Liquid Quart vs. Solid Quart

Date: 04/27/2001 at 19:24:12
From: James L. Erbes
Subject: Liquid quart versus solid quart

Why does a liquid quart consist of 57.75 cubic inches, whereas a solid 
quart consists of 67.2 cubic inches?

Thanks, 
James

Date: 04/28/2001 at 22:55:26
From: Doctor Peterson
Subject: Re: Liquid quart versus solid quart.

Hi, James.

"Why" questions in the area of units (or in history in general) don't 
tend to have satisfying answers, but our FAQ includes a link to a good 
site where such questions are answered as well as anywhere I know:

   How Many? - Russ Rowlett
   http://www.unc.edu/~rowlett/units/   

Look up "quart" and from there go to "gallon." You'll find that a 
likely explanation is that solids, such as grain, can be heaped up, 
while liquids can't. A dry gallon is a "heaping pailful," while a 
liquid gallon is only full to the brim.

Old units were very practical, while modern units are more consistent.

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/