Geography Lecture 1 Notes PDF

Yeah. So my name is Rajesh. Rajesh: Gohendraj. So I'm a faculty of, geography and environment. So here at Vision IS. So it's been ten years since, my association with Vision IS. So by background, I'm an engineer, studied, from Mysore, Karrataka. My native Es Karnataka. And after that, I'm here in D...

Yeah. So my name is Rajesh. Rajesh: Gohendraj. So I'm a faculty of, geography and environment. So here at Vision IS. So it's been ten years since, my association with Vision IS. So by background, I'm an engineer, studied, from Mysore, Karrataka. My native Es Karnataka. And after that, I'm here in Delhi since last, Fifteen years. So I've appeared for UPSC, quite a few times. And, so reached the Interview three times. Missed by a narrow margin. And, yeah, once I clearco you can see that is a different exam. So it was, assistant command and CAPF. It was se'ected for ITBP, So did not join because of few other conditions back then. In the meantime, I got selected through, KOSC product overview service commission also. I did not join. So by then, I had started to teach here. So I feel this is more interesting and challenging. It keeps looking to Learn more as teach. I've also done my masters from, Delhi University. It's a department of environmertal studies ir, MSC in environmental studies. And it has been a a good association with the GIS and, teaching the students here. And, so, you know, so the subject of geography has been something which, which has been a very Interesting one till now. The more I Leach, the more study, the the bellter it is becoming. And also I have the hobby of traveling and, you know, some wildlife observation, photography. So maybe that is one of the reason why maybe I Like the subject such. So this is in brief about me. So rest of what you guys, I'll get to know as I so do the classes. So I'll be taking geography for you guys starting from today. So with: the, so covering the basics of geography starting from ike, assuming that you guys don't know anything. Okay. 'll be starting from there. And, we have around 40 classes to complete, this geography section ir: total. Fine. So today, we'll briefly discuss regarding the subject of geography. What is this geography as a subject.? And, what exactly you have to prepare? How we have to prepare? Are you pacing? What's the orientation? Recause without understanding the orientation, it's like running without any kind of direction. Right? So whenever you have a shortage of time, snortage of resources, you have Lo ensure that you're doing the things in the right direction. So this is not something like that. I have to be very clear about this. So even if it is, going to take some time, it's fine. But if you understand the the proper approach and direction, it will be very easy for you. So when was the last time you guys studied geography? All of you. Any of you studied geography from, bachelor's? Okay. So Delani University? No? Any of you From Delhi University? Let's call it. Fine. So can't say with Astro. Any of you studied from masters, geography masters? No? fine. So what do you know about geography? What do you remember about geography? Except this, you have studied from bachelor's. Yes? That is what is geography? What are the topics you remember in geography? Okay. Landforms. Climate then. Yes? Let it do a longitude. Atmosphere. Rocks. Mountains, Climate mountains, earthquakes, soil, good, oceans, then forest volcanoes, then? Yes. Yes. Pleasure. Fine. How many of you read the NCRT? NCRT from six standard to 10 standard? At Least 11 standard, eleventh and twelfth standard. Any of you are planning to give twenty twenty five attempt.? The subject of geography. Let me give you a brief introduction. What do you mean by geography? What s the meaning of geography? Study of earth. Then what is geology? Geography is earth. Logic is study. Logi is study. Togi means study. Right? The study of Earth becomes dual logic. And what is geography? Okay. Okay. Anything else? Thank you. Alright. What do you mean by graphy? Description? Graphy means a description. So geography 's basically description o Earth. Okay. So it started as a description of Earth. When was the suoject of geography evolved? When any subject science subjects evolved? Science related. Okay. So Let's go to much more basic. Is geography science or arts? Then why do you study in BA program? You study more geography in BA program. BSC has no geography. It's both science as wel as art. It's science because it is methodological. t's arts because there's, more it's more descriptive. Ckay. So and it's more, you know, so analytical. The opinion based there are many things. It's it's a mix of bota. It's both science as well as art. Okay. So similar to many subiects of science as well as, you know, so the disciplines waich evolved a systematic study evolved. That was during the time of Greeks. It was during the time of Greeks. Right? Geography also evolved during the time of Greek as a subject. Otherwise, the description of Earth is there. It's there in Mahabharata Ramayana. Mahabharata has one of the wonderful description of geography. So is Ramayana. So so is Rigveda. Okay. The Vedic scriptures. So is even the other epics, Iliad Odyssey. Okay. So wherever there's scriptures, wherever there's Literature, they all have their description. Okay. For that matter, if you go into the pyramid, okay. So there are many things which are described over there. Okay. So in terms of the the the overall architecture or the way they have done from which part they have sourced these rocks, the brocks such huge logs. You know? So there's huge amount of geography involved over there. guess you go back to the tac ancient times. Okay. So prehistoric times. The stone age. Okay. Stone age times. There are cave paintings. Prehistoric times. There is also this description of geography. You know, one of the oldest cave, such kind of cave painting or we can say the the earliest stone age recordings o caves, they have the recording of constellations, the pattern of stars. So geography is that old, the description of earth. As a systematic study, it started during the time of Greeks. Similar to most of the subjects, it started as a systematic study during the time of Greeks. Many Greek philosophers have cont buted here. Rut the persor who made this as a proper subject study and who developed this into a very clearly defired discipline was who was that? Erastrophenes. Erastrophenes. He's called as the father of geography. He's the one who coined this term geography. Why did they develop this as a subject? What was the need of this? Because every subject which was evo ved during the earlier times, they it had some kind of practical utility. Okay. So it was required. What was the need of geography as a subject? That is the subject of map making and map reading. Okay. So the subject of map making. Why do you need map? What does the mao qive? Direction, travel routes. Earlier times there were travelers, traders who are there who are moving continuously from one part to another. Again, they were traveling across the world. They wanted a particular direction, particular, you know, so the way of navigating the space. Because during that time, as a subject of study of maps, it was evolved. Gradually, it started to include every different aspect related to tac carta. It started to include every different aspect related to the earth. Initially, it just was a description of earth. We're just going to describe what you are saying. Ther we start to include how they are formed, what is the process, ckay, what is the mechanism. Okay. So now above the earth and below the earth, in the oceans, everything related to the earth was included here. Okay. Everything related to the earth was included here. Every different aspect of earth was included here. What are the different aspects of earth here? One is physical aspect. Okay. So physical aspect is something which we can see, which we can feel, which we can experience. That is what is physical aspect. Second one is human aspect, the interaction of human beings with the earth. Okay, how the earth has influenced the human beings and their way of living that is human aspect. In physical aspect, the human beings are just one of the animals. Okay. We don't have a major role as such. Okay. So our role is limited in terms of, you know, modification as such. Human aspect's mainly about geography and human beings, how both are related. And then this, there are historical aspects. How the geography is a subject to world, so political aspects. Right? There are various dimensions to the subject of geography. So all of this together becomes different parts of geography. Okay. So if if geography is the study of earth or the description of earth more broadly to be called? There are various different dimensions. One is the physical dimension. Human dimension. Historical dimension. Political dimensions. Like this. The physical dimension of the geography involves the five various aspects. When I say physics, it involves the five various aspects. First one is land. Land is the area where we live. Okay. So the surface. The study of land and the physical features associated with the land is what is called as geomorphology. The study of land is what is called as geomorphology. Above the land, there is air, which we call it as a layer of air. What is it? Atmosphere. The study of various phenomena which happens inside the atmosphere is what is called as climatology. There's land, there is air, and the third aspect is water. The study of water because, you know, the other surface, 70% is covered with water. Right? The study of water is oceanography. Then there is study of life because wherever all three three are interacting, there's a possibility of life. This is where the soil exists. This is where the plants is where the life exists. That is what is biogeography. Together, all of this, the life exists in these conditions that is the surrounding environment that is environmental geography. Fine. Those are five parts of physical geography. Geomorphology, climatology, oceanography, biogeography, and environmental geography. Any of you have option of geography? Okay. Good. Okay. So here are the five core areas of physical geography. Then comes human geography. Human beings interactions and the surrounding environment surrounding geography. It happens in two different ways. One is an economic angle. Another one is social angle. Economic Geography and Social Geography Economic geography and social geography. These are two main parts of human geography. Human geography is mainly centered around human beings and the geography. Okay. Surrounding geography. Economic angle is about economic activities. What is an economic activity? What is an economic activity? Production of goods and services. Okay. Production of goods and services is basically economic activity. Okay. Right? It's about creating values, economic value. So that involves resources. Okay. So study of resources. The study of different types of economic activities. What are the different types of economic activities? Primary, secondary, tertiary, quaternary. Primary economic activities, agriculture. Second is industries, manufacturing. Third, tertiary is services. Fourth, quaternary is IT is also service, research, development, management, governance. Okay. So that is quaternary. What about social geography? What is it about? How geography has