Taking Measure of the Metric System in the United States : Short Wave From currency and commerce, food labels to laboratories, the metric system is the foundation of many science and math fields. To mark our 100th episode (a multiple of 10, which is the basis for the metric system!), we spoke with Elizabeth Benham, Metric Program Coordinator at the National Institute of Standards and Technology, about the presence of the metric system in our everyday lives.

The U.S. Doesn't Use The Metric System. Or Does It?

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Hey, everybody. Maddie Sofia here.


Hey. I'm Emily Kwong.

SOFIA: And here's the thing. Y'all have probably been listening to us for a while now, but have you gotten serious about us? Have you locked it down? Have you committed to this relationship?

KWONG: What Maddie means is please subscribe to this podcast - actually subscribe. And maybe tell a friend that you love it and that they should listen, too.

SOFIA: Thanks so much. OK, here's the show.


SOFIA: You're listening to SHORT WAVE from NPR.

Emily Kwong, we have a podcast milestone to celebrate today.

KWONG: Are we rich?

SOFIA: (Laughter) No. You know we're not. But we are rich in memories.


SOFIA: Like that one time, for the science of thrill-seeking, where we popped out of the studio and scared the crap out of you.


SOFIA: (Yelling).



KWONG: You are the worst.

I'm actively trying to forget that.

SOFIA: Or that time we learned about orangutan speech and we played kazoos.


SOFIA: You're kazooing. Just to be clear, you've brought a kazoo in here for a reason.


KWONG: Oh, I love that. Our favorite instrument, the kazoo.

SOFIA: Well, strike up the band, Kwong, because today marks our 100th episode.


KWONG: Pew, pew, pew, pew, pew, pew (ph).


SOFIA: Making this daily science show for all of you is such an honor. We've all aged about 100 years, to be honest.

KWONG: (Laughter).

SOFIA: But you make it all worth it. So to celebrate our streaming centennial...

KWONG: Our hundredth day of bringing you new discoveries, everyday mysteries and the science behind the headlines...

SOFIA: We were trying to think about what we could do with this hundredth episode. And I thought 100, delightful multiple of 10 - oh, the metric system.


SOFIA: Really. That is how my brain works.

KWONG: Yes, it's true. I saw it happen.

SOFIA: (Laughter).

KWONG: And we're here now to talk about it. So like the hundred candles on the SHORT WAVE birthday cake, the metric system is based on units of 10. As a standard unit of measure, it's the foundation of science and technology.

SOFIA: Right. You've got the second for measuring time, which we literally never have enough of.

KWONG: (Laughter) The meter for length.

SOFIA: The kilogram for mass.

KWONG: And there are others, such as the candela for luminous intensity, like the future of this podcast.


SOFIA: Today on the show, our 100th episode, we mark the occasion by taking measure of the metric system - a little history of why the United States avoids a measurement system the rest of the world embraces...

KWONG: And how, in practical terms, the U.S. may be kind of a metric nation after all.


SOFIA: All right, Kwong. Today, we are talking about the metric system. Honestly, once you're in a committed relationship with the metric system, like I was in grad school...

KWONG: (Laughter).

SOFIA: ...All other systems just don't do it for you.

KWONG: Well, the metric system, it's fitting for this podcast because it's used broadly across math and science to make sure measurements are precise and accurate - two of our favorite things. You wouldn't want to dose the wrong amount of medicine, for instance, or pipette the wrong amount of liquid into a petri dish.

SOFIA: The precision, Kwong - the precision you can have with the metric system.

KWONG: (Laughter) And because the metric system structures units around successive powers of 10, conversion is as easy as moving a decimal point.

SOFIA: Right. So 1,000 milliliters is 1 liter.

KWONG: And 1,000 grams is 1 kilogram. The powers of 10 are marked by prefixes - deci-, senti-, milli- and so on.

SOFIA: You basically just have to learn one system of conversions...

KWONG: That's right.

SOFIA: ...With base 10. Or you can use what we use in the U.S. and memorize 45 different ways to measure liquids...

KWONG: (Laughter).

