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DYKT: Did You Know That ...
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DYKT: Did You Know That ...
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"If you think in pounds and miles instead of kilograms and kilometers, you're in the minority. Only the United States, Liberia, and Burma still primarily use English units-the rest of the world is metric. And now the Moon will be metric too."
So says NASA in announcing that the agency will use metric units for all lunar surface operations when it returns to the moon. As NASA puts it, "The decision is a victory not only for the metric system itself, which by this decision increases its land area in the solar system by 27%, but also for the spirit of international cooperation in exploring the Moon. The decision arose from a series of meetings that brought together representatives from NASA and 13 other space agencies to discuss ways to cooperate and coordinate their lunar exploration programs. Standardizing on the metric system was an obvious step in the right direction."
"When we made the announcement at the meeting, the reps for the other space agencies all gave a little cheer," says Jeff Volosin, strategy development lead for NASA's Exploration Systems Mission Directorate. "I think NASA has been seen as maybe a bit stubborn by other space agencies in the past, so this was important as a gesture of our willingness to be cooperative when it comes to the Moon."
In theory, NASA has been metric since around 1990, but in practice, much of the U.S. aerospace industry uses non-metric units, occasionally leading to problems like the loss of the Mars Climate Orbiter in 1999, which crashed into Mars instead of going into orbit due to confusion between newton seconds and pound-force seconds. Visit www.metric.org/unit-mixups.html for more on that and other problems caused by unit mixups.
The shocking new National Council of Teachers of Mathematics (NCTM) 2006 position statement on teaching the metric system, which supersedes the 2000 position statement and abandons the previous recommendation to teach the metric system as the primary measurement system, is a stunning reversal.
NCTM's continued insistence on teaching both measurement systems ignores the fact that students must know the metric system, now, and that the inch-pound system is a relic. We should be teaching to the future needs of students, not to the past. Students' scores on national and international assessments in both math and science are mediocre, often declining on eighth grade tests from their fourth grade performance levels. Their test scores on measurement are even worse. Results from the most recent National Assessment of Education Progress, often referred to as the "The Nation's Report Card," indicate that "students' understanding of measurement lags behind all other mathematics topics."
This situation raises questions: Are students learning basic math concepts in the early grades? Why is their understanding of measurement so poor? USMA believes that teaching only the metric system through grade six will allow students to learn the simple, decimal-based metric system as their "first" measurement system while providing them with a good foundation in decimal arithmetic. Thus, students can be taught basic math concepts without burdening them with the fraction-based inch-pound system at a time when they do not yet comprehend fractions well. USMA believes that this seemingly intractable problem can and must be solved now. It calls upon the National Math Advisory Panel (NMAP) to research the effect of teaching two measurement systems on the learning of basic math concepts.
Some of the reluctance to teach only the metric system may lie within the education standards and tests that states developed to meet the requirements of President Bush's No Child Left Behind program. Most, if not of all, of these require that two measurement systems be taught, perpetuating the dual teaching of measurement. If the existence of these standards and assessments proves to be an impediment to teaching only the metric system, it is vital that the NMAP identify this barrier in its report to the President.
Here are the key points of the new, 2006 and old, 2000 positions:
From the 2006 NCTM position statement: "To equip students to deal with diverse situations in science and other subject areas, and to prepare them for life in a global society, schools should provide students with rich experiences in working with both the metric and the customary systems of measurement while developing their ability to solve problem in either system."
From the 2000 NCTM position statement: "The National Council of Teachers of Mathematics recommends the use of the metric system as the primary measurement system in mathematics instruction."
USMA asked NCTM President Francis Fennell to explain the rationale for the changes in their 2006 policy. He replied:
"The current NCTM Position Statement should not be thought of as a change in policy regarding the metric system of measurement. Our Board policy calls for retirement of position statements after 5 years in order to keep them timely and relevant. Consequently, the previous position statement was retired in 2005 because of its date of adoption in 2000. After this statement was retired, the Council was concerned about not having any statement on the metric system of measurement. So we started fresh with identifying what key points would be appropriate for a new statement, keeping in mind the increased emphasis on state assessments and frameworks which all call for considerable work in both customary and metric measure. Under current Council guidelines, position statements are limited in length to one page so that they communicate to the broadest audience. Of necessity, this means that we might not address every aspect of a topic, but rather the most important ideas that we want to communicate.
"As mathematics educators, we have all wished for a speedier transition to the metric system of measurement by the U.S. government. You will note that the new statement strongly supports the move to the metric system as the primary system of measurement in this country. The statement attempts to put forth this view strongly, while acknowledging the responsibility of teachers to prepare their students not only for state curricular expectations and assessments, but also for the world of work. Additionally, the current position statement supports the importance of the process of measurement.
"NCTM will continue to emphasize the metric system in all of the Council's publications and services related to measurement and welcomes continued connections/work with the US Metric Association. "Sincerely, Francis (Skip) Fennell, President"
When a manufacturing company such as QSI Corporation hires someone other than an engineer, we are pretty much forced to teach what our schools are failing to teach: the modern metric system.
