The subject is covered in SI-10 and defines conversion vs. substitution, here is a small part of the text: (Would have copied and pasted the whole thing but I don’t want to violate any copyrights).
B.7 Conversion versus substitution Transitioning from traditional inch-pound units to SI requires changing quantity values from one system to another. This can be done by direct conversion, using the factors and rules of this annex to determine an appropriate equivalent value with an SI unit. Another transition method uses substitution. In substitution, a new rational metric size is used for the value of the measurement for the item being converted. While conversion maintains the original standard value (rounded appropriately for accuracy and precision as defined in this annex), substitution defines a new standard value for the measurement. From: Kilopascal [mailto:kilopas...@cox.net] Sent: Tuesday, December 24, 2013 7:30 PM To: cont...@metricpioneer.com; U.S. Metric Association Subject: [USMA:53453] Re: Questions -- if you would be so kind to answer David, 1.) You make a very good point to tell her the US is already partially metric. In this case, we need to place emphasis on what industries are metric (both domestic and foreign transplants) to show and dispel the nonsensical notion that the nation is not metric at all. She and possibly the vast majority of the country believes the US is zero percent metric. 2.) We must never, never, never use the word “conversion” or the phrase “convert to” when we mean metrication. We don’t convert, we metricate. Conversion is translating one number into another and this is the habit we want to break. We don’t want to relate metric units to old units. We want to start fresh with the new units and we want to encourage measuring in metric. Not measuring in one unit and converting it to another. Nobody learns the new system by conversion. They will always cling to the old system if conversion is involved. To metricate means to cross the bridge and never look back. Lot’s wife looked back, and look what happened to her! She turned into a pillar of salt. When we look back, we turn into Luddites. Metrication is looking forward and that is the route to success. 3.) How sad, very sad, that a person who wrote a book and is possibly a teacher doesn’t know that a mass and volume are not the same and that a litre, which is already a unit of volume, would not be a ‘cubic litre”. Talk about the blind leading the blind. Maybe she meant cubic metre. I hope this isn’t the same Linda that is responsible for this webpage: http://milebehind.wordpress.com/2013/12/23/could-the-metric-system-help-our-student-assessments-and-education/ I hope not, because I thought this Linda knew better. [USMA:53453] Re: Questions -- if you would be so kind to answer contact Tue, 24 Dec 2013 09:10:10 -0800 USMA. I received three questions from Linda Dawson who wrote a book: Dradnats and the Metric Measurement Kids (Paperback ISBN 978-1492146261). I attempt to answer these questions and encourage you to address these questions as well because my answers may not be the best answers. Be sure to include l-daw...@att.net<mailto:l-daw...@att.net> when you reply. Hi Linda. I take a shot at addressing your questions: Question 1. When do you think the U.S. will go metric? 5 years? 10 years? Answer 1. The United States began efforts at metrication in 1866 with the Metric Act, so we have been riding around on training wheels for about a century and a half. The United States is already using SI to some degree (see http://metricpioneer.com/fact-sheet for more detail) so The US Metric Association advocates completing United States conversion to the International System of Units, known by the abbreviation SI and also called the modern metric system. The process of changing measurement units to the metric system is called metric transition or metrication. If Hawaii HB36 (see http://www.capitol.hawaii.gov/measure_indiv.aspx?billtype=HB&billnumber=36 for more detail) is successful, then a state-by-state approach could be a catalyst for a national trend that could start as early as 2018. Question 2. Do you see it as a gradual transition? How did other countries, such as Britain, make the change and how many years did it take? Answer 2. There are three common ways that nations convert from traditional measurement systems to the SI. The first is the quick, or Big-Bang route which was used by India in the 1960s and several other nations including Australia and New Zealand since then. The second way is to phase in units over time and progressively outlaw traditional units. This method, favored by some industrial nations, is slower and generally less complete. The third way is to redefine traditional units in metric terms. This has been used successfully (in China for example) where traditional units were ill-defined and had regional variations. (See http://en.wikipedia.org/wiki/Metrication for more detail.) Metrication in the United Kingdom remains partial. Most of British industry, government and commerce use metric units, but imperial units are officially used to specify journey distances, vehicle speeds and the sizes of returnable milk containers, beer and cider glasses. Imperial units are also often used informally to describe body measurements and vehicle fuel economy. At school in Britain, the use of metric units is the norm, though pupils are taught rough metric equivalents of those imperial units still in daily use. (See http://en.wikipedia.org/wiki/Metrication_in_the_United_Kingdom for more detail.) Question 3. Talking on the level of 9 and 10 years old, can you give me some interchangeable equations that kids could remember -- as I know that the meter, liter, and gram are interrelated. I'm looking for things such as: 1 kg =? cubic liters? If you could give me about ten, that would be fantastic! Answer 3. There is no such thing as a cubic liter, but rather, a liter is a cubic decimeter. Mass and Volume are not equivalent things, for example, a liter of air has less mass than a liter of water so they have different weights. I already offered to mail you a free SI Ruler that lists those interrelationships but you responded saying that you don't want it. See http://metricpioneer.com/shop/ruler/ for more detail. One liter of water fills one cubic decimeter and weighs one kilogram. So, one thousand liters of water fill one cubic meter and weigh one ton. Be cautious though; this equation works for water, but not for matter of different densities. Have a look at that ruler again and peruse it in its entirety. David Pearl MetricPioneer.com 503-428-4917 ----- Message from l-daw...@att.net<mailto:l-daw...@att.net> --------- Date: Mon, 23 Dec 2013 19:36:50 +0000 From: Metric Pioneer <l-daw...@att.net<mailto:l-daw...@att.net>> Subject: Questions -- if you would be so kind to answer To: cont...@metricpioneer.com<mailto:cont...@metricpioneer.com> From: Linda Dawson <l-daw...@att.net<mailto:l-daw...@att.net>> Subject: Questions -- if you would be so kind to answer Message Body: Hi, David, My children's book should be coming to you shortly. I know you know a lot more about metrics than I do. I was wondering if you could enlighten me. 1. I know this is a guesstimate, but when do you think the U.S. will go metric? 5 years? 10 years? ? 2. Do you see it as a gradual transition? How did other countries, such as Britain, make the change and how many years did it take? 3. Talking on the level of 9 and 10 years old, can you give me some interchangeable equations that kids could remember -- as I know that the meter, liter, and gram are interrelated. I'm looking for things such as: 1 kg =? cubic liters? If you could give me about ten, that would be fantastic! I know this is the holiday season, so you can answer this very long e-mail at your convenience or answer part of it and finish later. Most grateful, Linda l-daw...@att.net<mailto:l-daw...@att.net> -- This mail is sent via contact form on Metric Pioneer http://metricpioneer.com
