{"id":413,"title":"World's Roundest Object!","description":"Veritasium host Derek Muller visits a lab to see the world's roundest object, a perfectly polished 1kg sphere made of pure Silicon-28. He learns from scientist Katie Green about its incredible precision and its purpose: to help redefine the kilogram, a unit of mass currently based on a physical artifact that is losing mass over time. The video then explores the history of the kilogram, from its origin as the \"grave\" during the French Revolution to the current International Prototype Kilogram. The video explains how counting the atoms in this perfect sphere will allow the kilogram to be redefined based on a fundamental constant, making it a stable and universal standard.","slug":"world-s-roundest-object","creator":"veritasium","duration":703.169887,"tags":["Veritasium","Derek Muller","science","physics","metrology","kilogram","SI units","measurement","roundest object","silicon sphere","history of science","CSIRO"],"transcription":"Can I hold it? Only if you promise to be really, really careful. I promise I will be so incredibly careful. I will be incredibly careful with it. Okay. I promise. All right. So, it's slippery. Be careful. All right. Are you ready? I'm about to touch a 1 kilogram sphere of silicon-28 atoms. There are about 2.15 * 10^25 of them. It feels absolutely incredible. Wow. That is amazing. Besides its creators, I am one of only a handful of people ever to hold this sphere. The raw material used to make it was worth 1 million euros, but now that it has been so precisely sculpted... How much is that worth? It's priceless. This you are looking at now is the roundest object in the world. How can you say for sure that it's the roundest object? I mean, the Earth is pretty round, isn't it? If this was the Earth, then the highest mountain and the lowest valley would be about 14 meters apart. That is shocking. That is shockingly round. But why would you invest 1 million euros and thousands of man-hours perfecting a pure, polished silicon sphere? Well, the answer is grave. Or rather, grave, as it would have been pronounced in the original French. You see, the grave was the original name for the base unit of mass in the metric system, which became the Systeme International d'Unites, or SI units. In 1793, a commission, which included notable scientist and aristocrat Antoine Lavoisier, defined the base unit of mass as the weight of a cubic decimeter of water at the melting temperature of ice. Essentially, just a liter of ice water. The name grave came from the Latin gravitas, meaning weight, but it wasn't to last. It sounded too similar to the aristocratic title Graf, which is the equivalent of an Earl or a Count. And with the French Revolution in full swing, with a rallying cry of equality for all, you couldn't exactly have one unit nobler than the others. At this, Lavoisier lost his head, literally. Not because he helped devise one of the greatest systems of measurement of all time, but because he was collecting taxes as a nobleman. So, things really were grave. The new Republican government believed a grave would be too big for the things they wanted to measure anyway, and so they settled on a gramme, which was just a thousandth of a grave. But soon they realized that a gram was too small, and so they returned to the grave. But since they couldn't call it that, they invented the kilogramme, a thousand grams. And that is why, out of the seven base SI units, the kilogram is the only one to have a prefix in its name. In 1799, the kilogram definition was refined to be the mass of a liter of water at 4 degrees Celsius, the temperature at which it is densest. But water itself is obviously not the most sensible thing to use as a mass standard. So, a pure platinum cylinder was created to have the same mass as the water definition. And it was declared Kilogram of the Archives. Now, it's important to note at this point, the kilogram is no longer tied to the mass of a volume of water. The Kilogram of the Archives is, by definition, the kilogram. 90 years later, in 1889, the kilogram was upgraded to a platinum-iridium alloy cylinder. Now, it was much harder than the original but was otherwise basically identical. And to this day, it remains the definition of the kilogram. It is officially called the International Prototype Kilogram, though it's affectionately known as Le Grand K, or Big K. Oh, and it's about this big. It is the only thing in the entire universe with a mass of exactly 1 kilogram, because it is the kilogram. It is also the only SI unit that is still defined by a physical object. It sits under three bell jars next to six sister kilograms in a climate-controlled vault, locked by three independently controlled keys in the basement of the International Bureau of Weights and Measures on the outskirts of Paris. Now, if you were able to break into the vault and tamper with Big K, you would actually be changing the definition of the kilogram, a definition on which many of our measurements rely. And so you would throw the world into chaos. Well, no, not actually. But how would anyone ever know if the mass of Big K changed? Well, when it was first created, 40 identical replicas were also made. Well, they weren't quite identical. They had a mass which was slightly different to Big K, but those offsets were recorded. Now, these replicas were sent out to countries around the world to serve as their national standards. In 1948, the kilograms were reunited for a weigh-in. And this is when the problems started. Because even though all the cylinders were made of the same alloy and stored under virtually the same conditions, their masses had diverged over time. The mass of Big K wasn't even the same as the six sister cylinders stored with it. And to make matters worse, when they were brought together again 40 years later, their masses had further diverged, up to about 50 micrograms. That's about the weight of a fingerprint. But fingerprints were not the culprits, since the kilograms were carefully washed before their weigh-ins. So some physical process must have actually changed the mass of the cylinders. But how that exactly works remains a matter of speculation. One thing is for certain, the mass of a platinum-iridium cylinder is not stable over time. And this is a big problem. You can't have a unit which changes its value. And the fallout isn't limited to measurements of mass. Since of the seven base SI units, four of them depend on the mass of the kilogram. Not to mention all the derived units like Newtons, Joules, Volts, and Watts. At this point, those of you in countries that have not adopted the metric system, yes, I'm speaking to you, Liberia, Burma, and the US, you may be feeling rather smug that your base unit of mass, the avoirdupois pound, is no longer defined by a physical object. No, instead, it is defined as precisely 0.45359237 kilograms. Sucked in. So clearly, something needs to be done to eliminate the kilogram's dependence on a physical object. And this is where the silicon sphere comes in. But how exactly does that help? Here you have a physical object, and it's beautiful, but, you know, it's still a physical object. You're trying to get away from that. We're trying to get away from the physical object, but what we're doing with this particular object is counting how many atoms are in there. You can't actually count how many are in there, can you? You can't count how many are in there, but you can calculate how many are in there because this material is silicon. There's no voids or dislocations. So this is like a perfect crystal of silicon. That's right. Not only is it pure silicon, it contains only one isotope of silicon, silicon-28. And that explains why the original material was so expensive. And why a sphere? Well, a sphere is a pretty simple object. If you know the diameter of the sphere, you can characterize the entire dimension of the object. Well, that explains why the sphere has to be the roundest object ever created. But how do you actually make something that round? We actually start with an oversized sphere. So it was about 2 mm larger in diameter. And then we just grind it progressively finer and finer using an abrasive that's actually massaging atoms. You're down at that level of of trying to control the shape of an object down at the atomic