influenced the society? Okay. How geography has influenced the society? For example, the study of population, study of settlements, what is a settlement? The place of living, place of dwelling, the building structures, all of this we have made. Okay. Study of tribes, language, religion. So these are the various different aspects of society that how it is related to geography. Because everything every aspect of society is related to geography. Where do you find higher density of population? Plain areas, coastal areas, related to geography. Do you find higher density of population in hilly areas? Because it makes difficult. Life is difficult to go there. Right? Desert area, again, related to geography. So every different aspect of social social society is related to geography. That study is basically social geography. The historical aspect of geography's what we call as the geographical thought. The thinkers and their contributions. So I guess various different thinkers and their contributions. How the subject level, for example, Aristotle thinks what is his contribution? What is what did he what are what are his ideas? Again, so from the ancient times till the modern time, different philosophers and thinkers have contributed to the subject, what is what is the overall idea that is what is your critical thought.? So there's this political geography, what is political geography? Study of borders, frontiers, country, state. Okay. So this is where your political science will interact with geography. Okay. So both of them are very well connected. Why do we use the word geopolitics? Geography comes before politics. The politics are decided by geography only. Right? For example, the role of Indian Ocean in the the twenty first century as compared to the Atlantic Ocean in the twentieth century. Right? The role of, West Asia because of resources. Right? So like this, the rele, tac frontiers, tac borders. For that matter, ever tac the litler's nvasion of Russia, the Hit'er's invasior of, France, a of these are related to the geography only. He wanted to control the entire land. You wanted to control the heartland of Asia. Right? So that is political geography. Any other part of geography? This is region and geography. Regional geography is the study of regions in detail. Okay. So you Lake a particular region and you try to analyze in more detail, whole region and geography. And then comes the cartography. Cartography is the city of maps, which includes the AI, GPS, everything. Cartography, GRDTS, GPS. There's ore more aspect. That 's our cosmology. Cosmology. What is cosmology? What is cosmos? Study of what is cosmos? Space. Okay. So that Includes the larger picture. The Earth being part of solar system, solar system being part of Milky Way galaxy, the universe, the origin of universe, the galaxies, stars, the origin of stars, the different bodies n the universe. Okay. A11 these aspects, the background aspects, the background studies that is cosmic question. Is it related to geography truly? No. It's very difficult to draw the boundary. Okay. So it's all overlapping boundaries. For that matter, social geograpay is a over-apping arca between geography and society. Okay. So political geography is the overlapping boundary between geography and political science. I think that cosmology is there, of course, between physics and geography. Geography is much more wider. There are many many aspects. If those who have taken option, they wou'd know. Okay. So it's a very, very big area. It is regional planning. Tacre's geographical thought models and theories. Okay. So so so like this, there are many different areas out there. So do I have to study all of this? At least, we have a rough idea. Okay. What is geography? This is the overview. In that, how much you have to study, how much you have to prepare for UPSC? Where is it given? Who said you have to study only physical geography? What about humar geography? Which one? Physical and human. That way, you have to study both economic and social geography both as part of human. Political geography also. What about cosmology? You don't want cosmology? Regional geography we add So how will you come to a conclusion that what to study, what not to study? Where is the syllabus? Notification. It is in the notification. Okay. So every year, 't says releases a separate notification. So for 2025, there wiil be a separate notification. For 2026, there will be a separate notification. In that notification, you have to see. Okay. So so, basically, notification is, the one which is released by UPSC every year in the month of February calling for the application. In that notification, they would have given the definite, in deta syllabus. Okay. So if you take out that notification, there you will get this idea. Okay. What is what has to be studied? And this is what is given in the notification. Okay. would just take an Indirect screenshot from there. In the prelims in the prelims syllabus, it is given as party preliminary examiration. Ckay. I've seen that these are the subjects which are mentioned. Geography evaluated here. The subject is Indian and world geography. This is the name of the subject. What are the aspects? Physical, social, economic geography. Physical, social, economic geography. Only these three. Okay. You don't have to read political, thought, regioral. I guess all of these you don't have to read. But you car: see, you know, it's a little bit tricky. You know? Have to read a little bit of cost money even though it is not mentioned direct-y occause it's a over-apping area with general science. Facre's general science here. General science is so wide open. So from geography's perspective, you have to read a bit of cost managing. Otherwise, thought is not required. For GS, it is not required. Political geography is not required. Just a brie dea of what is frontier, border, and all. And, regional geography, cartography, all these are not required. Okay. So only two parts that is physical and human geography and human social and economic geography both are there. So guess, but what is not given is as a part of general science cosmology, we will add it. This is prelim syllabus. There's nothing. Ckay. So no other topics are not mentioned here. They have not said geomorphology, climatology, oceanography, nothing. But if you read if you see the notification very clearly, so the topics related to environment Es mentioned separately. Generally, issues on environmental ecology, Biodiversity, and climate change, that do not require subject specialization. Okay. So leave over that whatever the meaning of that, that do not require subject specialization, you’ll see that later. But environment is mentioned separately whereas environment is also part of geography, physical geography. Okay. So that is true. Because only in this new syllabus, new syllabus is this is the syllabus which was changed in 2011. It was in the year 2011. They took out environment from the physical part and they mentionca this separately. Before that, if you see the syllabus, there was no mentior of, ervironment as such. It was assumed to be part of physical geography and the questions were there. As usual, the questions were there. Okay. So it was started to be mentioned specifically from 2011. That is the present pattern. And the weightage of environment increased from 2014 Le 2015 with the introduction of Indian forest service in prelims. Okay. That is when the increased the weightage of environment as as such between 15 to 20 questions come from the environment section alone. So now the the basic area. So environment has been made totally separate. This is the main syl'abus. Okay. I’ve just taken the screenshot of the geography part only because mair service is little bit more detailed. We cannot put in this slide. In the geographical part, three topics are mentioned here. Okay. Let’s read them. The first one is salient features of world’s physical geography. What do you mean by that? Just a portion of key ratural resources across the world. Where is this natural resources? Economic geography. Economic geography as part of human geography. Okay. I told you in economic geography, there are two aspects. One is study of natural resources and another one is study of economic activities activitios, primary secondary tertiary that is mentioned here also. Distribution of key natural rescurces. Factors responsible for the Location of primary, secondary, and tertiary sector industries in various parts of the world. Again, we car call them as economic activities. Okay. The same thing which we discussed earlier. Economic activities. Okay. There are two parts here. Natural resources, you have to study in detail. Economic activities, you are studying that detail. The third one Es important. geophysical phenomena such as earthquakes, tsunami, volcanic activity, cyclone, etcetera, geographical features and their locational changes in flora, fauna, etcetera. So let’s call this as geophysical phenomena. Where is this in our discussion? We identified so many areas. Where are these topics? Physical geography only. Right? Okay. Water bodies, ice caps, oceanography, water bodies. Flora, fauna, biogeography. They are repeating the topics of physical geography. So what is the point of this? They have anyway completely mentioned the salient features of physical geography and still they are highlighting few of the other topics in insice this. Why? Why they are more important? Okay. Good. So you can see that it is important. You can see 't's mentioned this separately. That means it is important. Right? Why? What is special about these topics? Fuman, Yes, Good. Disaster management. Good. Anything else? Beginning? Check. Check. It's about human life. So, basically, these are the events in physical geography which directly impacts the human life. Okay. So which are, you know, capable of causing Large scale destruction and which we are experiencing the recent times in more frequency because of climate change, because of g'obal warming and various other issues. Okay. They are associated with the environmental issues. They're associated with the disasters. Aga'n, so they are associated with the governance. Okay. So it's all related to the current aspects. That is why it has been mentioned separately. Okay. Of course, you will not study this separately. You cannot selectively read this. You will not get the connection. You have to study this along with the other topics of physical geography only. Okay. But wherever these topics come, you have to go in a little bit more detail. That is the idea. Right? So geophysical phenomena is just part of physical geography only. That's the important phenomena which is associated with the physical features, physical locations and a. So otacrwise, what is missing? Social geography is missing. In prelims, there is social geography mertoned. It means there is no social geography mentioned. why? in paper one already, society is mentioned. Society is a separate subject in paper one. Right? Gs one, not paper one. Gs one. Gs one is paper two. You know this? Which is paper one? In Philippines, there's no data society. Okay. We have to study social aspects separately. In geography, we'll study some of social aspects. In economics, we'll study some of social aspects. Means, anyway, it is separated. And also why to waste again? Yeah. But questions will be there. So through geography, some questions will be there. There’s overlapping