We will start with the fundamental geography. We first study the latitudes. Now we know that latitudes are imaginary horizontal lines on the earth.
But this is more than that. When geographers were allowed to draw latitudes, what did they do first? They first drew a line connecting North Pole and South Pole.
And they drew a horizontal line at the middle point of that line. And this horizontal line was called as a reference line, zero degree or equator. After drawing that line, this line was called as a reference line.
The angle of the latitude given by this line is given as the degree. If a line is made from equator 15 degree, then it is called as 15 degree latitude. If a line is made from latitude 45 degree, then it is called as 45 degree latitude.
If it is made from 90 degree right angle, then it is called as pole. It is called as the line of Northern Pole and Southern Pole. This is just a point.
What is the definition of latitude? The definition of this is the angular distance of a place from the equator. Right? That means the equator is the reference line and the angle distance that is created from there is called the latitude.
Now you can see that all the latitudes are concentric circles. Concentric circle means that all the circles have the same center. Now if we see all these latitudes, then all their centers will be on this line. That is why the latitudes are called concentric circles.
and they are also called parallels because all the latitudes are parallel and they never touch each other. So this is the latitude. Now what we know is that some latitudes are very prominent and famous like this equator 0 degree, 23.5 north, 23.5 south, topic of cancer and topic of Capricorn. And after that 66.5 north, 23.5 south, topic of cancer 6.5 North and 66.5 South, the entire circle.
And beyond that, North Pole and South Pole. Now we know that the region between two tropics is called Tropical Zone. And the region between tropics and Arctic Circle is called Temperate Zone and it is called Beyond Polar Zone.
But how did this division happen? Here the tropical zone is the heat surplus region and the temperate zone is the heat deficit region. So, you...
Due to this difference in heat reception in tropics, temperate and poles, there is pressure difference on earth. Due to this pressure difference, the entire wind system has developed on earth. We will study this in detail in climatology.
But first we know how this heat surplus and heat deficit happened. If the earth was flat, the sunlight would have been visible everywhere. But because the earth is in a spherical shape, the sunlight reaches the equator region directly.
And you can see that the length of this line and this line is less and the length of this region is more. This means that the distance between the sun and the polar region is less and the distance between the sun and the polar region is less. the heat of the light is very high. When the temperature reaches the polar region, the light gets dispersed and diffracts.
Due to this, the heat intensity decreases. That is an area where the light gets dispersed. Due to this, heat is surplus in this region and heat is deficit in this region.
I see the question from the E.Cupesic preliminaries of 2001. Who among the following was first to state that Earth was spherical? a. Aristotle b. Copernicus c.
Ptolemy d. Strabo The answer is Aristotle. Factual Question We have seen earlier that Earth is spherical and that is why it is having heat deficit and heat surplus region. Let's go one step ahead.
Earth is not only spherical, it is also tilted on its axis. It is tilted from 23.5 degrees on its axis. Due to this, two situations are created.
In one situation, it is away from the northern pole. A southern pole is closer to the sun. This region is heat surplus region.
And this region is heat deficit region. In southern hemisphere, it will be winter. and in southern hemisphere, it will be summer and in northern hemisphere, it will be winter.
If we see in opposite, when northern pole is towards the sun and southern pole is away from the sun, then it will be summer in northern pole. and summer in northern hemisphere and winter in southern hemisphere. So, this is the second thing.
Because of the sphericity of the earth, heat deficit and heat surplus region is formed on earth. Second thing is that whenever earth is tilted, this is the reason for season on earth. Why is there season on earth? Because earth is tilted.
Let's go one step further. Earth is not a sphere and it is not only tilted. Third thing is that earth is not a sphere. Earth is revolving around the Sun in an elliptical path. Earth is created in four situations because of the elliptical path.
If Earth had a circular path around the Sun, then Earth would always be at equal distance from the Sun. But because of this elliptical path, Earth is farthest from the Sun. And these two positions are equally far away from the Sun.
So, Earth is at equal distance from the Sun. Because of this, if we look at the situation at the end of the elliptical path, then the northern hemisphere, where the northern pole is towards the sun and the southern pole is away from the sun, here is summer and here is winter. But in the summer here, there will be a day which is the longest day of the year.
That is, in this summer, their day length will be the longest. And this is called summer solstice. It comes in late June.
If we look at the reverse side, when the southern pole is towards the sun and the northern pole is away from the sun, and here is winter and here is summer, then in the summer of the southern hemisphere, there will be one such day which is the longest day of the year. This is called winter solstice. Now look, this is the longest day in the summer of the southern hemisphere, yet it is called winter solstice. The reason for this is that it has to be differentiated from the east term.
Plus, we have referenced the northern hemisphere. So, this winter solstice is happening in late December. So, this is called winter solstice.
Now, these two positions which are at equal distance from the sun, here there are equal days and equal nights. So, this is called equinox. If it comes in spring season, then it is called spring equinox.