level. But making the sphere is only half the battle. Then you need to accurately measure its diameter. The diameter is actually measured by a laser. So you're actually measuring, having the sphere in the center of a cavity and the laser is hitting both sides and you're actually measuring the gap. By knowing the diameter, you can determine its volume. And since the atom spacing of silicon is known to high precision, you can then calculate how many atoms make up the sphere. This allows you to redefine Avogadro's constant. At the moment, Avogadro's constant is defined based on the kilogram. It is equal to the number of atoms in 12 grams of carbon-12. But using this approach, the number of silicon atoms in the sphere would be used to fix Avogadro's constant, which would then define the kilogram. So even if the silicon spheres were lost or damaged, it would have no effect on the definition of the kilogram, because it would be defined not by a physical object, but by a concept. You would like to see the official definition of the kilogram say, a kilogram is the mass of 2.15 * 10^25 silicon-28 atoms. Yes. Which is not going to happen. There's a there's a high likelihood that it's going to happen. But there is another approach to redefining the kilogram, which involves fixing Planck's constant. And it's done using something called a watt balance. These two approaches are complementary. Each one provides a check on the other. And if they show good agreement and are able to bring their uncertainties down to about 20 micrograms, they may redefine the kilogram as early as 2014. And then the kilogram finally will be an unchanging unit, no longer defined by a physical object in the basement vault of some place in Paris. Now, if the kilogram was originally intended to be the mass of a liter of water at its densest temperature, then how well did we do? Well, if you look at a liter of water at nearly 4 degrees Celsius, it has a mass of 999.975 grams. So, I guess you could look at this two ways. On the one hand, you could say the kilogram is slightly heavier than it should be. But on the other hand, 214 years ago, scientists were able to create an artifact that was correct within the margin of error of a grain of rice. Now that is truly remarkable. Now, if you want to hear more about the watt balance, let me know in the comments and I will see what I can do. It does seem to be the front runner in terms of redefining the kilogram. So, we will have to wait and see what happens. One last thing, I should point out that it took an international collaboration of scientists to create the silicon sphere. But don't you think that the scientist who originally conceived of silicon as an element should receive some of the credit? Well, in 1787, that was none other than Antoine Lavoisier. So he's been involved in the definition of a kilogram from start to finish, or from cradle to grave.","timeline":[{"t":2,"speech":"Can I hold it? Only if you promise to be really, really careful.","visual":{"action":"A man asks a woman if he can hold an object, and she cautiously agrees.","colors":{"dominant":"gray","palette":["white","gray","blue","tan","black"]},"composition":{"angle":"eye-level","focus":"The two people are in focus.","framing":"medium shot"},"mood":"playful, anticipatory","objects":[],"people":[{"age_range":"40s","clothing":{"accessories":"glasses, small microphone clipped to shirt","bottom":"","footwear":"","top":"white short-sleeved collared shirt"},"face":"smiling","hair":"dark brown, tied back","hands":"out of frame","pose":"standing, facing the man","position":"left of frame"},{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"bright blue polo shirt"},"face":"smiling broadly, looking at the woman","hair":"dark brown, short","hands":"out of frame","pose":"standing, facing the woman","position":"right of frame"}],"setting":{"architecture":"standard laboratory","background":"A lab with a wall-mounted clock, photos pinned to the wall, and lab benches with equipment.","lighting":"bright, even fluorescent lighting","location":"scientific laboratory"},"text_on_screen":[{"content":"Ms. Katie Green","location":"bottom left","style":"white serif font in a gray bar"},{"content":"PRECISION OPTICS, CSIRO","location":"bottom left","style":"smaller white serif font below the name"}]}},{"t":9,"speech":"I will be incredibly careful with it. Okay. I promise.","visual":{"action":"The man leans down towards a shiny sphere on a stand, looking at it with excitement.","colors":{"dominant":"gray","palette":["blue","white","gray","silver","tan"]},"composition":{"angle":"eye-level","focus":"The man and the sphere are in focus.","framing":"medium close-up"},"mood":"excited, amazed","objects":[{"color":"silver, highly reflective","name":"silicon sphere","position":"center foreground","state":"sitting on a golden stand"}],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"bright blue polo shirt"},"face":"smiling, wide-eyed, looking at the sphere","hair":"dark brown, short","hands":"gesturing towards the sphere","pose":"leaning forward","position":"right of frame"},{"age_range":"40s","clothing":{"accessories":"glasses","bottom":"","footwear":"","top":"white short-sleeved collared shirt"},"face":"smiling","hair":"dark brown, tied back","hands":"partially visible","pose":"standing","position":"left of frame, partially obscured"}],"setting":{"architecture":"standard laboratory","background":"A lab bench with various pieces of scientific equipment and a wall with photos.","lighting":"bright, even fluorescent lighting","location":"scientific laboratory"},"text_on_screen":[]}},{"t":17,"speech":"All right. Are you ready?","visual":{"action":"The man puts on a white glove and prepares to touch the sphere, laughing with anticipation.","colors":{"dominant":"gray","palette":["blue","white","silver","green","tan"]},"composition":{"angle":"eye-level","focus":"The man's face and hand are in focus.","framing":"close-up"},"mood":"excited, humorous","objects":[{"color":"silver, reflective","name":"silicon sphere","position":"bottom center","state":"on a stand"}],"people":[{"age_range":"30s","clothing":{"accessories":"white glove on right hand","bottom":"","footwear":"","top":"bright blue polo shirt"},"face":"laughing, eyes wide with excitement","hair":"dark brown","hands":"Right hand with white glove hovering over the sphere.","pose":"leaning forward","position":"center right"}],"setting":{"architecture":"lab","background":"blurry lab equipment","lighting":"bright, fluorescent","location":"scientific laboratory"},"text_on_screen":[]}},{"t":25,"speech":"I'm about to touch a 1 kilogram sphere of silicon-28 atoms. There are about 2.15 * 10^25 of them.","visual":{"action":"The man, wearing a white glove, slowly lowers his hand and makes contact with the perfectly smooth, reflective sphere.","colors":{"dominant":"blue","palette":["blue","silver","white","skin tone","gray"]},"composition":{"angle":"low angle, looking up slightly","focus":"The man's hand and the sphere are in sharp focus.","framing":"close-up"},"mood":"dramatic, momentous","objects":[{"color":"silver, reflective","name":"silicon sphere","position":"center","state":"being touched"}],"people":[{"age_range":"30s","clothing":{"accessories":"white glove","bottom":"","footwear":"","top":"bright blue polo shirt"},"face":"intense concentration, mouth slightly open","hair":"dark brown","hands":"Right hand, gloved, touching the top of the sphere.","pose":"leaning over the sphere","position":"center"}],"setting":{"architecture":"lab","background":"blurry lab background","lighting":"bright","location":"scientific laboratory"},"text_on_screen":[]}},{"t":35,"speech":"It feels absolutely incredible. Wow. That is amazing.","visual":{"action":"The man lifts the heavy, reflective sphere off its stand, holding it in his gloved hand and looking at it in amazement.","colors":{"dominant":"blue","palette":["blue","silver","white","skin tone","gray"]},"composition":{"angle":"eye-level","focus":"The man's face and the sphere are in focus.","framing":"medium close-up"},"mood":"amazed, wondrous","objects":[{"color":"silver, reflective","name":"silicon sphere","position":"in the man's right hand","state":"being held"}],"people":[{"age_range":"30s","clothing":{"accessories":"white glove","bottom":"","footwear":"","top":"bright blue polo shirt"},"face":"smiling