and in the International System of Units (SI), used around the world for general and scientific purposes. The symbol for metre is m. Historically, the metre was defined by the French Academy of Sciences as 1/10,000,000 of the distance from the equator to the north pole through Paris. Now, it is defined by the International Bureau of Weights and Measures as the distance travelled by light in absolute vacuum in 1/299,792,458 of a second. This is approximately the distance from floor to hip bone on the average barefoot man.
Decimal multiples and submultiples of the metre, such as kilometre (1000 metres) and centimetre (1/100 metre), are indicated by adding SI prefixes to metre (see table below).
History
The word metre is from the Greek metron (Template:Polytonic), "a measure" via the French mètre. Its first recorded usage in English meaning International Prototype Metre bar, made of an alloy of platinum and iridium, that was the standard from 1889 to 1960.]]
In the 1870s and in light of
SI prefixed forms of metre
SI prefixes are often employed to denote decimal multiples and submultiples of the metre. The most commonly used factors of metre are listed below in bold.
| Submultiples | Multiples | |||||
| Factor | Name | Symbol | Factor | Name | Symbol | |
| 10 | decimetre | dm | 10 | decametre | dam | |
| 10 | centimetre | cm | 10 | hectometre | hm | |
| 10 | millimetre | mm | 10 | kilometre | km | |
| 10 | micrometre | µm | 10 | megametre | Mm | |
| 10 | nanometre | nm | 10 | gigametre | Gm | |
| 10 | picometre | pm | 10 | terametre | Tm | |
| 10 | femtometre | fm | 10 | petametre | Pm | |
| 10 | attometre | am | 10 | exametre | Em | |
| 10 | zeptometre | zm | 10 | zettametre | Zm | |
| 10 | yoctometre | ym | 10 | yottametre | Ym | |
Equivalents in other units
| SI value | Other unit |
|---|---|
| 1 metre | 10000/254 ≈ 39.37 inches |
| 2.54 centimetres | 1 inch |
| 1 nanometre | 10 ångströms |
See also
- Metric system
- SI (International System of Units)
- SI prefix
- Conversion of units for comparisons with other units
- Orders of magnitude (length)
- Speed of light
References
- Bureau International des Poids et Mesures. The BIPM and the evolution of the definition of the metre. URL accessed on 2006 June 3.
- ———. Resolutions of the CGPM. URL accessed on 2006 June 3.
- Penzes, William B. at the U.S. National Institute of Standards and Technology Precision Engineering Division (2005 December 29). Time Line for the Definition of the Meter. URL accessed on 2006 June 3.
- U.S. National Institute of Standards and Technology (October 2000). The NIST Reference on Constants, Units, and Uncertainty: International System of Units (SI):
- SI base units. URL accessed on 2006 June 3.
- Definitions of the SI base units. URL accessed on 2006 June 3.
- Historical context of the SI: meter. URL accessed on 2006 June 3.
Notes
- The term “most commonly used” is based on those with more than 5 million Google hits on the American spelling.
External links
- Length—Evolution from Measurement Standard to a Fundamental Constant at U.S. NIST
- The History of the Meter By Tibo Qorl (Translated by Sibille Rouzaud)