The metric system originated in France in the late 17th century and was fully developed by the late 18th century. It was based on practical and scientific considerations, using decimals and units linked to natural phenomena like the meter defined as 1/10,000,000 of the distance from the equator to the North Pole. The metric system spread throughout Europe in the early 19th century and is now the predominant international system of measurement.

1. The Everyday Metric System
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Early development
Most historians agree that Gabriel Mouton, the vicar of St. Paul's Church in Lyons, France, is the
“founding father” of the metric system. He proposed a decimal system of measurement in 1670.
Mouton based it on the length of one minute of arc of a great circle of the Earth (now called a nautical
mile, 1852 meters). He also proposed the swing-length of a pendulum with a frequency of one beat
per second as the unit of length (about 25 cm). A pendulum beating with this length would have been
fairly easy to produce, thus facilitating the widespread distribution of uniform standards. Over the
years, his work was revised, improved, and extended by a number of French scientists.
The political sponsor of weights and measures reform in the French Revolutionary National Assembly
was the Bishop of Autun, better known as Talleyrand. Under his auspices, the French Academy
appointed several committees to carry out the work of developing a usable system of weights and
measures for France. One of the committees recommended a decimalized measurement system
based upon a length equal to one ten-millionth of the length of a quadrant of the earth's meridian (i.e.,
one ten-millionth of the distance between the equator and the North Pole).
In 1790, in the midst of the French Revolution, the National Assembly of France requested the French
Academy of Sciences to “deduce an invariable standard for all the measures and all the weights.” The

2. Commission appointed by the Academy created a system that was, at once, simple and scientific.
The unit of length was to be a portion of the Earth's circumference. Measures for capacity (volume)
and mass were to be derived from the unit of length, thus relating the basic units of the system to
each other and to nature. Furthermore, larger and smaller multiples of each unit were to be created
by multiplying or dividing the basic units by 10 and its powers. This feature provided a great
convenience to users of the system, by eliminating the need for such calculations as dividing by 16
(to convert ounces to pounds) or by 12 (to convert inches to feet).
There are similar calculations in the metric system that can be performed simply by shifting the
decimal point in different directions. Thus, the metric system is a decimal (base 10) system.
The Commission assigned the name “metre” (in the U.S. spelled “meter”) to the unit of length. This
name was derived from the Greek word, metron, meaning “a measure” The physical standard
representing the meter was to be constructed so that it would equal one ten-millionth of the distance
from the North Pole to the equator along the meridian running near Dunkirk in France and Barcelona
in Spain.
A surveying team under the direction of two men, Pierre Mechain and Jean Delambre, spent 6 years
in measuring the “arc” that the earth made in a line between Dunkirk in France on the English
Channel and Barcelona in Spain. The surveyors underwent much harassment and even were jailed,
at times, while making their measurements, because some of the citizens and area officials resented
their presence and felt they were up to no good. The meter remains the invariable standard for the
metric system, and its length has not changed even though the official expression of the definition of
the meter has changed several times to improve the accuracy of its measurement.
Meanwhile, scientists were given the task of determining the other units, all of which had to be based
upon the meter.
The initial metric unit of mass, the “gram,” was defined as the mass of one cubic centimeter — a cube
that is 0.01 meter on each side — of water at its temperature of maximum density. For capacity, the
“litre” (spelled “liter” in the U.S.) was defined as the volume of a cubic decimeter — a cube 0.1 meter
on each side.
After the units were determined, the metric system underwent many periods of favor and disfavor in
France. Napoleon once banned its use. However, the metric system was officially adopted by the
French government on April 7,1795. A scientific conference was held from 1798 to 1799 (with
representatives from the Netherlands, Switzerland, Denmark, Spain, and Italy) to validate the metric
system's foundation.
Although the metric system was not accepted with enthusiasm at first, adoption by other nations
occurred steadily after France made its use compulsory in 1840.
The standardized structure and decimal features of the metric system made it well suited for scientific
and engineering work. Consequently, it is not surprising that the rapid spread of the system coincided
with an age of rapid technological development. In the United States, by Act of Congress in 1866, it
became “lawful throughout the United States of America to employ the weights and measures of the
metric system in all contracts, dealings or court proceedings.”

