Lecture - 03 - Summer Batch (Demo) - OL/IG O/N '26 & M/J '27 Live Class Solids,Liquids & Gas KPT

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[00:00:00][sighs] Hey everybody, we're live and in studio.

[00:00:04]So up until now we started talking about the concept of what? We started talking about the concept of an atom. And we learned that an atom is the basic unit of what? Of matter. And now we all know what matter is. What is matter? Matter is anything which has a mass and occupies space. And so the teeny teeny tiniest particle which will make matter up as of now is called an atom. And then we also learned what an element was.

[00:00:29]What was an element guys? It was a pure substance. Anything written in your periodic table, elements are pure substances. And the reason why they call them elements is because they all are made up of one type of atoms. And your periodic table has what? It has elements. Even H2, O2, N2, Br2, I2, Cl2, all of these guys, F2. Although you can see two atoms combined, two two two atoms combined. Since they are made up of one type of atoms which is hydrogen, oxygen, nitrogen, bromine, chlorine, florine, they're all what? They are all called elements. And by the way, they're all pure substances. And we also learned the concept of a compound. What are compounds? Compounds are also pure substances which are which forms when pure substances which form when two or more elements chemically combine. Two or more elements chemically combine. Now what do we mean by chemically combine?

[00:01:26]And you know all of this good stuff. You learn that in chapter 3. Yeah. And molecules we studied that molecules were when two or more two or more atoms combined be it the same atoms or different atoms. So two or more atoms combined. And you will learn more about compounds and molecules in chapter number three. Okay.

[00:01:50]Now today we are officially going to start off with our first chapter which is called states of matter. Now what exactly is matter? G everybody anybody what exactly is matter? This is chapter number one of your syllabus. What exactly is matter? But g sir I don't know shafir and this dal available. No I'm joking. What is matter? Matter is anything which has a mass and occupies space. So if you look at your human body, you guys have mass, you occupy space, so you are matter. The table, the chairs, everything has matter.

[00:02:24]Everything is matter effectively, right?

[00:02:26]The the AC remote, the pencil, the pen, the AC, everything, the iPad, the table, the mobile phone, everything, they are all matter because they all have mass and they all occupy a certain space.

[00:02:36]Now, chapter number one talks about states of matter. States of matter. So anything which has a mass and occupies space, they have certain appearances.

[00:02:48]They have certain forms or certain appearances which we call states of matter. I'll give you an example. For example, water. Water is matter. Why?

[00:02:57]Because it has a mass and it occupies space. But if you look at water, because it's matter, it also has a certain appearance. And we all know the appearance for water, which is what? It is a liquid appearance aka a liquid state. But if you look at the same water, the same what is water? Water is H2O by the way those who don't know it's H2O. Two hydrogen's bonded to oxygen.

[00:03:21]Can I call this a compound? Can I call H2O a compound? Absolutely I can. Why?

[00:03:26]Why is H2O a compound? Because it is two elements chemically combined together.

[00:03:30]One is hydrogen, the other one is oxygen. Done. So it's a compound. And so if you look at water, the state of water, the form of water is liquid. But then if you take the same H2O, if you take the same H2 and you represent liquid with an L. But if you take the same H2O and you freeze it up, it becomes ice. And ice is the same H2O.

[00:03:52]It's the same matter, but it has a form, a different form. This form is called the solid form. And then you have the same H2O. The same H2O. But now I'm going to take it. I'm going to take it and I'm going to start heating it, heating it, heating it, heating it so much that it becomes steam, you know, bop.

[00:04:13]And this steam is also a different appearance of the same matter, which is what? Which is a gaseous appearance, isn't it? So you realize that matter, they're all H2O. This is also H2O.

[00:04:25]That's also H2O. That's also H2O. But they have different appearances. One is a liquid appearance. The other one is a solid appearance. The other one is a gaseous appearance. So we realize that all matter, anything and everything which has a mass and occupies space, they have different forms and those forms can either be liquid, solid or gas. It's the same matter but it can have different forms. That's why chapter number one is called states of matter which is different appearances of matter. And these are the three states of matter that we study in O levels and in A levels. Also, fun fact, you should know that there are about more than three states of matter. You shouldn't know it, but hey, there's ionized plasma, there's quagluon plasma, there's bor Einstein condensate, there's fmonic condensate. Nobody cares. You only need to know the three states of matter, please. There are many more states of matter, but in OA levels, we couldn't care less, right? So, we are only concerned about the three states of matter. That's for sure. Now the question should be K why is H2O a liquid in the form of water? Why is H2O when it's ice? Why is it solid? Why is H2O when it's steam? Why is it a gas?

[00:05:37]Has anybody asked themselves this question? Why?