Why do assemblers and secretaries and salespeople need to know the metric system? Allow me to list a few reasons:
I hope these examples give you an idea of why this failure to teach the metric system in schools is a serious problem for American industry.
To meet its purpose, the National Mathematics Advisory Panel must find that teaching only the metric system of units in American schools should begin immediately.
Everyday, people see and use both metric and customary units almost interchangeably everywhere, except perhaps on highways and in gasoline stations. As more and more metric products entered our economy, people easily switched to, for example, buying soft drinks in liters and aspirin in milligrams. People adapted to using computers and the metric terminology associated with them. People who work in many industries, particularly technical industries such as medicine, engineering, and science but also basic industries such as automotives, electrical, and food packaging, use metric units at work and conventional units on their drive home.
Students don't need to spend time in mathematics classes to learn both systems and to learn the useless conversions among units. It is not only a waste of time; it also is an activity that misleads students into thinking that converting among units is an end in itself. In fact, units are merely the means of measuring quantities. Measurement, including its attributes such as precision, accuracy and uncertainty, and the way it is used to describe our perceptions of reality are the important concepts. Despite the persistence of U.S. customary units in our society, the National Mathematics Advisory Panel would fail if it missed the opportunity to declare the metric system of units the only system of units to be taught in our schools. Students need to learn the concept of measurement-and they can learn it best using metric units.
In summary, I have two recommendations:
Following are excerpts from a public presentation at the second meeting of the NMAP in Chapel Hill, North Carolina, on 29 June 2006.
Lacking a strong signal from the federal government's various agencies, schools continue to teach both the metric system and the increasingly obsolescent set of units rarely used outside the United States. The time spent on teaching measurement gets diluted by this two-pronged approach. Time is wasted on trying to teach conversion between these units when it would be better spent developing measurement skills and developing a good feel for metric units by using them in all school curricula. The best foreign language classes teach conversation comprehension before they teach translation and we should do the same when teaching measurements.
Students are quickly confused by this two-pronged approach. I have seen students pick up a dual-scale ruler and use the inch scale as if it were a metric scale, for example by counting 13 tick marks past the "4" mark and calling the measurement 4.13 cm. This was not an isolated instance. Ironically, with this dual unit training, our students understand and use the simpler metric system better than they do our old, complicated units, but even there they do not measure up.
When we first started toward national metrication thirty years ago, 75% of the world's people were metricated. Today 96% are metricated and the remaining 4%-we in the U.S.-are undergoing de facto metrication in the work force as I speak. Olympic Games are now broadcast in the U.S. in metric units, without "translation." The new shingles I put on my house a month ago were metrically designed, sized, and built by an American company; our regional GAF plant had discontinued its non-metric line. My new American-made stove and the thermostat put in my house last weekend can be set and used in degrees Celsius-and I do. Forty-six states now allow metric-only labeling on the retail goods under state-level jurisdiction.
The U.S. Department of Education needs to exercise leadership and send a strong message to the states that they should focus time and effort by teaching only the metric system. Any skills in using other units in their last, vestigial years can be picked up at home or-once students firmly understand measurement-as a special topic, much as we teach the quaint constructions of Shakespearian English. . . .
We need to prepare our students for the world as it is now and as it will be when they graduate-not the world that once existed when their parents graduated.
There is no question in the engineering community that designing in metric is easier, faster, less prone to error, and cost effective. . . . Each year more American companies are taking advantage of the worldwide market that is available for products that are designed in metric. This in turn increases the need for employees who are not only familiar with metric units, but also have the ability to work in that system. Teaching these metric skills is essential to prepare our children for those employment opportunities.
Just learning "about" the metric system won't do either. Our students need to learn to use the metric system with facility. What is needed is a major emphasis on using and teaching metric consistently throughout the mathematics curriculum. The best and surest way to do this is to stop teaching (and stop using) the Old English system at all levels of mathematics. Indeed, mathematics teachers need to solicit the aid of their colleagues in other disciplines to assist this effort by using metric in their teaching as well, from 2 cm margins on reports in English to 100 m dashes on the athletic track. . . .
There are those who would argue that we still need to teach Old English measurements because students will encounter them, since those old measurements are still in wide use in the U.S. (although nowhere else). I disagree! Instead, I maintain that the students know enough of it already. Those in the upper grades who will soon be in the job market have already had at least 12 years of schooling in the Old English system. They don't need any more. Those in the earlier grades who have 12 years of schooling yet ahead of them, will find that by the time they finish those 12 years, the metric system will be even more prevalent than it is now and it will be more necessary to know metric than to know the Old English measures.
Following are excerpts from a public presentation at the third meeting of the NMAP in Cambridge, Massachusetts, on 14 September 2006.
I left teaching to start my family in 1987 and when I returned to teaching in 1997 I was shocked at what I found in the chemistry classroom. At first I couldn't put my finger on the problem, but then when I taught physics the following year, I knew immediately what was wrong with science. The answer was mathematics. My students could not measure properly, were calculator dependent, could not estimate, and did not use or speak the universal language of measurement, also known as, the metric system. . . .