If it comes in autumn season, then it is called autumn equinox. Right. This thing should be remembered because there were questions in CDS 2014. In Table A, it was written that Winter Solstice, Summer Solstice, Spring Equinox and Autumn Equinox.
In Table B, it was written that June, December, September, March. So, I have to remember that Summer Solstice comes in June and Winter Solstice comes in December. Spring Equinox comes in March and Autumn Equinox in September. UPSC Prelim 2013 Question Variation in length of the daytime and night time from season to season are due to Earth rotation on its axis B, Earth revolution around the Sun in an elliptical manner, c. Latitudinal position of the place d.
Revolution of earth on tilted axis Let's see. Earth rotation on its axis is not possible. Because the axis is rotated, seasons are coming.
Why? Because Earth is winter and summer. Only from that we can know.
Latitudinal position of the place only tells whether it is in the heat surplus region or in the heat deficit region. Revolution on Earth tilted axis is same as A. Because it is tilted, we can know which seasons are coming on Earth. B is the reason. For that, I will take you back to the slide.
See, when here... in northern hemisphere, summer is its longest day. Then when it passes and comes here, then in its northern hemisphere, day and night time are equal. Then when earth reaches this position, then in the northern hemisphere, night will be shorter, it will be longer and day will be shorter.
Then when it comes in this position, then day and night are equal. So due to this elliptical path, differences are coming in day and night time. Right? Thank you. Daylight saving in temperate region.
We have learnt that in summer, day light is more and in winter, day light is less. But in tropical region, this variation is not seen quickly. For example, in summer, the sunset is at 6.30-7 o'clock, and in winter, it is at 6 o'clock. So, the difference between season to season is very less, maybe 1 hour or 1.5 hours. But when we go pole-wards from the tropics, then the variation in day and night time increases.
For example, if it is 1 hour here, then it is 2 hours, 3 hours, 4 hours. In this way, the variation increases. I want to explain this with my own two experiences.
One experience is in Moscow, Russia, and the other is in Alaska, USA. I went to Moscow, Russia when I was in 8th standard. I went to Moscow on a school trip. The teachers told us to go to sleep because we have to catch a flight to Istanbul the next day.
We all reached the room and the teacher told us to sleep at 10 pm. It was 10 pm but we saw the window and it was quite daylight. In India, it is 4-5 pm in the evening. It was that much daylight at 10 pm. We were surprised to see that the teacher was telling us to sleep at 10 pm.
But there is so much sunlight outside, how can we sleep? So, in this region, the night is very late in summer. The second experience is in Alaska. I had gone there two years ago. In Alaska, we had gone there in summer.
When the whole day trip ends, the tour guides come to the hotel. They say, good night, see you tomorrow. But good night, when the wish was strange because there was no night. Then in daylight, they say good night.
I have never seen darkness in my 20 days stay in Alaska. I used to sleep in daylight and wake up in daylight. In this region, night is only for 4-5 hours and day length is very long. In winter, the length of the night is increased.
Night time is more and it gets dark at 4-5 in winter. So, these are the temperate regions. What mechanism has been developed by the government? Whenever winter comes, the government notifies them. And it has become a habit for them that whenever a day comes, they give their watch one or two hours ahead.
According to the way the government has notified. So what happens with that is that their day starts early. One or two hours early. Suppose their office timing is 10 to 5. So what happens by giving two hours ahead is that from 8 o'clock they will start the day. Right.
Naturally, the time starts at 8 o'clock. That is why, when it is 4-5 pm, when it is night time, then their electricity is not used much. To continue office, to continue working hours, they do not have to consume electricity. And their maximum working hour is completed in natural sunlight.
So, this mechanism of conserving electricity, of energy conservation, and according to this, they can save their time, 1-2 hours, The system of further development is called Daylight Saving in Temperate Regions. Now we will study the Longitudes. When the geographers were to draw the equator, they drew a line from the North Pole to the South Pole and got a reference line.
We got the latitude, but how did we get the reference line for the longitudes? Because all the longitudes have the same length. So then it is very difficult to get the reference line.
So, how did the reference line get there? So, the geographers made a reference line of longitude near Greenwich city in UK. Why did they make it there?
There is an observatory called Greenwich Observatory in Greenwich. When the conclave of the geographers was made, where they decided the latitudes and longitudes, most of the geographers belonged to this observatory. Plus, this conclave was made in the area of Greenwich. during the colonization period or industrialization period, UK was the leader of the world. Great Britain was the leader of the world.
So, because of this, the reference line that was chosen was passed through UK, the line passed through Greenwich was chosen. This is the zero degree. This is also called Greenwich Meridian and Prime Meridian.
Now, we have made 180 degree waist line from green waste. We have made all the longitudes of 180 degree. We have also made all the longitudes of 180 degree on the eastern side.