3. Important dates in the history of the modern metric system:
1585
In his book "The Tenth" Simon Stevin suggests that a decimal system should be used for weights and
measures, coinage, and divisions of the degree of arc.
1670
Authorities give credit for originating the metric system to Gabriel Mouton, a French vicar, on about
this date.
1790
Thomas Jefferson proposed a decimal-based measurement system for the United States.
France's Louis XVI authorized scientific investigations aimed at a reform of French weights and
measures. These investigations led to the development of the first "metric" system.
1792
The U.S. Mint was formed to produce the world's first decimal currency (the U.S. dollar consisting of
100 cents).
1795
France officially adopted the metric system.
1866
The use of the metric system made legal (but not mandatory) in the United States by the (Kasson)
Metric Act of 1866 (Public Law 39-183). This law also made it unlawful to refuse to trade or deal in
metric quantities.
1916
The Metric Association formed as a non-profit organization advocating adoption of the metric
system in U.S. commerce and education. The organizational name started as the American Metric
Association and was changed to the U.S. Metric Association (USMA) in 1974.
1954
The International System of Units (SI System) began its development. Six of the new metric base
units were adopted.
1996 July
All surface temperature observations in National Weather Service METAR/TAF reports are now
transmitted in degrees Celsius.
The advantages of the Metric system are:
It was based on a decimal system (i.e. powers of ten). Therefore, it simplifies calculations.
It is used by most other nations of the world, and therefore, it has commercial and trade
advantage. If an American manufacturer that has domestic and international customers is to
compete, they have to absorb the added cost of dealing with two systems of measurement.

4. One of the mathematical advantages of the metric system is its combination of metric terminology
with its decimal organization.
There are several prefixes that are associated with a decimal position and can be attached to the
base metric unit in order to create a new metric unit. The knowledge of the decimal meaning of the
prefix establishes the relationship between the newly created unit and the base unit.
For example: the prefix "kilo" means 103 or 1000 so if I take a mythical base unit like the "bounce"
and I attach the kilo prefix in front, I create a new unit called the "kilobounce".
In addition, the relationship between the two units is now well established. Since I know that "kilo"
means 1000 then one kilobounce unit is the same as (or equal to) 103 bounce units. The prefixes that
are most important are listed below along with their decimal and exponential equivalents:
Metric System Prefix Table
Prefix Symbol Multiplication Factor Power of 10
yotta Y 1,000,000,000,000,000,000,000,000 +24
zetta Z 1,000,000,000,000,000,000,000 +21
exa E 1,000,000,000,000,000,000 +18
peta P 1,000,000,000,000,000 +15
tera T 1,000,000,000,000 +12
giga G 1,000,000,000 +9
mega M 1,000,000 +6
kilo k 1,000 +3
hecto h 100 +2
deka da 10 +1
deci d 0.1 -1
centi c 0.01 -2
milli m 0.001 -3
micro µ 0.000,001 -6
nano n 0.000,000,001 -9
pico p 0.000,000,000,001 -12
femto f 0,000,000,000,000,001 -15
atto a 0,000,000,000,000,000,001 -18
zepto z 0,000,000,000,000,000,000,001 -21
yocto y 0,000,000,000,000,000,000,000,001 -24
Why Decimal?
Question: Which column would you rather add?
Inch-pound units Metric units
1 yard, 2 feet, 3-1/4 inches 1.607 meters
1 foot, 11-3/16 inches 0.589 meters
2 feet, 5-1/2 inches 0.749 meters
3 yards, 1 foot, 6-5/8 inches 3.216 meters
==================== ===========
? yards, ? feet, ? inches ? meters
Hint: The two sums are the same.
Answer: 6 yards, 2 feet, 2-9/16 inches; or 6.161 meters