within geography and society. And so combining this, there are few other parts of the syllabus where geography topics are there. We really we tend to ignore those topics. Okay. Let me show you. In prelims, there’s a topic which is totally related to geography. I told you this is environmental geography. You guys see this mentioned this separately. In mairgs three also there is this environment.. Can you see it? Conservation, environmental pollution, degradation. Right? There’s environment over there also. So whenever these subjects of environment comes, please link it with geography. Without linking with geography, you cannot study this separately. You need to develop mastery over environment, so please connect well with geography. The physical geography, particularly physical geography. Other than environment, there is disaster management, disaster and disaster management. Every disaster, usually most of them are geographical phenomena only. To understand disaster and disaster management, you need to understand geography wel. Okay. That connect’on is very much required. Tr economics, there are few topics which are related to geography. You can mentior you can see here. The crops, cropping pattern in various parts of the country, different types of irrigation, Errigation systems. Okay. So agriculture produce Issues related constraints. These are related to agriculture. Agriculture As part of primary economic activity we’ll study there. Infrastructure, energy ports, roads, airports, railways, electricity, and tertiary economic activity. Procaps will study about this there also. So these two topics we study in both geography as well as economics. In geography, I’ teach as per geography. In economics, we will still study as por economics. I guess both you will still study over there. Environment, sir.ce UPS has made it separate, we also made it separata. Environment. will be taught. separately for you and not be calling environmental geography. That is anyway. We’ll go in detail. Disaster and disaster management, again, will be taken separately for you. Okay. So even though in the class, they are taught separately, but always remember wherever these Lopic comes, you have Lo connect with the geography, then only you will understand that better when only you wi you will write better answers over there. Over time, this is what we can say. The geography subjects, including prelims and mains. Okay. The topics inside geography, can divide this into two major three major areas. Physical geography of world, physical geography of India. Okay. So I cover this separately because physical aspects, one need to cover it separately. Okay. India and world, you have to delete separately. Whereas human aspects, you can go parallelly. Okay. So we don't have to go through this operator. You can go parallelly. So, for example, in physical, we will start with the cosmology. Okay. We'll not go into detail to cosmology here. So that. will be dealt in your physics. Okay. 11 take a very brief session on the cosmo ogy. Okay. Few classes on cosmology, which is required as per the, you know, so understanding of geography. Okay. To understand geography, how much is required, we'll study that. Ther. geomorphology, climatology, oceanography, biography, four major units, the landscape, environmental, geography. told you that will be taken separately. The same thing when you apply in the case of India, Physiography, drainage pattern, climate and soil. Okay. The same conditions. Then comes human. In human, you can see there is resources ocean, equine water resources, mineral and erergy resources, natural vegetation is also a resource. Then comes economic activity. Primary in agriculture. Secondary is industry industry, tertiary is transportation and Infrastructure. The social geography, I have given this one topic that in population and settlement. why this discrimination? Why social geography is just giver one topic? Because if you see the weightage, you will understand. In TYO there's not much weightage at all in social geography. Okay. So and given the minimum number of, the classes we have to allocate accordingly. Fine. And for all of this the mapping is common. Map location it is has to be done commonly. You can make a note of this. This is going to be our class structure. So what are the subjects that have been already started here in your branch? Policy? Quality? Modern history. Economics. Okay. Basically, history and economics. Is it right? World history. Okay. What about world history? Chromics? Capture with document. Or. That is it. So this is based on the syllabus analysis. Okay? But within this, how to come to a conclusion that, what are the topics to be covered? And it's a huge area. You see, for that matter, geomorphology Itself, geomorphology itself, you can study for a year. Such a big area. There's so many topics inside. Classroom is so is the case with climatology. Right? You need to narrow down what topics to be covered at what depta. So there you can use py q's, previous year's question papers. So what is the use of this pyq, p v qaralysis? The first thing you will understand, how many number of questions are coming? It is very important to understand, you know, so role weightage In prelims as well as mains. You're studying geography, Let's say, 40 classes you are giving for geography. Okay. So in that, how many questions for prelims is it justified? Should we give more classes? Should we give less classes? Or should you persora' ly give more time or less time is fine? Okay. So to understand that, basically, you will decide based on the number of questions. Okay. So I hope all of you are here to clear UPC only. Any of you who wants to become masters in geography, okay, subject scholars. Okay. So then you're in the wrong place. Okay. So my intention is not to, you know, to make you scholars in geography. My intention you too is to teach the subject as per the requirement of UPC only, 1 limit myself to that area. Of course, you cannot mechanically strict make it very strict. You need to develop Interest in the subject. For that, will stretch: and squeeze, variable is required. But my overall intention is to make you be prepared for UPCs expectation, both Williams as well as Maines. Like 't's all so therefore, it is so understand the demand of UPC, you need to first go through the pyg, and there first thing you will notice is how many number of questions are coming. Okay. So you will allocate the time accordingly. In that nature of questions, nature of questions will tell a lot of things, Analytical, factual, which gives all conceptual, current office based. What kind of questions are they? Recause because accordingly, we'll prepare. Right? If everything is being asked, we'l prepare everything. If only one aspect being asked, why to prepare everything? If they're not asking the facts, then ignore the facts. If they're focusing too much on the facts, we'll remember the facts according y, nature of the questions. Pattern, changing pattern. Is there the same pattern, changing pattern? Okay, so are they asking too much of current affairs? Are they asking, are they giving more importance to the static part? Okay, our map Locations. Okay, so what is the pattern? Alternate changes in tac pattern. Prediction of topics. Okay. If you analyze p by q, you will understand. So, okay, which areas are Lo be focused, which areas are not to be focused. Okay. So and, in which topic, for example, in geomorphology, the main focus area is about the landforms and their formation and their properties. You don't have to go into the details of geomorphological concepts, the annotation, chronology. Okay. So, ziver channel norphology. Like, there are many things. We don't have to study all of these in g s. The prediction of topic is very important here. And also depth of study. Of course, the limited time, whatever the limited time you have, you have to ensure that you spend it according to the necessity of APS. So let's say you have to study plate tectonics. You have to study population geography. You need to understand the depth of study it is required. Plate tectonics, "'ll take two and half classes completely for plate tectonics alone because that is where the questions have been asked. And not only the questions have been asked directly, even indirectly, its connection with the continental drift theory, 'ts connection its connection with the volcanism, its connection with the earthquakes, that depth of understanding is required. PYQ aralysis will help you in that to decide. The same population geography will finish in half half class. Sufficient. Whatever has been covered, whatever has been asked, they'll know that that would be covered. Okay. So we cover it as per the requirement. The depth of study is one thing which is very, very important, even in your own profession also. In some of the subjects, you will start to ike very much. Like, absolutely. t It feels like so. Yeah. So basically, you're wasting time. So understand the requirement of your policy. Understand the demand of the policy and study accordingly. For that, the best reference is py q. It is like a guiding Lamp for you. It will show in which path you have to travel. This is the weightage of geography in prelims. Since the time syllabus was changed, that is the present pattern record that was changed in 2011. So since then, this is the pattern which USC has beer following Yes. In terms of the number of questions, you can see the first five years, there was a good weightage for geography. Okay. Approximately around 16 to 18 questions over there out of hundred. Okay. I'm seeing number of questions, not the marks. Then from 2016 to 2021, so there was some, you know, sort of reduction in the number of questions on an average around 10 questions was there. The Last three years, again, it has increased. This year, there were 22 questions from geography, the highest among all the subjects. Prelims alone. have not ircuded environment. Technically, should include environment also. Right? Tac environment is also geography only, environment is geography. If I include environment also, so geography and environment together, it will cover 35%. Yes. So one of the highest as per the present trend. You can see at least once a trend is followed, you probably follows it for for some time. Okay. So Let's hope that it follows for the next two years also by the time you appear. Okay. So because this year's paper for that matter, so it was highly scoring because of geography only. Cut off went high. Because those who have Prepared geography, they have easily marked this. The questions were also conceptual type. Okay. Those who had made effort, they could have got the answer, I guess, honestly, even I would like that kind of paper. Not a factual one, of course. Factua one, what happens Es somebody knows something you wil market. Okay. So you have studied everything. You have missed the facts. You're gore. It should not be like that. This year's paper was one of the very good onc. Geography, I'm saying. This is the weightage in films. This is the weightage in mains. So let me add twenty twenty four here. Very recently concluded. In mains, the rate is just consistent. There's not too much of variation. Il varies between, like, 85 Lo hundred. It has gone once to one fifteen also. You take the average, it will come down to hundred only. On an average, hundred marks in gs one is from geography. On average, hundred marks