[USMA:36424] Re: Units used in popular science books: buy Canadian

[Bill Hooper]

On 2006 Apr 1 , at 10:22 AM, Jim Elwell wrote: ... Table 3 of BIPM's SI document (Derived Units with Special Names) Witness: klick for kilometer, nit for candela per square meter. Perhaps my citing Table 3 was confusing, but that is where most short names already reside: volt, watt, joule, etc. The Table 3 Jim refers to above is not for ANY short names. It is for DERIVED units only. Derived units inherently incorporate more than one word (two or more units as in newton-metre or modifier words such as square and cube). Jim's example of the candela per square metre is a case where a single short name like the nit (SI symbol "nt"?) would be  useful. (1 nt = 1 cd/m^2) If we are to develop a series of short names for all kinds of units (regular units like millimetre and derived units like kilopascal), that would be an entirely different thing. SI tries mightily not to have more than one name for the same unit. (There are exceptions like the litre for cubic decimetre, tonne for megagram, hectare for square hectometre, etc. I think these three may be the ONLY ones.) But to have two different names like klick and kilometre for the same thing is exactly the kind of thing SI seeks to avoid. But to allow a new "short" name for a millimetre, for example, would be a whole new class of units names. Now we are back to the Olde Engish mixture of units (almost) with it's plethora of unnecessary units names (and units). However, I can imagine a move not to ADD extra names but simply to REPLACE the long names by something shorter. Instead of having both the klick and the kilometre for 1000 metres, why not make a new name for the kilometre that BOTH (a) is shorter, and (b) follows a pattern of standard basic units and standard prefixes. This would be possible ... (I'm NOT saying DESIRABLE and I'm NOT at the moment PROPOSING such a change, just discussing possibilities) ... this would be possible by shortening ALL the unit names and prefixes. Why should metre be two syllables when it can be one: met. Then too, why must prefixes be two syllables when they can be one: kil instead of kilo, mil instead of milli, etc. In one well planned change of unit names and prefixes (not symbols), all  multiple syllable units are significantly shorter. Examples" 1 kilmet = 1000 mets (formerly metres) 1 met = 1000 milmets 1 kilpas = 1000 pas (formerly pascals) 1 kilnewt = 1000 newts (formerly newtons) 1 newt = 1000 millinewts 1 kilnewt-met - 1000 newt-mets (formerly newton-metres) Unit basic names that are already only one syllable, would not change. 1 kilgram = 1000 grams 1 megwatt = 1000 kilwatts 1 meghertz = 1000 kilhertz If the problem is really as serious as some of you think, then any change you propose should keep the simplicity of the SI (or even improve it), not just willy-nilly manufacture special names for everybody's favorite long unit. The candela per square metre noted by Jim is 7 syllables long. It would become (perhaps) the cand per square met, a considerable improvement at 4 syllables, but still long enough that an argument can be made for giving it a special name like the "nit" or something. Regards, Bill Hooper Fernandina Beach, Florida, USA ==========================    SImplification Begins With SI. <----- Let's Keep it that way! ==========================