broadly, eyes wide with awe","hair":"dark brown","hands":"Holding the sphere in his right, gloved hand.","pose":"sitting/leaning, holding the sphere","position":"center right"}],"setting":{"architecture":"lab","background":"blurry lab background with equipment and photos on the wall","lighting":"bright, even","location":"scientific laboratory"},"text_on_screen":[]}},{"t":48,"speech":"The raw material used to make it was worth 1 million euros, but now that it has been so precisely sculpted...","visual":{"action":"A person wearing gloves carefully handles a rough, cylindrical piece of dark, shiny silicon, taking it out of plastic packaging.","colors":{"dominant":"white","palette":["white","dark gray","blue","orange","black"]},"composition":{"angle":"overhead, slightly angled","focus":"The silicon cylinder and hands are in focus.","framing":"close-up"},"mood":"procedural, careful","objects":[{"color":"dark gray, metallic","name":"silicon ingot","position":"center","state":"being handled"},{"color":"clear","name":"plastic bag","position":"surrounding the ingot","state":"being removed"}],"people":[{"age_range":"unknown","clothing":{"accessories":"clear disposable gloves","bottom":"","footwear":"","top":"white lab coat over a blue shirt"},"face":"not visible","hair":"not visible","hands":"Carefully holding and turning the silicon ingot.","pose":"standing at a table","position":"center"}],"setting":{"architecture":"","background":"An orange cabinet and a dark tabletop.","lighting":"bright, direct","location":"workshop or laboratory"},"text_on_screen":[{"content":"CSIRO","location":"top right","style":"white logo in a blue circle"}]}},{"t":55,"speech":"How much is that worth? It's priceless.","visual":{"action":"The man and woman stand in the lab, laughing, as he points at the sphere on its stand.","colors":{"dominant":"beige","palette":["white","blue","beige","gray","green"]},"composition":{"angle":"eye-level","focus":"The two people are in focus.","framing":"medium shot"},"mood":"lighthearted, humorous","objects":[{"color":"silver","name":"silicon sphere","position":"center foreground, on a stand","state":"stationary"},{"color":"green and gray","name":"polishing machine","position":"background","state":"stationary"}],"people":[{"age_range":"40s","clothing":{"accessories":"glasses","bottom":"","footwear":"","top":"white shirt"},"face":"laughing","hair":"dark brown","hands":"gesturing","pose":"standing","position":"left"},{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"blue polo shirt"},"face":"smiling, looking at the woman","hair":"dark brown","hands":"pointing at the sphere","pose":"standing","position":"right"}],"setting":{"architecture":"lab","background":"A large polishing machine, a pegboard with tools, and other lab equipment.","lighting":"bright","location":"scientific laboratory"},"text_on_screen":[]}},{"t":102,"speech":"How can you say for sure that it's the roundest object? I mean, the Earth is pretty round, isn't it?","visual":{"action":"The man gestures with his hands as he questions the woman's claim about the sphere's roundness.","colors":{"dominant":"beige","palette":["white","blue","beige","gray","green"]},"composition":{"angle":"eye-level","focus":"The two people are in focus.","framing":"medium shot"},"mood":"inquisitive, playful","objects":[{"color":"silver","name":"silicon sphere","position":"center foreground","state":"on a stand"}],"people":[{"age_range":"40s","clothing":{"accessories":"glasses","bottom":"","footwear":"","top":"white shirt"},"face":"smiling, laughing","hair":"dark brown","hands":"out of frame","pose":"standing","position":"left"},{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"blue polo shirt"},"face":"smiling, gesturing as he speaks","hair":"dark brown","hands":"gesturing to make a point","pose":"standing","position":"right"}],"setting":{"architecture":"lab","background":"A large polishing machine and a tool pegboard.","lighting":"bright","location":"scientific laboratory"},"text_on_screen":[]}},{"t":113,"speech":"If this was the Earth, then the highest mountain and the lowest valley would be about 14 meters apart.","visual":{"action":"The man reacts with laughter and surprise to the woman's explanation of the sphere's roundness.","colors":{"dominant":"beige","palette":["white","blue","beige","gray","green"]},"composition":{"angle":"eye-level","focus":"The two people are in focus.","framing":"medium shot"},"mood":"surprised, amused","objects":[{"color":"silver","name":"silicon sphere","position":"center foreground","state":"on a stand"}],"people":[{"age_range":"40s","clothing":{"accessories":"glasses","bottom":"","footwear":"","top":"white shirt"},"face":"smiling, looking at the man","hair":"dark brown","hands":"clasped in front","pose":"standing","position":"left"},{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"blue polo shirt"},"face":"laughing, mouth open in surprise","hair":"dark brown","hands":"one hand on his stomach","pose":"standing, reacting","position":"right"}],"setting":{"architecture":"lab","background":"A large polishing machine and a tool pegboard.","lighting":"bright","location":"scientific laboratory"},"text_on_screen":[]}},{"t":122,"speech":"But why would you invest 1 million euros and thousands of man-hours perfecting a pure, polished silicon sphere?","visual":{"action":"The man speaks directly to the camera, posing a question, with a blurry background of a cemetery.","colors":{"dominant":"gray","palette":["gray","green","white","black","skin tone"]},"composition":{"angle":"eye-level","focus":"The man's face is in sharp focus.","framing":"close-up"},"mood":"serious, inquisitive","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"serious expression, mouth forming words","hair":"dark brown","hands":"not visible","pose":"standing","position":"center"}],"setting":{"architecture":"","background":"A large, crowded cemetery with many white tombstones, blurred.","lighting":"overcast, diffuse daylight","location":"cemetery"},"text_on_screen":[]}},{"t":132,"speech":"Well, the answer is grave.","visual":{"action":"The camera shows a wide shot of a cemetery with many white tombstones under an overcast sky. The word 'Grave' appears in large, brown, serif font.","colors":{"dominant":"gray","palette":["white","gray","green","brown","dark gray"]},"composition":{"angle":"eye-level","focus":"The entire cemetery scene is in focus.","framing":"wide shot"},"mood":"dramatic, mysterious","objects":[{"color":"white","name":"tombstones","position":"throughout the frame","state":"stationary"}],"people":[],"setting":{"architecture":"marble and stone tombstones and crosses","background":"A hill covered in graves, with some buildings in the far background.","lighting":"overcast, flat daylight","location":"cemetery"},"text_on_screen":[{"content":"Grave","location":"center","style":"large, brown, serif font with a drop shadow"}]}},{"t":138,"speech":"You see, the grave was the original name for the base unit of mass in the metric system, which became the Systeme International d'Unites, or SI units.","visual":{"action":"The man speaks to the camera in a cemetery, explaining the historical context of the word 'grave'.","colors":{"dominant":"gray","palette":["white","green","gray","dark blue","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus, the background is slightly blurred.","framing":"close-up"},"mood":"informative, historical","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"serious, explaining","hair":"dark brown","hands":"gesturing slightly","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"A cemetery with numerous white tombstones.","lighting":"overcast daylight","location":"cemetery"},"text_on_screen":[]}},{"t":144,"speech":"which became the Systeme International d'Unites or SI units.","visual":{"action":"Text appears on a textured, parchment-like background, explaining the origin of SI units.","colors":{"dominant":"beige","palette":["beige","brown","dark brown","gray"]},"composition":{"angle":"straight-on","focus":"The text is in focus.","framing":"full screen text"},"mood":"historical, educational","objects":[],"people":[],"setting":{"architecture":"","background":"A stained, aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"Système International d'unités","location":"center","style":"black serif font, animated reveal"},{"content":"SI