Realistically, the difference between the International and Survey yards can't be resolved with ordinary measuring gear, such as tapes, chains, etc that the average person might use. The difference is even below the resolution of ordinary surveying (one part in 10000 is acceptable). The difference arises only in geodetic survey and in the false origins used in state plane coordinate systems to clarify coordinates in states that have multiple zones. (Different false origins are added in the different zones to basically encode the zone in the coordinates, and have non-overlapping values. The false origins may be millions of feet and 2 ppm adds up.) The difference also arose in precision machining in WWII; that led to the conference to resolve the foot in 1959. As a result, use of the Survey foot is ONLY permitted in land measurement, and 99+% of us don't have the tools to measure the difference. Hell, my calipers couldn't resolve 2 ppm over their 155 mm span. In the case of real measurements vs textbook examples, VERY few past measurements would have been made with precision that would resolve 0.9144 m and 3600/3937 m yards. It is silly to obsess over the difference. Just use 0.9144 m unless you KNOW you are dealing with Survey yards. I belabor this point only because I think: *The dozens of definitions" argument is fundamentally weak as the other side recognizes it RARELY has practical consequence (UK and US gallons are a better example, at least there is a 20% difference) *It rallies defenders of the yard I think there are stronger arguments to encourage metrication.
--- On Fri, 10/9/09, Pat Naughtin <pat.naugh...@metricationmatters.com> wrote: From: Pat Naughtin <pat.naugh...@metricationmatters.com> Subject: [USMA:45977] Re: teaching customary units To: "U.S. Metric Association" <usma@colostate.edu> Cc: "USMA Metric Association" <usma@colostate.edu>, "Edgar Warf" <edgar.w...@gmail.com> Date: Friday, October 9, 2009, 5:55 AM Dear Aaron, I'm sorry if I upset you, I didn't mean to. My intention was to reveal the secret knowledge that is hidden when you look at an an apparently uncomplicated instruction like: Convert ten yards into metres To comply with this instruction properly you should at least take into account the fact that of the two different yards currently available in the USA, you have chosen only one of these. This has the effect of hiding the fact that there is a duality in the USA. It also hides the multiple yards that have existed previously. More importantly, however, it gives the illusion to your students that there is the metric system and there is another single alternative system and this is simply not so. The truth is that there is the metric system and there is no other system; there is only the remnants of all the thousands, perhaps millions, of old measuring words, with many different definitions, left over from previous centuries. My point is that the instruction, Convert ten yards into metres, hides this. This hidden complexity is so common that – as you say – almost 100 % of citizens are quite unaware of the complexity of old measuring words and by contrast they also remain unaware of the fundamental simplicity of the metric system. The tragedy of this misunderstanding is that it delays the process of metrication remarkably. Cheers, Pat Naughtin Author of the ebook, Metrication Leaders Guide, that you can obtain from http://metricationmatters.com/MetricationLeadersGuideInfo.html 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 for more metrication information, contact Pat at pat.naugh...@metricationmatters.com or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter to subscribe. On 2009/10/09, at 14:38 , Aaron Harper wrote: While I cannot say that I speak for 100% of Americans, I think I can safely state that when most people in the USA refer to a "yard", they are talking about the one with 36 inches in it. And, each one of those inches is equal to 25.4 mm. We don't know what year it was approved, agreed to, standardized or redefined. What's more, we don't care. It equals thirty six 25.4mm inches. Unfortunately, the point of my post was pretty much missed by everybody that responded. My point is, that the PROCESS of doing conversions develops skills that are related to and involved in the PROCESS of SOLVING problems. If a person can't set up the problem, then they can't solve it. If you can't set up the factors to perform a lengthy conversion, then you can't perform the conversion. The processes are very similar. Critical thinking and reasoning skills are only developed through practicing them. You can't look them up in a book or an ISO standard. If you withhold the teaching of the process of doing conversion completely, or until high school, you are withholding a tool that is an easy and fun way to start getting kids to THINK about what they are doing and why, and what they can do with a given piece of information. I didn't mean to touch a sensitive spot, but I get tired of hearing the members of this forum run down Americans as being "dumb" or "inferior" because we haven't yet adopted the SI to the degree that many out there think we should. Best regards. Aaron Harper On Thu, Oct 8, 2009 at 12:19 AM, Pat Naughtin <pat.naugh...@metricationmatters.com> wrote: On 2009/10/08, at 14:40 , Aaron Harper wrote: Having a student have to figure out how to get from one unit to an equivalent unit in another system Dear Aaron, I am having trouble with your line, 'Having a student have to figure out how to get from one unit to an equivalent unit in another system …' as I know of only one system of measurement. And I am also sure that only one system of measurement has ever existed. When the decimal metric system was developed from Wilkins universal measure in the 1790s, it became the world's first measurement system. Subsequently this first idea for a measuring system evolved from the decimal metric system through the simpler name of metric system to the International System of Units (SI). As you know this is a complete system of units that is able to measure everything from the smallest to the largest things in the entire Universe. As Condorcet put it in the early 1790s, the decimal metric system is: 'for all time; for all people'. I am aware that there were subsequent refits of bits and pieces of various small groups of old measuring words. The UK tried to develop a decimal currency based on 10 florins to a pound in about 1824 while they held to the idea of 24 pennies to a florin. Some scientists tried to copy the coherent properties of the metric system with their foot-pound-second "system" and the foot-poundal-second "system" while some engineers tried to do the same with their foot-slug-second "system"; all done while the foot changed its length in, at least, these years: 1824, 1834, 1855, 1893, and 1959. I find it impossible to recognise these attempts as comprehensive or universal measuring "systems". The point that I want to make is that it is not possible to convert from one system to another system when there has only ever been one single system – the metric system – that is formally known as the International System of Units (SI). All the rest are just more or less random collections of old pre-metric measuring words. Now let's consider an actual conversion problem. Convert ten yards into metres. This problem should not even be attempted until you answer this question: Which yard do you mean? Are you talking about the 1859 metric-defined international yard, the 1893 metric-defined yard, (the statute yard or the survey yard of the USA), the interim yard between 1834 and 1855 based on the length of a pendulum with no real fixed length, the 1855 UK yard based on an artefact, the 1824 UK Imperial yard (1832 in the USA) that got burned with the UK Houses of Parliament in 1834 or one of the many earlier yards that appeared from time to time all with slightly varying lengths (possibilities here are three Elizabeth I feet, the Edward I ulna, or three Roman feet, etc.)? If you don't ask all of these questions you infer that there are two "systems" metric and only one other, when the facts are that there has only ever been one system – the metric system as stated above – and all of the other old hodge-podge of measuring words with multiple definitions that have varied through time. Hhhrrrmmmph! P.S. Apologies for being so grumpy – you've hit a pet peeve! Cheers, Pat Naughtin Author of the ebook, Metrication Leaders Guide, that you can obtain from http://metricationmatters.com/MetricationLeadersGuideInfo.html 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 for more metrication information, contact Pat at pat.naugh...@metricationmatters.com or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter to subscribe.
