Metro | ||
---|---|---|
Standard | Basic units of the International System | |
Magnitude | Length | |
Symbol | m | |
Equivalences | ||
Planck units | 1 m = 6,19·10^{34} | |
Inches | 1 m = 39,37" | |
Centimeters | 1 m = 100 cm | |
The meter (symbol: m ) ^{[ 1 ]} is the coherent unit of length in the International System of Units . It is defined as the distance that light travels in a vacuum in an interval of 1/299 792 458 s . ^{[ 2 ]}
History of the metro and its definitions
Throughout history, attempts have been made to unify the different measures with the aim of simplifying exchanges, facilitating trade and the fair collection of taxes . In the French Revolution of 1789, along with other challenges considered necessary for the new times , Scientific Commissions were appointed to standardize weights and measures, including length. The task was arduous and complicated; it was considered as a pattern of the longitude of a Pendulum of seconds at a latitude of 45 °, but it would end up being discarded as not being a completely objective model ; would finally remember to measure a meridian arcto establish, on him and therefore on the Earth itself , the pattern of the meter. ^{[ 3 ]} Those in charge of this measure were Jean-Baptiste Joseph Delambre and Pierre Méchain , who between 1791 and 1798 and by means of a triangulation system from Dunkerque to Barcelona established the measure of said meridian arc on which the metro was established. ^{[ 4 ]} They had the collaboration of the Spanish mathematician and astronomer José Chaix Isniel, who was commissioned by the government of Spain between 1791 and 1793 to collaborate with the project led by Méchain. ^{[ 5 ]}
Definition of 1792
Initially, this unit of longitude was created by the French Academy of Sciences in 1792 and defined as the ten millionth part of the distance that separates the north pole from the line of the Earth's equator , through the earth's surface.
New pattern of 1889
The 28 of September of 1889 the International Committee on Weights and Measures adopted new prototypes for the meter and then to the kilogram, ^{[ 6 ]} which materialized in a pattern meter of platinum and iridium deposited in chests located in underground of the Breteuil pavilion in Sèvres , Office of Weights and Measures , on the outskirts of Paris. ^{[ 4 ]}
Definition of 1960
The 11th Conference on Weights and Measures adopted a new definition of the meter: "1 650 763.73 times the wavelength in vacuum of the orange radiation from the atom of krypton 86." The precision was fifty times higher than that of the 1889 standard. ^{[ 4 ]} (Equivalences: one breaststroke = 2.09 m; one span = 0.2089 m).
Definition in terms of the speed of light
This is the current definition was adopted in 1983 by 17 ^{to } General Conference on Weights and Measures . ^{[ 2 ]}
Etymology
The word meter comes from the Greek term μέτρον ( metron ), which means 'measure'. ^{[ 7 ]} It was used in France with the name of mètre to designate the standard of measurement of length.
Basis of definition | Date |
Absolute uncertainty |
Relative uncertainty |
---|---|---|---|
^{1} / _{10,000,000} part of the distance between the North Pole and the Equator along the meridian line through Paris | 1795 | 0.5–0.1 mm | 10^{−4} |
First prototype Meter des Archives of standard platinum bar. | 1799 | 0.05–0.01 mm | 10^{−5} |
Platinum-iridium bar at the melting point of ice (1 ^{to } General Conference on Weights and Measures ) | 1889 | 0.2–0.1 µm | 10^{−7} |
Platinum-iridium rod at the melting point of ice, at atmospheric pressure, supported by two rollers (7 ^{at} CGPM) | 1927 | n.a. | n.a. |
Hyperfine atomic transition; 1 650 763.73 wavelengths of light in transition with Krypton 86 (11 ^{at} CGPM) | 1960 | 0.01–0.005 µm | 10^{−8} |
Distance traveled by light in vacuum in ^{1} / _{299,792,458} parts of a second (17 ^{to} GFCM) | 1983 | 0.1 nm | 10^{−10} |
Multiples and submultiples of the meter
Submultiples | Multiples | |||||
---|---|---|---|---|---|---|
Value | Symbol | Name | Value | Symbol | Name | |
10^{−1} m | dm | decimeter | 10^{1} m | dam | decameter | |
10^{−2} m | cm | centimeter | 10^{2} m | hm | hectometer | |
10^{−3} m | mm | millimeter | 10^{3} m | km | kilometer | |
10^{−6} m | µm | micrometer (micron) | 10^{6} m | Mm | megameter | |
10^{−9} m | nm | nanometer | 10^{9} m | Gm | gigameter | |
10^{−12} m | pm | picometer | 10^{12} m | Tm | thermometer | |
10^{−15} m | fm | femtómetro (stationary) | 10^{15} m | Pm | petameter | |
10^{−18} m | am | attometer | 10^{18} m | In | exameter | |
10^{−21} m | d | askometer | 10^{21} m | Rev | zettametro | |
10^{−24} m | etc. | yoctometer | 10^{24} m | Ym | yottametro | |
The most common prefixes appear in bold. |
Subway equivalences
- 1 meter equals :
See also
References
- ↑ Written in round, lowercase letters, not in italics; Note that it is not an abbreviation, so it does not accept a capital letter, period or plural.
- ↑ ^{to } ^{b} 'International System of Units " ; 8th edition, 3rd edition in Spanish.
- ↑ Estrada, H. Ruiz, J. Triana, J. The origin of the meter and confidence in mathematics Archived January 17, 2017 at the Wayback Machine ., 2011, ISSN 0120-6788, pp. 89-101.
- ^ ^{A } ^{b } ^{c} Denis Guedj, El metro del mundo , Anagrama, Barcelona, 2000, ISBN 84-339-7018-6 , pp. 330-331.
- ^ "José Chaix and the optical telegraph" . Forohistorico.coit.es . Retrieved November 12, 2019 .
- ↑ See History of the metric system .
- ↑ «METRO».
- ↑ Cardarelli, Francois Encyclopaedia of scientific units, weights, and measures: their SI equivalences and origins, Springer-Verlag London Limited 2003, ISBN 1-85233-682-X, p. 5, table 2.1, data from Giacomo, P., «Du platine a la lumiere.» Bull. Bur. Nat. Metrologie, 102 (1995) 5–14.
external links
- 17th General Conference on Weights and Measures, (1983). Resolution 1. International Office of Weights and Measures.
- Bureau International des Poids et Mesures. The BIPM and the evolution of the definition of the metre.
- National Institute of Standards and Technology. The NIST Reference on Constants, Units, and Uncertainty: International System of Units (SI) (web site):
- Penzes, W. Time Line for the Definition of the Meter. Gaithersburg, MD: National Institute of Standards and Technology. Precision Engineering Division.