Today, Explained - Do it for the gram

Episode Date: November 16, 2018

Massive news: Scientists in France voted to officially redefine the kilogram today. They’ve been weighing their options for centuries. Learn more about your ad choices. Visit podcastchoices.com/adchoices

The weather outside can be frightful, and KiwiCo wants to help you make your kid's holiday season delightful. They've got these projects that'll encourage learning about science and technology and math and art. Your kid gets to build them. They even have a couple of projects that you, an adult person, might enjoy. You can start your KiwiCo experience for free at KiwiCo.com slash explained. Brian Resnick, you report on the sciences here at Vox, and I hear you have big, breaking scientific news for us this Friday. The news isn't just big, Sean. It's massive.

Tell me more. What has happened? Scientists have met in Versailles, France, and have voted to redefine the kilogram. And these changes will take effect next year. The kilogram like the weight? Alright, so how do I explain this? What do you think a kilogram is? I grew up in Canada. It's a whole lot of grams. Yeah, it's a thousand grams. Okay.

But do you know what it is? What's the definition lot of grams? Yeah, it's 1,000 grams. Okay. But do you know, like, what it is? Like, what's the definition of a kilogram? No, I don't know more than, like, 1,000. I mean, let me think here. I mean, I could tell you how much in, like, weed, I guess. Well, really, a kilogram is a real physical object, and it's in France. It's a thing? It's a literal weight that's kept under three bell jars outside of Paris. It was created in the late 1800s to be this permanent representation of weight

that the whole entire world can use. What does it look like? Well, it's about an inch and a half, two inches high. It's like a hockey puck. Huh. Yeah, it's made out of a shiny metal, and it weighs exactly a kilogram. Okay, so why are they redefining this classic thing? Why not leave it be?

Because the kilogram right now is really kind of frustratingly imperfect. So if anything happens to that IPK, that international kilogram standard in France, all the other kilogram standards across the world have to adjust. Since, like, this thing was created, scientists think it's lost about 50 micrograms, which is about, like, the weight of an eyelash, which is really basically nothing. But everything else now has to adjust to meet the international standard. That thing that's housed outside of Paris, a few atoms of air can stick to it. It maybe accidentally gets scratched and it loses some material. You want these units to be anchored to things that are constant. This cylindrical object upon which the kilogram is based, or it is the kilogram. It is the kilogram. So what are the practical implications of this,

that the kilogram is changing and it needs to be updated? So right now, you need to go to Paris. You need to go to the U.S. government to verify what a kilogram is. It's something that's guarded under lock and key. It's something that needs to be verified. So what's changing is actually like a kind of a democratization of the kilogram, where it will just be fixed to the fundamental truth of the universe. How are they going to define this new kilogram? So it turns out it's really complicated. I went to the National Institute of Standards and Technology, which has scientists that have been working on this redefinition for decades to help

me understand it. Can I come with you? Of course. All right, here we are at NIST. The National Institute of Standard and Technology, they have a campus in Gaithersburg, Maryland. We took an elevator down. We're about 12 meters below, or 40 feet below, And these are the special labs that are most isolated. So this is the place where they store the United States' copy of the master kilogram. So there are three keys you need to get into it, and these standard kilograms are basically the final verdict on what a kilogram is

in the United States. You're the keeper of... I'm the guy. You're the guy. But the keeper of mass.'m the guy. You're the guy. But like the keeper of mass. I am. I am. Is someone trying to steal the kilogram or something?

Is this like National Treasure 3, the kilogram? It's 40 feet below the Earth because, you know, when they make measurements of this thing, they don't want like any vibrations. They want it like super isolated. They want to like make a really pristine environment to not just store this thing, but to measure it, because we're

comparing every single other weight measurement in the United States against these things. And we only have like seven of them. One of them, which I saw, which is called K4, is made from the exact same metal that the original is made out of. So it's like its sister.

The real reason I was at NIST was to see this really massively, awe-inspiringly complicated machine. But first I had to put on a hairnet and booties. We have to be clean, which means we've got to put on booties and a jacket and a little cap. In this room, what is the fear if we don't do this? Contaminating the masses and adding mass to them. And then that would add mass to everything? It would potentially add mass to everything.

