metric system metric system internationally agreed system measurement originally based des archives des archives introduced years definitions metre kilogram refined metric system extended incorporate units number variants metric system emerged late nineteenth early twentieth centuries term synonym official system measurement country world metric system officially sanctioned use united_states remains country adopted metric system official system measurement sources cite countries united_kingdom uses metric system administrative trade purposes imperial units widely public permitted purposes road signs intended system equally accessible proved necessary use prototype units custody national local authorities standards control prototype units measure maintained french government passed organisation beginning main features metric system standard set base units standard set powers base units derive larger smaller units replace huge number units measure existence system developed commercial use development coherent units measure particularly suitable science engineering use metric system different scientific engineering disciplines particularly late 19th century resulted different choices base units based definitions metre kilogram 20th century efforts units published internationally recognised standard metric system features metric system changed developed inception basic concepts hardly changed designed use consisted basic set units measurement known base units derived units built base units logical relationships base derived units based identified standard set outbreak french revolution countries cities system measurement different countries units measure foot local language consistency magnitude units relationships like modern day differences gallons metric system designed universal words french philosopher people time designed ordinary people engineers worked human related measurements worked numbers small large huge range defined investigated idea system measurement concept practice acting advice invited british american secretary state george_washington work french producing international standard promoting legislation respective legislative bodies early failed custody metric system remained hands french government languages distinction unit names common proper use character set follow rules language concerned example kilometre unit symbol independent language example kilometre volts etc metric system units follow pattern concept identified possibility flemish mathematician introduced europe cost losing simplicity associated traditional systems units division result awkward example foot inches simplicity debated rejected metric system introduction proceedings british association mathematician summarised advantages based system non system simple rules practice pure system interrupted entrance system column column carry tens common set based effect division power applied units large small practical use concept consistent classical latin greek names proposed report french revolutionary commission weights measures prefix example unit prefix indicate unit kilogram kilometre thousand grams metres respectively millimetre metre respectively relations written symbolically early days positive powers given greek derived negative powers given latin derived extensions prefix system follow convention example greek roots 19th century prefix derived greek word applying derived units area volume expressed terms units length squared square cube operators applied unit length including prefix illustrated usually indicate second greater units minute hour day instead hand non unit volume prototypes base units metric system reference natural phenomena unique artefacts base units accompanied practical published describes detail way base unit measured possible definitions base units developed laboratory equipped proper instruments able realise standard reliance held country practice auspices mutual acceptance arrangement metre kilogram original version metric system base units derived specified length metre weight mass specified volume cubic metre pure water initially facto french government day considered defining metre length period second altitude equal sea level altitude latitude specified accommodate variations gravity specified latitude compromise latitude london paris median parallel united_states accommodate variations mathematician persuaded assembly survey having ends sea level based spanned earth quadrant appropriate basis available technology use definitions basis kilogram metre prototypes represented quantities manufactured june prototypes adopted definitive reference pieces deposited archives known des archives des archives copies distributed france artefacts replaced new prototypes manufactured international supervision possible new prototypes exact copies original prototypes later technology ensure better stability kilogram metre prototypes chosen lot serve definitive international reference piece remainder distributed signatories generally accepted theory nature light specific light accurate value prototype metre year prototype metre replaced formal definition defines metre terms specified light accepted speed light vacuum constant constant provided procedure measuring length metre terms speed light definitions better allow suitably equipped laboratory standard metre base units base units rely prototype based phenomena directly use years formally metric system second facto base unit metric system derive units associated values absolute measurements earth magnetic field second based earth rotation constant earth rotation slowing solar day longer known years consequently defined second terms earth rotation year measurements time readings based astronomy launch 11th adopted definition years followed atomic significantly reliable precise 13th second terms specific frequency spectrum component atomic provided means measure time associated astronomical phenomena astronomical phenomena basis time measurements absolute unit electric current defined terms force parallel current carrying wires 1940s adopted variant definition adopted temperature based phenomena degree based freezing boiling points water adopted scale renamed temperature scale