[00:05:41]Why does H2O appear in these three forms? G does anybody know why H2O appears in these three forms? It can appear in a liquid state. It can appear in solid state. It can appear in gaseous state. Why? Nobody has asked themselves just oh H2O to water can water is liquid. Ice is solid. Steam is gas. But why? Why? Why? Why? You know and the answer to that is called the kinetic particle theory. I call it KPT. Kinetic particle theory states that hold up before you learn about these three states you should know why these three states exist in the first place. And kinetic particle theory says that all matter all matter is made up of teeny teeny tiny particles.

[00:06:35]And these teeny teeny tiny particles can be atoms, they can be molecules, they can be a lot of other things. Right? So kinetic particle theory says that all matter is made up of tiny particles and the only particle tiny particle that we currently know of as O level IGCSC students is what it is atoms. So it says that since matter is made up of teeny teeny tiny particles, it also these teeny teeny tiny particles also has a certain motion and also has a certain arrangement and it also has a certain particle separation Pep particle separation which results in particles either being liquid or solid or gas. Sir, what do you mean by this? I tell you what I mean by this is okay what is the state of water? Water state is what guys? G water water is liquid which we represent with an L with an L loser. Solid is represented with an S state symbol and gas is represented with a G state symbol. Now water is a liquid.

[00:07:41]Why is water liquid? Kinetic particle theory says that water is a liquid because the teeny teeny teeny tiny particles which make water up are in such a motion and has such an arrangement and has such a particle separation that it results in water being a liquid. The reason why ice is a solid, the reason why ice is a solid is because the teeny teeny tiny particles which makes up ice have a certain motion and a certain arrangement and a certain particle separation that results in ice being a solid. Why is steam a gas? G you guys now tell me why is steam a gas?

[00:08:21]It's the same H2O. But why is steam a gas? Because the teeny teeny tiny particles which make up steam have a certain motion have a certain arrangement have a certain particle separation that results in steam being a gas. Now the question should be what should be your question? What should be your question sir? What is that motion?

[00:08:39]Shouldn't it be? You guys should all be curious. What motion? What arrangement?

[00:08:43]Not the loose motions guys please. But what motion? What arrangement? What particle separation are we talking about? You know what particle separation? What motion? What arrangement are we talking about? Why is chair a solid? The reason why chair is a solid is because the teeny teeny tiny particles which make up chair have a certain motion, have a certain arrangement and a particle separation that results in chair being a solid. But why? What is sorry but what is that motion? What is that particle separation? What is that arrangement or arrangement is also known as structure.

[00:09:16]What is that structure or arrangement?

[00:09:19]The question is I don't know for now I don't know. As an O level student, you shouldn't know this as of now. You'll learn it in a moment. Before you learn what that motion, particle separation, and arrangement is. I want you guys to know certain properties. These are basic properties. But I don't know why students are not taught this in elementary classes. I want you guys to know certain properties of solids, liquids, and gases through just observation. I want you to first observe solid, liquids and gases and I want you to determine certain properties for them. Right? And you all will determine it on your own. I'm just going to be guiding you. I'll tell you how you can determine it on your own.

[00:09:59]Okay? So, first of all, let's observe some properties and then we look into why solid is a why something is a solid.

[00:10:06]Why something is a liquid? Why something is a gas? You already know why. It's because of the motion arrangement and particle separation of those tiny particles. But what exactly is that for a liquid? for a solid for a gas. We'll learn that in a moment. Okay. But before let's talk about certain observations.

[00:10:21]Now let me add something here. I want to add something. I want to add a a beautiful picture for you all. Hold up.

[00:10:29]I want to add something. Mike Wazowski.

[00:10:33]I want to add something guys. Hold up.

[00:10:36]Mhm. Just give me a moment. Just give me a reason. Just a little bit enough. just the thing, baby. So, I want to add this good picture right here. And the reason why I'm adding this is because I want you guys to do something for me. I want you guys to look at the shape. I want you guys to look at uh volume. I want you guys to look at compression.

[00:11:01]And I want you guys to look at density.

[00:11:08]And I want you guys to tell me this for solids. I want you guys to tell me this for liquids. I want you guys to tell me this for gases. And what are we going to do? We are just going to use our teeny tiny brains. And those brains are going to be used in our in our observations.

[00:11:25]Let's use our brains. Let's use them. So if I look at a solid, if I ask you solid has a certain shape. Yeah, it's good if you make your own notes. That's my recommendation. All of this will be uploaded at the end of every chapter.

[00:11:38]These notes will be uploaded. But my recommendation is That's my recommendation. So if you look at solids, liquids and gases, if I first ask you Kr, what is the shape of a solid? What that means is that question means is it does it does a solid have a fixed shape or is it not a fixed shape?

[00:11:59]Now I want to give you guys an idea. The chair that you are sitting on today as of now or the table that you are sitting on as of now tomorrow when you today when you go to sleep and tomorrow do you when you wake up does the shape differ does the shape change on its own the door that you have right here the the walls that you have you wake up the next morning and the shape has different oh my god it does not have a fixed shape it's different today it's different it looks like a Pokemon today it looks like a unicorn tomorrow yeah does that happen to you guys absolutely Not that doesn't happen to us do it does it? So you realize if I ask you about the shape of solids so do you say solids have a fixed shape or do they not have a fixed shape?