That's correct. Okay, I'm going to be very careful in here. Once I had this gear on, I was able to go see this beautiful machine, which makes the redefinition of the kilogram possible. What is the thing? It's called a kibble balance. The kibble balance? The kibble balance. It used to be called a watt balance, and it does something

kind of crazy. One of the scientists there, Doreen El-Haddad, explained it to me. So you can see, as I told you, you have a 60 ton concrete block, but you can see it's separate from the wall in the lab, so it's, um, and the whole thing can float.

It's like a thing out of HG Wells. It has this great wheel at the top, it has lasers, it has magnets. Can I, like, Google it? Can I see it somewhere? Yeah, let me show you some pictures. Oh my gosh, look at this thing! It looks like something out of a

brewery, if you've ever been to the back of a brewery and seen all the tanks and the vats, but way more technical. There's like copper pipes and all these little wheels everywhere. Yeah, it looks like if a brewery was capable of time travel. Yes, that's it! This is

what you would imagine. Doc Brown is going to run out any second with some gasket blown. Marty! You've got to come back with me! I still need to explain why the kibble balance is so important, and I think to do so, we should talk about light speed and the meter. It used to be the meter was literally just a metal pole in France. The meter, too, was a thing in France? It was a thing in France.

Wow. What scientists did in the 80s is they redefined the meter to be the distance light travels in a vacuum, like over a certain amount of time. I think it's like 1 300 millionth of a second or something like that is a meter. They were baking in the definition of the meter to our understanding of the speed of light.

You take the meter, and suddenly it's something permanent. We know the speed of light, we know it doesn't change, and then we just decided that some proportion of the speed of light is a meter, and now the meter never changes. So how does that relate back to the kilogram? Basically what they're doing here is something similar. They're affixing the kilogram to something that's called the Planck constant. The Planck constant.

The Planck constant. This is actually quantum mechanics. It basically describes how energy works and really small bits of matter. Okay. What's important, though, is the Planck constant will never change. It's like the speed of light. Wherever you go, it's true. So this is where the Kibble balance comes in.

It allows us to define the Planck constant, but it also allows us to make sure our understanding of the kilogram is tied to the Planck constant, in the same way that our understanding of the meter is fixed to the speed of light. The scientists I was talking to, they were saying this is the most exciting moment of their career. And this whole quest to find a way to make sure our measurements are attached to the things in the universe that will never change is actually kind of beautiful.

One of the scientists was describing to me, they know this is technically a lot more complicated, but philosophically, it's a lot simpler. It's basically asking the universe, like, what are the stable things? And then we base our measurements off of light, and now the kilogram is permanently tied to this mathematical concept, the Planck constant. How should I picture it? Like, how should I picture the Planck constant? One of the scientists I talked to actually had the Planck constant tattooed on his arm. What does it look like? I have a picture of it. Oh my god. It's like the most complicated equation tattoo I've ever seen. It's probably the only equation tattoo I've ever seen. H equals 6.62607015 times 10 to the negative 34.

And then it says JS. Yeah, joule seconds is energy times time. And under the tattoo you've got on this guy's arm, it says in French cursive, a tout le temps, a tout le peuple. Yeah, for all times, for all people. Wow. That's the founding motto of the metric system,

which became the international system of units. Okay. That's why they love this work, because when you attach something like the kilogram to a constant of nature, you basically unleash it from the vault outside of France. So right now, if you're an airplane manufacturer, it's really important to know how much an airplane weighs, so you want to make sure all your scales are calibrated right. In the future, they won't have to go to a place like NIST to calibrate their scales. They could just have like a kibble balance on their factory floor

and determine precisely what a kilogram is because it's not something under lock and key anymore. It's just like a truth of the universe. Brian, you said earlier that they were democratizing weight, but now like I really see that you meant it. Yeah, absolutely. You don't have to rely on a government anymore to tell you what something weighs. A kilogram is now baked into our definition of one of the constants of the universe. Now the kilogram will never change because it's so closely tied to the Planck constant. The meter will never change because it's

so closely tied to the speed of light. It's like almost transcendent. Like you take our messy humanness and we've kind of made it permanent and celestial even. I know a lot of the science can sound really complicated, but the simple part of it is that these scientists, their work is about finding the constant things in the universe that will never change. The things that we can depend on year after year, century after century, perhaps even when the Earth is no longer around. You know, if you think of all the things, you know, in the world that are just so topsy-turvy, that are just so not stable. It's really nice that there are people whose work is dedicated to finding the things that will never change. There's definitely a world before the kilogram.

