Pourquoi on dit que le verre est un liquide ? avec @MariannesStudio

This video is sponsored by Incogni. Do you see yourself doing a stained glass window? I think I can do it. Because look, you have the shapes well defined. You have the blue that makes the little circles. I might not have the same gradations. Yeah, that's it. Because from there to there. Yeah, and I don't know how to do that. Is there a way? Is there a way? Is it a little stained glass stylobus? Yeah. So the order is launched. I would like a stained glass, like that. I allow you to make a mini version. Ok, challenge accepted. Before sending my sister to do this challenge and learn a little more about glass on the occasion, I wanted to talk to you about the sponsor of this video, Incogni. Incogni solves an unbearable problem that I'm sure you know. Spam. I receive calls, texts, WhatsApps that are just spam. And of course, I never gave them my number. No, they bought it through what we call data brokers and whose job it is to recover personal data and resell it to other companies without us knowing it. And even if I'm super careful about what I give as information and to whom, it's impossible to be in total control. And that's where Incogni comes in. Because we still have the right to ask to be removed from these lists. But you have to know which lists we exist on, you have to find the procedure to request the suppression of our personal data, you have to harass them until they do it, and you have to start again every month for all the lists to which we have been added in the meantime. It's hell to do by hand. And that's what Incogni does automatically. It's been more than a year since I signed up on their website and I see the list of data brokers they have removed from me or which they are still relaunching to delete my data. And clearly, I did not sign up to any of them voluntarily. And I would not have known that it was with them that I had to unsubscribe. If you are interested in trying to get rid of these damn spams, you have a 60% discount on the annual subscription to Incogni by going through the link in the description or with the code SYLLABUS. Now I give the microphone back to Marianne. If I tell you stained glass, what comes to mind, I'm sure, it's the windows of churches. But stained glass in itself is a panel made up of pieces of colored glass which are then assembled together, either with tin or lead. That's all. Then, depending on the region, you can also see it either in houses or in the head of a store, for example. And it's even something you can do yourself at home, on a smaller scale, if you're a little crazy like me. So I'm not going to lie to you, I was looking for an excuse to talk to you about stained glass on Syllabus. And I quickly found, in fact, by doing online research on glass, there is a sentence that comes up all the time. The glass is a liquid. Uh, sorry. I specify, we are well on Syllabus there. Me, it's Marianne, hi. I just replace Viviane the time of a video because I'm a little busy right now. But still, I'm going to do my best to embody the character and follow, me too, a rigorous scientific approach. So, first step, we're going to do an experiment to determine whether the glass is a liquid or not. According to my observations, the glass has a firm consistency. So it's a solid. Well, but if it's so obvious that the glass is not a liquid, why does everyone seem to be asking the question? In fact, the categories are complicated. The fact of saying the glass is a liquid or the glass is a solid, it's less easy than it looks. As soon as we try to define a thing, we find ourselves a little stuck by the definitions we adopt. For example, in this article from 2017, which won an Ig Nobel, the author demonstrates that, by their property, cats are liquids. We agree that this is not a liquid, it's a pile of hair. But this kind of article, what illustrates it very well, is that according to the definition we take, we end up with completely different categories. So, what about the glass? What strange definition do we have to take to make it a liquid? By digging a little bit, I understood that this liquid glass thing is actually a matter of molecular arrangement. So the glass, when we look at how it is structured inside, it's a mess. In fact, in the same way that a liquid has its molecules scattered in all directions, since a liquid moves, the molecules of the glass are also scattered, except that they don't move. And this is a very particular property of the glass, keep it in mind, we'll come back to it. So, concretely, how do we end up with a solid which has the molecular arrangement of a liquid? The glass is formed like this. We take a solid material, like sand, we melt it at more than 1000°C, and there, now that it's a liquid, BAM! It's hot! We cool it down quickly, and it becomes glass. And it's because this cooling is done so quickly that the material doesn't have time to store its things or to arrange its molecules properly. And that's how we end up with a material that has its molecules in a mess. The materials with the molecules in a mess, we call them amorphous, so without shape. Obviously, the object itself has a shape, it's at the molecular scale, as it goes in all directions, that we consider that the shape is not really defined. Besides, the glass is not something that humans invented, it's something that we find in nature. And in particular, there is a natural phenomenon of madness that shows this wonderfully, the fulgurites. If you don't know it, I promise you'll like it. It's formed when the powder falls on a rock, it raises the temperature of the rock to thousands of degrees, but on a very, very, very concentrated surface, and it looks like this. Here are the fulgurites, it's glass created by the powder. Ah, shit. Well, I tried the devil. I really had a very, very marked curve. I didn't take it well, and suddenly, my piece is... It's completely broken in the middle. So, I'll have to trace it again. Fortunately, I still have a small drop of glass. And try to do better next time. If I take back my glass, which has its molecules in a mess, the liquid material becomes glass because it is cooled very, very quickly. Okay, but if we gave it time to cool down quietly, what would happen? In fact, when the liquid material cools down little by little, there are atoms that