in ga one is from geography only. Geography and society are two major subjects ings one. Okay. Geography and society. Usually, society, they used to ask around, 75 marks because geography was around hundred marks. This time, they have made both equal. Okay. 85, 80 five, 80 five, 90, something like that. Okay. So and there's one question overlapping for both geography and society. Okay. So almost both both of them are equal. And this is excluding the paper three questiors. In paper three, we have usually two questions related to agriculture, one question related to disaster management, and two questions related to environment. There is 75 marks more over there. Hundred plus 75, one 70 five. One 70 five out of seven fifty. That is the weightage of geograpay. Yean. So very easily you can see that geography is a subject which you cannot igore. Okay. So whether you are strong or weak, you cannot ignore. You have to work upon that. Fire. Let me show you a "ew sample quest'ons. Okay. So okay. Yeah. Before that, 'll show you the weightage before the sample questions. This is the the weightage of different sections in prelims. You can see physical geography of world, physical geography of India, Economic Geography. Okay. So social geography, there's not many questions. Okay. So I think in the last fifteen years, you will get, two, three questions only. So socia geography, there's not many questions at all. Majorly, this area and maximum physical geography of one. And in that mapping is the the largest section. This is mains. Okay. Mains, you can see 50% is physical geography, fifty percent is human geography, economic geography, basically. In physical geography, the highest weightage goes to geophysical phenomena. Remember these topics? That carries the highest weightage. Out of all the physical geography questions, this carries the highest weightage. In the entire geography subject, this carries the highest weightage, 37%. Three to four questions will be there from this area. Economic activity and natural resources is almost equal weightage. Okay. So I'll show you a few questions just to give you an idea how the questions are asked in geography. So please try to answer. What is that, sir? K. So more than the answer, it's about understanding the nature of the question. Whether you get the answer or not, remember the question. And such kind of topic comes when you read geography, it should come to your mind. That is the idea. And, sir, anyway, you will get it. It is there in NCRT. Okay. So this kind of, you know, so going through the PYQ and remembering them helps you narrow down narrowing down the way you have to prepare. Fine. Is that clear? These more graphs, P views are recorded earlier than S, so that is right. P views and individual particles vibrate to and fro. S as a particle vibrates up and down both are right. Right? What about this? Okay. So, again, answer is not the important thing here. So what you have to focus? The nature of questioning. It's not like you will be about every type of mineral and in which country it is found. That is practically impossible. We'll focus on those which are in news. This totally was in news. DRC was in news. Okay. And second thing, if any country is the largest producer, major producer, then you will remember it. Okay. So any technologies, current related aspects requires those. You'll remember that. All three are coinciding here. DRC is the largest producer of this cobalt. Okay. So three fourth of the world's cobalt is present present over there. Electric vehicles, e mobility, in that context, batteries, you need that. And environmental issues were there in the extraction. The social issues were there in the extraction. We know that it is one of the very easy questions. What is the difference between the first question and this question? Static. Not fact. So that is conceptually only. Understand the concept, you'll get the answer. That was static. Okay. You will read from NCRT. This one, it may have been given in the NCRT, but it is difficult to focus. Among the so many countries, how will you focus on this alone from current affairs? That was static. This was current related. Fine? So read this question and give me the answer. What is the answer? Okay. This is map based question in Pilims. Okay. So different peaks and where exactly they are located. And again, this is not something random. Understand the pattern. Namchabharva. What is Namchabharva? The easternmost peak of Great Himalayas. Great Himalayas are the largest and tallest Himalayas, and they extend from east to west. The easternmost part is Namcha Barba. The westernmost part is Nanga Parbat. These are two extreme points important.. Yes. Nanda Devi. Yes. Biodiversity hotspot. Okay. So there are many national park, biospereza, like a pellegrimate site, there's a glacier, Important.. No Creek, biospereza. UNESCO recognized biospereza. Okay. So they're not random Locations. That's the importance and they're not from current affairs. Okay. So this 's this is how you reed you need to see that depending upon the significance, depending upon the importance in geography, environment, in culture. It gets overall the location. This is based on that. You have to choose. This is a location based which is static. This is totally from current affairs. Again, a particular lake is in news, particular mountain is in news. Okay. So river is in news. Whatever the news location news items, so it is make because of the news, Et isn't there. It is it has been asked. And it usually in the news in Cast two years, you don't have to go into details. Okay. So old news, you don't have to read. You're understanding the difference here? These are the static Location. These are the current related locations. So in prelims, we have what? Four type of questions. Okay. So this is totally static from NCRT textbook conventional notes. This is this 's daily in NCR but supported by current affairs. This is daily in atlas. This is also daily in atlas. You cannot note that as it is you need to have current affairs reference. This one you can note because of their significance. These are four type of questions asked in mains. Keeps taree demands. This is an example of corteostatic question. You will get it from NCRT only. What are ocean currents? Describe their role in pushing industry. Direct questior. It has been repeat question also. Fine. Discuss the multidimensional implication of annual distribution of mineral oil in the world. This is the content is static, but the answer is dynamic. Dynamic in the sense, there’s no fixed answer as such. You will not find the answer here in NCERT or notes. You will make an answer there and there. That is why I’ve written it as applied. Okay. Based on the content you have studied, you will make an answer because they are not they are not asking you to extend the distribution of mineral oil in the world. Okay. So you know the distribution even they know the distribution. They’re asking what is the implication of this kind of distribution? Economic, political, environmental, social, different dimensions you have to bring out. International. Okay. So that is this question. Those are mix of both static as well as current affairs. Again, water crisis is there since long time. You have to use the current examples. Totally current affairs. Color coded with that warning. Four type of questions, it means. Lucky, we have more number of questions from here. There are 10 questions you can expect maximum two, three questions only here. I get to hundred marks, maximum two, three questions here. Overall, the pattern is still okay. So in the last 2,013, so we can have we talked to the question papers I have. So we are lucky that the questions in geography has been more static and static applied in nature. That makes it scoring in nature. Okay. So geography is something you can target and repair. If it is going to be more current related, more, you know, dynamic aspects, so today it will have been a little bit difficult. Okay. So in prelims, the more focus is on location. 40% of the questions are directly on location. Okay. So in the six rest of the 60%, again, 40% is static based, 20% is current based. This is overall weightage. This is just a glimpse of the p y q analysis. Strongly suggest you to go through these links. Okay. This is the prelims analysis from 2014 to 2024. Okay. So it is must If you are preparing for 2026, you have enough time to make use of it. I only discussed this. Okay. So on behalf of Vision AI, we conduct this, open sessions for, all the students, okay, so respective of their affiliation. Okay. So anyone can come and sit and watch. Okay. So as well as they they can see online, those kind of sessions. It’s there in the YouTube. K. For your, notes, understanding how put everything all these links in one slide, this this will be shared with you. K. We will try to watch this. This is eleven years from 2014 to 2024. I get to you better start from here, going this direction. I will discuss all The questions. Eleven years of papers if you see, you'll get a thorough idea. This is means. Okay. So 2014 to 2018, there are two parts, 2019, '20 '20 13. Twenty '20 '4, I was not here in Delhi this time, so another faculty has taken. So et me add that.. We car. you can see that also. Fine. So means that is also important. Please go through al these questions. So do use that.. So if you remember, if you go through whenever you see a particular subject, particular topic, you wil be ab'e to rarrow down what exact" y how to prepare. It will give you a proper direction. Okay? So as I told you, if you remember the p by q questions, whenever you read a particular topic, you can just correct. Okay. So that time the question had come. Okay. Maybe you will have to face these kind of questions again. Okay. So accordingly, you can pretend that will save a lot of time for you. Sources for geography. These are the three basic sources core for physical geography. This is for physical geography. Eleventh part NCERT, two parts. This is world physical. This is Incia paysica. Fire. This is physical geography. It's easy long you overheard. Small book. Now they would change the color. Okay. Cover page only. So in some Inside, figures are changed. Rest everything is same. Rven if you have the older one, it's sti fine. You can purchase this. It's better to keep a hard copy. It will be useful. Okay. So this is for physical geography. This is for human geography. Well, standard part one, well, standard part two, world humar, Indiar: humar.. Okay. So out taese two are, you know, no sight, you know, no general sense. You can see this has become a little bit more specific, particularly resources and economic activity. There you need some more content, some more latest updation. For that, I have suggested that book. Don't miss this. Read this. Also read that. Total geograpay is CICI syllabus. Again, there is ICICI syllabus, 10 standard. So in that, the Lopics related Lo agriculture, resources, okay, so as well as, industries, transportation, only those topics you can refer to. K. These are the compulsory sources. You have to finish this whether you are coming to my class or not. Because even if you're coming to my class, still you have to read that. Okay. expect all of you. And this is, the map reading. For map reading, I'm sure all of you wou'd have already purchased the map. So usually, somebody's preparing for you. Whether it is you see it or not as a, you