sistema métrico vs. sistema ingles. metric system vs. english system by kenneth weaver 1977 how...

8/16/2019 Sistema métrico vs. sistema Ingles. Metric System vs. English System by Kenneth Weaver 1977 how soon will we…

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NATIONAL GEOGRAPHIC

August 1977

HowSoon

Wl e MeauItic?By KENNETH F. WEAVER

ASSISTA N EDITOR

Drawings by DONALD A. MACKAY

"Thou shalt not have in thinehouse divers measures, aeat and a small. But thoushalt have a peect and justweight, a peect and justmeasure shalt ou have....

DEUONOM 25: 14-15

EACH DAY in the United

States an estimated 20 bilion meurements

are made. The scientist, r hismeuring, uses the metricsystem-logical, simple, anduned But fr most of us,what an antiquated, crazyquilt hodgepodge we custom

arily employ!We have, fo example, a dry

quart that is larger than aliquid quart; both are smaerthan a British quart An ouncefr measuring uids is not thesme as an ounce used rweighing; moreover, the avoirdupois ounce is lighter than thetroy ounce and the apothe

caries' ounceOr consider tons There's

a long ton nd a short ton, aregister ton and a measurement ton, a wheat ton and ametric ton-al dierent.

Our barrel ranges fom 31 to42 galons We divide the galoninto ur quarts, eight pints, or16 gilsto say nothing ofve fths.

We split the mile into eighturongs, 80 chains, 320 rods,880 fathoms, 1,760 yards, and

5,280 fet Then we divide thefot by 12 to ge inches

Actualy the United Stateshas three kinds of miles Oursurvey mile, used in land measurements, is roughly oneeighth of an inch longer thanthe internation mile. Conusingy, both e known asstatute mies, and both are

shorter than the nautic mieWe dea with hands and

cords, drams and scruples,pecks an carats, gains andpoints, rkins and hogsheadal part of a gloriously ilogicalminglemangle of soe 80separate meures.

Yet we count by tens, by thedecima system, because ten is

the only number that createsmultiples of itself by simpychanging the rst digit. Thenwhy not meure by tens?

How we got into this muddeis a story that goes back to the

THIS ARTICLE TEARS OUT ALONG PEFOED LINE

Babyonians and Egyptians, tothe Romans and Vikings, andto assorted English monarchsof centuries ago

In Egyptian papyrus texts,thousands of years old, thereappears the gure of a rearm,symbol r the cubit This

earliest recorded unit of measurement was bed on thelength of the arm om elbowto ngertiproughy 18 inchesThe Great Pyramid of Cheopswas built to cubits And so, according to Genesis, was Noah'sAr-300 cubits ong

Even in Noah's time themeurement conusion h

aready begun Forearms, afteral, vary in ength Moreover,there were dierent cu bits Legend has it at the EgyptianKing Menes decreed a royal

287

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or sacred cubit 14 percentlarger th the coon cubit.This oversize measure wused in building his own palacebut w frbidden to others.The origina meaning of "pharaoh, incidentaly, w "greathouse

For measuring weight, theanciens used grains of wheator barleycorns; the grain tothis day is one of the smaestunits of weight, 1/7,000 of apound The carat, used inweighing gems, w derivedfrom the tiny carob seed

The mie ce to us om

the Romans vía Britn nCaesar's day the mie was themille passus, 1,000 doublesteps by a Roman egionaryt w 5,0 Roman feetQueen Bess, in the late 16th

1YA.

century, added 280 et so the

mile woud be exacty eight"furrow-ongs, or furongs

No one knows just how theyard got started, athough itmay be no coincidence that itis a doube cubit n any case,it is a undenta unit ofEnglish meurement Theword itself comes om the OdEnglish word gierd, rod, thest used fr meuring. Henry estalished the yard hedistance om the tip of hisroyal nose to his ngertips

As fr the inch, in the tenthcentury it ws the span of theknuckles on Kng Edgar's

288

thumb. And the ot w decreed by Charemagne to bethe ength of his own oabout 127 present-day inchesBut the Engish statute booksof 1305 sandardized the ot 36 bareycorns "aen fomthe middle of the ear and laid

end to endStl another denition of the

fot comes om a 16th-centuryGerman regulation:

"Stand at he


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cubing a tenth of a meter toproduce the liter. And a iter ofwater prodced a basic nitof s, te kiogram

For larger nits, mutiples onthe bis of 0 ere eventalyprovided, it Greek prexes:

thus deketer fr 0 meters,hectometer fr 100, kiometerr 1,0, megeter r a miio, and so on For sbdiviions, Latin prexes ere seddecimeter or a tent of aeter, centimeter fr a 100th,ilimeter fr a 1,000t, andicrometer fr a milliont

