Gustaf asks:
> From: Gustaf Sj�berg <[EMAIL PROTECTED]>
> Subject: [USMA:8830] Re: Cribsheet
>
> What is this idea about only using 1000-multiples?
The idea is that, of the twenty (20) prefixes in SI, sixteen (16) are powers
of 1000 and only four (4) are not. Those four are deci, centi, deka and
hecto.
> The cm and cL are two of the most useful units in everyday-metric system.
I don't argue that they are not used at all but only that they are less used
than the powers of 1000. Gustaf's opinion is that they are among "the most
useful units". My personal opinion is that SI would be better without them.
There are many who suggest that these prefixes should not be introduced
where they are not already in common use. I agree with that suggestion.
In any case, I certainly do not deny Gustaf's statement that decilitres and
centilitres (and others) are in common use in Europe and elsewhere,
particularly for beverages and cooking.
By way of an example, in the set of olde English units, knots and furlongs
are in use in special fields, too, but no one would encourage anyone to
begin using furlongs to measure the height of mountains or the altitude of
orbiting satellites, or to use knots to measure the speeds of automobiles or
the speed of electrons in cathode rays. It's bad enough that they are in use
in some special fields (like horse racing and boating) without introducing
them into new areas where thay are not presently used.
> They might not fit in some 1000-pattern but
> that is no reason to prevent people
> from using them. Ordinary people don't care about 1000-patterns.
If the individual powers of ten (like 10 and 100) are so useful, why isn't
that pattern used throguhout SI? It is not. It stops with 10 and 100 (and
one-tenth and one-hundredth.) From 1000 on up (and down) all steps between
prefixes are 1000.
A system of prefixes that consist only of powers of 1000 is simpler than one
that consists of some powers of 1000 and also some other multipliers like 10
and 100. In addition, a system that contains only the powers of 1000 has
fewer prefixes to learn than one which contains, in addition, powers of 10
and 100.
Regards,
Bill Hooper