unités","location":"center bottom","style":"black serif font, animated reveal"}]}},{"t":151,"speech":"notable scientist and aristocrat Antoine Lavoisier, defined the base unit of mass as the weight of a cubic decimeter of water at the melting temperature of ice.","visual":{"action":"An 18th-century style illustration of Antoine Lavoisier is shown, with his name appearing as text.","colors":{"dominant":"beige","palette":["beige","brown","dark green","white","yellow"]},"composition":{"angle":"straight-on","focus":"The illustration and text are in focus.","framing":"medium shot of the illustration"},"mood":"historical, formal","objects":[],"people":[{"age_range":"40s-50s","clothing":{"accessories":"cravat","bottom":"dark green breeches","footwear":"black shoes with buckles","top":"brown coat over a decorative waistcoat"},"face":"stoic, looking to the side","hair":"white, powdered wig style","hands":"one resting on a table","pose":"standing next to a table with scientific apparatus","position":"center"}],"setting":{"architecture":"implied 18th-century room","background":"A plain, light-colored wall with some scientific equipment.","lighting":"soft, directional","location":"illustrated study or lab"},"text_on_screen":[{"content":"Antoine Lavoisier","location":"bottom center","style":"yellowish serif font"}]}},{"t":157,"speech":"as the weight of a cubic decimeter of water at the melting temperature of ice.","visual":{"action":"A simple animation shows a cube being drawn, labeled with its dimensions and temperature, representing the definition of the original kilogram.","colors":{"dominant":"beige","palette":["beige","brown","black","light blue"]},"composition":{"angle":"straight-on","focus":"The animation is in focus.","framing":"close-up on the animation"},"mood":"educational, simple","objects":[{"color":"light blue","name":"cube of water","position":"center","state":"being drawn and labeled"}],"people":[],"setting":{"architecture":"","background":"A stained, aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"0.1 m","location":"below the cube","style":"handwritten black font"},{"content":"0°C","location":"right of the cube","style":"handwritten black font"}]}},{"t":204,"speech":"The name grave came from the Latin gravitas, meaning weight, but it wasn't to last.","visual":{"action":"An animation shows a cube of ice water with the word 'Grave' which then changes to 'Gravitas (weight)'.","colors":{"dominant":"beige","palette":["beige","light 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screen"},"mood":"historical","objects":[],"people":[{"age_range":"40s","clothing":{"accessories":"","bottom":"dark breeches","footwear":"black shoes","top":"brown coat, white shirt"},"face":"stoic","hair":"white powdered wig","hands":"one gesturing","pose":"standing","position":"right"}],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"illustrated room"},"text_on_screen":[{"content":"Graf (Earl/Count)","location":"center","style":"large black serif font"}]}},{"t":216,"speech":"And with the French Revolution in full swing, with a rallying cry of equality for all, you couldn't exactly have one unit nobler than the others.","visual":{"action":"A famous painting of the French Revolution, 'Liberty Leading the People', is shown with the word 'Égalité' overlaid.","colors":{"dominant":"brown","palette":["brown","dark red","blue","beige","yellow"]},"composition":{"angle":"straight-on","focus":"The painting is in focus.","framing":"full shot of the painting"},"mood":"revolutionary, dramatic","objects":[{"color":"red, white, blue","name":"French flag","position":"top center","state":"being waved"}],"people":[{"age_range":"various","clothing":{"accessories":"","bottom":"","footwear":"","top":"19th-century revolutionary attire"},"face":"various expressions of struggle and determination","hair":"various","hands":"holding weapons, waving flag","pose":"dynamic poses of fighting and dying","position":"across the canvas"}],"setting":{"architecture":"barricades in a city","background":"a smoke-filled Parisian street","lighting":"dramatic, chiaroscuro","location":"Paris, during the French Revolution"},"text_on_screen":[{"content":"Égalité","location":"bottom left","style":"large, elegant serif font"}]}},{"t":225,"speech":"At this, Lavoisier lost his head, literally.","visual":{"action":"A black and white historical illustration depicts a beheading by guillotine during the French Revolution.","colors":{"dominant":"white","palette":["black","white","gray"]},"composition":{"angle":"eye-level","focus":"The entire illustration is in focus.","framing":"wide shot"},"mood":"gruesome, historical","objects":[{"color":"wood/metal","name":"guillotine","position":"center","state":"in use"}],"people":[{"age_range":"various","clothing":{"accessories":"","bottom":"","footwear":"","top":"18th-century attire"},"face":"various","hair":"various","hands":"operating the guillotine, holding up a severed head","pose":"various poses related to the execution","position":"around the guillotine"}],"setting":{"architecture":"","background":"a simple room or platform","lighting":"n/a","location":"place of execution"},"text_on_screen":[]}},{"t":243,"speech":"and so they settled on a gramme, which was just a thousandth of a grave.","visual":{"action":"An animation shows a large blue cube representing a 'Grave' shrinking into a tiny blue cube, with the word 'gramme' appearing.","colors":{"dominant":"beige","palette":["beige","light blue","black","brown"]},"composition":{"angle":"straight-on","focus":"The animation is in focus.","framing":"full screen animation"},"mood":"informative, simple","objects":[{"color":"light blue","name":"cube","position":"center","state":"shrinking"}],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"gramme","location":"bottom center","style":"black serif font"}]}},{"t":254,"speech":"they invented the kilogramme, a thousand grams.","visual":{"action":"An animation shows a large cube made of 1000 smaller cubes appearing, with the word 'kilogramme' below it.","colors":{"dominant":"beige","palette":["beige","light blue","dark blue","black"]},"composition":{"angle":"straight-on","focus":"The animation is in focus.","framing":"full screen animation"},"mood":"educational","objects":[{"color":"light blue with dark blue lines","name":"cube made of smaller cubes","position":"center","state":"appearing"}],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"kilogramme","location":"bottom center","style":"black serif font"}]}},{"t":300,"speech":"the kilogram is the only one to have a prefix in its name.","visual":{"action":"A list of the seven base SI units is displayed on a parchment background, with 'kilogram' highlighted in red.","colors":{"dominant":"beige","palette":["beige","black","red","brown"]},"composition":{"angle":"straight-on","focus":"The text is in focus.","framing":"full screen text"},"mood":"informative","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"mol","location":"top left","style":"black serif font"},{"content":"Kelvin","location":"top right","style":"black serif font"},{"content":"candela","location":"middle left","style":"black serif font"},{"content":"second","location":"middle right","style":"black serif font"},{"content":"Ampere","location":"bottom left","style":"black serif font"},{"content":"metre","location":"bottom right","style":"black serif font"},{"content":"kilogram","location":"bottom center","style":"red serif font"}]}},{"t":306,"speech":"In 1799, the kilogram definition was refined to be the mass of a liter of water at 4 degrees Celsius, the temperature at which it is densest.","visual":{"action":"The man stands in a cemetery by the ocean, holding a clear plastic container of water and explaining the refined definition of the kilogram.","colors":{"dominant":"gray","palette":["gray","white","dark blue","green","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"medium shot"},"mood":"educational","objects":[{"color":"clear","name":"plastic container of water","position":"in the man's hands","state":"being held up"}],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"explaining, looking at the camera","hair":"dark brown","hands":"holding the container of water","pose":"standing","position":"center"}],"setting":{"architecture":"white marble tombstones and a colonnaded structure","background":"A cemetery overlooking a choppy ocean