Thus al te units ere intiatey and uniformy reatedr te rst time te ord adailable a consistent, niederement system in iccculations oud be e o more nieldy actions, noore memorizing a ost of conersion factors

"Never as anyting more and simpe, more coherent in al its parts, issed

fom te and of man, rotentoine Lavoisier, te mostfamous Frenc scientist ofte time

Over te decades te metricsystem as been moded dexpanded into at is knon

today SI, Le Systme Inter- national d'Unités. SI provides ve oter basic nits besideste meter and te kilogr Forexampe, te unit r time iste second; te pere is tebaic nit r electricity; andr temperatre te degreeCesis (rmerly centigrade)

For scientic se, temperatresare mered in kelvins starting it absote zero (-27315ºC) A kelvin is equa to adegree Celsis n addition,the meter as been redened,fr even greater accracy, 1,650,76373 aveengts oforangered ligt emitted by tekrypton86 atom

Gradualy at rst, ten evermore rapidly, te metric system

lIetric (S) prefn"

took root in Europe in te 19thcentury t spread to oter continents unti, today, 95 percent

of te ord's inabitants speakits langage Only in te UnitedStates (and in Brnei, Brma,Liberia, and Yemen) is it not yet te system generaly in se

Repeatedly our nation approaced metrication, but it alays backed aay fromll embrace Neverteess, byact of Congress, metric asbeen "ega in the UnitedStates since 1866

Multiplication factor Prex Symbol Meaning (in USA) In other countries

1 ooo ooo ooo ooo ooo ooo= 1010

exa1 000 000 000 000 000= 10s peta

1 000 000 000 000= 102 ter

1 000 000 000= 109 giga

1 000 000=106 mega

1 000=103 kio

100= 102 hecto

10= 10 deka

0.1= 10- deci

0.01= 102 centi

0.001= 103 milli

0000 001= 10-6 micro

0.000 000 001= 109 nano

0000 000 000 001= 10-2 pico

0.000 000 000 000 001= 105 femto

0000 000 000 000 000 001=100 atto

Ep

T

G

M

k

h*

da*

d

c*

m

µ

n

p

f

a

one quintillion timesone quadrillion times

one trilion times

one bilion times

one million times

one thousand times

one hundred times

ten times

one tenth of

one hundredth of

one thousandth of

one milionth of

one billionth of

one trillionth of

one quadrillionth of

one quintillionh of

trilionthousand bilion

billion

miliard

milliardth

billionth

thousand billionth

trilionth

*While hecto, deka deci and cent are SI prexes, the use shoud generaly be avoided except for the S unt-multplesfo a rea and volume and nontechncal use of centimeers as for body and clohng measurement. The prefx hecto shouldbe avoided aso because the longhand symbol h may be confused wth


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V.�-

Moreover, our representative signed the Treaty of the

Meter in París in 1875. Thuswe joined the other major

nations of the world in endorsing the metric system as theinternationly prefrred system. We also gave backing to apermanent International Bureau of Weights and Meures.

Further, in 1893 the UnitedStates bece an "ocialymetric nation. Three yearsearlier we had received om

the Internationa Bureau newand rened meter bars andkiogram weghts These weredecared to be the nation's"fndamenta standards ofength and ms. The pound,the fot, and other customaryunits were redened actions of the metric units

And yet we did not gve upthe weter of customary units.Bitter opposition fom bothabor and business met everyattempt to get a metric bilthrough Congress As recentyas 1920 pphets were pubished with tites such as "WhatRea He-Men Thin of theCompusory Metric System.

Earier, antimetric rceshad pubished their themesong a dtt entited "A Pint'sa Pound the World Around,with this ringing stanza:

Then down with eve"metric scheme

290

Taught by the foreign school,

We'll wohip still ourFather's God!

And keep our Father's· "rue!

A peect inch, a peect

pint,The Anglo's honest

pound,Shall hold their plae

upon the earthTill Time's last tmp

shall sound!

But thoughtu citzens contnued to point out the merits

of the metric system. As Alexander Graham Bel testied

bere Congress (his statementw printed in the March 1906GEORHIC):

"t is sae to say that, afterthe metric system has beenadopted by the United Statesand our people have becomeaccustomed to its use, we

would no more dream of going bk to the present system ofweights and meures than wewoud think of carrying on theprocesses of arithmetic throughthe medium of the old Romanletters in pace of the Arabicnumeras we now employ.

Eventualy the ant-metrcagitation died away GreatBritain began conversion tothe metric system in 1965. Australia owed in 1970, Canadain 1971 The Unied States wasisolatean isand in a metricsea. Our huge multinational corporations, with many branchesabroad, fund themsevesfrced to use metric as wel as

customary units. Quite naturaly they favored conversion to asingle system

Many began converting ontheir own, spurred by a decision from the nine Common Market countries that aterApri 21, 1978, they would ac-

cept no imports unless abeledin metric dimensions

Finaly, on December 23,97 5, President Gerad R Fordsigned the Metric ConversionAct of 975, calling for vountary conversion to the metric

system and establishing a U S Metric Board to coordinatethat conversion.