[00:12:42]G everybody says everybody's right solids have a fixed shape. You can also call fixed as definite.

[00:12:51]And this is just through observation.

[00:12:53]I'm not giving you any reason for it.

[00:12:55]I'm just saying when you look at a solid does the shape change? If you take a chair, if you take a big fat chair and it's in your room and tomorrow you put it in the dining room and day after tomorrow you put it in a container and day after tomorrow you put it in the lounge. Does the shape of the solid change? Does the shape of the solid change when you take it from the lounge and put it into a container and then put it into somewhere else? No, it doesn't.

[00:13:16]So, it has a fixed shape. It has a definite shape. Great. Next, if you look at the shape of a liquid, now this is something this is something very interesting. This is something Bruce Lee also said. But if you take a liquid like for example water and you pour it into a jug.

[00:13:33]If you take water, sorry this is a pathetic jug. But if you take water and pour it into a jug, what happens to water? Because water is a liquid.

[00:13:40]There's something so special about a liquid which is the fact that when you put a liquid in when you pour a liquid into the jug, it becomes the jug.

[00:13:49]Becomes the jug. When you put it into a cylinder, when you put a liquid into a cylinder, it becomes the cylinder.

[00:13:56]That's what Bruce Lee said. Okay?

[00:13:58]Whenever life throws curve balls at you, you become be like water. That I don't know if you know Bruce Lee, guys. He was a guy, he was a man of our time. Bruce Lee is was one of the you know famous jiu-jitsu person. So Bruce Lee used to tell students, become water, my friend.

[00:14:13]If you pour water into a cup, it becomes the cup. If you pour it into a jug, it becomes the jug. If you pour it into a cylinder, it becomes the cylinder. What he meant by this was if you take any liquid, it will take the shape of the container. He wanted people to be flexible in their lives. So what you realize is that liquids, they don't have a fixed shape. By the way, if you pour it into a cup, it becomes the cup. It takes the shape of the cup. You know, like chai, if you pour chai into a jug, it will take the shape of the jug. If you pour it into a cup, it'll take the shape of the cup. So you ask water or liquids they have a they don't have a fixed shape. So their shape is not fixed. And you tell the examiner this you say it's not fixed. And what do you say? You say it takes shape of container. That's what you tell the examiner all the time. So you say okay it's not fixed and you describe it. You say it takes the shape of a container.

[00:15:13]Yeah. But if you take a chair and you put it into a big container, it'll still be a chair. The shape is the same. If you put it into a small container, if you put it into a bathroom, it'll still be a chair. It wouldn't change, would it? Yeah. Now, last but not least, if you if you look at gases, gases, if you fart inside the washroom, the fart is going to take the shape of the washroom.

[00:15:36]You know, if you fart if you fart inside your room, it'll take the shape of that room. So gases also they do not have a fixed shape. Sorry girls for being disgusting. Boys drool.

[00:15:50]Yeah. You know if gas is inside a syringe it will take the shape of that syringe. So gas is also not. That's why gas can gas can you know reach your nostrils.

[00:16:04]Now let's talk about volume. My question to you is if you have a a cube, if you have a cube and it's a solid cube, does it have a fixed volume?

[00:16:18]Absolutely. Let's suppose the volume of a cube is maybe if you've studied in your math. Let's suppose it's 100 cm cube. The volume of cubes L into L into L. It's 100 cm cube. Does this volume change? If you if you if you take this cube, does the volume of this cube change? No, it's just mathematics. Your L into L into L the volume of solids are fixed. Solids volume, they don't change, do they? It's just a fixed volume.

[00:16:44]That's all. It has a fixed volume.

[00:16:48]You know, just like a chair, a table, you you can ma mathematically calculate it. Let's also talk about water. This is where a lot of students make a mistake.

[00:16:57]This is where a lot of students make a mistake. Now my question to you all is if you take a cup and you pour 5 cm cube of water into that cup 5 cm cube of H2O liquid into that cup which is water and then you take the uh a cylinder and you pour the water from this cup into this cylinder into this beautiful cylinder right so firstly I poured it into a cup second case may I poured it into a cylinder pay very close attention here guys Pay very close attention. My question to you is what happened to the shape of water? When you put it into a cup, it becomes the cup. So, it took the shape of this cup. When you took the same water and pour it into a cylinder, it took the shape of the cylinder. It is not fixed. The shape is not fixed. But if I say what will happen to the volume of water? What happens to the volume of H2O? If it's in a cup, it will be the same 5 cm cube. If it's in the cylinder, it will be the same 5 cm cube volume.

[00:18:05]If it's the same five drops, let's suppose you have five drops of water inside a cup. If you pour it into a cylinder or if you pour it into a jug, what will happen to that five drops?

[00:18:14]It'll still be five drops, wouldn't it?

[00:18:17]It will obviously change its shape, but the volume will be fixed, wouldn't it? it'll still be the five drops.

