The Metric System

By: John Salco

Definitions

Metric system

a decimal system of weights and measures based on the meter and on the kilogram

Length

a measured distance or dimension

Area

the surface included within a set of lines; specifically : the number of unit squares equal in measure to the surface

Weight

a unit of weight or mass

Mass

the property of a body that is a measure of its inertia and that is commonly taken as a measure of the amount of material it contains and causes it to have weight in a gravitational field

Volume

the amount of space occupied by a three-dimensional object as measured in cubic units (as quarts or liters) : cubic capacity

Some Facts

• Used by most countries.
• Developed by French scientists in the late 18th century.
• Replaced the chaotic collection of units.

The metric system has prefix modifiers that are multiples of 10.

• A kilogram is 1000 grams
• A hectogram is 100 grams
• A decagram is 10 grams
• A gram is the stem unit of mass
• A decigram is 1/10 gram
• A centigram is 1/100 gram
• A milligram is 1/1000 gram

Time Line

1670

Records of a first Metric System by Gabriel Mouton, a French vicar

1795

Republic of France adopts the first basic Metric System proposed by the French Academy of Sciences

1820

Belgium, Luxembourg and the Netherlands are the first of a growing number of other countries to switch to the Metric System

1866

Congress legalizes the use of the Metric System in the US

1893

The US adopts metric units as fundamental standards for length and mass

1902

Congressional legislation requiring the federal government to use SI exclusively was defeated by a single vote

1959

English units are defined in terms of metric units

1970

Practically all the world has adopted the Metric System - the US, Liberia and Burma remain the only countries still using the English Imperial units

1975

Metric Conversion Act (Public Law 94-168) passed by Congress

2001

The US still have no definitive plan in sight for an adoption of the Metric System

Conversion tables

 

METRIC SYSTEM1
LENGTH
Unit	Abbreviation	Number of Meters	Approximate U.S. Equivalent
kilometer	km	1,000	0.62 mile
hectometer	hm	100	328.08 feet
dekameter	dam	10	32.81 feet
meter	m	1	39.37 inches
decimeter	dm	0.1	3.94 inches
centimeter	cm	0.01	0.39 inch
millimeter	mm	0.001	0.039 inch
micrometer	µm	0.000001	0.000039 inch

AREA
Unit	Abbreviation	Number of Square Meters	Approximate U.S. Equivalent
square kilometer	sq km or km2	1,000,000	0.3861 square miles
hectare	ha	10,000	2.47 acres
are	a	100	119.60 square yards
square centimeter	sq cm or cm2	0.0001	0.155 square inch

VOLUME
Unit	Abbreviation	Number of Cubic Meters	Approximate U.S. Equivalent
cubic meter	m3	1	1.307 cubic yards
cubic decimeter	dm3	0.001	61.023 cubic inches
cubic centimeter	cu cm or cm3 also cc	0.000001	0.061 cubic inch

CAPACITY
Unit	Abbreviation	Number of Liters	Approximate U.S. Equivalent
			cubic	dry	liquid
kiloliter	kl	1,000	1.31 cubic yards
hectoliter	hl	100	3.53 cubic feet	2.84 bushels
dekaliter	dal	10	0.35 cubic foot	1.14 pecks	2.64 gallons
liter	l	1	61.02 cubic inches	0.908 quart	1.057 quarts
cubic decimeter	dm3	1	61.02 cubic inches	0.908 quart	1.057 quarts
deciliter	dl	0.10	6.1 cubic inches	0.18 pint	0.21 pint
centiliter	cl	0.01	0.61 cubic inch		0.338 fluid ounce
milliliter	ml	0.001	0.061 cubic inch		0.27 fluid dram
microliter	µl	0.000001	0.000061 cubic inch		0.00027 fluid dram

MASS AND WEIGHT
Unit	Abbreviation	Number of Grams	Approximate U.S. Equivalent
metric ton	t	1,000,000	1.102 short tons
kilogram	kg	1,000	2.2046 pounds
hectogram	hg	100	3.527 ounces
dekagram	dag	10	0.353 ounce
gram	g	1	0.035 ounce
decigram	dg	0.10	1.543 grains
centigram	cg	0.01	0.154 grain
milligram	mg	0.001	0.015 grain
microgram	µg	0.000001	0.000015 grain