SOFIA: ...Like, without a straightforward conversion between them - gallons, quarts, ounces. Who has this kind of time, Kwong?

KWONG: Well, like it or not, Maddie Sofia, that's the common system of measurement in the United States.


SOFIA: (Laughter).

KWONG: The American household uses what's called the U.S. customary system. And for that, we have early settlers with roots in the British Empire to thank - the gallon, the foot, the yard, the pound.

SOFIA: The nonsense.

KWONG: (Laughter).

SOFIA: Is there anything dumber than a gallon?


SOFIA: So why would the United States resist a system of measurement used by the vast majority of the world?

KWONG: Yeah. So in the United States, Liberia and Myanmar, the metric system is not the main system of measurement. And our relationship to the metric system in the U.S. is complicated. So the metric system gained its footing during the French Revolution. Thomas Jefferson looked into it, but Congress ultimately rejected adopting metric as the system of the U.S. And there have been government-led attempts to fully metricate the U.S. ever since, most recently in the 1970s.


MARK ROSS: (Singing) Well, there's something new for Uncle Sam. South with the pound, and in with kilogram. Out with the foot. In with the meter. Out with the quart, and in with the liter.


KWONG: Out with the quart. In with the liter.


ROSS: (Singing) All going metric.

SOFIA: I actually didn't know that we almost went metric.

KWONG: A few times. So this is an educational video called "A Metric America," created around the time President Gerald Ford signed the Metric Conversion Act in 1975, which sought to increase the use of the metric system in the U.S. by appointing a 17-member metric board...

SOFIA: Sure.

KWONG: ...To guide the country's transition. And you start to see PSAs like this from the then-called U.S. Office of Education.


UNIDENTIFIED PERSON: (Singing) Take 10, America, to learn the metric way. It's a simple system based on tens that you can start today. Efficient, more accurate, more universal, too - it's good for our economy, our country and for you.

SOFIA: Wow. It's beautiful.


KWONG: The world you want to live in.

SOFIA: It's beautiful.

KWONG: I know.

SOFIA: So what happened?

KWONG: Well, the problem with the Metric Conversion Act, you could argue, is that it didn't go all the way. It made swapping systems voluntary, not mandatory. The metric board said it lacked the congressional mandate to really make this switch happen, and their calls for conversion were largely ignored by the public.

ELIZABETH BENHAM: I think there were concerns with labor that maybe the transition to metrication would maybe put people out of jobs. They wouldn't have the skill set or the tools that they needed to transition and learn this new thing. So there was a bit of labor resistance going on.

KWONG: That's Elizabeth Benham, the metric program coordinator for the National Institute of Standards and Technologies (ph). Her job, Maddie, is to help companies that want to transition to the metric system do so. And there were plenty of what she calls early adopters to the metric system in the 1970s.

BENHAM: Companies like IBM, Caterpillar, Xerox and so forth - they were manufacturing their equipment or having a kind of international supply chain, and they needed those parts to fit together when they assembled their product.

SOFIA: So basically, they were working internationally so it made sense for them to work under that system.

KWONG: Exactly. And other companies, especially those with products on the global market, have hopped on board.

BENHAM: And as things are replaced, they get replaced with metric designs and best practices. Other economies, other organizations are further along than others, but everyone is headed in that same path.

KWONG: Basically, as the world has globalized, science and industry in the U.S. have metricated. But like an iceberg, Elizabeth says, the metric system lies below the surface, invisible to most consumers.

BENHAM: What they see is going to the gas pump every day. They see what they see in the grocery store. They see U.S. customary units being there. That's their prospective and their experience.

KWONG: And public divisiveness towards the metric system is real. There are those who wish we had converted a long time ago, but there are plenty who are fervently against it. But to be fair, converting the U.S. to metric would be a huge undertaking. And the customary system, it's what people know and what they're comfortable with. But what I realized from talking to Elizabeth is that, whether you like it or not, there are traces of the metric system in the United States everywhere, literally lining our pockets.

SOFIA: OK. You've brought some coins to the studio.

KWONG: Yes, like this one.

