On Mon, 07 Jul 2003 11:05:54 GMT, "Bob Harrington"
wrote:



"Gene Nygaard" wrote in message

On Sat, 05 Jul 2003 22:03:29 -0500, David Ball
wrote:

On Sun, 06 Jul 2003 01:43:15 GMT, Gene Nygaard

wrote:

On Sat, 05 Jul 2003 20:11:42 -0500, David Ball
wrote:
snip
Actually, there is a hectopascal. What you are objecting to is
its use as common jargon. The goal of such jargon is to
facilitate communication. If you know that it is equivalent to
millibars, what are you complaining about? Meteorologists will
continue to use
millibars because it is convenient to do so. If it ain't
broke, don't fix it.

It is broke. That's the only reason hectopascals exist in the
first place, is the pressure to get rid of those obsolete
millibars.
snip
Millibars are bad, a unit which has outlived its usefulness.
Hectopascals are worse, wrong from the beginning. But even worse
than that are the millimeters of mercury used for blood pressure by
doctors in Canada and the United States. Of course, the inches of
mercury
used in meteorology in the United States are a couple more steps
below that.

A very important part of SI is that it is an interdisciplinary as
well as an International System of Units. There is absolutely no
reason
whatsoever why we should have to learn a whole new set of
measurement units, just to learn about and discuss some field of
activity we
haven't been involved in before. There's no reason why scientists
involved in interdisciplinary activities should have to make
conversions one way for one tribe of scientists, and the other way
for a different tribe, just to work together.

But above you mentioned the importance of communicating with the
public - why would you then force hundreds of millions of people to
learn a new system when the old one has served them perfectly well for
decades?

I guess you were sleeping when David Ball told us that the Canadian
public has made the change quite easily, and that he does use the
proper SI units when communicating with them--it is just the
meteorologists who have difficulty getting it right.

Conversions aren't all that hard for folks, especially scientists
(recent NASA Mars probe snafus notwithstanding), if nothing else, it
keeps the brain keen. This clamoring for change simply because it is
the current True Way of those who think they know better than the rest
of us is little more than...

Conversions are a pain in the ass, and most people don't bother making
them--for one thing, they don't know the conversion factors. They
waste time when they need to be done. Furthermore, any time you
convert between units (at least those not related by exact powers of
ten), you lose something. The most common losses are either some of
the precision of the original measurement, or the sense of how precise
it actually is. Most importantly, the need to make conversions is an
unnessary opportunity for error. Not only errors in the calculations
and the transcription of the numbers, but as that Mars Climate Orbiter
example shows, one common error is a failure to recognize that a
conversion is even necessary.

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/