Ann in Houston wrote:

The jug is 10" in diameter and 14" tall. The volume of a cube is
Length*height*width=1728 cubic inches for a 1' cube. The volume of a
cylinder is Pi*Radius*Radius*height= Pi*5*5*14=1100 cubic inches. Not
surprisingly; smaller than a 12" cube. :-)


Well, okay. I can't argue the facts since you went to the trouble to
measure
it. It sure seemed close, though. I know that the water bottle also is
sort of cone shaped at the bottom. Do your calculations treat the bottle
as
a full cylinder, or did you stop at the top of the neck? That could make
a real difference too. Thanks for being intrigued enough to check it out.

I treated it as an exact cylinder - if I wanted to figure out the difference
due to curvature, I'd actually have emptied the contents into a proper
measuring container, as otherwise I'd have to take into account the
curvature on the bottom, the tapering on the top, the size of the neck (at
least, the one I used had some water in the neck), and the thickness of the
plastic (which looks like it probably isn't even uniform). It's a lot
easier to make assumptions :-) (besides which, since I couldn't get an
exact measurement, it was all rough anyway). In fact, either our water
supplier is cheating us, or the jug is actually a little bigger than my
calculation, because it should really be about 1150 cu.in. for a 5 (US)
gallon container.
--
derek