I'm Sean Ramos-Ferrum. This is Today Explained. All right, Vanderplug. That's me. Yeah, hey, so you're the youngest person on staff here at Today Explained. So I was wondering if you could be my stand-in for a small child and open up this gift that KiwiCo has sent us. And I want to get your reaction to find out how impressed a young person would be by a KiwiCo project. People often describe me as childish, childlike. Yeah. So yes. Good. Open it, open it, just go for it. So this is the box in the box. Whoa. Are these paints? No big deal. Various craft-like things. Okay. There's cardboard.

There's like foam. Good. These are like these little cotton ball-y things of different colors. You've got blue and green cotton ball-y things. Oh, look at this beautiful little book. It says, Explore, a magazine to experiment, learn, and play. How delightful. What's the title of that particular one?

Whale Tales. Sounds nice. This looks like it's salt. Oh, good. It says, not for food use. Do not. This looks like it's salt. Oh, good. It says not for food use. Do not consume. Yeah, it is salt. Oh, I see. All of this comes together to build a mechanical sweeper

that looks like a whale. What do you think of that? I mean, it's pretty cool. KiwiCo.com slash explained. What did you just do? Remember blogs? Linda Anderman still has one. My most popular blog post of all time, which has gotten more than 150,000 page views, is the top 10 reasons why the U.S. should switch to the metric system. Her blog's called More Than a Mile Behind, America and the Metric System. Linda's also writing a book about this stuff.

She is obsessed with measurement. What happened before we had this fancy kilogram out there in Paris? What was humanity using to measure everything before that? A lot of things were based on body parts. The definition of an inch was three barley corns taken from the center of the ear and placed end to end, and that was your inch. You would actually measure fabric out. You would hold the cut end to your nose and then hold out your entire arm and that would basically be used as a yard. And you know a foot was a foot. But like it didn't matter that your foot was different than his foot and her foot and the small child's foot? And that's the problem isn't it it? So if you were measuring out fabric, you wanted the shortest person in your family to measure that fabric out. Right. And hands are still used with horses. What do you mean?

Horses don't have hands. No, but you would measure how tall a horse was by hands. You know, I even have a personal example of this that just came to mind. My mom would always tell me when I'm making rice to measure how much water I should have, my water to rice ratio. I should fill the water until the first line on my finger. And I still use that even though it's totally imprecise and probably not the best way to make rice. Yeah, you probably don't want your doctor dosing your medicine that way. So how does this work for weight? I guess it's got to be a little different. I mean, how did it work then for weight? For a long time, people used balance scales to weigh things.

And so a merchant would have a standard that he would put on one side of the balance scale and then would measure things out. And that's what you got. You had to know that that standard hadn't been shaved off know, shaved off a little bit. And in fact, merchants, because they were buying large amounts of material, they would actually have their own standard and would check their weights against the merchant's weight to make sure that they evened up. Was that widespread, sort of cheating using counterweights and stuff like that? Yeah, you know, there's so many ways to cheat with weights and measures.

And in fact, there are prohibitions in all of the major religious canons against cheating with weights and measures. And that's why Lady Justice is blindfolded and holding a scale. So how did all this start to change? France was very advanced in terms of their scientific endeavors. In fact, the France Academy of Sciences began in 1666. Okay. And because of the Age of Enlightenment that started in the 17th century, and the idea that it really wasn't evil spirits that were making the milk go bad.

People started to rely on logic and reason, and science was really starting to take off, and it was recognized that, you know, science contains a lot of measurement, and if scientists wanted to communicate their results to each other, they really needed to have one system that when they were talking about their units, they all knew what those units were. Standards are things that people need. Nature doesn't need standards. A river doesn't care how fast it's going and a flower doesn't care how tall it gets. People need standards so that they can deal with each other. So when does this hodgepodge of a system that might be different in every town you go to sort of start to coalesce into a real set of standards? Thomas Jefferson in our country, the UK and France were all looking at metric-based systems.

Jefferson was suspicious of the fact that this meter research was not going to be taking place on our soil. But there has been resistance in this country for a long time. The people who were against the metric system were really against the metric system. Clearly, Americans didn't like it. Was it controversial in France? Oh, hell yeah. Hell yeah. And it still is in this country. But, you know, at some point people had to change over, particularly in France, where this really, you know, took off. It was legislated. I mean, you really didn't have a choice. And obviously, it never worked out in America. What did the United States miss out on as a result?