prefer to go with each other. And then, as time goes by, we have a crystal that grows, grows, grows from the outside, with all the bricks that go in the right place. So there, I said crystal, not glass. The glass cools down quickly, while the crystal puts chandeliers at low temperatures. And since the crystal takes its time, these molecules have time to coordinate in a super-orderly way. We have the same structure that repeats itself infinitely. Unlike glass, it is extremely well arranged. The crystal is Marie Kondo, and the glass, well, it's all the people who buy Marie Kondo's book. There you go. We're going to compare. Basically, if I superimpose my little piece of paper on my glass sheet, it should stick together. I have to accentuate the curve here, and we're going to be good. I wanted to know more about these crystals, so well arranged, so I went to ask Valentin from Sciences de Comptoir to tell me about it. Basically, there are, let's say, seven forms, of which all the crystals we know are derived, including the hexagonal rhomboid. Anyway, there are seven large facies, we say, of minerals. You have to imagine yourself a bit like a sculptor, that is, the diamond, when you see it, you don't think it's a cube. In fact, it's derived from a cube, so you have a cube, and then you carve facets in it. Well, it's nature that carves facets in it, and in the end, we get to the shape of a diamond that we know. Even if nature doesn't carve facets, in fact, it works the other way around. It grows, rather than carving things. The crystal is the opposite of glass, so it's really a bit like Lego pieces that you would put on top of each other, so it's actually a pattern that repeats itself in the three directions of space. It's an organized structure, while glass is really completely in pieces. And I think that, in terms of minerals and so on, it's the only one that's really in pieces. Like that. To sum up, glass is a liquid that didn't have time to become a crystal, to put it bluntly. These molecules, they would have liked to order themselves in order to reach the minimum energy position, like crystals, but they just didn't have the time. If we go back to my question earlier, why do so many articles insist that glass is a liquid, when it's not? Well, it's because the disordered molecular structure means that technically, yes, it could flow, but over several billion years. Here, we are on a geological time scale. Even us, after a few centuries, we wouldn't be able to see the difference. So, people who tell you that, yes, the old church windows are thicker at their base than at the top, and so, it's proof that glass flows, no, that's not it. It looks like it's more due to the fact that, in the medieval era, the glass sheets that were produced were not all of the same thickness, they were maybe not as well rounded as they are now, and so, out of concern for stability, we put the thickest sheets at the bottom. That's all. The knowledge in stone that we have today, we owe it to him, Abbot René Haoui. He founded the field of study of crystallography in the 18th century, and frankly, the story of how he discovered the well-arranged structure of crystals is just as crazy as the idea of being a stone enthusiast. Legend has it that he was playing on his desk with a mineral of calcite, like this one, and then, he's clumsy, he dropped it on the ground. You see the shape it has? It's what we call a rhombohedron. Basically, it's a parallelepiped that's not straight. He took a truck that's a little tilted. And what he did when he dropped his mineral, he realized that it made a lot of small crystals of the same shape. And he said to himself, wait, if I keep dropping them like this, how far can I go? And so, he hypothesized that at first, we had an elementary mesh, so the shape you see there, there was the same thing, but at the level of the atoms. And this primordial motif, basically, this motif that repeats infinitely in a crystal, that's what he called the integrating molecule, and which was later called elementary mesh. So that's really the founding principle of crystallography. And it's a Frenchman who had the idea, so it's a bit classy. Conclusion. The glass is a liquid, yes or no? Well, let's say yes, if we look at its crystallographic arrangement. But for us, poor mortals, no, it's insolid. Okay, but before I show you the result of my glass, to you and Viviane, I have to tell you about something, about an incalculable coolness, the Uraline. So there, if there are any of you who are very hippie, new age, magical lover, you're going to go crazy. Imagine a magical object of video games that would emit a mystical glow, which means 100% that it's a cursed object. Well, here it is, Uraline, it's radioactive, fluo green, there's uranium in it. And in addition, we have a lot of Uraline objects that are for sale at antique shops, because it was very fashionable in the second half of the 19th century. Apparently, it's not too dangerous for your health, but anyway, if you want to know more, Dr. Nozman made a whole video on the subject, go see it, it's crazy. Are you ready? I'm ready. I can't wait to see it. Wow, nice. That's it. It's so good. It's super beautiful. Not bad, right? But how did you... It must have been so hard to manage the gradients. Yeah, the gradients, so... I had to choose where to cut the blue, the red and all that. Then there's a type of green, the red at the top, which is a slightly degraded red itself, where there are slightly orange colors in it. So it also allows you to modify the colors a little bit. Wait, if I put it on you... Wait, put the word in the sun, yeah. There, like that. Ah, yeah, yeah. Hey, what you did is super beautiful, Marianne. Thank you. Here it is, the little syllabus panel. Bravo. How long did it take you to do that? I think 10 to 15 hours, something like that. Okay, still. Super beautiful. Bravo, Marianne. Thank you. If you liked seeing the creation process of my stained glass, I invite you to come to my channel, Marianne Studio, where I talk a lot about art, artistic creation, all that. So it's in English, but feel free to take a look and see if you're interested. Anyway, thank you in advance for your kindness. It's not easy to replace Viviane, but I hope you had a good time anyway. Anyway, I really enjoyed making this video. So, see you next time. Bye.