History of the Meter

Meter is the basic unit of length in the SI system . This unit is defined as the distance light travels in a vacuum ( vacuum ) during 1/299.792.458 seconds . Meter abbreviated using the symbol m . Meters can be written as in English meter , or meters with the American spelling .

It should be noted that the definition of the meter as the basic unit of length is dependent on the definition of the second , as indicated by the above equation .

History

Meter was originally defined by the French Academy of Sciences ( Académie des sciences ) as 1/10.000.000 distance along the Earth's surface from the North Pole to the Equator meridian through Paris in 1791 , and on 7 April 1795 the French use the meter as an official for a long distance . The uncertainty in the measurement of the distance causes the International Bureau of Weights and Measures ( BIPM - Bureau International des Poids et Mesures ) set 1 meter as the distance between two etched line platinum - iridium on the rods stored in Sevres , France in 1889 .

In 1960 , when the laser was introduced , the General Conference on Weights and Measures ( Conférence Générale des Poids et Mesures / CGPM ) to change the definition of the meter - 11 as 1,650,763.73 times the wavelength of light orange-red spectrum of krypton - 86 atom in a vacuum chamber . In 1983 , the BIPM set the meter as the distance traveled by light in vacuum 1/299.792.458 sec ( speed of light is set at 299,792,458 meters per second ) . Because of the speed of light in a vacuum is the same in any course , this definition is more universal than the long- distance ukurlilit earth or certain metal rod . Therefore , if the metal rod was lost or destroyed , the length of a standard meter can still be repeated in any laboratory . Besides, he could in theory be measured more precisely than the other sizes .

The size of the meter turns fluctuate throughout the ages have always been revised by the scientists of each era. Here's his review :

May 8, 1790 - The French National Assembly ( French National Assembly ) set 1 meter is equal to half the length of a pendulum which cover the period of one second .

March 30, 1791 - The French National Assembly approved the proposal of the French Academy of Sciences stated that 1 meter is equal to 1/10.000.000 times the distance along the surface of the earth from the north pole to the equator meridian through Paris .

1795 - Created a temporary restriction of 1 meter brass .

December 10, 1799 - The French National Assembly set a limit of 1 meter platinum made ​​on June 23, 1799 and deposited in the National Archives , is used as a final standard .

28 September 1889 - General Conference on Weights and Unit ( General Conference on Weights and Measures - CGPM ) was held for the first time and determine the 1 -meter as the distance between the two platinum finish line on the rod with a mixture of 10 % iridium, measured at the temperature of the melting point of ice ( 0 degrees Celsius ) .

October 6, 1927 - 7th Conference CGPM adjusts the definition of 1 meter for distance , at a temperature of 0 degrees Celsius , between the axes of the two central lines marked on the panel yan platinum - iridium prototype , this panel becomes the subject of a standard atmospheric pressure and support on two cylinders at least 1 cm in diameter , symmetrically placed in a horizontal plane at a distance of 571 millimeters from each other.

October 14, 1960 - Conference on the 11th CGPM set 1 meter is equal to 1,650,763.73 times the wavelength in a vacuum with respect to the transition between the 2p10 and 5d5 quantum levels of the krypton - 86 atom ( Kr - 86 ) . ( From other sources that mention 1 meter is equal to 1,650,761.73 times the wavelength of orange light emitted by the atoms of the gas krypton - 86 ( Kr - 86 ) in the vacuum chamber on an electric stepping . )

October 21, 1983 - Conference on the 17th CGPM set equal to 1 meter distance the speed of light ( in a vacuum ) in Waku 1/299.792.248 second interval .

2002 - International Committee on Weights and Unit ( The International Committee for Weights and Measures - CIPM ) considers the meter to the unit proper length and thus recommends that limits the definition of " short enough length ℓ with the effects predicted by general relativity can be ignored for realization of uncertainty " .