[00:18:25]Otherwise, if this was the case, you could have solved the water problem in Africa. What you could have done is you could have took a you could have taken a five drops of water in a cup and then you would have poured it into a tanky and voila Africa cuz that 5 cm cube would apparently become 5,000 cm. That's not possible, is it? So Africa the volume of water is fixed. It doesn't change. Yes, the shape changes but the volume is the same. I hope it made sense. Huh? So it has the it has a fixed volume or a definite volume. Please keep that in mind. But the shape is not fixed. This is a very basic concept that students in even in A levels they mess up. I swear I don't know how. Remember Africa. But gases, gases are on a whole new level.

[00:19:18]Gas is car the volume isn't fixed and the shape isn't even fixed. The shape isn't fixed and the volume isn't fixed.

[00:19:24]Because if you take a gas, it will and and you fart inside a room, it will take the shape of that room and it'll also take the volume of that room. If you fart inside the washroom, sorry guys or girls for being a if you pour if you use perfume inside the washroom. But happy.

[00:19:38]So if you use perfume inside the washroom, it'll take the shape of that washroom and also take the volume of of that washroom. Right? So gases volume is not fixed. Just like its shape, the volume is also not fixed. This is states of matter.

[00:19:56]Next, compression.

[00:20:00]Compression.

[00:20:02]What is compression? Now this is a physics concept but in chemistry you need to understand compression a little bit.

[00:20:10]Compression what exactly is compression guys? It's very basic. Compression is the reduction in volume when you apply force or pressure by applying force or pressure.

[00:20:32]This definition is not going to come in your exam by the way. I'm just saying that's what compression is. It's the reduction in volume. Okay? It's the reduction in volume. This is the key term. Whenever I say something is being compressed, the volume is being reduced.

[00:20:46]Why? Because you are applying force or pressure to it. Now, if I look at solids and if I look at liquids and if I look at gases, the only way I'll be able to understand compression is because is if I am able to visualize them. That's why I added this picture right here.

[00:21:03]Now, why would why would there be reduction in volume in the first place?

[00:21:08]That's the question. Why would why would there be reduction in volume? The reason why there would be reduction in volume is if is if the solid particles had spaces between them, right? If solid particles had spaces between them, you could apply force and reduce their volume even further. But the question is, are solid particles having spaces?

[00:21:33]Do solid particles have spaces? Look at them. Just observe them. I don't want to go into the chemistry for it. I just want you guys to observe it first. Tell me, do solid particles have spaces in between them? Absolutely no. There are no spaces. So my question is, is there going to be a reduction in volume if you apply force? If I apply force here, is there going to be a reduction in volume?

[00:21:55]The answer to that should be no. So can solids be compressed? The answer should that to this should be no. We call it incompressible.

[00:22:05]And this is one of the most favorite questions of the examiner in your O level IGCSE is okay. Why are solids incompressible? Why? Because there are no spaces between solid particles.

[00:22:24]This is the reason for it. There are no spaces. That's very basic, isn't there?

[00:22:27]You know, cuz you know, compression is reduction in volume. And the only way volume would reduce if there were spaces between them, you could push them further closer together. But you can't cuz there are no spaces. Let's look at liquids. Look at liquids. Liquid particles, they are close together. But can't you can you see some spaces here?

[00:22:44]Can we see some spaces, guys? Please.

[00:22:46]Yes, we can see some. Liquid particles are very close together just like solid.

[00:22:50]They're very close together, but there are slight spaces between them. It's slightly separated. You know the particles are very close but slightly separated.

[00:22:59]Now if I apply force guys, if I apply force, would these particles come close together and the volume be reduced? The answer to this should be yes. As part of you know science students, your answer should be yes. But in O level and IGCSE your answer will be no. Why? I'll tell you why. You will say liquid particles are also incompressible. They're almost incompressible. Do you know why? Because there are they are also the liquid particles are also very close together.

[00:23:34]There are literally literally very few spaces between them. So you say the particles are so close. Okay, it's also incompressible.

[00:23:44]And you might think but sir, no. Can't liquid be compressed because there are spaces. So wouldn't these spaces reduce?

[00:23:50]The answer to that is yes guys, yes they would. But for this you need to apply a lot of force, a lot of pressure and that force and pressure you learn in university.

[00:24:03]So before you reach university and think sir Sulman lied to you. I told you the reality here. Liquids can also be compressed guys but at university level.

[00:24:12]In orals liquids can't be compressed because the liquid particles are also very close together. There are slight spaces but for this you need to apply a huge force and the force you learn in uni. So we say hey liquid particles can't be compressed then but no one says lied to us when you go to unis. I have not lied. I've told you the truth but I said it requires so much force that's why it is almost incompressible. Done.

[00:24:38]So in the exam if the examiner asks is is liquid incompressible? You say yes it is because the particles of liquids are also very close together. There are minimal spaces. There are there are literally you say there are almost you say there are almost no spaces. This is what you say. Hey, you tell the exam there are almost no spaces between liquid particles.