I first realized that the United States was at a disadvantage using the inch-pound system 5 years ago when I was judging a Science Olympiad event called Metric Estimation. The students had no clue to what a kilogram of mass was or distances in millimeters. The winner of the competition was not a United States citizen but a boy from a foreign country. This boy had an excellent ability to estimate and he had a grasp on using the metric system. I began pre-testing my students on their abilities to estimate and I was shocked at the results. They had no clue as to points of references in measurement using the metric system, the system used exclusively in science and medicine. I then pre-tested my students on their abilities using the inch-pound system and the results were even worse. . . .
Students listen to their teachers. Children follow in their parent's footsteps. It is up to us, as educators, to look at the problems associated with the fact that the United States of America is the last of the industrialized nations to convert totally over to the metric system. It is up to us as educators to realize that the United States is falling behind other countries in math and science, and one of the pieces of the puzzle to fix this problem is to simply teach and use the metric system exclusively, just like the rest of the world. . . .
With the "extra time" saved by not having to teach both systems of measurement, mathematics teachers could address other topics or cover topics in greater detail. Science teachers would not spend hours and hours trying to teach a 16 year old the universal system of measurement. If children used this system at home and in school, they could estimate better and then compete successfully in the world. . . . Just remember, students will learn what we teach them. If students learn only the metric system and live metrically at home, it will make our jobs as educators easier. I have done my job in chemistry teaching and living the universal system of measurement. Leave no child behind! I have done my part to make my students successful in math and science, now you have the opportunity to help math and science.
In 1979, the European Union (EU), then known as the European Economic Community, approved Council Directive 80/181/EEC, which specified the International System of Units as the legal units of measurement in Europe and, more significantly, forbade the use of “supplementary indications”—dual units—after 31 December 1999.
As it became clear that the deadline was a bit optimistic, Directive 1999/103/EC in January 2000 postponed the ban on supplementary indications for a decade, until 31 December 2009.
So, beginning in 2010, it will generally be illegal to use dual units in the EU. And although this is usually described as a labeling law, it goes much farther than that. With a few exceptions, it applies to all measurements, not just package labels, so it also covers measurements marked on items and measurements in product brochures, manuals, advertisements, etc. It would probably even require separate, metric-only Web sites for European visitors.
Because the U.S. generally requires dual units and forbids metric-only labels, and Europe will require metric-only labels and forbid dual units, companies on both sides of the Atlantic will face challenges beginning in 2010.
The April 2006 issue of Physics Today reports on two candidates for redefining the kilogram. The idea, of course, isn’t to change the size of the kilogram, but to find a way to express its definition in terms of a fundamental physical constant instead of a physical artifact.
The meter, for example, was originally officially defined as the distance between two lines on a particular bar of platinum-iridium. Today, the meter is defined in terms of a fundamental physical constant, c, the speed of light: “The meter is the length of the path traveled by light in vacuum during a time interval of 1/299 792 458 of a second."
Similarly, the kilogram’s official definition—the mass of a particular lump of platinum-iridium near Paris—will eventually be replaced by a definition related to a fundamental physical constant. There are two candidates.
One approach uses a watt balance, which balances a mass by sending an electrical current through a coil in a magnetic field. This is more complicated than it sounds, and an explanation of the process is available from the International Bureau of Weights and Measures (BIPM, at http://www.bipm.org/en/scientific/elec/watt_balance/) as well as the National Institute of Standards and Technology (NIST, at http://www.nist.gov/public_affairs/releases/electrokilogram.htm). The watt balance, for reasons explained in BIPM’s “principle of the watt balance,” relates the kilogram to the value of Planck’s constant, h.
The second approach relates the kilogram to the value of Avogadro’s constant, NA. It would define the kilogram in terms of the mass of some number of atoms. But counting atoms is likewise not easy, and for an idea of how it’s accomplished, visit the Avogadro Project at UK’s National Physical Laboratory (http://www.npl.co.uk/mass/avogadro.html).
The government of Japan has renewed its call for the U.S. to go metric. In a statement issued at the World Trade Organization (WTO) Trade Policy Review of the U.S., held at the organization’s headquarters in Geneva on 21 March 2006, Japan prevailed upon the U.S. Government “. . . to ensure thorough adoption of the metric system in public and private sectors of the United States.”
In its statement, the Japanese Government noted that, despite being a signatory nation to the Meter Convention, the U.S. continues to use the yard and the pound, causing “not only inconvenience in daily life, but also obstacles in international trade.” It also cited in its argument a provision of the Agreement on Technical Barriers to Trade (TBT), which recommends reducing trade barriers through the adoption of international units. The statement was followed by a request for information on specific policy measures being taken by the U.S. to promote metrication.
The U.S. answered Japan by noting the effort to remove barriers to metrication through a proposed amendment to the federal Fair Packaging and Labeling Act (FPLA). The amendment would grant manufacturers the option of labeling products either in dual units (both inch-pound and metric) or in metric units only. Also mentioned was the considerable progress toward metrication at the state level, where a model regulation permitting the metric-only labeling option on state-regulated products has been adopted by 46 out of 50 states.
