One might consider grams per deciliter. Numerically that is the same as
"percentage"--but neither by volume nor by mass, of course. It is,
however, the compound unit in which blood alcohol content (BAC) is
measured. Diabetics are used to measuring their serum sugar levels in
milligrams per deciliter ("milligram percent" it is called...shudder!),
though most do not know this. If the content of the bottle or can were
also given in deciliters even a middle-schooler (sober of course) could
calculate the total alcohol content in grams in the container.
If strict "percentage by volume" is desired, then of course one would
use milliliters per deciliter. I believe that wines and spirits are
measured in those terms.
Jim
Bill Hooper wrote:
On 2008 Jan 26 , at 11:04 AM, Paul Trusten wrote:
Also, since percentages by weight or volume are defined
in metric units (g/100 mL or mL/100 mL),
Percentages must be found from a ratio of two similar quantities. You
can find the number of grams per milllilitre if you want to, but it's
not a percentage and can't be expressed as a percentage. It could be
called a concentration, perhaps.
One can express percentage by mass as "grams per gram" or percentage by
volume as "millilitres per millilitre"*, but not in the form of grams
per millilitre.
Regards,
Bill Hooper
Fernandina Beach, Florida, USA
*I think of this calculation as, first, finding the ratio of the two
things (in this case volume of alcohol divided by volume of beverage)
and then, separately, expressing the first result as a percent by
dividing by 100. Certainly it is OK to combine the steps into one as
Paul does in referring to "mL/100mL".
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SImplification Begins With SI.
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--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(H) 931.657.3107
(C) 931.212.0267