[00:25:08]Almost no spaces.

[00:25:11]Yeah. Ibrahim just a moment please. Let me finish this first then I'll take your question. Next, let's talk about gases. Oh, let's talk about gases. Look at gases.

[00:25:24]Are there spaces? Are there spaces?

[00:25:28]Yeah, man.

[00:25:33]Are there spaces between gas particles?

[00:25:35]Come on, use your brains, guys. Use your brains. Yes. Oh, who saying no? Why?

[00:25:40]Look at this particle and look at this particle. Gas particles are so far from each other. There are large spaces between these gas particles, aren't there? Abdullah moment, please. There are large spaces between gas particles.

[00:25:51]I'll take your questions, guys. Just give me let me finish this. Huh? There are large spaces between. Look, one particle is in the east, the other is in the west, the other is in the south, the other is in the beast, you know, beast west but yeah, so there are large spaces between gas particles. And so if I apply force these particles can be that they can be they can be pushed closer together. Why? Because they have large large spaces between there are large spaces between gas particles. And you know what they are called? If you want to sound more bougie, you could say there are large inter intermolecular spaces. Intermolecular means this is one molecule, that's the other molecule. So between these molecules, these are called intermolecular between them. So you can say there are large intermolecular space. If you want to sound bougie, if you don't, you can just say there are large spaces between gas particles.

[00:26:48]Hence, gas particle is easily compressed.

[00:26:56]Done. And last but not least, and then I'll take your questions. Last but not least, density. Now, density is a concept that you learn in physics. It's not part of chemistry by the way.

[00:27:07]Density guys is not part of chemistry at all. At all.

[00:27:14]It's not. Now, before we talk about density also, compression, reduction in volume by the application of force. And why would volume reduce? Ask yourself, why would volume reduce G? Now you guys can answer this. Why would volume reduce? Because of because of spaces between particles. So it's the reduction in volume because of spaces between particles.

[00:27:38]And that's why solids and liquids they are not compressible. They are incompressible because there are they are there are almost no spaces for liquid particles and almost and obviously for solids there are no spaces between solid particles. But gases may there are spaces and I can even show it to you right here. You know one fart molecule is here the other one is here.

[00:27:58]Just then just give me a moment. I'll answer your I'll take your question.

[00:28:01]Huh? Okay then.

[00:28:04]Next let's look at density. Density.

[00:28:09]Density. Density is not part of O levels and IGCSC chemistry. But for now I just say density is how much mass you pack in a certain amount of volume. how much mass you pack in a certain amount of volume. For example, the volume that you have right here.

[00:28:32]This is the volume of a solid. That's the volume of a liquid. That's the volume of a gas. Right? Now, solids, they'll have many many many particles.

[00:28:42]Let's suppose the volume is 10 cm cube.

[00:28:44]Let's suppose the volume of the container is let's suppose 10 cm. In all cases, it's 10 cm cube. Let's suppose in all cases let's assume that in all cases the volume is 10 cm cq. But in solids you'll have these many particles. In liquids particles will look something like this. And in gases you'll have particles like this. Right? Now my question to you all would be KR which guy is going to have the highest density. Density is how much mass you pack in a certain amount of volume. Now if the volume is the same this is also 10 cm cube. This is also 10 cm cube.

[00:29:15]This is also 10 cm cube. Which guy will have the most mass? G I want you guys to understand density from the perspective of particles. In physics, you'll learn more about it. But in chemistry, you learn about particles. So look at solids. In the same volume, solids have how many particles? Solids have more particles compared to liquids and gases, don't they? In the same volume, solids would have more particles. Why? Because they are close. They're very close. So you can pack in more particles. And more particles mean what? More particles mean more mass.

[00:29:49]More particles mean more mass. So if you have more particles that would mean more mass and more mass means what? Greater numerator. And greater numerator would mean what? A higher answer. A greater answer. You know let's suppose the mass here is 5 g because of more particles.

[00:30:06]The mass here is let's suppose 2 g because of fewer particles. And let's suppose the mass here is 0.5 g because of the fewest number of particles in the same volume. If you want to calculate the density, how do you do it? You say, okay, for solids, it is 5 g over 10 cm cube. For liquids, it will be 2 g over 10 cm cube. For gases, it will be.5 g over 10 cm cube. Which guy would give you the highest or the biggest answer?

[00:30:29]The one that has a higher numerator in this case. So obviously solids have the highest density. Where did everything go? Oh, sorry. Here. Solids have the in chemistry you just need to know. Soils have the highest density. Liquids have gases have the lowest densities and liquids have higher density than higher density than gases but lower than solids.

[00:31:04]And that's it. Then and why why is this the case? Because solids have more particles. Solids have more particles in the same volume compared to liquids and gases. That's the reason. But do you need to know this? Why? The answer is no. Any questions, guys?

[00:31:28]We can move forward.