A 29 March 2006 Washington Post article revealed previously untold details regarding the demise of the U.S. Metric Board (USMB) at the hand of the Reagan Administration. The USMB was the body created by the Metric Conversion Act of 1975, and charged by that act to carry out a broad range of U.S. metrication duties. Frank Mankiewicz, former Democratic party strategist and past president of National Public Radio, wrote in the Post article that, in 1981, he encouraged Reagan political adviser Lyn Nofziger to convince the president to abolish the USMB. Mankiewicz was writing two days after Nofziger’s death at age 81.
In the article, Mankiewicz recounted that, at the time, he had sent Nofziger a copy of an anti-metric column, that he had written some years before, in which he ridiculed “the attempt by some organized do-gooders to inflict the metric system on Americans, a view of mine Lyn had enthusiastically endorsed.” Mankiewicz claimed in the Post article that he collaborated with Nofziger to collect anti-USMB material for presentation to President Reagan. Nofziger later told Mankiewiecz that their efforts had been successful. Ostensibly to reduce federal spending, the Reagan Administration removed funding for the USMB from the FY83 budget. The metrication functions of the USMB were transferred to the Office of Metric Programs (OMP) as a part of the Office of Productivity, Technology, and Innovation (OPTI), a division of the U.S. Department of Commerce.
A booklet containing U.S. labeling requirements for packaged products sold by weight has been revised in an August 2005 Department of Commerce edition. Kathryn M. Dresser, of the Weights and Measures Division, National Institute of Standards and Technology (NIST), has released the Consumer Package Labeling Guide: Selling by Weight (NIST SP 1020-1). The publication is a digest of labeling information contained in the Uniform Packaging and Labeling Regulation (UPLR) of the NIST Handbook 130. The latter is a compilation of uniform laws and regulations developed by the National Conference on Weights and Measures (NCWM), an association of government, industry, and interested parties.
The booklet is available from NIST Weights and Measures Division, 100 Bureau Drive, Stop 2600, Gaithersburg, Maryland 20899-2600, or by download from the Internet at http://ts.nist.gov/ts/htdocs/230/235/labeling%20guides%20-%20weight.pdf.
America’s largest industrial trade association may be moving to effectively break the logjam in the domestic debate over optional metric-only product labeling. The National Association of Manufacturers (the NAM) suggested in an October 2005 fact sheet that it would back a metric-only labeling option amendment to the Fair Packaging and Labeling Act (FPLA). However, this support would depend upon the European Union (EU) canceling its Metric Directive (80/181/EC) deadline. The proposed change in the FPLA would allow U.S. manufacturers the choice of using either metric-only or dual-unit product labeling. Currently, the FPLA requires both metric and inch-pound units on U.S. product labeling. If left unchanged, the EU Metric Directive would require manufacturers to label Directive-covered products exclusively in metric units by 1 January 2010.
The problems we face in math and science education today are tumultuous, but they are not insurmountable. In fact, they are solvable, if we get on the right track. But, time is growing short. We must change direction now if we want to maintain our global leadership in the high-tech world and ensure our future economic security. The U.S. can make a huge leap toward these goals by teaching the metric system only; and by passing the amendment to the Fair Packaging and Labeling Act (FPLA), we can accelerate students' learning of the metric system. Together, these two steps can benefit all sectors of our economy and the nation as a whole.
Measurement is the cornerstone of science. But, science doesn't use the inch-pound (I-P) system. Unless we stop promoting the myth that we can offer a modern education equal to today's science and technology needs by continuing to teach inches and pounds, we will continue to propound the same education failures that now persist. For decades, critics of our math and science curriculum have offered a multitude of fixes, many of them excellent and needed. Yet none of these critics have promoted the idea of teaching the metric-system only. Industry forms part of this voice, and its voice, too, is silent. All these critics bemoan the unacceptably low science and math scores of our high school students on national and international tests. They cite the decline in the number of students enrolled in advanced courses in college, the dwindling number of degrees earned, and the shrinking volume of post-graduate papers being published in these areas. This results in an insufficient supply of home-grown mathematicians, scientists, and engineers available to fill the employment needs of U.S. industry. Companies have tried to fill this void by employing foreign scientists, but that may not be the most desirable solution for the nation.
Critics frequently condemn the shallowness of the math curriculum as "A mile wide and an inch deep." One would think they would depict it as "a kilometer wide and a centimeter deep" if the metric system was being employed by the mathematics educators as would be expected. Lack of metric-system education is a glaring deficiency in our present elementary and middle school curricula. The majority of our teachers do not have a good foundation in metric, and too many textbooks are weak in their presentation of the subject. The I-P system can be presented to students, but all calculations should be done using metric units. The idea that we must continue to teach both systems prevails. But, why? Grade school teachers report that youngsters are confused when trying to learn two measurement systems, with the result that they learn neither system well. This cripples their learning of measurement. But also, and more importantly, it severely retards their mastery of math concepts. We hear frustrated students complain, "I hate math," and "math is too hard." Could it be that our continued insistence upon their muddling through two measurement systems contributes to these attitudes? Most alarming, they achieve good scores on 4th-grade tests, but their scores decline miserably when they are tested in high school. They are not ready for advanced high school course work if they cannot measure. Chemistry teachers, in particular, complain that they have to rob time from teaching chemistry because they must teach the metric system first.