know, sort of declaration to the world. So what is the point of this? What is the purpose of this map? Okay. Okay. Usually, it is the case that people forget only there is a map on the wall. It becomes part of the wall. A wall paper, okay, some pattern on the board. So please don't do that. You have to use it for both the subject of geography as well as for map reading. For both of it, you need to use that. Okay. So I'll tell you in one of the class in between, '11 take, what the maopire and how to do mapping. I'll I'll tell you then. Okay. So far now so please don't ouy all of them if you're buying. So you can buy the world physical map. This is compulsory. Okay. So for physical geography, again, it is compulsory. World physical map. Yep. So rest, I'll tell you. And the k one atas must for every d'ass. Okay. So Oxford is fine. Oriental is also fine. f you have ar Any of this is fine. Any of the latest edition is fine. older edition, that is also fine. Don't purchase a newer one. Yep. So because it is map anyway. It's not going to change every year. Fire. So for many, you know, the subject of geography is, very difficult one. I'm sure. Okay. So how many of how many of you find it difficult? You can be honest, Patay. Yes. So for the rest of it, it's a'l easy. Interesting. Okay. So the problem with geography as a subject waen you start to study, so people have this misconception that you have to remember all the locations. You have to remember all the countries ard tacir capitals. Okay. This is like the old generation. Uncle, aunties, they used to tell. Okay. So as soon as you te that you are want to be very busy, they' 1 start asking, okay. Capital k. Okay. You don't have to do that. So Start with the basic concepts and understanding that is very, very important because geography is subject is the most practical one. It's the most practica. subject comparco to any other subject Cor that maller. Okay. So you can correlate whatever you're studying with the outside world because you have been living on this earth for twenty years minimum. Okay. Twenty, twenty five years in some cases. So you know something about 't. Right? And even after reading, you can at Least correlate outside. So Let's say you read about clouds. You go outside and see clouds. You can correlate. Okay. What type of cloud is this? Why is it there? Why it is this time of the year we have clouds? If there is a rainza, what type of rainfall it is? Fine. So if there's a winter rainfall in Haryana and Punjab in the month of December, January, why it is happening? Okay. So what is this disturbance? Way is it so you can correlate here? Geography is the most practical subject. You will get that interest only if you start from the basics. Only if you start from the basics and only if you give attention in the class. Fine. You need to have a genuine curiosity in the subject. Like, if you show some genuine curiosity, I'll make you love this subject. That is my promise. Fine? But you have to be honest with me. Tell me. = can repeat hundred times, but don't talk among yourself. Otherwise, So start from the basics, develop a conceptual clarity. To develop a conceptual clarity, you can use many of these multimedia, Images, videos, pictures, again, animations. I'll also show in the class. They can make it interactive. So because a geographical phenomena, you have to imagine, you have to, you know, visualize, then only you will understand. It's not like a two dimensional picture, black and white picture. No. Because you need to think in the real world. You need to visualize, then only you will understand. There's so many resources in the Internet. Make use of it. Don't limit yourself. Okay. So read from NCERT, read from my class notes, but go back and refer anything you want for visualization, for understanding, for better clarity. Practical application is a must. Any subject for that matter in you can see every subject request practical application. Geography requires more practical application. Find if there's any kind of news that there's a cyclone in the open world, why it is there? What is the name of it? And which direction it is traveling. Okay. So what is the reason behind the formation? K. So what if there's a a pheromenon called as eliro? K. So it is there in the news, immediately you should be able to correlate, K. What is practical application? And linking with the current affairs both are there. After this, start to remember the facts and information, it becomes a cakewalk actually. You try to do this in the beginning only, mug up the things and then you go for concept of clarity. By then, you would have lost the, interest in subject. Please don't do that mistake. Because start from here. Even if you don't remember the fact, it's okay. It'll come later. Okay. So it will come automatically. Fine, Particularly more importance to conceptual clarity, the subject understanding. In practice, the diagrams, figures and maps. Every subject has a Lanquace, I kept saying which you have to express it. In geography, it is through figures, maps, and diagrams. Okay. So you have to draw as many as possible in your answers also. And that will start from the classroom and don't think you wil write 't there in the exam. Inmediately, whatever you are writing is immediately, roughly you do it. I don't want need scautiful diagrams. I want it to be there then ard there. Okay. Simple, legible. It has to be there. Again, so don't do, like Like, I'l Leave some space and go back and draw it later. don't have that much of time. Trust me. You draw it in this moment here, whatever the maximum is more maximum possible, you know, so the wave so you you try to do it. You have to do t. The more you do, the better it 's. You will you will get a good score scoring in, mains because of this. And current affairs, every issue related to geography, every consequence related to geography, please try to link it with current affairs if there's anything in the news, whatever comes in the current office. So then, you know, the subject becomes easier. The subject becomes easier, interesting, as well as fun. So that is an overview of the subject of geography. So I learn this. There are few specific Instruction. One instruction I already to'd you two times today. No talking 'n between and I'm very serious about this. Again, stop the class. If somebody is talking, anything whatever it is, douots, you should ask me or_y. Fire. So because when I'm teaching, so I have to give my s. If I if I see somebody who's talking among themselves, feel you're not interested. Okay. L's a loss for you, and I don't expect any kind of discontinuity In between. And other than that, please maintain a proper notes in the class. Okay. So I'll dictate brief-y. I'll give you a brief dictation for every concept which we are going to discuss. So because yoga is slightly technical subject and, whatever we are discussing, so if you can write down and go back and revise as it is, it will be easier. Fine. And having your single notes is going to be useful in a subject like geography. I'm not sure about other subjects. I'm not going to comment on that. But geography, expect you to maintain a proper single notes. Read NCRT. Read GC Deon. Fine. So but come back to the notes always. Notes is from where you are going to revise multiple times. Fine. And, those who have not read NCRT, whatever the primary source suggested, I have a very easy plan. Go with the class. Whatever we are covering in the class, just cover it from NCRT also. Okay. Let's say today we have discussed regarding the cyclone. Again, after the class, when you go back first, read from the class notes, revise it from the class notes, then read the same chapter from NCRT. NCRT may not you don't have to go in the sequential order. It's fine. At least cover the topic, which is which we are covered in the class. So the point is it's not like you will get anything extra over there. Many of the times you you would have got more in the class. Okay. Sometimes you may find something extra also. That is also there. It's not. about adding more information. It's about reading the same thing in a different language, in different. context to better understand the subject, to have a better clarity. Fine. So whatever the extra thing you get it there, add it in the notes. Don't make separate notes for NCRT. Okay. If you find something extra information, something, add it in the notes so that next time you can device from the notes only. But still keep NCRT. Once the entire subject is done, once everything is read before the exam, just glance through it. Because sometimes what happens, you basically directly fix the statements from NCRT. Okay. So you cannot completely skip it. Okay. So that is how you keep the notes comprehensive. Along with the class, if you cover the NCRT, that will also be covered parallelly. Okay. And there's also a VJNAS printed material. So that you can cover if you have time, if you already read NCRT. Okay. If you have time, then you can go through that. Otherwise, you finish this, then you can go through that later. Okay. The order is class notes. Class notes is your primary. Okay. So second is NCRT. NCRT includes the geology and total geography also, respective topics. The third is vision AI is printed material. Okay. First, color the notes. Daily basis, you have to revise. Okay. So I have told you, so it is my job to make you fall in love in this subject provided you show genuine curiosity, provided you daily revise it. Whatever you have covered, just go back and revise that at least. It's a very simple exercise, but very, very effective. Okay. So doing just what is done today, completing that, then you do whatever your plan. You want to prepare for option, go ahead with option. You want to read others, okay, go ahead with that. But what is covered in today's class, it has to be covered today only. Complete it. Right? This is this is must for sure. Right? Anything else? If you have anything any any doubts, you can ask me. You can ask a doubt as much as possible. Okay? As I don't talk among yourself, you can talk to me. You can ask any doubt for that. But even if you think it's a si y coubt, it's okay. I guess it's better to clear off the ground and to keep it in your mind. That becomes more siy. Okay. So and who knows? You krow, something would may come out of it. And if you are hesitating hesitating to ask in between the class, you can ask ir the end of the class. You can come and talk to me. Or, if there's anything that you want to go in little bit more detail because restrict only to GS. K. So GS geography. take option class also here in visionaries. Okay. So but it is very much important to restrict the depth. I restrict that for GS. So if you have anything in detail to discuss, you can come and discuss in the end of the class, not ir between. In between, you can ask anything related to what we have discussed. You want to go beyond that, you can ask in the end of the c'ass. So let's not waste others time for that. Fine? Any doubts? So so we'll start with the first, unit that is, a general introduction LO cosmology because I told you this is, introductory part, right, before we start with the, you know, geomorphology. So I'll give you at the beginning of every unit, 1 give you the topics to be covered. Okay. S0 and these are the topics in the same order I'll be covering. So do you also have a charity? Because many of the times it happens that you are getting