[00:31:31]G. Ask away guys. I'll pause the recording right now and you guys can ask your question. Genius. Okay. So, Zan has asked such a beautiful question. Zan is a a genius. He has sitting amazing. I love it. I love students who ask such questions. Zan is saying, "Sir, you are saying the solids were incompressible, right? But sir, when I looked at some YouTube videos in that you see a lot of hydraulic presses, you know, taking an iPhone, you put an iPhone right here below the hydraulic press and when the hydraulic press, you know, comes down on it, the iPhone gets it gets everything gets broken. You know what the hell, sir? What the hell?

[00:32:09]That's true. There's some there's there's a difference between something being broken, you know, something being broken into pieces. If you break an iPhone into multiple pieces, that does not mean it has been compressed. Compression is a concept that happens on a very molecular level. You can break a solid. You can take your iPhone and break it into two pieces. Then you can take an iPhone and break it into two pieces. You can go onto your TV and you can smash the TV with a baseball bat and break it into pieces. That's not a reduction in volume. You know that is not compression because compression means reducing the spaces between the particles on an on a molecular level. You're just breaking them. You're not reducing the spaces between them on a molecular level because on a molecular level they're already close together. You can snap a solid off. I can snap this solid off into two. But still what will happen?

[00:33:04]The particles are still close together.

[00:33:05]I can't compress it. You know I can reduce the volume by breaking it into two. But that's compression is it? Zan is a genie. Next question guys, I'm going to pause the recording again cuz a lot of students recording.

[00:33:19]Okay, so this part is done. Now let's talk about let's talk a little about let's talk about a little about the kinetic particle theory again. Now kinetic particle theory states once again I'll recap it. Kinetic particle theory states that the reason why something is a solid, the reason why something is a liquid, the reason why something is a gas has to do with the fact that has to do with the fact that the teeny teeny tiny particles which make solid, liquids and gas up, they have a certain motion, a certain and a certain arrangement and also a certain particle separation, right? But it mainly focuses on motion arrangement or chemistry particle separation. So if I ask you why does this should be your question now your question should be sir oh my god why does why does why does a solid have a fixed shape why does it have a fixed volume why is it incompressible why you've learned the idea of compression but why does solid have all these properties why does liquid have all these properties why does gas have all these properties the idea lies within the kinetic particle theory it's because something is a solid why is something a solid it's because it has a certain motion arrangement and a particle ical separation that makes it into a solid.

[00:34:34]Why is something a liquid? Is because it has a certain motion arrangement, particle separation that makes it into a liquid. Why is something a gas? Is because it has a certain motion arrangement and particle separation that makes it into a gas. Sir, oh my god, can you stop with the suspense? Can you actually tell us okay what is the motion? What is the arrangement? What is the particle separation? And the answer to that is absolutely I can. So, we're going to write solids, liquids, and gas again. And today, for the first time in your life, you're going to know why something is a solid, why something is a liquid, and why something is a gas. Up until now, you only knew, okay, something is a solid, something is a liquid, something is a gas. You only knew the properties for it. It has a fixed shape. Even those properties weren't clear to you. But now you will learn the real idea why something is a solid. Again, why would something be a solid? Kinetic particle theory. Kinetic particle theory is a is a beautiful theory. But in your course you just need to know Hajra just a moment please in your course you just need to know the kinetic particle theory tells me actually it helps me realize why something is a solid why something is a liquid and why something is a gas and what's the reason for it the reason is the arrangement the motion and the is the arrangement the particle separation and the and the motion right now. Why exactly is something a solid? Let me show you the picture once again.

[00:36:07]It's you guys know the answer to this. I will just be showing you the picture and you will answer it on your own. I promise you will. Now, arrangement and structure are the same thing. So you could say arrangement or you could say structure.

[00:36:23]Then you could say structure and or you could say arrangement. G. Now if you look at a solid, can you see a pattern? Can you see a pattern? G. Yes or no? Can [clears throat] you see a pattern? Just answer this. Can we see a pattern?

[00:36:40]Yeah, we can see a pattern. Can't we?

[00:36:42]Look at this beautifully arranged. Look at this beautiful pattern.

[00:36:46]D there's a beautiful pattern and whenever you see a pattern in science you see you say it's regular arrangement you guys are one of the very lucky people who get to study like this you know no teacher would teach me like this I promise [laughter] yeah the best of the best alhamdulillah you know I boast because I want students to help their friends out as well guys don't get kippy Help your friends out as much as possible because it's a once in a lifetime opportunity for you to study O levels.

[00:37:27]Nobody the threshold is not going to if 100 more students studies for me or five 600 students study for me. So help your friends out as well. So whenever we see a pattern we say that the arrangement is a regular arrangement. So these solid particles remember particles is just a broad term that we use. Particles is a broad term we can use for anything. We can call these particles. Even though they might be atoms, they might be molecules, we can call them particles.

[00:37:53]Particles is just a very broad term.