We don't realize how complicated we've made our lives by not using the metric system. People are dying in this country because we don't use the metric system. Really? I mean that very, very literally. The Emergency Care Research Institute came out with the top 10 patient safety concerns for healthcare organizations, and number seven was medication errors related to pounds and kilograms, because doctors and nurses are constantly going back between pounds and kilograms, because the metric system is a basis for all science and medicine across the world.

Which is to say, even in the United States, our scientists are doing their work in the metric system. Yeah, and that's part of the problem because if a doctor is writing that prescription in milliliters, and if you go and pick up your prescription and it's got teaspoons and tablespoons on it, there's been a conversion. And wherever there's a conversion, there's a potential for conversion error. Just a couple of months ago, some medicine, the outer packaging had one set of units on it, and the little cup on the inside had other units on it. And they had to pull their product off the shelves because of it. Are there other ways the US system's holding us back? We actually did send a probe to Mars, and we smashed it into the surface of the

planet. The Mars Polar Lander was to have given mankind its first look at the red planet's southern pole. But as it descended, a computer on board signaled that it had already landed. The main engine switched off prematurely and Mars became the recipient of one of the most expensive piles of scrap metal in space history. Because even though the contract itself called for metric units, we were working in U.S. customary units, and as a result of that, there was a translation error. The Mars Orbiter is part of a $300 million project known as Mars Surveyor 98, NASA's latest in a series of relatively inexpensive attempts

to mock underfunded public schools. Linda, why do we do things that don't make sense? Well, you know what? You need a mental health professional to address part of that. If killing people and crashing a probe into Mars isn't going to get us to convert, I'm guessing the fact that we now have a precisely defined, democratic, universal kilogram ain't going to do it either, huh? Well, yeah. Here's how I fundamentally look at it. If you don't know how a change is going to

affect you, the knee-jerk reaction is to reject that change. And when you're talking about something that's as fundamental as measurements, people get twitchy because they're afraid that it's going to be difficult to do. And it really isn't. I mean, you know, a quart and a liter are about the same size. There's roughly two kilometers in a mile. And the difference between a meter and a yard is only three inches. They were trying to get my mother to change to the metric system. My mother hadn't even been on the internet by the time she died at 88. But our kids don't expect anything to stay the same from one minute to the next. So the rate of change has accelerated so much,

I think it would actually be much, much easier to implement now than it would have been back in the 70s. We're wasting an unbelievable amount of time for our kids in school, teaching them two systems, one of which nobody else uses, because nobody else uses U.S. customary units. It's just us. Linda Anderman is working on a book on the history of the metric system. It's called America's Biggest Miscalculation. She also blogs. I've gotten over 300,000 page views.

I'm Sean Ramos from This Is Today Explained. Irene Noguchi is weighing her options. Bridget McCarthy is waiting on the world to change. Afim Shapiro is Today Explained. Irene Noguchi is weighing her options. Bridget McCarthy is waiting on the world to change. Afim Shapiro is bloodthirsty. He loves to kill a gram. Noam Hassenfeld can't wait. Luke Vanderplug loves pound cake. Catherine Wheels is

way out of line. Anna Altman's favorite sculptor is Ai Wei Wei. The massive Breakmaster Cylinder makes music for us and you should wait and review us on Apple Podcasts. Today Explained is produced in association with Stitcher, and we're part of the Vox Media Podcast Network. The news isn't just big, Sean. It's massive. Did you get the pun?

Of course I got the pun. But the listeners don't know it's a pun yet, Brian. Brian! Brian! Thanks again to KiwiCo for supporting the show this week. KiwiCo makes projects for your kids this holiday season. They've got all sorts of different ones. They'll start coming in the feed, but what else can people hear in there?

Well, they can hear episode two, if they like, and I encourage them to because it covers the legendary cannonball run. We talked to the current record holder for the unsanctioned, unlicensed, and possibly illegal transcontinental race from New York to Los Angeles. Guy named Ed Boley lives here in Atlanta, and he managed to do it with two people he barely knew in a car in, oh, you know, under 30 hours straight. Nuts. Okay, cool. And that episode's in the feed right now. Yeah, that's in the feed right now. Go ahead. Put it in your ears. Great. It seems smart wherever you find your podcasts.