On Sat, 9 Jun 2001 17:37:30
Gene Mechtly wrote:
...Please forgive my typo error...
No problem, I evidently realized it was an innocent typo! :-)
My preference is D for deca as an alternative
>to da for a trial period, just as both l and L are for a trial period.
>...
And I have no personal problem eventually supporting your motion despite my being very
used to 'da'! :-)
>The CCU recommends to CIPM and on to the CGPM. Perhaps the CIPM will
>not accept the CCU decision to add no options to prefix
>symbols.
>...
Would therefore be a way that we can, somehow, 'lobby' the powers at be directly for
their rejection of such ludicrous 'recommendations' (SIC)?
>Marcus, recall that in SI there is one and only one coherent unit for each
>quantity (whether it be a base or derived quantity and respective unit).
>...
Of course, Gene, I do realize that. That's exactly why I commented that talking about
'coherence' as related to prefixed units was actually moot, or illogical or
inappropriate or out of context (pick one or all! ;-) ).
>Marcus, there are only a few "coherent" units in SI (one and only one for
>each quantity), but many many multiples and submultiples...
'Course, please see my comment above. But I honestly don't see relevancy here to the
issue of using SI units or units of the SI, given what I commented earlier.
>> If we accept that 'multiples' of SI units are not really *new* units,
>> but rather just a *cosmetic representation* of the value to save us
>> either unnecessary zeros or decimal places, why calling these SI units
>> would 'damage the concept of coherence', as you put it?
>
>The situation would be U = 10 U, U = 100 U, U = 1000 U, etc. all at the
>same time for every SI Unit (each represented by U in the above equations).
>Do you accept these equations as mathematically correct for U in general?
>
?? Now, you completely lost me here. Sorry... :-S
What I meant was simply that 0.002 m is *exactly* the *same measurement value* as 2 mm
or 2 000 um (sorry, I can't reproduce the 'micro' prefix, so I'm using 'u' instead),
etc. It's simply wrong to think of 20 cm as being a new unit/measurement when
compared to 0.2 m.
It's like this, Gene. I use my measuring tape calibrated in *meters* to measure some
object. I have a choice to present the result of this measurement as, say, 210 cm, or
2.1 m, or 2 100 mm!
>...The CCU decision departs from that distinction and accepts U = 10 U, etc.
>That is my objection!
>
Ok, but if you think of my argument earlier (that this should actually be moot or
non-applicable - I'm probably missing the more appropriate adjective to use, that's
why I've been trying to use several expressions here, sorry... But I do hope you get
the spirit of my point) this should not be a concern.
>>
>> To me, it should be this simple: prefixed units are *actually* the *same*
>> unit.
>
>Yes, only if you mean that the unit name (root) is embedded in the name
>of the multiple. e.g. meter is the root part of kilometer.
>
No, Gene, N-O! Please understand me clearly: 20 cm is *exactly* 0.2 m 'in disguise',
if you will, or stated differently! The *parameter* or reference being used for the
**measurement** is and has always been the *meter*!!! Prefixes are just clever ways
of presenting the result of the measurement in a way that is more mathematically
convenient for use.
>> Just like cents are still dollars!
>
>Would you be willing to give me a dollar (even a Canadian dollar) for
>every cent I give you? After all cents are still dollars as you put it.
>
??? A cent is actually 0.01 *dollars*, Gene!!! What I meant was that *the unit for
measurement* (currency measurement in this case) IS the dollar! It has never been
anything else REALLY! You have never 'abandoned' the dollar unit when dealing with
cents.
Therefore, to answer your question, no, evidently not. I would be willing to give you
100 cents for your dollar though, as they are exactly equal in value! ;-)
>> Therefore, I am ok with calling 'the whole lot' SI units, after all.
>
>Really, Marcus? If so, there is where we part company, unless you send
>me your dollars for my cents, one for one.
>...
Well... I hope you understood my explanations above.
Marcus
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