Allowing U.S. companies the option of labeling their products solely in metric units may seem to have a negligible effect on the nation's students. But, in fact, the impact may be considerable. There's probably not a school-age child in America who does not know what a liter is, thanks chiefly to the soft drink industry. In the 1970s, 7-UpTM was the first company to market its beverage in a liter size, using the slogan, "Follow the Liter." Soon all other soft-drink companies adopted the liter. And 7-UpTM did it in the best spirit of competition. In a long-range plan, 7-UpTM redesigned its bottles, packaging, labeling, and shipping procedures so effectively that they sold the liter bottle for the same price as the previous quart size, delighting consumers, and still turning a profit. This was clearly a benefit to all sectors of the economy. Who better than American industry can sell an idea?!
Recently there has been a notable increase in the number of U.S. companies marketing their wares in hard metric containers, possibly in anticipation of the EU Directive that will allow only metric units on labels of imported products after 31 December 2009. And why not? Research has shown that long-range planning is the most economical way for companies to accomplish this label change.
There is a reason why we are struggling to get this amendment introduced and passed, and why effective metric education policy is difficult to establish: no company or group is willing to lead the initiative alone. The latest news about the amendment (see page 1 of this issue) tells of U.S. companies refusing to " . . . take an 'out front' public position in support of a metric issue." More than 10 years ago, in 1994, the Goals 2000 Educate America Act was passed by Congress, recommending strengthening of metric system education, especially in the lower grades, and increasing the number of teachers with a substantive background in the metric system. But, the education community did not provide the needed leadership and it was never implemented. Senator Claiborne Pell and Representative George Brown were the stewards of this legislation but they are gone from Congress now. The only outspoken 21st century metric proponent in Congress is Representative Vernon Ehlers but he can't solve our metric problems alone. The Congress and the private sector do not fear the metric system, but the U.S. public is not as well informed. Both public and private officials are highly sensitive to the views of voters, consumers, parents, and stockholders, who, with the power of their votes and their dollars, can decide the outcome of elections and the fate of consumer products.
For now, the No Child Left Behind program may have contributed to saddling U.S. education with the teaching of two measurement systems. To meet that program's requirements, many states have drawn on the curriculum recommendations of the National Council of Teachers of Mathematics, the respected leader in developing math standards which stipulate that both measurement systems should be taught. To its credit, the council also recommends that metric should be the primary system taught and that teachers should receive in-service training. But I have seen very little done to carry out these recommendations, and it's not happening as part of a national metric curriculum.
By teaching only the metric system and by passing the FPLA amendment, the U.S. can make huge strides toward swelling the pool of its own well-educated mathematicians, scientists and engineers. These actions will move us toward our goals of maintaining global leadership in the high-tech world and strengthening our economic security. As I have outlined, if we establish the metric system as the anchor of measurement education, students can make immense gains in learning math concepts and raising their comfort level in studying math. Armed with a greatly improved math education, fewer students will be inclined to avoid more demanding majors in the fields of math and science. By allowing companies to label their products with metric-units only, similar to the 7-Up™ experience, students will have greater exposure and opportunity to use the metric system in their daily lives, resulting in it becoming their first measurement language. Hence my conclusion: the FPLA amendment + metric education = good economics. For the time being, no one faction wants to speak first. But the time will soon arrive when we will have to join together and advance the metric system with a national voice.
In what may be a first in the history of U.S. metrication, Robert R. Bullard, P.E., President of the Absolute Engineering Group of Daytona Beach, Florida, is fighting with state and local officials to use the metric system exclusively in his structural plans. Although he cited the 1988 amendment to the Metric Conversion Act of 1975, which makes metric the preferred measurement system for trade and commerce in the U.S., Bullard at first had his plans rejected by Florida state and county officials because they were metric. He says he has encountered what he calls “xenophobia” and the “arrogant, insidious exercise of raw power” in his attempts to submit his metric plans to agencies of the state of Florida and Volusia County for approval. A rare appeal to the county adjustment board finally won Bullard the right to leave his plans in SI. But the feisty engineer wants to sue for relief from what he sees as continuing discrimination and harassment over his use of metric units. “It’s the law!” he exclaims repeatedly as he builds the case for his preference for metric.
In addition to the federal law, Bullard defends his professional use of metric by quoting from the 1999 American Society of Civil Engineers’ (ASCE) Policy Statement 119 on metrication, which declares, in part, that ASCE “… actively supports the conversion to SI (Système International d’Unités), the modernized metric system of measurement, in civil engineering practice and research.” This policy statement was issued by ASCE with the rationale that all federal agencies had been using SI for civil engineering design and construction work since 1996. Lamenting the responses he has received to his legal arguments, Bullard commented, “There is a new tribe in Florida, the Sosumi tribe.” The regulators tell him that if he doesn’t like the status quo, “They say, ‘So, sue me.’”