under a cloudy sky.","lighting":"overcast daylight","location":"seaside cemetery"},"text_on_screen":[{"content":"1799","location":"top right","style":"large black serif font"},{"content":"4°C","location":"right side","style":"large black serif font"}]}},{"t":320,"speech":"So, a pure platinum cylinder was created to have the same mass as the water definition. And it was declared Kilogram of the Archives.","visual":{"action":"A photo of an old, dark metal cylindrical weight with a knob on top is shown on a parchment background, with a stamp-like graphic appearing.","colors":{"dominant":"beige","palette":["beige","dark brown","black","gray"]},"composition":{"angle":"straight-on","focus":"The cylinder is in focus.","framing":"close-up"},"mood":"historical, official","objects":[{"color":"dark metallic","name":"Kilogram of the Archives","position":"center","state":"stationary"}],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"KILOGRAM of the ARCHIVES","location":"right side","style":"black text in a circular stamp graphic"}]}},{"t":336,"speech":"The Kilogram of the Archives is, by definition, the kilogram.","visual":{"action":"A photo of the 'Kilogram of the Archives' is shown with French text overlaid.","colors":{"dominant":"yellow","palette":["yellow","dark brown","black","beige"]},"composition":{"angle":"straight-on","focus":"The image and text are in focus.","framing":"close-up"},"mood":"definitive, educational","objects":[{"color":"dark metallic","name":"Kilogram of the Archives","position":"center","state":"stationary"}],"people":[],"setting":{"architecture":"","background":"A solid light yellow background.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"Ceci est un kilogramme","location":"bottom center","style":"brown cursive font"}]}},{"t":341,"speech":"90 years later, in 1889, the kilogram was upgraded to a platinum-iridium alloy cylinder.","visual":{"action":"The man stands in a cemetery with a palm tree, explaining the history of the kilogram.","colors":{"dominant":"gray","palette":["gray","white","green","dark blue","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"medium shot"},"mood":"informative","objects":[{"color":"green and brown","name":"palm tree","position":"right background","state":"stationary"}],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"speaking to camera","hair":"dark brown, slightly windblown","hands":"gesturing","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"A large cemetery with a checkered floor pattern in the foreground.","lighting":"overcast daylight","location":"cemetery"},"text_on_screen":[{"content":"1889","location":"top left","style":"large black serif font"}]}},{"t":351,"speech":"And to this day, it remains the definition of the kilogram.","visual":{"action":"The man continues his explanation in the cemetery.","colors":{"dominant":"gray","palette":["gray","white","green","dark blue","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"close-up"},"mood":"emphatic, educational","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"serious, speaking with emphasis","hair":"dark brown","hands":"not visible","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"Blurry cemetery background with a palm tree.","lighting":"overcast daylight","location":"cemetery"},"text_on_screen":[]}},{"t":358,"speech":"It is officially called the International Prototype Kilogram, though it's affectionately known as Le Grand K, or Big K.","visual":{"action":"Text appears on a parchment background, stating the official name of the kilogram prototype.","colors":{"dominant":"beige","palette":["beige","black","brown"]},"composition":{"angle":"straight-on","focus":"The text is in focus.","framing":"full screen text"},"mood":"informative","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"International Prototype Kilogram","location":"center","style":"black serif font"},{"content":"Le Grand K (Big K)","location":"bottom center","style":"black serif font"}]}},{"t":407,"speech":"It is the only thing in the entire universe with a mass of exactly 1 kilogram, because it is the kilogram.","visual":{"action":"The man stands in the cemetery, holding up a small, shiny, cylindrical metal weight to the camera.","colors":{"dominant":"gray","palette":["gray","white","green","dark blue","gold"]},"composition":{"angle":"eye-level","focus":"The man and the small weight are in focus.","framing":"medium close-up"},"mood":"emphatic, educational","objects":[{"color":"gold/brass","name":"small cylindrical weight","position":"held in the man's right hand","state":"being displayed"}],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"smiling, speaking with conviction","hair":"dark brown","hands":"holding a small weight","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"Blurry cemetery background with a palm tree.","lighting":"overcast daylight","location":"cemetery"},"text_on_screen":[]}},{"t":421,"speech":"It sits under three bell jars next to six sister kilograms in a climate-controlled vault,","visual":{"action":"An image shows the International Prototype Kilogram under multiple glass bell jars on a golden base.","colors":{"dominant":"black","palette":["black","glassy blue","gold","silver"]},"composition":{"angle":"eye-level","focus":"The kilogram prototype is in sharp focus.","framing":"close-up"},"mood":"secure, scientific, precious","objects":[{"color":"silver","name":"International Prototype Kilogram","position":"center","state":"under glass bell jars"},{"color":"clear glass","name":"bell jars","position":"covering the kilogram","state":"stationary"}],"people":[],"setting":{"architecture":"","background":"solid black","lighting":"studio lighting, highlighting the object","location":"vault (implied)"},"text_on_screen":[]}},{"t":431,"speech":"in the basement of the International Bureau of Weights and Measures on the outskirts of Paris.","visual":{"action":"A satellite view zooms in from Europe to a specific building complex in Paris.","colors":{"dominant":"green","palette":["green","gray","blue","brown","dark green"]},"composition":{"angle":"overhead (satellite view)","focus":"The entire map is in focus.","framing":"zoom in"},"mood":"informative, geographical","objects":[],"people":[],"setting":{"architecture":"various buildings","background":"satellite imagery of land and sea","lighting":"daylight","location":"Paris, France"},"text_on_screen":[]}},{"t":440,"speech":"you would actually be changing the definition of the kilogram, a definition on which many of our measurements rely.","visual":{"action":"The man stands in the cemetery holding the small weight, explaining the consequences of altering the prototype.","colors":{"dominant":"gray","palette":["gray","white","green","dark blue","gold"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"close-up"},"mood":"serious, cautionary","objects":[{"color":"gold/brass","name":"small cylindrical weight","position":"held in the man's hand","state":"stationary"}],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"serious expression, explaining a concept","hair":"dark brown","hands":"holding the small weight","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"Blurry cemetery background.","lighting":"overcast daylight","location":"cemetery"},"text_on_screen":[]}},{"t":453,"speech":"But how would anyone ever know if the mass of Big K changed?","visual":{"action":"The man poses a rhetorical question to the camera.","colors":{"dominant":"gray","palette":["gray","white","green","dark blue","gold"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"close-up"},"mood":"inquisitive","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"questioning expression","hair":"dark brown","hands":"holding the small weight","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"Blurry cemetery background.","lighting":"overcast daylight","location":"cemetery"},"text_on_screen":[]}},{"t":508,"speech":"Now, these replicas were sent out to countries around the world to serve as their national standards.","visual":{"action":"An animation on a parchment-textured world map shows kilogram replicas being distributed from France to various countries.","colors":{"dominant":"gray","palette":["gray","beige","dark 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And this is when the problems started.","visual":{"action":"The man stands in a seaside cemetery, explaining a