Re: OT: Units (was Re: Numbers in Qthen|gai (and in Tyl Sjok) [long]) (Modified by Tristan McLeay)

On Fri, Jan 14, 2005 at 04:30:52PM +1100, Tristan McLeay wrote:
> Playing with the ever-so-useful unix program units, I discover that an
> Imperial tablespoon was 17.758165mL (or thereabouts), whereas an
> imperial teaspoon was 5.9193884 mL (again, a third). Now obviously the
> nearest multiple of five to 5.9 mL is 5 mL, whereas the nearest
> multiple of five to 17.75 mL is 20 mL (but not by much), so that's
> probably how the Australian measurements came about.
No doubt.

> Of course I understand you Americans have dry measures and wet measures
> for volume so I wouldn't trust them if I were you :)
Heh.  True.  But the "dry" measures are used almost exclusively at the
larger end of the scale: bushels, pecks, etc.  Those units are
theoretically defined in terms of "dry gallons" of four "dry quarts"
each, etc - where the "dry" units are about 16% larger than the
corresponding wet ones (due to the higher density of liquids and the
origin of the units as shortcuts for measuring by weight), but the
smaller "dry" units aren't used in everyday life, and most Americans are
probably unaware or at most vaguely aware of their existence.

For the smaller volumes used in (non-industrial) cooking recipes, the
"wet" measures are used exclusively: 1 gallon of exactly 231 cubic
inches (therefore exactly 231 x 2.54^3 = 3785.411784 cubic
centimeters/milliliters) divided into four quarts of two pints each of
two cups each of 8 fluid ounces each of two tablespoons each of three
teaspoons.  Although you almost never see recipes call for a given
number of (fluid) ounces; this might be due to potential confusion with
the avoirdupois ounce of weight.  For volumes above a tablespoon,
fractions of a cup are usually used instead: 1/4 cup, 1/3 cup, 1/2 cup,
etc.

> (Flour was just meant as a stand-in for a common ingredient when
> following recipes; it like most solids is sold by the kilo here.)
Ah, but there's a difference with flour: its density can vary greatly,
which is why the persnickety cooks measure it by weight rather than
volume.  Almost all other recipe ingredients (sugar, salt, etc) are
measured exclusively by volume.