Even though Congress andthe President did not go so far to requir mandatory conversion, most observers see thechangeover coming with increaing rapidity anyway.Ocias and businessmen to

whom I have taed give varying estimates soe see a predominanty metric UnitedStates by the eary 80's Morepessimistic frecasts suggest1990 But al agree we aremoving ft on the metric road.

Even without metric legisation we have aready gone aconsiderabe distance down

that road. Scientists use meticmeurements exclusivey. Sodo many of our engineers

MADE IN u.s

Most of us are famiiar wit35miimeter camer and 500miligram vitin pi

skis labeed in centmeterhypodermics meured in cubcentmeters the se miiiters), and cars with engidispacement stated in iteThe airines have ong weigheour luggage in kiogr ooverse ights We ha


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�Ietric (S) units

Quantity Common units Symbol Acceptabe Symboequivaen

length kio meter k

meter mcentmeter cmmillimeter mmmicrometer Jm

rea square kilometer km2

square hectometer hm2 hectare hasquare meter m2

square centimeter cm2

square milimeter mm2

volume cubic meter m3

cubic decimeter dm3 liter* Lcubic centimeer cm3 mililiter* m

velocty meter per second m/skiometer per hour km/h

acceleraion meter per second squared m/s2

frequency megahertz MHzkilohertz kHzherz Hz

ass megagram Mg metric ton tkilogram kggram gmiligram mg

densty kogram per cubic meer kg/m3 gram per lter g/L

force kilonewton kNnewon N

pressure kiopasca kPa

energy, work or megajoue MJ

quantity of heat kiojoue k

1joue Jkiowat-hour kW.h

1 power or ha fow kilowatt kW1 rte watt w

emperaure kevin Kdegree Cesius ºC

elecric curren ampere Aquany of eectrcity couomb e

amperehour A·h

lectromove force volt V

ectrc resstance ohm numnous ntensy candela cd

*To be used nly fr lids (bth gases and lquids) and or dry ingredients in eipes. Do not se any prex wh liter"except mlli.


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Co1non 11etric (SI) covrsios

lf

you Multiply Toknow by find

lengthinches X 25.4 = mmeters

feet X 0.305 = meters

ards X 0.914 = meters

mes X 1.609 = kometers

reasquare ards X 0.836 = square meters

acres X 0.405 = hectares

volumequarts (q) X 0946 = ters

cubc ards X 0.765 = cubc meters

mass

ounces (avdp) X 28.35 = grams

pounds (avdp) X 0.454 = kograms

temperature

degrees Fahrenhet X 5/9 (aftersubtractng 32) = degrees Cesus

engthmlmeters X 0.039 = nches

meters X 3.281 = feet

meters X 1.094 = ards

kometers X 0621 = mes

reasquare meters X 1196 = square ards

hectares X 2.471 = acres

volumelters X 1.057 = quas (q)

cubc meters X 1.308 = cubc ards

massgrams X 0.035 = ounces (avdp)

klograms X 2205 = pounds (avdp)

temperaturedegrees Cesus X 9/5 (then

add 32) = degrees Fahrenhet


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F1T

�,t-t(_

MA

¡oo :'

watched ces in the Olympic gmell in metic.

In t lest 14 sttes se rad sins sh bth milend kilmete distnces

eed limits. The sme is nte f sins in se ntinlks. fe mnths theDeptment f Tnspttinpsed tht ll speed-limitis be chned t metic be gnin in July 1978. Ccla, 7Up, PepsiCl, epe, nd Shst e nketed in lite cntines.B the end f 1979, ll ines spiits must be bled inetic sizes. The fili hwll becme 7 50 millilites-aut ne pecent less.

edel encies incegly use metic meuements.e eptment f icultueblishes cp yields nd inipments in metic tns. lNS epts ive metic, ithtmy ues dded. Theatent nd Tdem Ocew equies tht ptent ppliains include metic dimens f items.

f the tp 1,000 mj mntuin nd industil cners in the United Sttes, me

n 60 pecent e estimted be metic in tnsitin. ll fu mj mt cmnies e cnvetin. deg ten yes nd pieeed ith e desinin fe metic Pint enine. Genal Mts flled in 1975

ith the lely metic Chevette. Since 1973 GM hs desined ll ne ps in metic.

Hs cnvesin psed nneus buden n industy? I

sked this questin f numbf industy epesentives Thei nse is unifmly n.

