On 2008 Mar 17 , at 9:33 PM, Ziser, Jesse wrote:
Life is hard without centi- and deci- and the like when one is
working in square or cubic dimensions, especially if you also don't
like liters.
I agree. That is the one situation that I find makes centimetres seem
useful and almost necessary.
Is there any other way to avoid that problem?* The litre was created
in an effort to solve it but it raises issues of its own.
Bill Hooper
1810 mm tall
Fernandina Beach, Florida, USA
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* Specifically, the problem is:
When one uses lengths in steps of 1000 only (µm, mm, m, km, etc.), as
I for one prefer to do, and then uses these lengths to form volume
units (cubic µm, cubic mm, cubic m, cubic km, etc.) then the steps
between one volume unit and the next are multiples of 1000-CUBED,
which is 10-to-the-9th, or a billion (in American usage of that word).
That means there is an extremely wide range between one unit and the
next. Within that range, most measured volumes would be either
inconveniently large numbers of the next smaller unit or
inconveniently small fractions of the next larger one.
As a specific example, for buying liquid commodities by volume (milk,
beer, gasoline, etc.), the cubic millimetre is too small to be
convenient. The common volume used to measure milk, etc. is a million
cubic millimetres. But measuring it with the next larger available
unit (if we stick with just steps of 1000 in length units) that milk
would be one one-thousandth of a cubic metre. It was precisely because
of this difficulty that this common size I've been referring to was
formalized into a special unit of its own and called the litre.
But, because it breaks the pattern, the litre cannot be made to be
coherent with the rest of SI. It's a quandary, I agree.
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SImplification Begins With SI.
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