SOFIA: OK. That's a penny.

KWONG: How much do you think a penny weighs?

SOFIA: OK. Weirdly, I do know this one, which is not that fun, but it's 2 1/2 grams.


SOFIA: (Laughter).

KWONG: So that's correct. What about this, Dr. Sofia? This is a nickel.

SOFIA: That, I would say, is 4 grams.

KWONG: Five grams. And if you're wondering what a kilogram feels like, give me your hand.

SOFIA: OK. This is a lot of coin. This is...

KWONG: That is five rolls of nickels.

SOFIA: Are these for me?

KWONG: If a nickel is 5 grams, five rolls of nickels is about a kilogram.

SOFIA: Got it. So even our money is designed to meet metric specifications.

KWONG: Yes, the U.S. Mint follows the metric system when it's making our money, exactly. And this water bottle on the table right here - so the Fair Packaging and Labeling Act was modified in 1992 to require that metric units be displayed alongside customary units. So I can see from this label here that I'm drinking 16.9 fluid ounces of water, but then, in parentheses, it says I'm drinking...

SOFIA: Five hundred mills.

KWONG: ...Five hundred milliliters, exactly. And it really is all about what system you're paying attention to. When you're looking at packaging, you'll see the metric system is actually quite omnipresent.

SOFIA: So what are kids being taught to, like, pay attention to in schools?

KWONG: Well, kids are absolutely being taught the U.S. customary system in school and using it at home, for sure.

SOFIA: Yeah. Gallons of milk.

KWONG: Right. And we measure kids' height in feet, right?

SOFIA: Sure.

KWONG: But the Common Core math standards in the United States require knowledge of the metric system by the fourth grade and the ability to convert using the metric system by the fifth grade. Elizabeth's office actually sends out metric kits to teachers every year. And tried and true - her office has an animated series.

SOFIA: Absolutely, they do.

KWONG: Educational videos have been used throughout time with the metric system. And this particular series depicts the seven base units as superheroes - the measurement league, fighting uncertainty, imprecision and inaccuracy.



UNIDENTIFIED ACTOR #1: (As Professor Second) Stop right there, Major Uncertainty.

SOFIA: (Laughter).


UNIDENTIFIED ACTOR #2: (As Major Uncertainty) Ha-ha. You're too late, Professor Second. My power grows with every error.

KWONG: Elizabeth loves this. She's particularly partial to Candela.

BENHAM: Everywhere you go, you light up a room. So who wouldn't want to be Candela?


UNIDENTIFIED ACTOR #1: (As Professor Second) We haven't forgotten. But we've become a lot more accurate and precise since then.

SOFIA: I'm so happy.

KWONG: And listen - it's her job to be pro-metric and to support the conversion to the metric system that, whether we like it or not, is happening in the U.S. And Elizabeth's big point is that students genuinely benefit from fluency in the metric system, especially those keen to work in math and science, engineering and technology.

BENHAM: The STEM career pipeline starts young. And, you know, our economy will benefit from having, you know, knowledgeable young people that are going to take the jobs of all of our retiring boomers, right (laughter)?

KWONG: Yeah.

BENHAM: So we need them coming up the pipeline and ready to go and prepared for the - you know, the future.


KWONG: But for now, the U.S. makes it work as a dual-measurement country, operating in both metric and customary, depending on what you're looking to measure.

SOFIA: Thank you for celebrating our 100th episode birthday. Our gratitude knows no measure.

KWONG: Metric or customary.

SOFIA: And the best gift you can give us is, again, to hit that subscribe button if you haven't already. Honestly, we're offended it's taken you so long.

KWONG: Hm. And I would also suggest telling one friend, who you think would value more science-based news and newsy science in their ear holes, about SHORT WAVE.

SOFIA: This episode was produced by Brit Hanson and edited by Viet Le.

KWONG: The facts were checked by Emily Vaughn.

SOFIA: I'm Maddie Sofia.

KWONG: And I'm Emily Kwong.

MADDIE SOFIA AND EMILY KWONG: Thanks for listening to SHORT WAVE from NPR.


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