doubts related to those topics or which comes later. Okay. 30 so we can hold it till then. Right? So make a list of this. Make it, write this in the first page. So we'll continue after the break. So so in prief, I told you what is geography. Geography is basically the study of places the study of places on the earth and, the relatonship between the people and their surrounding environment altogether. Okay. This entire studies, what is basicaly caed as geography. That is how the subject of geography evolved. Right? From mapping to description of physica. features to tac explanation of resources, cconomic activities, kip, so all of this. The Lern geography was actually coined by Frasathians, who is called as the the father of, geography for for his contribution. You know, he gave it a very definite shape to the subject. You know, we had this idea of flat earth. It was thought to be completely flat for a Long period of time. Two thousand one hundred, two thousand two hundred years ago itselt, Eraslothians had come to a conclusion that earth was spherical in shape. Not only that, he had even predicted the circumference of the earth. He has calculated the circumference of the earth: that long ago. It took a very long bit of time for people to accept this notion that Earth is very sentient. So that is why he's called us the the father of geography. Let's write the definition. Geography's description of earth. Geography's description of earth. The term was coined by Frasthenes. The term was coined by Erasathians, a Greek philosopher What is known as the father of geography? Next point. Geography is the study of places. Geography is the study of places and relationships between relationships betweer people and their environment. People and their environment. First topic, shape of the Earth. Shape of the earth. What is the shape of earth? Okay. You have read something over it? It's okay. So let's keep that aside. Tell me how does it look? It looks like spherical. So this is a globe, the representation of earth. But when you go out and see, do you see a spherical shape of earth? Can you actually see the spherical shape of earth outside? Then or what basis you are seeing the earth is spherical in shape? Just because somebody has made this globe, somebody is giving this idea, will you pelieve? Even if cube car also evolve? Yes. Okay. People went to space from the space. You saw you can see the pictures. Have the satellite imagery. Let's say evidence direct evidence. Okay. When you went to the space, first you send the satellites. So then so we had the chance to go by ourselves. So when you go into the space, you wi see the actual spherical saape of earth. That too, you have to go a very, very far distance to see the complete circle of the earth. That is very, very big in size. Okay. Earth is very, very big in size. There are very few people in the humanity who have seen the complete circle of the earth. Very few. You can count the tip of your fingers. Very few people are there. For that, you have to go to a very far distance. And those, of course, those who wert to moon during Apolo miss'ons. Recause even from the Ingresser space station, ingresser space station is here at this height. You'll not see the entire circle. Of course, you'll see tac curvature from there, but you not see the entire circle. Fine. So satellite imageries and the videos and pictures taker. So through the the space navigation, that is one of the important evidence to prove the spherical shape of other than that, satellite imagery is something which came very recently only. We've sent satellites, we sent human beings in the last sixty, seventy years. How about before that? How did we come to conclusion the earth was spherical in shape? Two thousand one hundred years ago, Aristoteles had come to conclusion the earth was spherical in shape. Why? He had satellite? No. What are the evidences to prove the spherical shape of earth? For a long time, people used to believe that the earth was flat. Is that right? There's the thing that there is totally flat area. You travel continuously. They will they will lose the end of the earth. You travel further, you will fall down from the earth. You'll go into Pathal Gok. Is that right? So what are the evidences to prove the spherical shape of earth? Yes. Yes. And then sunrise and sunset somebody is seeing. Then anything else? Yes. Would not. It will not. Days are longer. Nights are shorter. Okay. Inclination of sun is good. Repetition of climatic conditions. Good. Anything else? Thank you. Good. Anything else? Title? Action. Okay. Good. So let's go to basics. There's few more concepts required a little bit more understanding. Okay. So most basic things. One of the direct evidence to prove that Earth is very current shape is that you can take a circumnavigation around the earth. What do you mean by circumnavigation? I told you, so if you go straight, you will end to go to Pathalu. That doesn't happen. You travel continuously, you will come back to the same point. Okay. So if you travel continuously, you will not see any end of the earth. For you, it is it it appears like you're going straight only. You're going it It appears as if you're going on a flat surface. Okay. So after complete the entire circumnavigation, you will come back to the same place. This is possible only on a spherical body. Circumnavigation is possible only on a spherical body. You can do circumnavigation on the earth. It's a direct evidence. Who completed first circumnavigation on the earth? First person to complete the circumnavigation. Megha fifteen nineteen. In 1519, he completed the first circumnavigation. He gave a direct evidence. When? First one. Shape of Earth is the overall topic in that surveying is evidences to prove the spherical shape of earth, evidences to prove the spherical shape of earth. First one, circumnavigation Circumnavigation of Earth is possible. Circumnavigation of Earth is possible only due to its spherical shape only due to its spherical shape. So first circumnavigation by Magdalene fifteen nineteen. Now another very important evidence which enables us to, you know, come to a conclusion regarding the spherical shape is the The approach of ships near to the coastal region. The way ships reach the coastal region, the ships the way ships move away from the coastal region. Ship's visibility. Any of you are from coastal region? Caesars? Gurter. Good. Anyone else? No? Anyone from coastal region? You ever been to coastal region? When you go to coastal region, so you see that ships or big sized boats can moving away from the coast or coming towards the coast. So this phenomena is more clearly visible if you are in the water. You go into the water, you take a ship and go into the water. Okay. You start to see other ships coming. Okay. Army ship which approaches you will not. approach completely as it is in this in a totally straight. manner. Appears like it is rising from the water. Okay. So let's say this is this As your ship. You are here. Okay. Or you can imagine to be on the land also. So let's say this is your ship. In case you are standing somewhere here. Again, you're trying to see in the vernacular. If any ship is coming here, you will not see the ship appearing completely straight. No. This is revertheless scenario because of the curvature of the Earth. Okay. So this is what the surface is. Wherever a saip is approaching, the first thing you will see is its lag. From here, you try to see you will see only flag. That is the light.. There's only flag above the water. After some time, you try to see the ship has come here. You will try to see some parts of the deck. Okay. We'll try to see this. Only some part of the deck. After some time, you see the case of the railing of the deck along the flank. Then when the ship has completely has raised up on the surface, then you will see the entire ship. Lappears like the ship is rising from the water. It's because of this curvature. Because of the curvature, the shio appears to be rising from the water. If 't in going away, it appears like 't is sinking into the water. Okay. Part by part. Yes. Some part, some part, some part, it goes as 'f it 's going into the water. Those phenomena people had observed long back. From the time of Indus Vacy civilization, we have been doing the sea trade. Mesopotamian Egyptian civilization doing sea trade. We have already seen. Okay. So that time only, we should have come to a conclusion. It's a very clear evidence to prove that earth is critical in shape. Because of the curvature, they appear to be rising from the water as well as sirking into the water. Next point. Ship's visibility. Ship's visibility. A distant ship appears to be a distant ship appears to be rising or sinking in the water. The Occurrence of Different Timing of Sunrises and Sunsets The occurrence of different timing of sunrises and suns and sunset at different location is a very important evidence to prove the spherical shape of Earth. Okay. So what do you mean by this? You must have heard about this phenomena by yourself. Okay. Put all you have spoken to anyone from a different country or if you're watching any of these international events, cricket, Olympics or something, tennis or something. The time is always different in different locations. Right? You're watching live. You're watching it nighttime. There there is night daytime. Right? The time is different in different location, not the clock time. I'm saying the sun time itself is different. Here it is morning. Another place it is afternoon. Third place it is evening. The fourth place is night. How is it possible? And the way it changes, you may say, okay. Spherical body is there. In that case also, there is a possibility of the the the sun rays and sunset are happening at different location, time being the different imagine a box here. So here there is afternoon. Here it is morning. Here it is evening. Here there is night possible, but the way it changes. There's a proper uniformity here. Instead of a spherical shape, if there is a box here, when the sunrises have when the noon is there, every place will experience the noon here. I guess when it is morning here, every place experience morning here. When it is evening here, every place experience evening here. When it is night, every place experiences night. But the time doesn't change like that. There's a proper time change. Okay. So for example, for a person who is standing here, he sees that the sun is setting. Okay. So for him, sun is setting. That means evening, 06:00 it is. Okay. For a person was stands here, it is 35:00. Okay. So this is the horizon for me. It's slightly above it. For a person who is standing here, it is 04:00. "t's 03:00, two o'clock. For a person who is standing here, it is afternoon, 12:00. Can you see the weight gradually changes that gives out the curvature? Okay. So to make it simple, we call it a spherical shape for a person who is looking here, he observes evening. For a person who is looking here, he observes morning. Here it is, afternoon. And in between, there is a gradual change from morning to afternoon, afternoon to evening, evening to night. Uniformly gradually changes. Okay. So this kind of variation is possible only on a spherical body. Fine? The way the time changes. So gradually, the difference of sunrays and sunset at different locations. So then, Eraso things can do using a Different thing, not the day and night. The observation of Eraso things was different. 