turning point in the history of the kilogram.","colors":{"dominant":"gray","palette":["gray","white","dark blue","green","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"medium shot"},"mood":"foreboding, informative","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"serious, explaining","hair":"dark brown","hands":"gesturing","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"Cemetery next to the ocean.","lighting":"overcast","location":"seaside cemetery"},"text_on_screen":[{"content":"1948","location":"top right","style":"large black serif font"}]}},{"t":527,"speech":"their masses had diverged over time.","visual":{"action":"A simple graph is drawn on a parchment background, showing multiple lines diverging from a single point over time.","colors":{"dominant":"beige","palette":["beige","black","brown","dark gray"]},"composition":{"angle":"straight-on","focus":"The graph is in focus.","framing":"full screen"},"mood":"scientific, concerning","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"Change in Mass","location":"y-axis","style":"handwritten black font"},{"content":"Year","location":"x-axis","style":"handwritten black font"},{"content":"1948","location":"on the x-axis","style":"handwritten black font"}]}},{"t":539,"speech":"their masses had further diverged, up to about 50 micrograms. That's about the weight of a fingerprint.","visual":{"action":"The graph on the parchment background extends, showing the lines diverging even more over time.","colors":{"dominant":"beige","palette":["beige","black","brown","dark gray"]},"composition":{"angle":"straight-on","focus":"The graph is in focus.","framing":"full screen"},"mood":"scientific, illustrative","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"Change in Mass","location":"y-axis","style":"handwritten black font"},{"content":"Year","location":"x-axis","style":"handwritten black font"},{"content":"1990","location":"on the x-axis","style":"handwritten black font"},{"content":"50µg","location":"top left","style":"handwritten black font"}]}},{"t":552,"speech":"So some physical process must have actually changed the mass of the cylinders. But how that exactly works remains a matter of speculation.","visual":{"action":"The man stands in the seaside cemetery, explaining the mystery of the changing mass of the kilogram prototypes.","colors":{"dominant":"gray","palette":["gray","dark blue","green","white","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"medium close-up"},"mood":"mysterious, scientific","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"pensive, explaining a complex problem","hair":"dark brown","hands":"gesturing","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"A blurry background of the cemetery and the ocean.","lighting":"overcast","location":"seaside cemetery"},"text_on_screen":[]}},{"t":600,"speech":"One thing is for certain, the mass of a platinum-iridium cylinder is not stable over time. And this is a big problem.","visual":{"action":"The man stands in front of a background of the ocean and sky, making a definitive statement about the problem with the kilogram.","colors":{"dominant":"gray","palette":["gray","light blue","dark blue","white","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in sharp focus.","framing":"close-up"},"mood":"serious, conclusive","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"serious, looking directly at the camera","hair":"dark brown","hands":"not visible","pose":"standing","position":"center"}],"setting":{"architecture":"","background":"A blurry view of the ocean meeting a cloudy sky.","lighting":"overcast daylight","location":"seaside"},"text_on_screen":[]}},{"t":617,"speech":"Since of the seven base SI units, four of them depend on the mass of the kilogram.","visual":{"action":"A list of the seven base SI units is shown on a parchment background, with four of them plus the kilogram highlighted in red.","colors":{"dominant":"beige","palette":["beige","black","red","brown"]},"composition":{"angle":"straight-on","focus":"The text is in focus.","framing":"full screen text"},"mood":"informative, highlighting a key point","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"mol","location":"top left","style":"red serif font"},{"content":"candela","location":"middle left","style":"red serif font"},{"content":"Ampere","location":"bottom left","style":"red serif font"},{"content":"kilogram","location":"bottom center","style":"red serif font"}]}},{"t":637,"speech":"your base unit of mass, the avoirdupois pound, is no longer defined by a physical object.","visual":{"action":"A man's hand holds a small, historical-looking metal weight with a wooden handle.","colors":{"dominant":"white","palette":["white","brown","silver","skin tone"]},"composition":{"angle":"eye-level","focus":"The weight and hand are in focus.","framing":"close-up"},"mood":"humorous, historical","objects":[{"color":"silver and wood","name":"avoirdupois pound standard","position":"center","state":"being held and examined"}],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"light blue shirt"},"face":"smiling","hair":"dark brown","hands":"holding the weight","pose":"examining the object","position":"center"}],"setting":{"architecture":"","background":"a white shelf with other antique-looking objects","lighting":"soft, indoor","location":"indoors, possibly a museum or collection"},"text_on_screen":[{"content":"avoirdupois pound","location":"bottom center","style":"black serif font"}]}},{"t":645,"speech":"No, instead, it is defined as precisely 0.45359237 kilograms.","visual":{"action":"A long decimal number appears on a parchment background, showing the exact definition of a pound in kilograms.","colors":{"dominant":"beige","palette":["beige","black","brown"]},"composition":{"angle":"straight-on","focus":"The number is in focus.","framing":"full screen text"},"mood":"ironic, factual","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"0.45359237","location":"center","style":"large black serif font"}]}},{"t":651,"speech":"Sucked in. So clearly, something needs to be done to eliminate the kilogram's dependence on a physical object.","visual":{"action":"The man smiles cheekily at the camera after revealing the pound's definition, then becomes serious again.","colors":{"dominant":"gray","palette":["gray","light blue","dark blue","white","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"close-up"},"mood":"humorous, then serious","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"smirking, then transitioning to a serious expression","hair":"dark brown","hands":"not visible","pose":"standing","position":"center"}],"setting":{"architecture":"","background":"A blurry view of the ocean and sky.","lighting":"overcast","location":"seaside"},"text_on_screen":[]}},{"t":700,"speech":"And this is where the silicon sphere comes in. But how exactly does that help?","visual":{"action":"A gloved hand carefully places the perfectly round, reflective silicon sphere into a container filled with white protective material.","colors":{"dominant":"white","palette":["white","silver","light brown","gray"]},"composition":{"angle":"high angle, looking down","focus":"The sphere and hands are in focus.","framing":"close-up"},"mood":"careful, scientific","objects":[{"color":"silver, reflective","name":"silicon sphere","position":"center","state":"being placed in a container"}],"people":[{"age_range":"unknown","clothing":{"accessories":"white gloves","bottom":"","footwear":"","top":""},"face":"not visible","hair":"not visible","hands":"gloved, carefully handling the sphere","pose":"handling an object","position":"center"}],"setting":{"architecture":"","background":"a light brown wooden table","lighting":"bright, indoor","location":"laboratory"},"text_on_screen":[]}},{"t":710,"speech":"We're trying to get away from the physical object, but what we're doing with this particular object is counting how many atoms are in there.","visual":{"action":"The woman explains the scientific process, gesturing with her hands for emphasis.","colors":{"dominant":"beige","palette":["white","blue","beige","gray","green"]},"composition":{"angle":"eye-level","focus":"The woman is in focus.","framing":"medium shot"},"mood":"informative, expert","objects":[{"color":"silver","name":"silicon sphere","position":"foreground","state":"on a