Why the Metric System Hasn’t Failed in the U.S.

And has an important place in the education system

The Mars Climate Orbiter, which was lost in space because of a metric-measurement mixup (Reuters)

When Sally Mitchell, a science teacher at East Syracuse Minoa Central High in Syracuse, New York, spoke to a group of students at the recent U.S. Department of Energy National Science Bowl, she remarked that one of her projects is to “finally metricate the U.S.A. once and for all.” Much to Mitchell’s surprise, her comment about the metric system—officially it’s known as the International System of Units (SI)—evoked a strong reaction. She received a standing ovation from about 300 middle-school scientists.

Mitchell has been recognized as an outstanding teacher by Barnes & Noble, RadioShack, and the Boy Scouts of America. She’s also won numerous awards, including the American Chemical Society’s James Bryant Conant Award, which recognizes outstanding high-school chemistry teachers. She says the recent wild applause by the kids, however, truly confirms her metric mission.

“It was amazing to see the support of the the little ones. I do it for their future,” said Mitchell, who is this year’s Albert Einstein Fellow at the U.S. Department of Energy. Mitchell is tasked with producing an instructional video to help teachers deeply understand and easily teach the decimal-based metric system.

Hold the hate email, though. Mitchell and many others who consider themselves metric proponents are well acquainted with measurement controversy and vitriol. She recounts the time she called her local airport—an international hub—merely to inform them that their new sign displayed only Fahrenheit, instead of Celsius and Fahrenheit. (Technically, Celsius isn’t even metric but Americans like to think of it as in the metric-ish family.) Soon the issue blew up, and she found herself on a radio program and featured in the local newspaper as a metric pusher. Then Facebook threats of bodily harm started rolling in. Seriously.

Nonetheless, she perseveres. Currently enrolled part-time in a Syracuse University doctorate program, some of her research centers on why every industrialized country went metric but the U.S. “One of the questions I started with was sort of like ‘Why haven’t we gone metric?’” Mitchell said. “And here’s the answer: We have, many years ago.” Well, yes and no. While many U.S. enterprises—from soft drinks and distilled spirits to cars, photographic equipment, pharmaceuticals, and even the U.S. military—are essentially metric, everyday use—Americans’ body-weight scales, recipes, and road signs, for example—hasn’t converted. And neither has the country’s educational system.

“I would say that the United States of America is at least 40 percent metric, perhaps even a little over 50 percent metric in practical terms,” said David Pearl, an Oregon government worker who, in his free time, is a self-appointed U.S. metric historian and purveyor of MetricPioneer.com. “But in the minds of many older Americans, metric measures are annoying at best and the work of the devil at worst, so some folks might say that America is 100 percent non-metric.”

Pearl will gladly send anyone his 31-page document, “SI: An Educational Overview For Americans,” which explains that the Metric Act of 1866 legalized the use of the metric system for weights and measures in the U.S.

It also explains that the U.S. founding father Benjamin Franklin helped develop the metric system and that Thomas Jefferson championed a version of it, though most Americans still think of metric as not American. What happened with the country’s measurements between 1866 and 1975, when President Gerald Ford signed the Metric Conversion Act—which established the Metric Board and was supposed to mean Americans would all be using kilograms and millimeters instead of pounds and inches by now—is rather complicated. Suffice to say going metric has always been a political football. In the early days, the metric proponents lost elections and the customary—that is, pounds and inches—guys won. The issue continued to get tossed around, however. Then around the late 1870s, U.S. manufacturers of high-end machine tools effectively blocked the country’s metric conversion. By that time they were using a measurement system based on the inch and argued that retooling would be prohibitive.

Ford’s Metric Act, however, promised to right that once and for all. And, to a large extent, U.S. businesses that trade internationally went metric (except for their U.S. consumer-facing info). For a brief time, a metric-only U.S. education looked certain, too, though often criticized and opposed by the public largely on the grounds that it simply wasn’t American.

Then President Ronald Reagan, using public opposition to his advantage, dismantled the U.S. Metric Board in 1982. It was a move that John Bemelmans Marciano called “the day the metric died” in his book Whatever Happened to the Metric System?

“I can’t overstate how much resistance there’s always been to metric in any country that adopted it,” Marciano said. “In Brazil, it caused a riot that went on for months. In France, it took decades and decades.” Yet, in the U.S., resistance seemed to prevail. Unlikely characters such as the novelist Tom Wolfe weighed in, defending customary measures as both more civilized because they’re based on human scale (i.e. a foot is supposed to be about the size of a real foot in a shoe, an inch about the width of your thumb) and more American because, of course, America was the only country using them. Marciano chalks up metric’s 1980s defeat primarily to the typical public resistance to change combined with the nation’s love affair with Reagan’s budget cuts. According to Pearl and many others, though, the U.S. has paid dearly for the haphazard embrace of metric that ensued.