The USA is becoming a metric country. Yes, there are those who will forever prefer their inches, feet and miles to meters, but it is undeniable that the USA is already metricating and will be a metric country in a few years. Consider how much we already use metric: automobiles are entirely metric, the U.S. military is largely metric, electronics has always used metric measurements (volts, amps, watts, etc.), and most new electronic components are in metric sizes. Most of the hard sciences, the health industry and pharmaceuticals are metric. Metric is starting to creep into the consumer world: beverages, nutrition labels, many cleaning and hair products (have you noticed?), and many sporting events are now metric. The reason for the change is clear to this magazine’s readers: SI metric is a simpler, more rational system than American colloquial measures. It is not perfect, but it is far better designed than our feet, inches, miles, cups, pints, quarts and gallons. This is the reason it has become the dominant system in the entire world, leaving the USA as the only non-metric country.
There are those who claim that metric is somehow “un-American,” but that is difficult to take seriously. Metric units came from many countries, and, fundamentally, the science of physical measurement has no political affiliation. There are also naysayers who claim that metric is actually harder to use than our colloquial measurements. Any engineer who has done structural dynamics calculations using pounds and slugs knows that is a foolish claim. You should start metricating your company now. The sooner you start, the better and less costly the change will be. If you do not metricate you will soon begin to lose market share, first from the metric countries that are resisting non-metric products (the EU now, other countries sure to follow), and later from U.S. companies who have metricated and need metric suppliers. The sooner you start, the fewer problems you will have with legacy products. Depending on the product lifetimes in your industry, by starting now you reduce the number of legacy products that will have to be redesigned to remain viable. For example, if your industry has five-year average product lifetimes, and you start metricating now, by the time most countries forbid non-metric products, you won’t have many left.
By starting now rather than when market pressures force you to metricate, you will also have more time to learn how metrication will work in your company and in your industry, and more time to educate your employees and vendors. I started metricating QSI Corporation several years ago, and we are now almost entirely a metric company – even our word processing is done with millimeter margins. While we still must use some non-metric products (e.g., 9-pin “D” connectors), having had a few years to learn and implement our metrication has made it a relatively painless effort.
Where do you start? (1) Go to the NIST link http://physics.nist.gov/Pubs/SP811/contents. html and download the free document SP 811, Guide for the Use of the International System of Units – this is an in-depth technical reference. (2) Optionally, buy a copy of IEEE/ASTM SI 10-2002. This has similar content to SP 811, but is much more accessible. (3) Visit the U.S. Metric Association (www.metric.org) and SI Navigator (www.metric1.org) Web sites. Both will give you a wide range of reference information, as well as links to a wide variety of training materials, consultants, vendor lists, etc.
The choice is yours: start metricating now when you can take the time to do it right and to minimize legacy product redesigns, or wait until you start losing business and you will be forced to metricate in a hurry and have to suffer numerous expensive legacy product redesigns that could have been avoided.
NOTE: Jim Elwell is President of QSI Corporation (http://www.qsicorp.com), a corporate member of the U.S. Metric Association. This article appeared in the November 2004 issue of Machine Design magazine, and is reprinted by permission.
An article in the 4 December 2002 Wall Street Journal notes that a significant cause of errors in hospitals has been shown when hospital personnel miscalculate the weight of patients (from pounds to kilograms) in determining the amount of medicine required for a patient. The article noted that making errors in converting from inch-pound units to metric units provides a serious risk, particularly to children and emergency-room visitors. A 2001 study (by the U.S. Pharmacopeia's Center for the Advancement of Patient Safety) indicates that large workload increases for doctors and nurses, plus various types of distractions can easily cause errors in making conversions from inch-pound to metric (and vice versa). However, it did not attribute all the drug dosage errors to faulty conversion between measurement units. The study, which covered 368 health-care facilities, also found that, of the 105,603 medication errors documented by the hospitals surveyed, there were 14 deaths due to those errors. Also, 353 patients required initial or prolonged hospitalization and 70 patients required intervention to sustain life.
Reprinted from: Metric Today, 2003-Mar-Apr, Vol 38(2)
"You, in this country, are subjected to the British insularity in weights and measures; you use the foot and inch and yard. I am obligated to use that system, but I apologize to you for doing so because it is so inconvenient, and I hope all Americans will do everything in their power to introduce the French metrical system ... I look upon our English system as a wickedly brain destroying piece of bondage under which we suffer. The reason why we continue to use it is the imaginary difficulty of making a change, and nothing else; but I do not think in America that any such difficulty should stand in the way of adopting so splendidly useful a reform."
Excerpt from a lecture delivered by Lord Kelvin (William Thomson) in Philadelphia, 29 September 1884
“It is safe to say that after the metric system has been adopted by the U.S. and our people have become accustomed to its use we would no more dream of going back to the present system of weights and measures than we would think of carrying on the processes of arithmetic through the medium of the old Roman letters in place of the Arabic numerals we now employ.”