stand"}],"people":[{"age_range":"40s","clothing":{"accessories":"glasses, microphone","bottom":"","footwear":"","top":"white shirt"},"face":"serious, explaining","hair":"dark brown","hands":"gesturing","pose":"standing","position":"left"},{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"blue polo shirt"},"face":"listening intently","hair":"dark brown","hands":"at his side","pose":"standing","position":"right"}],"setting":{"architecture":"lab","background":"Polishing machine and tool pegboard.","lighting":"bright","location":"scientific laboratory"},"text_on_screen":[]}},{"t":725,"speech":"You can't count how many are in there, but you can calculate how many are in there because this material is silicon.","visual":{"action":"The woman explains that the number of atoms is calculated, not directly counted, due to the material's purity.","colors":{"dominant":"beige","palette":["white","blue","beige","gray","green"]},"composition":{"angle":"eye-level","focus":"The woman and man are in focus.","framing":"medium shot"},"mood":"educational","objects":[{"color":"silver","name":"silicon sphere","position":"foreground","state":"on a stand"}],"people":[{"age_range":"40s","clothing":{"accessories":"glasses","bottom":"","footwear":"","top":"white shirt"},"face":"explaining","hair":"dark brown","hands":"gesturing","pose":"standing","position":"left"},{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"blue polo shirt"},"face":"nodding, understanding","hair":"dark brown","hands":"at his side","pose":"standing","position":"right"}],"setting":{"architecture":"lab","background":"Lab equipment and a tool pegboard.","lighting":"bright","location":"scientific laboratory"},"text_on_screen":[]}},{"t":732,"speech":"So this is like a perfect crystal of silicon. That's right.","visual":{"action":"The man confirms his understanding that the sphere is a perfect crystal, and the woman agrees.","colors":{"dominant":"beige","palette":["white","blue","beige","gray","green"]},"composition":{"angle":"eye-level","focus":"The two people are in focus.","framing":"medium shot"},"mood":"collaborative, clarifying","objects":[{"color":"silver","name":"silicon sphere","position":"foreground","state":"on a stand"}],"people":[{"age_range":"40s","clothing":{"accessories":"glasses","bottom":"","footwear":"","top":"white shirt"},"face":"smiling, nodding","hair":"dark brown","hands":"at her side","pose":"standing","position":"left"},{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"blue polo shirt"},"face":"asking a question, looking at her","hair":"dark brown","hands":"gesturing","pose":"standing","position":"right"}],"setting":{"architecture":"lab","background":"Lab equipment.","lighting":"bright","location":"scientific laboratory"},"text_on_screen":[]}},{"t":744,"speech":"And why a sphere?","visual":{"action":"A man in a white lab coat grinds a grey, unfinished sphere in a bowl-like machine.","colors":{"dominant":"gray","palette":["gray","white","beige","silver"]},"composition":{"angle":"high angle","focus":"The grinding process is in focus.","framing":"close-up"},"mood":"industrial, procedural","objects":[{"color":"grey","name":"unfinished sphere","position":"center","state":"being ground and polished"},{"color":"beige","name":"grinding bowl","position":"center","state":"in use"}],"people":[{"age_range":"50s-60s","clothing":{"accessories":"","bottom":"","footwear":"","top":"white lab coat"},"face":"focused on his work","hair":"balding, gray","hands":"guiding the grinding tool","pose":"standing, working at a machine","position":"partially visible"}],"setting":{"architecture":"","background":"A workshop with various machines and tools.","lighting":"bright, functional","location":"workshop"},"text_on_screen":[]}},{"t":750,"speech":"Well, a sphere is a pretty simple object. If you know the diameter of the sphere, you can characterize the entire dimension of the object.","visual":{"action":"A graphic overlay appears on the sphere, showing a line representing the diameter labeled with 'd', while the woman explains.","colors":{"dominant":"silver","palette":["silver","brown","white","blue","green"]},"composition":{"angle":"eye-level, straight-on","focus":"The sphere and graphic are in focus.","framing":"close-up"},"mood":"educational, technical","objects":[{"color":"silver, reflective","name":"silicon sphere","position":"center","state":"stationary"}],"people":[],"setting":{"architecture":"","background":"A blurry lab background with a person in a blue shirt visible.","lighting":"bright","location":"laboratory"},"text_on_screen":[{"content":"d","location":"center of the sphere","style":"white serif font"}]}},{"t":803,"speech":"We actually start with an oversized sphere. So it was about 2 mm larger in diameter. And then we just grind it progressively finer and finer using an abrasive","visual":{"action":"A person wearing gloves uses a brush to apply a grey paste to an unfinished sphere in a grinding bowl.","colors":{"dominant":"beige","palette":["beige","gray","white","silver"]},"composition":{"angle":"high angle, looking down","focus":"The sphere and hands are in focus.","framing":"close-up"},"mood":"meticulous, scientific","objects":[{"color":"grey","name":"unfinished sphere","position":"center","state":"being prepared for grinding"},{"color":"brown","name":"paintbrush","position":"in hand","state":"applying paste"}],"people":[{"age_range":"unknown","clothing":{"accessories":"clear disposable gloves","bottom":"","footwear":"","top":""},"face":"not visible","hair":"not visible","hands":"holding the sphere and a brush","pose":"working over a bowl","position":"center"}],"setting":{"architecture":"","background":"A stainless steel bowl.","lighting":"bright, direct","location":"workshop"},"text_on_screen":[]}},{"t":819,"speech":"you're down at that level of of trying to control the shape of an object down at the atomic level.","visual":{"action":"A man in a lab coat operates a complex polishing machine with two large bowls, working on a sphere.","colors":{"dominant":"white","palette":["white","gray","silver","brown","green"]},"composition":{"angle":"eye-level","focus":"The man and the machine are in focus.","framing":"wide shot"},"mood":"focused, industrial","objects":[{"color":"silver","name":"polishing machine","position":"center","state":"in operation"}],"people":[{"age_range":"50s-60s","clothing":{"accessories":"","bottom":"dark pants","footwear":"","top":"white lab coat"},"face":"concentrating on his work","hair":"balding, gray","hands":"adjusting the machine","pose":"standing, leaning over the machine","position":"center"}],"setting":{"architecture":"","background":"A laboratory filled with equipment, bottles, and papers.","lighting":"bright, fluorescent","location":"laboratory"},"text_on_screen":[]}},{"t":830,"speech":"The diameter is actually measured by a laser. So you're actually measuring, having the sphere in the center of a cavity and the laser is hitting both sides and you're actually measuring the gap.","visual":{"action":"A close-up shot shows a laser interferometer measuring the diameter of the silicon sphere with extreme precision.","colors":{"dominant":"dark green","palette":["silver","dark green","black","gray"]},"composition":{"angle":"eye-level","focus":"The sphere and the measurement device are in focus.","framing":"close-up"},"mood":"technical, precise","objects":[{"color":"silver, reflective","name":"silicon sphere","position":"center","state":"being measured"},{"color":"gray metal","name":"laser interferometer","position":"above and around the sphere","state":"in operation"}],"people":[],"setting":{"architecture":"","background":"A dark, controlled lab environment with a green surface.","lighting":"focused, technical lighting","location":"metrology lab"},"text_on_screen":[]}},{"t":842,"speech":"By knowing the diameter, you can determine its volume. And since the atom spacing of silicon is known to high precision, you can then calculate how many atoms make up the sphere.","visual":{"action":"An animation on the sphere shows the formula for volume, then divides by the density of atoms to get the number of atoms.","colors":{"dominant":"silver","palette":["silver","brown","white","blue","green"]},"composition":{"angle":"eye-level","focus":"The sphere and graphics are in focus.","framing":"close-up"},"mood":"educational","objects":[{"color":"silver, reflective","name":"silicon