[00:37:55]It's like an umbrella under which different terms fit in. So you could say it's a regular arrangement of particles.

[00:38:01]Why am I calling it a regular arrangement of particles? G, why is it a regular arrangement of particles? Because I can see a pattern.

[00:38:08]You're not going to tell the examiner because I can see a pattern, it's a regular arrangement of particles. No, you just tell the examiner solid arrangement. It's a regular arrangement of particles and you know on your own.

[00:38:17]Why is it a regular arrangement? Because you can see a pattern. Now the next answer is your guys. Do you see a pattern for liquid? Huh? Yana below.

[00:38:26]Huh? Yana. Do you see a pattern? Be honest to yourself. Do you see a pattern? Those who are saying we can see a pattern. What's the pattern? G. What pattern do you see? Huh? What pattern do you see? One is here, the other one.

[00:38:38]This is a beautifully arranged pattern.

[00:38:40]What pattern do you see here? I don't see any pattern do I? There's no pattern.

[00:38:45]It's irregularly arranged. There's no pattern. So if there's no pattern, I say it's an irregular arrangement or you could also call it in nowadays examiner is calling it a random arrangement. So both are correct. Yes.

[00:39:02]Hajra you may ask the question. Your hand has been up for quite some time. G ask Puchi.

[00:39:09]Okay. Continuing with the idea because I can't see any pattern I say it's a it's a random arrangement. Nowadays the examiner is using the word random in some marking schemes you'll also see the word irregular. Both are correct but for gas can I see any arrangement? Can I see any pattern here? Can I see any pattern here? Can I see any pattern? It's a random arrangement of particles.

[00:39:28]Obviously we write particles everywhere.

[00:39:30]So of particles it can be atoms, ions, molecules whatever. We'll learn different type of particles later on but you can just use the broad term for it right now. The I don't see any pattern here. So I can also say it's a random arrangement of particles.

[00:39:48]You know today's my last demo class with you guys unfortunately or fortunately.

[00:39:53]So what do we say? We say it is a solid is a regular arrangement of what circa it's a regular arrangement of what? Of particles.

[00:40:03]For liquids we say it's a random arrangement of particles.

[00:40:10]For gases, we say it's a random arrangement of particles. You can also call liquid irregular. That's up to you. But nowadays, your examiner is using the word random. So, it's a random arrangement of particles.

[00:40:28]Done. Now, one more thing, guys. One more thing, one more concept here.

[00:40:32]Whenever there's a pattern that you can see, and this will come in handy even in your A levels. Whenever you can see a pattern guys, whenever you see a pattern, you call it a regular arrangement or there's an alternate term for this. There's a very bougie term for this. Do you know what that term is?

[00:40:46]That term is lattice.

[00:40:49]You must have heard this in your O levels, wouldn't you have, but you never knew the meaning for it. Now you know.

[00:40:56]Latis is literally a fancy way of saying regular arrangement. So instead of saying a regular arrangement of particles, you could also say it's a for solids, you could also say it's a lattice of particles. Latis means regular arrangement. That's all. It's a bougie term.

[00:41:14]Done. Next.

[00:41:17]Next.

[00:41:19]What about the particle separation?

[00:41:22]What about the particle separation, guys? Look at the particle.

[00:41:26]You have to look at it and tell me. Do you see any particles being separated here? Are the particles separated? G be quick, guys.

[00:41:34]G. Are the particles separated? The answer to that is no. They are close together. The particles are close together. There's no separation between them. There are no spaces between them.

[00:41:46]So, we say particles are close together.

[00:41:49]And there's also another word you could use for it which in in prior classes you have been using it. You could say that they are tightly the particles are tightly packed. Please use the word particles. So particles are close together. Particles are tightly packed.

[00:42:04]In liquids, look at the particles. They are close together but slightly separated. So you tell them, yeah, liquid particles are close together.

[00:42:12]Look at them. They're almost touching.

[00:42:14]These guys are touching. These guys are touching touch-ing. So these particles are also close together, but slightly separated. Although your examiner says just write close together. But since you guys are my students, I would recommend you guys write liquid particles are close together. You can just see them, you know, the particles are close together. Look at them. They're close together. They're touching. So you see the particles are close together. But as my students, I would recommend you guys write but slightly separated.

[00:42:41]This is my recommendation. It's up to you. The examiner does not want you guys to write this, but my recommendation to you is you will not even find this in the marking schemes, but it's up to you.

[00:42:50]My recommendation is to write particles of liquid are close together and in brackets always write but slightly separated because that's what you see.

[00:42:58]Okay? Don't just say they're close together. Say they're slightly the examiner only writes particles are close together of liquids. So it's up to you but I would recommend also writing this in the brackets. Next gas particles are they close together east west.

[00:43:14]So gas particles they are far and apart from each other. So they are far and apart.

[00:43:22]Done.