"The y is etly vestessed, sys P. E. uke f meicn Mts. "It tuns utt be myth tht it uld cstenmus sums. Eveettuh f Gene Mts sys,"Gin metic in the Cheveecused n me thn ipple. nd Gee ssue fPcte nd Gmble puts iteven me succinctly

"Gin metic is n bi del!Pehps nt f business nd

industy. ut h ill it ectdiny peple h n hvet len t think in deent

mesuement lnue? yunstes t let it isn pblem. The the dy my9yeld ndduhte his excited but cllectin insecs descibin he ltestnd. "Its just but centi mete ln, she sid.

The metic system ill hldn es f he. Like mst

childen in the U. S., she islenin metic meuemensin schl. Se schl systemsin fct, e phsin ut instuctin in custmy units Sesttes n equie tht ll netextbks use the metic ystemexclusively.

lde enetins cnvesin ill men me et.ut mnufctues e helpin t ese the tnsitin. LeviStuss is puttin dul lbelinn its bys pnts. ess pttens f yes hve iven bth

mesuements Metic ecipese ppein in mens mzines. nd cey stes e ll f

dullbeled pckes. Recently I fund ice, 16 z (454 );cnned bens 15 z (425 );pinepple juice 36 uid z(1.06 L); cem by the pint (473 mL); nd chclte bs 4 z

(113.4 ). nd by cntst, mustd 1 k (35% z)While cnvesins like these

help t st the dvice f the

cunties n successully

mkin the tnsitin is tvid tnsltin s much pssible "Len t think meticfm the beinnin, theycunsel. "Then the chevees smthly

fe tips help ne et feel metic dimensins

293


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and quantities. For example: a meter is only a little longer

than a yard; a kilogr is only a little

heavier than two pounds;.. a liter is only slightly more

than a quart.

A teaspoon is ve milliliters;a tablespoon 15. A 21-gallontank holds about 80 liters ofgasoline. A dollar bill or apaper clip each weighs aboutone gram A golf ball weighs46 grams, a year's NTIOLGEORPHICS fll just under

ve kilograms and an averageman weighs 75 kilograms

A dime weighs two gramsand is one millimeter thick. Astick of gum is 75 illimeterslong, a pencil 190. he longdimension of a standard manilalder is 300 millimeters.

he ordinary char seat isabout 450 millimeters high; adoorknob is usuly about ameter om the oor. he

Washington Monument is 170meters tall, the mpire tateBuilding 380 meters andMount verest 8848.

hicago to New York ity is1,200 kilometers he earthis 40000 kilometers around,and the moon is 400,000 kilometers away.

And the national 55mileperhour speed limit comes toout 90 kilometers per hour

emperatures in elsius willnot be dicult if one emembers that at 0° water reezesand at 100° it boils; 18° isrecommended room temperature r saving energy, 22° to

26° is coortable; 35º is a hotday; 37 is body tempeature.

For cooks 185°

is a moderateoven and 215° is hot.

All in all switching gradually to metric should cause noserious inconveniences or expense to the average personaccording to the experience ofsuch countries as Australiaand anada. With eectivepublic education, people discover most of their fears aboutmetrication are ununded.

For example a the American National Metric ouncilpoints out cooks will not needto throw away fvorite cookbooks or recipes; they will continue using them they do

now. For metric recipes nowbecoming available metricmeasuring spoons cost only afe cents. Meuring cupsalready on the market areconveniently marked in bothilliliters and ounces a well as

in factions of a cupMechanics will need metrictools of course But many ofthem have long since made theinvestment because of the needto work on foreign cars

Will new packaging sizessubstantially raise fod osts?Food producers say not t'ssimply a matter· of adusting

machinery, not of makingentirely new machineryoe things won't change

even after we are predominantly a metric country ur moneysystem will remain unchanged;so will units of time. welvewill still make a dozen, 20 ascore. Drivers will continue tosay, "Fill 'er up! or "Five

dolls worth We'll still talkabout "rst down and ten yardsto go. And we will retn suchexpressions ilestone, tengallon hat, and inchworm.

We will not likely switch tosaying "2835 grs of prevention are worth 0.4535 kilogr of cure, or "Give him254 centimeters and he'll take1,609 meters

With a little time, we'll all nd that switching to metric isindeed no big dealexcept,perhaps, fr the worried farmwife who said she sn't sureshe could get her hens to layeggs in metric sizes O

Meter or metre? The French, of course spel it with an -re, as do

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al the English-speaking countres except the Unied Sates. One argumenr hat spelling is that i distinguishes between he woíd MIcrometre ameasurement and miCRMeter, a too! r measuring. n the United States,boh spelings are ocialy recognized. Soe fderal agencies use one frm,soe he other. The American National etric ouncil prers er, whilethe American Society r Testing and aerials stands by the re frmUnti the question is resolved, the GRPHC wi continue to use meter.

sistema métrico vs. sistema ingles. metric system vs. english system by kenneth weaver 1977 how...

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