From Pearl’s “Educational Overview”:

[If the U.S. converted to metric] we could avoid costly disasters like that embarrassment in 1999. The use of two different systems was the root cause in the loss of the $125 million Mars Climate Orbiter. NASA specified metric units in the contract. NASA and other organizations worked in metric units, but one subcontractor, Lockheed Martin, provided thruster performance data to the team in pound force seconds instead of newton seconds. The spacecraft was intended to orbit Mars at about 150 kilometers altitude, but the incorrect data meant that it probably descended instead to about 57 kilometers, burning up in the thin Martian atmosphere.

The Mars Climate Orbiter Mishap Investigation Board agreed. The Board said the cause of the mission failure had to do with a miscommunication between the spacecraft’s software, which calculated in metric, and the ground crew, who used customary measurements.

Public-health officials have also raised concerns about the prevalence of drug misdosing due to Americans’ incomplete embrace of metric. Children are of particular concern since they’re often prescribed liquid medications given by parents at home. Researchers have recently called for a metric-only standard for children’s medication. They hope that without tablespoons and teaspoons in play, parents will find it easier to dose correctly as prescribed (in metric). This year, ECRI, a nonprofit that studies effective medical procedures and processes, ranked medical errors related to pounds and kilograms as No. 7 on their Top 10 Patient Safety Concerns. ECRI now recommends that the U.S. health-care system eliminate all non-metric body-weight scales because too many serious errors have occurred when health-care providers calculate medication based on a patient’s weight but fail to convert body weight from pounds to kilograms. Even the 8.5 by 11-inch paper is an affront to metric advocates. The rest of the world uses the metrically measured A4 paper.

When it comes to education, the U.S. National Institute of Standards and Technology (NIST) contends that a complete switch to the metric system would be a positive move. In recent years, a couple of states have attempted to take measurement into their own purview. Both Hawaii and Oregon have had legislation introduced to make metric the official measurement of those states. The Oregon bill died in committee. In Hawaii, the bill got a hearing last year but went no further. In education, though, the solution thus far has been to continue with measurement bilingualism, says Chad Colby, a spokesman for Next Generation Science Standards, a multistate effort to develop new educational standards in coalition with the National Science Teachers Association, the American Association for the Advancement of Science, the National Research Council and other educators. “Metric is the assumed system of measurement in science,” Colby said. (The Common Core State Standards for mathematics include learning both metric and customary measurements.)

Some research posits, however, that teaching two measurement systems may be a waste of valuable class time and education dollars that could be spent in more productive ways. Metric proponents point out that metric is essential knowledge to enter science and technology fields, whereas customary measures have no essential work application. And Mitchell, the science teacher, says she’s witnessed firsthand that measurement bilingualism simply doesn’t work well in the classroom. “I think it’s just very confusing for kids.” She fears measurement confusion contributes to U.S. math and science woes. U.S. students have slid on their global ranking in science and math, according to the National Center for Education Statistics. In the most recent ranking, the U.S. was slotted between the Slovak Republic and Lithuania—just behind Russia. Still, there’s no evidence that Americans’ shaky embrace of metric accounts for math and science troubles. And Marciano, who spent three years researching his book, finds Mitchell’s argument preposterous—akin to saying humans can’t master two languages.

When I admit my lack of metric mastery, Mitchell tells me to start cooking. “I raised all my kids in a totally metric household,” she said. “Cooking will give you a real feel for the measurements.” I tried it. I converted a recipe for homemade play dough and used our new metric scale to whip up a batch with my 5-year-old. My 12-year-old and I made blueberry muffins with a metric recipe from The Bread Bible, a cookbook recommended by Mitchell, who teaches the chemistry of cooking (using only metric, of course). My sons liked weighing and measuring metrically, but I don’t think they cared as much about the units as they did about the cool new scale. Mitchell was right, though; I noticed that even after a few metric cooking sessions we were getting the feel for the tininess of 1.9 grams of baking soda and the relative largeness of 135 grams of flour.

Why, then—if junior scientists applaud the effort, NIST supports it, and my kids and I had so much fun going metric in the kitchen—has a total switch to metric been such an epic battle with the public?

“I fought getting an iPhone and I can’t live without it now. Everyone hates change,” Mitchell said. But, she added, it may also have something to do with how Americans erroneously associate the metric system with failure. “Many people believe that metric failed here in the United States. When I hear this, I ask them ‘How many times have you failed? Do you just give up?’” Her point: It’s a process. Mitchell is focused on preparing teachers to teach the system in exciting ways that make sense to kids. She’s convinced this is the elusive key, the thing that will—this time for sure—tip the U.S. scales resoundingly in metric’s favor.