'll tell you about that. That's what people did not believe. There was not much of communication. People took a long time to believe this. It was not a wide opinion. For a long time, people used to think that earth is flat. Some of them were telling. They're not listening. So it took a long time for them to understand. Okay. Yes. This is right. And rest of these, how did they come to conclusion? 'll tell you. This is difficult to communicate. Yes. Different timing of sunrise and sunset at different locations. Please wait. Different timing of sunrise and sunset At different Locations. So next, Bedford Level experiment. Just write the name of it. I'll explain the experiment. Bedford level experiment. Bedford evel experiment. Fire. No. So this you can do it by yourself. Okay. Only that you need a very big area. Take three poles of equal length. Okay. Exactly equal length. Instal on an area of completely flat surface. Totally no difference in the elevation. All three poles of equivalent. Again, so you stand at a very long distance, use a telescope or binocular or something to try to see the height of all the three. The surface is completely flat. The poles are equal length. All the three should be visible at the same height, but it never appears like that. Because of the curvature, the central one always appears taller than the other two. The central one always appears taller than the other two because the curvature just becomes taller. Right? This has been done. Okay. So with proof, this experiment is what is called as Bedford level experiment. Okay. So we don't have to describe this. Remember the idea. Fine. How eclipse can be evidence to prove the spherical shape? Which eclipse? Somebody was saying eclipse. Which eclipse? Solar eclipse, another eclipse. Why not solar? Earth's shadow will not be visible during solar eclipse. Right? You want to see earth's shadow. During the solar eclipse, you'll see moon's shadow. Moon is visible. Moon is blocking the sun. During the lunar eclipse, earth's shadow is falling onto the moon, particularly not the total lunar eclipse, the partial lunar eclipse. Total lunar eclipse will completely cover the moon. Partial Lunar eclipse partially covers during that time you will see the curvature. A part of the moon is blocked, that part of the moon is visible. During that, there is a curvature visible. If there is a curvature, that means it is a spherical body. Okay. So do you think if any other shape will give a curved surface here? The shadow is very clear indication that earth is a spherical body. Lunar eclipse, partial lunar eclipse particularly, expert, partial lunar eclipse, during which circular shadow of earth is visible. Circular shadow of Earth is visible. So we have a query here. Does that mean that there is no flat surface on the earth at all? So, technically, no. Everything is a curved surface. But in our scale, in human scale, it appears like flat. It is a very minute curvature, but overall, the surface difference in terms of topography is so high. You'll not be able to notice that. It's a curvature everywhere. And other than this, the other spherical bodies in the solar system, most of the planetary bodies, they're so spherical only. Right? Do we have any other shape other than asteroids? Right? All the planets, we have identified the planets long back. Again, so the Lewide discovered telescope and the pre true telescope here not or'y seer jupiter, he had also seen the moors of jupiter. All o these are spherical shaped bodies? Okay. When every body of the solar system is spherical in shape, all should also be spherical in saape? The spherical shape, next point, spherical shape of other planetary bodies, stoical shape of other planetary bodies of solar system. So how did Erastothemes come to a conclusion? Different Length of shadow at different Locations. Length of shadow will not remain the same at every ocation. So shadow. You know, the concept of shadow. If there's a block, Let's say, assume a building aere. Let's say suniigat Es falling here. Okay. So if it is falling in this direction, this wil be the area of shadow. Is it right? The sunlight is falling here. This will be the area of shadow. The sunlight is falling straight. No shadow. Is it right? _f you observe the objects of same height at the same time in different Locations, you will find different Length of shadow. Like, it's so for example, at 07:30, you are trying to see a building. Okay. Buiding, Let's say, 30 meters height. So there is a length of shadow ir: a particular place. You go to a different latitude, higher latitude or lower latitude. The same time, same height ouilding will give it different Length of shadow. why? The reason is the angle at which the sunlight falls on the surface is not same everywhere. Okay. So if this is the surface of Earth, this is how the sur's light come. Okay. Sun's light comes totally in parallel rays. Okay. This is how the sun's ght come. As I can start with imagination. Okay. So sunlight, sur is like this. It comes out, lies like this. Drawing Because this is the size of sun compared to this carta. When sunlight comes out of the sur, for earth, it is always parallel rays. It always comes in parallel ways. Fine? Since the Zarth was completely flat, the sunlight will fall at same angle in every Catitude. Is that right? Length of shadow will remain the same at every latitude, and that is not the case. The same sunlight okay. So ignore this. Because of the curved surface of earth okay. Here you can see it falls straight. Imagine this is 12:00. Sunligat is falling straight here. Okay. So at. only in this time, it is falling straight. Here, there is no shadow at all. Okay. So imagine a building here. Okay. So this building is not giving out any kind of shadow building or tree or any object, a pole. But if you magire the same buiding here, This light is not falling straight. Can you see the shadow here? Okay. So now imagine the same building here. This light is falling like this. This is the area of shadow. It has increased. No. See this? This is the entire area of shadow. Lengt.h of shadow also all those increases, I'm Leiling at the same time, same height building or same height structure, all those gives a different ens of shadow. You know, Crastatine observed long back because of it his curiosity. Once the traveler was coming from Equator towards the northern part, Northern Alexandria, I think Alexandria was where he was there. And also things. Where is where is Alexandria? Egypt.. Okay. So near to the Mediterranear, Alexandria was there. He met a traveler who came from the South, near from to the Equator towards the northern part. And while talking about the different observations which he made, the traveler explained a very peculiar event which he observed. He said on a particular date on a particular date, while observing a well, he did not see a shadow inside the well. You have seer a well, open well? Usually, open we'l almost wil have a shadow unless the sunlight is falling exactly straight. Okay. Only when the sun-ight follows exactly straigat, there will not be any shadow in any part of the wall because it's completely circular. The surght is falling in any angle. There is always at least one part of the shadow will be there. For that, sunlight has to fall exactly at 90 degree. And remember, sunlight will not. a exactly at 90 degree in every light. If you don't think at 12:00 everywhere, sunlight falls at 90 degree. No. Because of the curvature, you will really observe this phenomena. Okay. He said on that particular day observe that kind of phenomena in a well. And Aristotle was very clear that he did not observe that on that day in his place. Again, his place on that day, he did not observe that phenomenon. Okay. So he tried to measure the length of shadow. Okay. So in that particular latitude, there was no shadow. Here, in this latitude, there was shadow. How much of shadow is there? What's the length of shadow? Okay. If you try to calculate this more accurately, it will give out the curvature. At what rate the shadow is increasing, if you try to measure it more accurately, you can actually measure at what rate the surface is undergoing the curvature. That is how he came to a conclusion regarding the Earth's curvature and he was almost right. Okay. So by measuring the the way the length of shadow varies from one place to another, from one latitude to another. Because of this only, he observed this. He very clearly come came to a conclusion. Okay. This is how it is. Here, the traveler was there. On the same day, he observed shadow here. Here, there was no shadow. Okay. So you understand the difference in the latitude, difference in the latitude, length of the shadow, how it is changing. You can easily calculate this. Of course, it's technical, but you can get the correlation. That is how he was able to come to conclusion about this long time long ago. So write this. Next part. Different length of shadow. At different altitudes. Is possible only due to spherical shape of the Earth. Now the last but most important, the shape of horizon. What do you mean by horizon? What is horizon? It is where the surface appears to be meeting the sky. Where the land appears to be meeting the sky or if you're in the ocean, the water appears to be meeting the sky. Okay. So that is what is called as horizon. Have you seen horizon? It's difficult to see horizon in a city like Delhi. Okay. So you have to be on a tall building. Okay. So elevated mountain or somewhere. Okay. So where you can see the actual edge. Okay. Here you go out and see what you see is just the building. Okay. So the horizon when you try to see, the shape of horizon, if you observe, horizon never ends. Have you seen a horizon ending? No. There's no end to the horizon. Okay. There is horizon. If you continuously try to see, it's always a continuous line. There's no break. There's no end. There's no shaft and as such. That means what is the shape of horizon? Circular. Only a circle can be continuous. Horizon is always circular. Fine? Horizon is always circular and circular horizon is possible only on a spherical body. Circular horizon is possible only on a spherical body. No other shape can give circular horizon. If you stand here, your view ends here. Okay. If you stand here, let's say you're standing here. Your view ends here. So if you continuously see, this is always a circle. Circular horizon is possible only on a spherical body. Any other shape, the curvature is different. The way the surface is changing, that becomes different. If it's completely flat, that's a totally different thing. Okay. So only on a spherical body, the curvature sorry. The horizon becomes completely circular. Fine. There's one more thing. The spherical shape causes the horizon to be shorter than actually it is. What happens if it is totally flat? You will be able to see little bit farther horizon. When it's completely flat, it is going till the edge, so it takes up to the visibility. Okay. The edge of the horizon doesn't depend It depends upon your visibility, how far you can see. So that means the horizon is little bit farther in case of flat surface. In case of curved surface, it curves and horizon ends before the actual part only. That is always the case. It is very clearly visible if you go into the sea or into the ocean. Okay. So you take a ship or Leave the land and slightly go into the water. Because after