5. Let’s look at the metric units of measurement in different areas of measurement. The types of
measurements are :
1. Mass
2. Dimension
3. Volume
Mass Measurement
The measure of mass in the metric system has several units that scientists use most often.
The gram is the standard unit of mass in the metric or SI system. The gram(g or gm) is roughly
analogous to the English dry ounce. It takes about 29 grams to equal one dry ounce.
A larger mass unit analogous to the English pound is the kilogram. The kilogram is the same as 1000
grams and represents 2.2 pounds in mass. Other metric mass units include:
1. the centigram (cg)
2. milligram(mg)
3. microgram (ug)
4. nanogram(ng).
The basic instrument used to measure mass is the mass balance. There are some digital balances
today that can display the mass of an object in several different mass units both in the English and
Metric systems.
Dimensional Measurement (length, width, height)
Now let us go over dimensional measurement that is measure of length, width, and height. The basic metric unit of
dimension is the meter (m). The meter is analogous to the English yard. A meter is equal to slightly more than a yard
(about 10% larger).
One meter is equal to 1.09 yards or 39.36 inches.
A larger metric unit used often is the kilometer (km) which is comparable to the English mile. One kilometer is equal to
0.62 miles. In countries where the metric system is the national standard, signposts and posted speed limits are in km or
km per hour. For example, the most common speed limit in Mexico is 100, but that is 100 km/hr or about 60 miles per
hour!!
Other dimensional units include the
1. decimeter (dm)
2. centimeter ( cm) which is comparable to the English inch. One inch is equal to 2.54 cm
3. millimeter (mm)
4. micrometer (um)
5. nanometer (nm). The nanometer is used when very small inter-atomic or intermolecular distances are called
for.
The main instrument in the science lab that measures dimension is the metric ruler. The metric ruler comes in various
sizes. All metric rulers are calibrated the same. The numerically numbered positions (major calibrations) are equal to
centimeter marks, and then there are ten equally spaced positions (minor calibrations) in between each of the numbered
positions each of which are equal to 0.1 cm(1 mm). According to this calibration, one can record measurements with one
position of estimation to the nearest 0.01 cm.
Volume Measurement
The third type of measure is measure of volume. Actually we can break this down into the measure of
1. solid volume
2. fluid (liquid and gas) volume

6. Volumes of Regular Solids
Regular Solids are those that have well defined dimensions of length, width, height, and diameter. These can first be
measured with a suitable dimensional instrument like a metric ruler. Then a suitable geometrical formula might be applied
to get the volume.
For example, if the solid was rectangular shaped, you would measure the dimensions of the rectangle and then use the
formula Volume = length x width x height in order to determine the volume of the rectangle.
Measurement of Fluid Volumes
Let's now discuss measure of fluid volume. There are several instruments used to directly measure fluid volumes. The
graduated cylinder is the most commonly used in the lab. However, there are several others. The pipette, burette, and
volumetric flask measure fluid volumes more precisely than most graduated cylinders.
The basic metric unit of measure for volume is the liter (l) unit. The liter is analogous to the English quart. One liter is the
same as 1.06 quarts. It is basically a fluid volume unit as is the smaller metric unit called the milliliter (ml). The milliliter is
analogous to the English fluid ounce. One fluid ounce is equal to about 30 ml.
Other metric units of volume that are more often associated with volumes of solids is the cubic centimeter (cc or cm3)
which is equal to a milliliter. To a careless observer the cc may look like a dimensional unit since it has the word
"centimeter" in it. However, it also has the word "cubic" which always indicates a volume unit.
Some special relationships:
• 1 milliliter = 1 cubic centimeter
• 1 milliliter of water has a mass of approximately 1 gram
• 1 liter of water has a mass of approximately 1 kilogram
• 1 cubic meter of water has a mass of approximately 1 metric ton