The fraction 355/113 gives a better representation of pi (correct to 7 significant figures, not 3 significant figures (which is the accuracy of 22/7)
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of James Frysinger Sent: 27 December 2008 01:16 To: U.S. Metric Association Subject: [USMA:42211] Re: A pint's a pound the whole world round You folks are squinting too hard. Again, I think that this was never meant to be more than a rule of thumb, a bit like "pi equals 22/7". It's made a bit cuter by the fact that both a pint and a pound contain 16 ounces, albeit different kinds of ounces. Jim Jon Saxton wrote: > I never heard that rhyme until I read it on this list. I assume it is > based on the idea that there are 16 ounces in a pound and 16 fluid > ounces in a pint. If a fluid ounce of something weighs one ounce then > in a sense the pint and pound are equivalent. Of course it depends on > what you fill the pint container with. A pint of naphtha would be > somewhat lighter than a pound, whereas a pint of mercury would be much > heavier. > > So what is the substance which makes the rhyming equation true? The > most likely candidate is water. So presumably the rhyme says 16 oz of > water is a pint or a pound, "the whole world round". > > I grew up in Australia using British pints of 20 oz so it would have > been plain wrong there and it is not surprising that the rhyme was not > part of my culture. Only in the USA is the 16 oz pint used. Since 1824 > the pint used in all other English-speaking countries was the 20 oz pint > of my youth. The part that says "the whole world round" is simply wrong. > > Interestingly enough, the rhyme is wrong in the USA as well. A pint is > simply not equivalent to a pound. The USA inherited the pint from the > UK as it was at the end of the 18th century. The gallon of the time was > the Queen Ann "wine gallon" of 1707 based on the volume of eight troy > pounds of wine. Because the USA seceded from the British Empire in the > latter part of the 18th century it did not adopt the 1824 uniform > redefinition of the gallon as the volume occupied by 10 lb (avoirdupois) > of distilled water (measured at 62ºF in air at a pressure of 30" of > mercury *). The British ounce of water by weight and by volume were > established as equivalent. The volume of a UK (Imperial) gallon worked > out at a bit over 277 in³ or 4.55 L whereas the US gallon (i.e. the old > wine gallon) was 231 in³ or 3.79 L. There are 160 fluid ounces to the > Imperial gallon which, as mentioned above, preserves the water > weight/volume relationship. A UK fluid ounce is about 1.74 in³ or 28.4 > ml. However the USA divides its gallon into 128 fluid ounces which > means each fl oz is about 1.80 in³ or 29.6 ml. So a US pint of 16 US > fluid ounces of water weighs about 4% more than a pound. > > So the "whole world round" part is not true in the USA either. It is > just wrong everywhere^. > > *Ref: R. D. Connor, _The Weights and Measures of England_, Science > Museum, London, 1987. ISBN 0 11 290435 1 > > ^This discussion only addresses liquid measures. When we bring dry > pints into consideration then we have a whole new set of ways for the > rhyme to be wrong. > > > > > James Frysinger wrote: >> >> I was fortunate in the 7th grade; our math teacher ignored the school >> board and taught us algebra. However in the 8th grade, we had a math >> teacher who started off by saying that he hated math and was just >> waiting until a coaching job came up at the high school (grades 9 to >> 12). The only thing I recall doing that year (apart from mischief) was >> spending untold hours memorizing U.S. customary weights and measures >> tables and key facts, such as the number of square feet in an acre. I >> think the rest of the year must have been spent on arithmetic, working >> percentage and interest problems, for example. >> >> One of the essential facts that we learned was "a pint's a pound the >> whole world 'round" and my parents said they had learned that in >> school, too. My recollection is that this was given as a "rule of >> thumb" and not an exact conversion and one easy to memorize because >> both a pint and a pound comprised 16 ounces (albeit of different >> natures). So it was also a reinforcement of the facts that a pint >> contains 16 fluid ounces and a pound avoirdupois contains 16 ounces >> avoirdupois. Yes, we learned all about Troy pounds and ounces, too. I >> think our textbook in that 8th year had been published in 1811, just >> before the British set fire to the White House. (I'm just kidding >> about the publication date; the arson is fairly well accepted as fact.) >> >> By the way, my father and his brothers had the same teacher for their >> 7th grade math classes and she taught them algebra, too. They recalled >> her as being old to the point of being ready for retirement at the >> time they had her. >> >> Jim >> >> Pat Naughtin wrote: >>> Dear All, >>> >>> I was looking for the origins of the maxim, 'A pint's a pound the >>> whole world round' when I happened on this reference at >>> http://makezine.com/16/diyhome_measure/#msg3308 where they say: >>> >>> There's a difference between a U.S. pint (16 fl oz) and an Imperial >>> pint (20 fl oz), which means that a pint's a pound only in the USA. >>> An Imperial gallon of water weighs ten pounds, which means, (if I've >>> got my old pre-metrication sums right) that a fluid ounce of water >>> weighs an ounce. Now, it seems that the U.S. gallon is also different >>> from the U.S. gallon, which make sense. >>> >>> Does anyone have any 'Rules of thumb' that apply to gallons, quarts, >>> pints, and fluid ounces in the USA. >>> >>> Cheers, >>> >>> Pat Naughtin >>> >>> PO Box 305 Belmont 3216, >>> Geelong, Australia >>> Phone: 61 3 5241 2008 >>> >>> Metric system consultant, writer, and speaker, Pat Naughtin, has >>> helped thousands of people and hundreds of companies upgrade to the >>> modern metric system smoothly, quickly, and so economically that they >>> now save thousands each year when buying, processing, or selling for >>> their businesses. Pat provides services and resources for many >>> different trades, crafts, and professions for commercial, industrial >>> and government metrication leaders in Asia, Europe, and in the USA. >>> Pat's clients include the Australian Government, Google, NASA, NIST, >>> and the metric associations of Canada, the UK, and the USA. See >>> http://www.metricationmatters.com >>> <http://www.metricationmatters.com/>for more metrication information, >>> contact Pat at [email protected] >>> <mailto:[email protected]> or to get the free >>> '/Metrication matters/' newsletter go to: >>> http://www.metricationmatters.com/newsletter to subscribe. >>> >> > -- James R. Frysinger 632 Stony Point Mountain Road Doyle, TN 38559-3030 (C) 931.212.0267 (H) 931.657.3107 (F) 931.657.3108