[00:43:24]That's all. And at the end what is the motion? Now the beauty is here. Kinetic particle theory told me what? Kinetic particle theory told me that all particles teeny teeny tiny particles have a certain motion, don't they? They're all in a constant random motion. All particles are in a constant random motion. All be it solid, be it liquid, be it gas. They're all in the con sir. But when I look at a table, I don't see any motion. When I look at a chair, how are I can't see any chair moving. I can't see my mobile phone moving. They are the particles that make up all these fellas. If you look at them under a microscope, you'll realize they are yes, they are in fact in a constant random motion. And in university, you'll probably if you opt for chemistry, you'll probably also learn those motions.

[00:44:17]So they are in a constant even though you might not be able to see it but on a very molecular level the solid particles the liquid particles they are all in a constant random motion and the gas particles the question is what is that motion for solids because solid particles are tightly packed can I say solid particles they have uh the motion is that they are going to move. Can I say solid particles are going to move?

[00:44:41]Can I say that the answer? Can I say solid particles move? Please, that is the biggest misconception among students. Solid particles don't move.

[00:44:52]Remember, you don't use the word move.

[00:44:54]This is not English. This is science.

[00:44:55]You say they vibrate.

[00:44:58]They vibrate about a fixed position.

[00:45:03]They don't move. Why don't they move?

[00:45:07]Remember, they don't move. Moving means they go from one place to another. They don't move from one place to they just vibrate wherever they are. Why? because they're very close together. These particles are very close together. So, they can't move. They vibrate only. This is the biggest misconception. If somebody asks you in the exam, can solid particles move? No, they vibrate in a fixed position. They just go, that's all. They don't move. Okay? They vibrate about a fixed because they're very close together. They're tightly packed. But liquids, they aren't very tightly packed. Liquid particles are close together but slightly separated.

[00:45:44]So can they move? Yes, liquid particles can absolutely move. And how do they move? Liquid particles move? They move randomly. Obviously, liquid particles, solid particles, gaseous particles, they all have a random motion. But what is that motion? For solids, it is a vibratory motion. Solid particles, they vibrate about a fixed position. They vibrate. And liquid particles, liquid particles move. Have you ever seen waves, guys? Have you ever seen waves?

[00:46:10]Waves is H2O liquid, isn't it? Waves, the way they move is they slide over each other. Have you ever seen them?

[00:46:17]It's one wave on top of the other wave.

[00:46:20]So waves they slide over each other and that's how all liquids move. Liquids they also have a random motion. They they all three have a random motion but one vibrates the other one it slides over each other randomly. So slides over each other just like waves.

[00:46:37]Waves Watch a YouTube video on this. And last but not least, gases. They also have a random motion. They don't slide. They just have a random motion. And gas particles, they move very randomly at very high speeds. So you say gas particles have a random motion at high speeds. And you know how you could remember this? I'll tell you the wise later on. But you know how you could remember this? You can remember this by somebody farting. If somebody farts in the leftmost corner of the room, it will reach your nostrils instantaneously.

[00:47:14]Why? Because gas particles they have a random motion at high speeds. That's why it reaches you instantly because they move very fast. Gases have very high energy compared to solids and liquids.

[00:47:26]Solids have the lowest energy and you know why. Now this is a beautiful question right here. I leave you guys here today. What is this question? The question is sir why is something a solid? Something is a solid because it has a why is chair a solid? Chair is a solid because it has a regular arrangement of particles. The particles are close together and they vibrate about a fixed position. That's why chair is a solid. Why is water liquid? Because the water particles have a random arrangement and it is particles are close together but slightly separated and the particles slide over each other.

[00:47:53]That's why water is a liquid. Why is why is fart a gas? Because fart particles have a random motion of particles. They are far and apart from each other.

[00:48:02]That's the particle separation. And they have the particles are randomly arranged. The motion is random motion at high speeds. That's why something is a gas. Now the question is what should be the next question?

[00:48:25]Why does all of this happen? Why does all of this happen? It was because of this the arrangement, the motion and particle separation. But the question is, why do solids have this motion? And why do solids have this arrangement? Why do liquids have this arrangement? Why do gases have this arrangement? Why do solids have this separation? Why do liquids have this separation? Why? Why?

[00:48:44]Why? Why? And the why has to do with a gluing force that you learn tomorrow about uh not tomorrow inshallah from Monday cuz tomorrow or classes you know from Monday we'll be starting regularly and we'll continue from here guys I have request I want to request you guys one thing if you've enjoyed my classes if you've lost these two three classes I promise you I will bring your grid this is my promise you just need to take my classes look at this I will solve a gajillion things with you don't worry look at this look at questions. Look at this. It's about 100 100 pages chapter and I'll do everything with you. Don't worry, that's my job. I am responsible for your grid. I promise you this. But if you find me helpful, do share it with your friends and family. I want to become famous. That's been my goal since day one. And alhamdulillah, that's happening slowly and gradually. But I want you guys to help others out to not leave your friends out of this beautiful classes. G questions. I'm going to start taking questions and you guys can go for everything.

[00:49:55]WhatsApp please. Thank you. by