Alexander Graham Bell, 1906
Metric foes often argue that we should keep our traditional units because Americans understand them. But a recent survey refutes that notion. While Americans' knowledge of SI leaves much to be desired, they seem to understand metric units a heck of a lot better than gallons, fluid ounces, inch fractions, and other antiquated units. A simple 30-question test on everyday measuring units--half SI and half inch-pound--was given to all students and faculty at an Arizona high school. The median score on SI units was 55% for students and 64% for adults, while the median on inch-pound units was only 16% for students and 34% for adults. Two-thirds of the students (and 83% of the adults) could read a metric ruler to the nearest millimeter. But only 20% of the students and (73% of the adults) could read an inch ruler to the nearest 16th. Curiously, most students treated the inch fractions as decimals, mistaking the 1/16 inch marks for 0.1 or 0.05 inch marks. For example, they often misread the measurement 2 11/16 inches as 2.8 or 2.65 inches.
Three-quarters of both students and adults knew that a liter measures volume and equals 1000 mL (cm3). However, not one person knew the definition of a U.S. gallon (231 cu in.), acre (43,560 sq ft.), or U.S. bushel (2150 cu in.). Most estimates were wildly off. Only 6% of the students (and half of the adults) knew that a U.S. quart is 32 fluid ounces. Two-thirds of both students and adults knew the meaning of the prefixes kilo, milli, and mega, and were able to apply them to specific units (for example, 1000 mg = 1 g, 1000 g = 1 kg, 1 km = 1000 m). Most students (and 77% of the adults) could estimate the distance to a nearby city in kilometers. By contrast, only 30% of the students (but 63% of the adults) knew that a [statute] mile is 5280 feet.
Most respondents recognized that an average man is about 75 kg, although only 20% knew that water is 1 kg/L. On the other hand, most students did not know that a pound is 16 ounces [avoirdupois] or that a [short] ton is 2000 pounds. Not one student or adult knew that a gallon of water is approximately 8.3 pounds. About 70% of the students (and 89% of the adults) knew that water freezes at 0 °C, while only half of the students (but 87% of the adults) knew water's freezing point in Fahrenheit (32 °F).
Back in 1974, when I was a pharmacy student taking a course in pharmaceutical calculations, pharmacists were taught that they were inheriting not one, but three, systems of measurement for their professional use: avoirdupois, apothecary, and metric. I soon came to realize not only which system was the best of the three, but also which two systems (avoirdupois and apothecary) were insults to the dignity of the professional cadre of which I was soon to be a part.
It was at that moment in time that the Metric Conversion Act of 1975 was being debated in Congress. I was so moved by my calculations that I met with some of my student colleagues in an open class session to "lobby" for the bill. We were disappointed, though, that the bill was watered down from its original target of mandatory 10-year conversion.
Standards abound in my healthcare profession: Joint Commission standards, some measurement standards, legal standards, procedural standards. We are awash with them. But it never ceases to amaze me that when it comes to a universal standard of measurement, we American healthcare folks are still using the WOMBAT (Way Of Measuring Badly in America Today) measurement system.
When I enter a patient's height and weight into the computer at work, I must obtain and enter it in WOMBAT, and the computer converts it to the centimeters and kilograms it is supposed to be in. I can't ask patients how many centimeters tall they are; they just don't know. An established standard of measurement is essential to any modern nation, and certainly should be required by the one nation which claims to set the standards for so many things in the world: the U.S.
Most people do not realize that the standardization of the inch for worldwide use did not occur until 1959. Prior to that the inch had been defined differently among the major inch-using countries: the U.S., Great Britain, and Canada. Each of those countries had their own definition of the inch, and in each case the inch was defined in terms of metric units, the only set of internationally-accepted standards of length, mass, etc.
In the U.S. the metric system was made legal for all purposes, by the Metric Act of 1866, long before any law defined our common U.S. measures. Later, the Mendenhall Order of 1893 defined our common non-metric units in terms of metric units. That law regarded metric units as the fundamental and internationally-accepted standards for the U.S. It was this law that formally defined the inch based on the conversion factor of 39.37 inches = 1 meter as stated in the Act of 1866. This ratio gives an inch approximately equal to 25.40005 mm.
In Great Britain the National Physical Laboratory made comparisons of the Imperial Standard Yard to the International Meter, which yielded differing values for the inch over the years. The 1922 value of 25.399956 mm per inch by was arbitrarily selected for use in calibrating the most precise measuring devices.
The Canadian Parliament in 1951 established their inch based on a legal definition of the yard as 0.9144 m. This ratio defined the inch as 25.4 mm, a third definition of the inch. The Canadian inch was about 2 parts in 106 smaller than the U.S. standard and about 2 parts in 106 larger than the British standard.
The differences in definitions of the inch were enough to cause confusion, inefficiencies, and difficulties during World War II in attempts to interchange various precision products. It was not until later, in 1959, that the definition of the inch was standardized worldwide as 25.4 millimeters exactly.
But that agreement has not completely solved all the problems caused by differing values for the inch. A problem still exists for the foot, where the international foot (based on the 25.4 mm inch) and the survey foot (based on the 25.40005 mm inch) are both still in use. The Coast and Geodetic Survey continues to use the survey foot, whereas the rest of industry uses the 25.4 mm inch. This leaves us with two definitions of the mile, one based on the international foot and the other based on the survey foot. Although this may not seem like much, it causes the two miles to differ by about 3.2 mm (1/8 inch), or in 100 miles to differ by about 32 cm (over one foot)!