defined terms triple point water mole accepted respectively defined parties reference phenomena artefacts variant metric system degree derived units directly related base units need intermediate conversion factors example coherent system units force energy power chosen hold introduction unit conversion factors set coherent units defined relationships physics use units automatically true mass energy equation require expressed coherent units system units energy related mechanics related thermal energy bear coherent relationship base units design aim resulting unit energy defined coherent system unit power defined second customary system measurement non coherent unit power horsepower defined foot pounds second pound context pound force similarly imperial cubic foot cubic yard cubic inches imperial cubic inches concept introduced metric system quarter 19th century original form metric system non coherent particular derives units mass length related physical properties water having designed mass cubic water freezing point history flemish mathematician published small pamphlet called tenth employed extraction square roots centuries time numbers daily life declared important universal introduction weights measures matter time earliest proposals system length area volume mass linked secretary essay essay real character philosophical language proposal beat second basis unit length years later french abbot scientist proposed system length based earth suggestion unit defined minute arc suggested system sub units dividing factors ideas attracted interest time supported studied london year independently proposals similar pre revolutionary europe state system units measure countries spain russia saw advantages units measure trading partners interests variations units measure opposed particularly prevalent france huge size units measure causes led outbreak french revolution early years revolution including set commission opinion country adopt completely new system measure based principles logic natural phenomena logic dictated system based counting report march considered rejected view system counting replace existing system view system bound fail prevailed commission final recommendation assembly promote based system measurement leaders assembly accepted views commission initially france attempted work countries adoption common set units measure supporters international system units presented document plan establishing weights measures united_states congress advocated system traditional names units inches foot report considered adopted congress original metric system french law april defined units measure length area land volume stacked volumes liquid mass system continued tradition having separate base units related dimensions lengths areas dry capacities liquid capacities equal area square metres acres use early metric system included thousand originally defined later renamed water melting point ice called grave alternative grave word grave synonym title count aristocratic renamed suggested france officially adopted metric system december decreed use mandatory paris year provinces following year decree universally observed france international adoption areas annexed france napoleonic era inherit metric system napoleon introduced system known names pre metric units measure defined terms metric units example metric pound metric metres congress vienna france lost territories annexed reverted pre revolutionary units measure adopted modified version france kept system measurement intact netherlands reintroduced metric system pre revolutionary names example thumb certain german states adopted similar systems german customs union adopted customs pound commerce newly formed adopted metric system official system weights measures newly formed likewise following lead given adopted metric system devoted stand metric system thirds european population close half world population adopted metric system principal european countries adopted metric system russia united_kingdom countries comprising world population mainly english speaking imperial system mainly metric system remaining million people united_states sent petitions backed urging congress adopt metric system petition opposed manufacturing industry citing cost conversion international standards committee including later lord introduced concept coherent system units based metre second extended include electrical units international treaty known convention metre convention signed states treaty established following organisations conduct international activities relating uniform system measurements general conference weights measures conference official delegates member nations supreme authority actions consisting selected scientists prepares decisions responsible supervision permanent laboratory world centre scientific activities include establishment basic standards scales principal physical quantities maintenance international prototype standards adopted recommendations electrical units followed series units measure defined set specific task overseeing electrical units measure followed inaugural meeting initiated definition related units measure metre convention extended cover units measure length mass 8th resolved work international bodies agree standards electrical units related international prototypes committee oversees definition units measurement representatives international organisations including variants number variants metric system evolved descendants base units differing definitions derived units second systems second system units coherent metric system having developed 1860s promoted system formally promoted system characteristics density expressed force expressed mechanical energy thermal energy defined energy required raise temperature water meeting proposed sets units electrical magnetic properties set units electromagnetic set units systems units electricity work international electrical congress held chicago defining international definitions based metre kilogram second showed adding electrical unit fourth base unit electromagnetic systems resolved metre kilogram second metre kilogram second systems examples systems international current international standard metric system