some time, you can clearly see that there is no any other land. If the overall area covered by the horizon is actually smaller in case of curved surface than the total flat surface. Horizon is always smaller in a curved surface. Right? One more thing. The area covered by the horizon depends upon the altitude from where you are making the observation. Area covered by the horizon depends upon the altitude. Let's say your your height is here. You are trying to see the horizon. This will be the horizon which you are seeing. Again, if you try to see from here, this will be the horizon. You try to see from here. This will be the maximum horizon you can see. In fact, itself is a very far distance. That is another thing. With increase in altitude, the area covered by the horizon increases. That is also possible only in spherical body. Okay. So horizon very easily gives out the Earth's spherical in shape. Okay. So here there is a very simple representation here. Okay. If you are observing the earth from here, this is the area called by the horizon. Okay. The complete circle. If you observe from here, this will be the area called by the horizon. Much more bigger circle. If it is totally flat circles you observe from here or here, this is always the horizon. From this altitude, from this altitude, can you say this is the area caught by the horizon from here? You can see up to here. That is the meaning of this. The Earth is completely flat. Corizon is actually wider. At the same altitude, you will see a bigger horizon here, but if you increase the altitude, in this case, this remains the same, but this will increase. Fire? So write this. The horizon appears circular, the horizon appears circular only from a spherical body. Only from a spherical body. The area covered by horizon increases with increase in altitude. Next point. At a given altitude, the area covered by the horizon horizon for a spherical body is smaller than “o” a flat surface, smaller than for a flat surface. Okay. Just a second. So for many, this is this may be difficult to imagine. So let me just make it a little bit more clear because many of you might not have seen a horizon actually. Okay. So horizon is best always viewed from the ocean. So by the way, this 's Google Farth, the actual representation of Farth based on the satellite imagery. This is totally different from the Google Map which you regularly use. Okay. So imagine you are in a boat or ship in Bay Of Bergal. So 've taken you to Bay Of Bengal. Okay. So this is this is how you will see the horizon. At least in this, you can see the horizon little curving, but near to the surface, you will never see horizon curving. Even from the flight also, you will never see horizon curving because you are always lying very, very near to the surface. Horizon always appears straight. The thing is 't appears completely continuously straight. You take a three sixty degrees of rotation, it always appears straight. Okay. So let me show a three sixty degree view. Okay. As you take a rotation, can you see? So it is always red. There is no end to it. That means, horizon is circular. Okay. Friimeter three sixty degree rotation. You saw it. Right? Can you see? Horizon is circular. There's no end to it. And circular horizon is possible only on a spherical body. There's no other way around. So now let me, tell you about this second thing which I told you. If we increase the area code by the horizon sorry. If you increase the altitude, the area code by the horizon increases. Right? So it's very easy to observe this. don't know if any of you observed this by yourself. So this is our daily? Okay. So let's go to India. You can see the satellite imagery. The Google, they have added some augmented reality also. You can it feels like there's a structure about that. This is this is India Gate. Have you guys have visited India Gate at Least? Fine. Okay. So so let's try to see the horizon from the top of India Gate. Fine. Okay. This is not top. You're going inside the end of it. That's fine. Right. Okay. You've seen the horizon? Fire. Let's take a three sixty degree rotation. Okay. So from acre so behind that part, you can see these buildings. So I give you a three sixty degree rotation from here. Can you see this? This is, Java Masjid. Fine. Satellite to measure. It's almost clear. You can trust Google at Least for this. You are seeing up to the horizon is near to the moment. Right? There's the horizon. From indicate, if you see at this altitude, what is altitude? Two sixty five meters from the surface. Okay. So I have to do this two sixty five meters from the surface. So horizon you will see up to the atmosphere. Okay. So let me give you a taree sixty degree rotation on this side so you can see Parliament. Okay. The old parliament is visible and the Norta Lock, South Lock. Okay. So that is almost near to the horizon. And from this side, okay. So even think the mira is also not visible. That is also a little bit far. Okay. So you can see. So that is the that is the homogeneous. Right? So let me increase altitude. From two sixty five meters, I'm increasing the altituce. Okay. So at this altitude, Let's see. Can you se១៣? just, you know, so doubled or nearly doubled, like, seven ninety meters. I'll tell you that seven ninety meters. know we're seeing til here. Now it has almost gore there. Not only Delhi, we have gone into the UP border. Okay. So one try to observe on this side. The entire Delhi is visible. Okay. You car see. The entire Delhi is visible. The Horizon has become bigcer or not. Richt? Can you see Cimalayas? And tais already over, you can see up to Himalayas, the horizon has become so wide. Zarlier, only this bit of horizon. Now the horizon has expanded up to that part. That is a proof of spherical shape, is it clear? You want to observe it practically? I guess many of you are from UBER. Again, any of you are from Lucknow, Patna, Kolkata? Any of you are there? Yeak. Okay. So do you see Himalayas from Lucknow, from Patna? Himalayas, From Lucknow or Patna, do you see? You will get an opportunity to fly from Delhi towards the east. Okay. Let's say you take a flight from Delhi to Guwahati or Delhi to Kolkata. It flies above Lucknow and Patna. Okay. So in that travel, try to sit on the left side of the window, left side of the plane. You can very clearly see the Great Himalayas. You can very clearly see Great Himalayas goes beyond the cloud line. Very beautiful view. It will go beyond the cloud line. You can very see clearly see the the snow capped peaks of Himalayas on a clear day. Okay. So how is it possible from Lucknow? It was not visible. And if you fly other Lucknow, you can very clearly see the Himalayas. That means the horizon has widened. Your horizon was smaller near to the surface, but flying above horizon has widened. That is a proof that Earth is spherical in shape. Right? Yes. That is this evidence. Is that clear? So like this. So few more evidences are there. So most of them are related to a little bit more advanced concepts. We'll discuss that later. These are the basic ideas, basic evidences using which we can come to conclusion that this spherical inch here. Tell me. What are the evidences? Number one, circumnavigation of earth. Okay. So first one by Magellan in 1519. Next, ship's visibility. Okay. So ship appears to be rising and sinking from the water. Then different timing of sunrise and sunset at different location. Then bed flight level experiment. Then partial lunar eclipse, spherical shape over the planetary bodies, and then different length of shadow, different, latitudes, and then yes. Circular horizon and the area called by the horizon widens. Okay. These are the various evidences to prove the spherical shape of the Earth. Now with this smooth out difficulty, we established that Earth is spherical in shape. Okay. So people start to believe and suddenly one guy comes and says no. No. Earth's not spherical in shape. Okay. Okay. I mean, no. It's not spherical in shape. Et, is he was anyone else, we could have ignored him, but he was Newton. Okay. So it is not perfectly spherical in shape. Okay. So there he said, it is not perfectly spherical, what is spherical? Spherical is the one which has the same diameter in any direction. The diameter should be same in any direction. You measure the diameter, it should be same in any direction, but earth's diameter vary. If we measure the diameter along the Equator, it comes out to be seventeen fifty six kilometers. If we measure the diameter on the Pole, it is sorry. 12,756 kilometers. Here in this case, 12,714 kilometers. There is a gap of nearly 42 kilometers. The equator wave diameter is longer than the pole wave diameter. That means earth is slightly flattened near to the poles and buged at the equator. Okay. So it is not a perfect circle. There's a distortion away from the circle near to the poles as well as near to the equator. Near to the equator, it is slightly elongated. Near to the pole, it is slightly shortened. Okay. So tacrefore, we cannot consider Earth to be a perfect sphere. So okay. So it is not a perfect sphere. Then what should we call it as? Why? Why the ooid? What is the meaning of the ooid? If it is a sphere, the body is called a spheroid. If any body is sphere, it will be called a spheroid. Cube is called as cuboid. We don't know what to call this earth because there is no such shape 'n any other part of the universe. Earth has only a very peculiar body of its own shape because every planet has this kind of distortion that varies from one planet to another. So we don't know what to call it as we kept the name of Earth: only. Spirod, Zarth is geoid. Okay. So basically geoid means the shape of earth. Fine. All such distorted spircids because every planet is distorted only. What is the reason behind this, spiroid? Sorry, gecid. The rotation. Because continuous rotation causes the mass to be thrown away from the poles and some of them accumulate rear to the center. Okay. The rotation. Newtor said this at that time only because of the rotation only. Not only for that, every planet has this kind of distortion. So all such distorted bodies are called as colate spheroid. Okay. That is distorted sphereia. Tacy're called as oblate sphercia. Finc? That is the idea of cecid. Let's write over this. Submitting geoid. First point. The Earth is flattered near to the poles. So this flattened near the poles and ouzzed at equator and buzzed at equator. So rext point, it's due to the continuous rotation of Farth t is due to the continuous rotation of Earth. It was first proposed by Newton. It was first proposed oy Newton. Next point. It is applicable to other planets too. It is applicable to other planets too. Next point. This shape of Larth is called as this shape of Zarth is called as geoid or oblate spheroid. Geoid or oblate spheroid. That is regarding the shape of Earth. Any doubts here? No. It is almost constant. It happened during the early revolution of Earth when it was in a molten state. Yes. And now it is almost stable. Anything else? So rest all clear? So Let's leave early today. So tomorrow we have afternoon class. Okay. Yes. So in tomorrow's class, we'll cover, Latitudes, longitudes, rotation, revolution, and, if time permits, we'l start with seasons. And those who have not read these parts from NCRU, you can refer to sixth standard NCRT. Okay. These topics are not there in 11 standard NCRT. It's there in six standard NCRT. Thank you. Thank you.