Thanks to the work of the early pioneers of aerology, the units used for meteorological measurements of the upper atmosphere were largely standardized long before those measurements became routine. In particular, there is one system of upper-air pressure units, unlike we see for surface weather measurements.
Much of the groundwork for the standardization of these upper-air measurements was due to Wilhelm Bjerknes (1862-1951), a pioneer of modern meteorology best known along with his son, Jakob, for the air-mass and polar-front theory of cyclones.
One of Bjerknes' contributions to meteorology was his push for widespread use of the CGS (centimeter, gram, second) system of units in meteorology. This was an early version of the metric system that later took second place to the MKS (meter, kilogram, second) system in the development of the International System of Units (SI).
The pressure unit in the CGS system is the bar, defined as one million (106) dynes per square centimeter, a value approximately equal to the standard atmospheric pressure at the surface of the earth. The bar is subdivided into 1000 millibars (hectopascals in SI) to measure surface and upper-air pressures. The use of the bar might not have been common without Bjerknes' insistence. He succeeded at having these rational units be recommended for all uses in aerology by the International Meteorological Committee at their meeting in Rome in 1913. This resulted in the use of the millibar, rather than the millimeter of mercury (Hg) for upper-air pressures. The millimeter of Hg was used for surface pressures throughout most of the world, and in the U.S. the inch of Hg was and still is common.
To promote his idea, Bjerknes showed that the use of the bar/millibar was more logical and was required for a strict application of CGS units. Had the millimeter of mercury been used, it would have been necessary to introduce a conversion factor of 1.333 millibars per millimeter of Hg in order to balance units in the dynamic equations of the atmosphere. The millibar made the equations coherent or without the need for such numerical factors in multiplication and division among units.
Bjerknes was forward thinking in pushing for the full adoption of the CGS system, which at the time was the best system for meteorology. He predicted that the universal application of CGS could not be prevented in the long run. At least he was right about the use of a universal system of metric units, not necessarily about the CGS system. Bjerknes thought it unfortunate that synoptic meteorology had not adopted the unit of pressure of the CGS system from its inception. He would have liked to see a universal change of all surface pressure readings to millibars, rather than the pressure related to a column of mercury. But he realized that the time was not right since the world's measurement systems were far from standardized. His suggestion was to await the time when the transfer to one system of meteorological units could become truly universal, "the time when the British Empire and the U.S. shall have adopted the metric system."
It was not until this century that balloons were regularly used to gather upper-air meteorological measurements. And our present network of upper-air balloon radio soundings (radiosondes) was established during World War II. Few people realize that because of some of the early weather pioneers, there is standardization in the measurement of upper-air pressures, unlike there is for surface weather. Upper-air temperatures are also standardized in degrees Celsius worldwide. Variations occur for surface temperatures only, with the U.S. the sole user of the degrees Fahrenheit scale. However, complete universality is not unthinkable should the United States convert since it is the only nation still officially using non-metric units for measurements of the weather.
A transition to metric usage in the U.S. would be a major factor in correcting the poor performance shown by U.S. students in math and science, according to an article in the February 1996 Evaluation Review, by Richard P. Phelps, a consultant to the Education Consumers Clearinghouse. Phelps’ study shows that the current practice of teaching two systems of measurement in U.S. schools wastes time and is very costly. The use of the metric system is mandatory for working in many key professions such as medicine, science, and engineering; therefore, metric must be included in the curricula. However, there is no overwhelming need to use inch-pound units in daily lives because metric units can easily be substituted.
In the article, Phelps’ conclusions are reached by examining three methods of teaching measurement. He calculates the net benefits of each system by development of quantitative measures of benefits and costs, then compares the results. His research shows that teaching solely metric system measurement could save 82 days of mathematical instruction-time annually and would provide a yearly $17,653 million in savings to U.S. education. The time and funds gained could be used to teach more math, giving students better skills, and increasing their scores in international mathematics tests. [Presently, the U.S. ranks 13th out of 17 countries on international math tests given to 8th graders.] The current practice of trying to teach both metric and inch-pound usage is wasteful and unnecessary.
The author lists a number of practical reasons why teaching only metric measurement would greatly benefit U.S. education. One example: In learning inch-pound measurements [for length, capacity, and weight (mass)], the student must memorize 21 names and 18 conversion ratios, versus needing only to remember 9 names and 2 conversion ratios for metric measurements. Therefore, time is saved in teaching only metric measurement, and students can make metric calculations with greater facility and fewer errors.
Phelps used the Addison-Wesley Mathematics series as a basis for his calculations to determine instructional-time, and used data from the U.S. Dept. of Education to calculate dollar amounts of education costs. The article also reviews background and current status of U.S. conversion. He makes the provocative suggestion, based on his calculations, that the dollar savings from teaching only the metric system in schools would pay, many times over, for converting all U.S. highway signs to metric. Evaluation Review is a Journal of Applied Social Research and is published in the U.S. by Sage Publications Inc.; Phone: 805-449-0721.
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