system widely world extension system base units metre kilogram second mole metre second systems metre second system units based metre second unit force unit pressure invented france industrial use france soviet_union systems metric systems use kilogram force base unit force mass measured unit known mass metric passed resolution defining standard value acceleration gravity units 9th met years end second world war years 8th response formal requests establish practical system units measure requested prepare recommendations system suitable adoption countries recommendation symbols important units measure time recommendations concerning derived units time formally adopted recommendation writing printing unit symbols numbers draft proposal extensive revision metric unit definitions symbols terminology based system units 10th accordance proposals recommended base unit units derived definitions previously use discarded units derived units based metre second kilogram negotiations base units degree proposed base units system international adopted 11th october years followed definitions base units particularly methods applying definitions refined formal definition associated resolutions passed published form regular intervals eighth edition international published available internet october 24th proposals change definitions base units changes affect average person real world published theory meet requirements commerce science technology certain units measure acquired position world community likely years come order units consistently world units tables categories units accepted use list includes hour minute angular measures degree minute second arc historic non coherent metric units originally agreed units values units obtained table list includes units measure atomic nuclear physics astronomy electron mass electron astronomical unit solar mass number units measure established dependent determined physical quantities units table list number units measure internationally certain defined spheres including bar pressure atomic physics nautical mile knot navigation units associated system units table table number units measure based system dating nineteenth century appear frequently literature continued use discouraged usage world usage metric system varies world according adopted official system weights measures nations world burma united_states identified united_states country metric system predominant system units reports published hold longer true report stated passed law replace imperial system metric system system measurement neighbours guinea reports suggest country planning adopt metric system united_states metric units authorised congress widely science medicine military partially industry customary units household use retail stores commonly unit volume especially bottles amounts grains hand non metric units certain regulated environments nautical miles knots international aviation resistance particularly connected perceived cost involved sense patriotism lack desire conform internationally countries metric system replaced imperial system varying degrees australia new_zealand commonwealth countries africa totally metric india metric canada partly metric united_kingdom metric system use permitted trade government business industries including building health engineering measure weight trading situations wholesale retail imperial system widely british public feet inches measurement height weight stone pounds legally mandated cases road sign distances given yards miles announced abandon requirement metric packaged goods allow dual metric imperial marking continue indefinitely jurisdictions hong_kong laws permitting systems measurement parallel metric system contexts variations spelling symbols metric units intended identical regardless language unit names ordinary use character set follow rules language concerned example unit symbol kilometre world local language word unit vary language variants kilometre unit include italian kilometer german kilometer dutch french greek portuguese spanish russian variations found spelling unit names countries language including differences american english british spelling example meter united_states metre english speaking countries addition official spelling rarely prefix american english term metric ton normal usage varieties english common spelled english speaking countries united_states older usage declining conversion calculation incidents dual usage confusion metric non metric units resulted number incidents include flying aircraft miami florida venezuela degree consistent ground crew reading kilogram markings cargo pounds reported confusion grains grams led patient receiving grams instead grains grams canadian accident boeing jet ran fuel mid flight mistakes calculating fuel supply aircraft use metric measurements mechanics fuel required aircraft result metric units root cause loss nasa million mars climate units spacecraft engineers calculated thrust forces required velocity changes customary units lbf team built expecting value metric units agreed specification conversion legacy units evolution metric system adopted units measure introduction way units measure defined list units use official table lists units measure catalogue shows conversion factors connecting equivalent units use eve adoption certain units widely matters everyday life units exactly defined values terms units particular circumstances satisfy needs commercial legal specialised scientific interests units include future developments metre kilogram base unit relied specific clear divergence international national prototype kilograms observed 23rd mandated investigate use natural basis units measure artefacts use meeting held reading united_kingdom september resolution draft changes presented meeting october agreed principle proposed addition speed light define nature constant elementary charge constant constant exact values retire international prototype kilogram revise current definitions kilogram mole use nature wording definitions base units meeting october found conditions set 23rd meeting fully met reason propose revision present time sponsor resolution 24th changes agreed principle expected finalised 25th
Metric system