sphere","position":"center","state":"stationary"}],"people":[],"setting":{"architecture":"","background":"Blurry lab background.","lighting":"bright","location":"laboratory"},"text_on_screen":[{"content":"V=πd³/6","location":"top right","style":"white serif font"},{"content":"÷ density of atoms","location":"middle right","style":"white serif font"},{"content":"=# of atoms","location":"bottom right","style":"white serif font"}]}},{"t":851,"speech":"This allows you to redefine Avogadro's constant. At the moment, Avogadro's constant is defined based on the kilogram.","visual":{"action":"An animation on a parchment background shows that the kilogram currently defines Avogadro's constant.","colors":{"dominant":"beige","palette":["beige","black","brown"]},"composition":{"angle":"straight-on","focus":"The text and graphics are in focus.","framing":"full screen"},"mood":"informative","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"kg → NA","location":"center","style":"large black serif font"}]}},{"t":906,"speech":"the number of silicon atoms in the sphere would be used to fix Avogadro's constant, which would then define the kilogram.","visual":{"action":"An animation shows how the number of atoms in the sphere can be used to fix Avogadro's constant, which in turn defines the kilogram.","colors":{"dominant":"beige","palette":["beige","black","brown","red"]},"composition":{"angle":"straight-on","focus":"The animation is in focus.","framing":"full screen"},"mood":"educational, conclusive","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"kg ← NA","location":"center","style":"large black serif font, with NA circled in red"}]}},{"t":924,"speech":"a kilogram is the mass of 2.15 * 10^25 silicon-28 atoms.","visual":{"action":"The man and woman discuss the potential new definition of the kilogram, smiling.","colors":{"dominant":"beige","palette":["white","blue","beige","gray","green"]},"composition":{"angle":"eye-level","focus":"The two people are in focus.","framing":"medium shot"},"mood":"optimistic, scientific","objects":[{"color":"silver","name":"silicon sphere","position":"foreground","state":"on a stand"}],"people":[{"age_range":"40s","clothing":{"accessories":"glasses","bottom":"","footwear":"","top":"white shirt"},"face":"smiling","hair":"dark brown","hands":"at her side","pose":"standing","position":"left"},{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"blue polo shirt"},"face":"smiling, gesturing with hands as if holding something","hair":"dark brown","hands":"gesturing","pose":"standing","position":"right"}],"setting":{"architecture":"lab","background":"Lab equipment.","lighting":"bright","location":"scientific laboratory"},"text_on_screen":[]}},{"t":938,"speech":"But there is another approach to redefining the kilogram, which involves fixing Planck's constant. And it's done using something called a watt balance.","visual":{"action":"The man stands on a grassy hill overlooking the ocean, introducing an alternative method for redefining the kilogram.","colors":{"dominant":"green","palette":["green","blue","gray","white","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"medium shot"},"mood":"informative","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"speaking to camera","hair":"dark brown","hands":"gesturing","pose":"standing","position":"center"}],"setting":{"architecture":"","background":"A grassy coastal path with the ocean and a cloudy sky.","lighting":"overcast daylight","location":"coastal park"},"text_on_screen":[{"content":"Watt Balance","location":"center left","style":"large black serif font"}]}},{"t":951,"speech":"Each one provides a check on the other. And if they show good agreement and are able to bring their uncertainties down to about 20 micrograms, they may redefine the kilogram as early as 2014.","visual":{"action":"The man continues his explanation on the coastal path, outlining the conditions for redefining the kilogram.","colors":{"dominant":"green","palette":["green","blue","gray","white","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"medium close-up"},"mood":"hopeful, scientific","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"explaining, looking at the camera","hair":"dark brown","hands":"gesturing for emphasis","pose":"standing","position":"center"}],"setting":{"architecture":"","background":"A blurry background of a grassy hill and the ocean.","lighting":"overcast daylight","location":"coastal park"},"text_on_screen":[]}},{"t":1037,"speech":"Well, if you look at a liter of water at nearly 4 degrees Celsius, it has a mass of 999.975 grams.","visual":{"action":"A number appears on a parchment background, showing the actual mass of a liter of water.","colors":{"dominant":"beige","palette":["beige","black","brown"]},"composition":{"angle":"straight-on","focus":"The number is in focus.","framing":"full screen text"},"mood":"factual, surprising","objects":[],"people":[],"setting":{"architecture":"","background":"Aged parchment texture.","lighting":"n/a","location":"n/a"},"text_on_screen":[{"content":"999.975g","location":"center","style":"large black serif font"}]}},{"t":1059,"speech":"214 years ago, scientists were able to create an artifact that was correct within the margin of error of a grain of rice. Now that is truly remarkable.","visual":{"action":"The man concludes his thought, expressing admiration for the precision of early scientists.","colors":{"dominant":"gray","palette":["gray","light blue","dark blue","white","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"medium close-up"},"mood":"admiring, conclusive","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"smiling, impressed","hair":"dark brown","hands":"gesturing","pose":"standing","position":"center"}],"setting":{"architecture":"","background":"A blurry view of the ocean and sky.","lighting":"overcast","location":"seaside"},"text_on_screen":[]}},{"t":1120,"speech":"One last thing, I should point out that it took an international collaboration of scientists to create the silicon sphere.","visual":{"action":"The man speaks to the camera in a cemetery, adding a final point.","colors":{"dominant":"gray","palette":["white","gray","green","dark blue","skin tone"]},"composition":{"angle":"eye-level","focus":"The man is in focus.","framing":"close-up"},"mood":"informative, concluding","objects":[],"people":[{"age_range":"30s","clothing":{"accessories":"","bottom":"","footwear":"","top":"dark blue t-shirt"},"face":"speaking directly to the camera","hair":"dark brown","hands":"gesturing","pose":"standing","position":"center"}],"setting":{"architecture":"tombstones","background":"Blurry cemetery background.","lighting":"overcast","location":"cemetery"},"text_on_screen":[]}},{"t":1134,"speech":"Well, in 1787, that was none other than Antoine Lavoisier. So he's been involved in the definition of a kilogram from start to finish, or from cradle to grave.","visual":{"action":"The historical illustration of Antoine Lavoisier is shown again as the narrator makes a final, clever connection.","colors":{"dominant":"beige","palette":["beige","brown","dark green","white","yellow"]},"composition":{"angle":"straight-on","focus":"The illustration is in focus.","framing":"medium shot of the illustration"},"mood":"witty, historical, conclusive","objects":[],"people":[{"age_range":"40s-50s","clothing":{"accessories":"cravat","bottom":"dark green breeches","footwear":"black shoes with buckles","top":"brown coat over a decorative waistcoat"},"face":"stoic, looking to the side","hair":"white, powdered wig style","hands":"one resting on a table","pose":"standing next to a table with scientific apparatus","position":"center"}],"setting":{"architecture":"implied 18th-century room","background":"A plain, light-colored wall with some scientific equipment.","lighting":"soft, directional","location":"illustrated study or lab"},"text_on_screen":[{"content":"Antoine Lavoisier","location":"bottom center","style":"yellowish serif font"}]}}],"created_at":"2026-05-07 07:41:30","processed_at":"2026-05-07 07:45:27","view_count":1,"thumbnail":"/data/videos/86a76faf-7870-4125-8afe-d679c04d6132/thumbnail.jpg","video":"/data/videos/86a76faf-7870-4125-8afe-d679c04d6132/web.mp4","urls":{"page":"/v/world-s-roundest-object","api":"/api/v1/videos/world-s-roundest-object","timeline_file":"/data/videos/86a76faf-7870-4125-8afe-d679c04d6132/timeline.json"}}