International System of Units Metric system

the 9th cgpm met in 1948, 3 years after end of second world war , fifteen years after 8th cgpm. in response formal requests made international union of pure , applied physics , french government establish practical system of units of measure, cgpm requested cipm prepare recommendations such system, suitable adoption countries adhering metre convention. recommendation catalogued symbols important mks , cgs units of measure , first time cgpm made recommendations concerning derived units. @ same time cgpm formally adopted recommendation writing , printing of unit symbols , of numbers.

the cipm s draft proposal, extensive revision , simplification of metric unit definitions, symbols , terminology based on mks system of units, put 10th cgpm in 1954. in accordance giorgi s proposals of 1901, cipm recommended ampere base unit electromechanical units derived. definitions ohm , volt had been in use discarded , these units became derived units based on metre, ampere, second , kilogram. after negotiations international commission on illumination (cie) , iupap, 2 further base units, degree kelvin , candela proposed base units. full system , name système international d unités adopted @ 11th cgpm in october 1960. during years followed definitions of base units , particularly methods of applying these definitions have been refined.

the formal definition of international system of units (si) along associated resolutions passed cgpm , cipm published bipm in brochure form @ regular intervals. eighth edition of brochure le système international d unités—the international system of units published in 2006 , available on internet.

in october 2011, @ 24th cgpm proposals made change definitions of 4 of base units. these changes should not affect average person.

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