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The Metric system WHY
CAN'T
WE
EVER
GET
IT
RIGHT? Isn't
it odd that Americans and even some Europeans - some of the most technologically
sophisticated people on earth - are so sloppy and at times ignorant in their
communications between themselves and others? Since
1866 the so-called “metric system” of units (weights and measures) has been
legal for trade in the United States. In the EU it is now the only system
that can legally be used for trade. In
1960 an international group formalized the units used all over the world.
The international “General Conference on Weights and Measures” met in
Paris and agreed the coherant system of units (based on the meter,
kilogram, second, ampere, Kelvin,mole
and candela) the “International System of Units.”
The Conference also established the abbreviation SI
(Système International d'Unités) as the official abbreviation, to be used in
all languages. SI
UNITS AND
STANDARD USAGE There
are seven basic SI “base units,” these are:
The SI units are used to derive units of measurement for all physical quantities and phenomena. Note
particularly that there is no SI unit
for volume.
Volume is a cube function of length, as in the case of a solid or
hollow cube that has a length, a width and a height.
You will also notice—even if you read every document you can find that
even mentions SI units—that there is no such thing as a litre
(liter) in the SI system of units. This
is because the proper way to describe volume is in terms of the SI base unit
(meter) that volume is derived from. For
example, the proper way to describe one (liter) of water is to use one of the
two terms: 1000 cubic centimeters (1000 cc) or one cubic decimeter (1 dm³).
Which is the preferable term to use is detailed later on in this missive. Note
also that even those well-intentioned but incorrect people who use “metric”
names (even if these names are made up ones such as “litre,”( “liter”)
which comes from another bastardized system that SI was intended to replace),
often get the capitalization use rule wrong.
The rule is: if, and only if, the unit is named after a person, use upper
case for the letter designator. There
is no record of a scientist named Liter The SI derived units are listed here with their derivative units:
Supplementary
units:
SI
PREFIXES The
names of multiples and submultiples of any SI unit are formed by application of
the prefixes: (where possible a prefix representing 10 raised to a power which
is a multiple of three should be used)
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