Today, Explained - How to kill a gram

Episode Date: May 20, 2019

Today, a new definition of the kilogram officially takes effect. But it's just one piece in the massively complicated history of weight. Learn more about your ad choices. Visit podcastchoices.com/adchoices

Bright and Resonate Vox Science. Big news in the science world today. What's going on? The news isn't just big. It's massive. Tell me more. What's happening? Back in November, scientists in France voted to redefine the kilogram,

which is the world's standard unit of mass. And that change goes into effect today. Today? Today. Today? Today. Today Explained. Wait, how do you redefine the kilogram? All right, 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, like, what it is? Like, what's the definition of a kilogram? No, I don't know more than like a

thousand. Let me think here. I mean, I could tell you how much in like weed, I guess. Well, before today, a kilogram was a real physical object 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. Yeah, it's made out of a shiny metal and it weighs exactly a kilogram. Okay, so why are they redefining this classic thing? 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 before today, the kilogram was frustratingly imperfect. So if anything happened to that IPK, the International Kilogram Standard, then all the other kilograms around the world would have to readjust. Since, like, this thing was created, scientists think it's lost about 50 micrograms, which is about the weight of an eyelash, which is really basically nothing. A few atoms of air can stick to it.

Maybe it accidentally gets scratched and it loses some material. You want these units to be anchored to things that are constant. What are the practical implications of this, that the kilogram is changing today? Well, beforehand, you had to go to a government. You had to go to Paris. You had to ask the U.S. government, what is a kilogram? And now a kilogram is just attached to this fundamental to ask the U.S. government, what is a kilogram? And now a kilogram is just attached to this fundamental concept in the universe. You can find it here, you can find

it anywhere. It's kind of like a democratization of mass. What's the new definition of the 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 Standards 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 like there's three keys you need to get into it. And these standard kilograms are basically the final verdict on like what a kilogram is in the United States. You're like, you are the keeper of...

I'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. Okay. And which means we got to put on booties and a jacket and a little cap. In this room, like 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. That's very, okay, I'm gonna be very careful in here. Once I had this gear on, 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 you told, we 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 like a brewery if you've ever been to the back of a brewery and seen all the like tanks and the vats but but way more technical there's like copper pipes and all these little wheels everywhere and 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 one three hundred millionth of a second or something like that is a meter. They were baking in the definition of the meter to our 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 on 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, what are the stable things? And then we base our measurements off of the stable things in the universe. So the meter is permanently tied to the speed of light, and now the kilogram is permanently tied to this mathematical concept, the Planck constant. How should I picture it?

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 peuples. 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. 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 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. Thank you. It's called Nice Try, and it's about utopias and failed utopias. And it's in collaboration with Curbed, which is one of my favorite websites. It's like about urbanism and cities. And so a lot of this is from like the planning perspective and about people who've gone out to build new worlds and the ways that they in some ways have gone haywire and in some ways have succeeded.

It's very interesting. Will you wet the appetite with one of these failed utopias? Oh, my God. I love them all. I fall in love with every single one of them. But the one I'm working on right now is about a free love utopia that went corporate and it turned into a company and it makes something that's still around you today. Like you would never know that this is the history of this thing. Oh my God. Is it the Shake Weight? I'm not going to tell you. That's a really good appetite wetter because you won't even tell us what it is. Now I really have to listen to find out. You really, really, really do. Okay. So what do people do in the meantime then if they want to find the show? Is there a trailer?

There's a trailer. We've got a trailer. There's a little website. It's got some graphics. But yeah, they're going to drop, I think, every Thursday starting May 30th. And there are going to be seven of them. Seven utopias and seven failures. Nice try.

Find it where you listen to your podcasts right now. Right now. 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? 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, you 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 counterweight 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? So 1790 was when three major countries,

it was us, Thomas Jefferson and 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 U.S. 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.