So, the opposite of this line will be 180 degree. 180 degree exactly opposite to greenwich meridian and this line also has importance which we call international date line. Here you can see this is the greenwich meridian 0 degree and in its exactly opposite 180 degree international date line.
Now you can see that this line is zigzag. No longitude is zigzag. It is straight line.
Why this international date line is zigzag? Because international date line means that whenever someone crosses this line, then we have to change the date. From here, you can see that this is Russia. And here is New Zealand. When the border between the two countries is closed, Sunlight is the beginning of our day.
First day of any year should start from here. And then the day ends. Here you can see many small islands.
This is Russia, this is Alaska, this is Canada and this is USA. Alaska is the 50th state of the USA. USA is the most important state of the world. The Alashka is here. It was a part of Russia but the US bought it.
The islands here are called Aleutian Islands. The islands here are called Pacific Islands. These islands are divided into three parts. Macronasia, Malinasia and Polynesia. You should study these islands because these islands are in the news.
These islands were neglected before but now due to climate change negotiations, These countries have become very vocal. If the sea level rises, then these countries will have to suffer the most damage. If you open the political map of these islands, you will find that many islands are under the rule of UK, USA, France and New Zealand. They are overseas territories.
There is an island here which was in the news in 2014. It is Marshall Island. There was an issue in Marshall Island that earlier it was Japan's colony. Japan lost the second world war and the USA occupied it.
When this island came under the USA, the USA tested a lot of nuclear weapons, tested hydrogen bombs and the testing of hydrogen bombs was so devastating that some islands were submerged. And even today this region is the most radioactive, the region affected by radioactive radiation. So, in 2014, Marshall Island Not only USA but all the nuclear states of the world have been charged in the International Court of Justice Including those who have not signed NPT India, Iran and Pakistan Sorry, India, Israel and Pakistan They have been charged against these three countries That is why Marshall Island is in the news It is in the Micronesia Another island that is in the news is Fiji There the Indian Diaspora is in high number During the coronation, Indian Diaspora was there and our Prime Minister Narendra Modi visited Fiji in 2014. So, look at their locations, all the islands, this region is in the news.
So, I wanted to say that if the international deadline passes over these small islands, then what will happen is that there will be two dates in one country and it will be very difficult to manage that. And these are all countries, they are very small, dispersed islands. So, that is why geographers are saying that... So, we decided that the international date line should be passed only by water bodies and not by land. So that the people living on the land do not face any problem.
Only the ocean-faring vessels or airlines have to change the dates. That is why the international date line is zigzagged so that it cannot be passed between any country. This is the international date line.
I have told you that the date starts like this. Earth moves from west to east. But because of Sun's movement, we think that Sun rises from the east and sets in the west.
But Earth's movement is from west to east. So, it is apparent that our day starts here and ends here. Now, Earth is rotating 360 degrees. Because it is a sphere, it will move 360 degrees.
Now, 360 degree move of Earth is... Earth moves 15 degrees in an hour. We can take it further that Earth moves 15 degrees in an hour.
But we keep it till here that Earth moves 15 degrees in an hour. I want to explain you with an example. See, the international deadline is passing from here. This is Russia and this is Alaska.
The international deadline is passing from here. This is Aleutian Island. If there is a day here, So, on the western side of the international deadline, it will be 31st December morning here. But in Alaska, one day later, on the eastern side of the international deadline, it will be one day later, here it will be the morning of 30th December. Right?
So, if here, If they celebrate New Year party on 30th December in Russia, then Alaskan people will not celebrate it because it is still 30th December. But if they want to enjoy this party, they will cross international deadline on western side and come to Russia. And they will also celebrate New Year party. And when Russia will cover whole Earth 360 degree and when 1st January will come in Russia, then Russian people will also be able to go to Alaska.
Because there 30th December is... It will be held on 31st December. New Year party will be held there.
There they can celebrate New Year party and come back. But there are not so good relations between both countries. Alaska is part of US. So they have done jumping.
This tells us that if we go to the western side of international deadline, then we will have one day loss. If we go to the eastern side, then we will have one day gain. If you see here, if Russians go here on 31st December, He has lived for the whole day on the 38th December.
So, for him, it is a gain. But if people of Alaska go to Russia, then for them, the whole day of December will be a loss. So, this is the loss of one day. Standard Time Now we have decided from international date line that how date is managed internationally But how time is managed internationally So that is from Greenwich Meridian Geographers have decided that every country has to follow two steps One step is that the country which is coming in the middle of the longitude In all those longitudes, choose one of the longitude And make it your standard meridian Then what we will do is that the Greenwich Meridian and we will find the difference between the two and calculate the time of that country.
For example, I am taking the example of India. India is located between 68 degree east and 97 degree east. India has declared its Indian Standard Time as 82.5 degree east. Now we have to find the difference between Greenwich and Greenwich. Greenwich is at 0 degree and India's standard is 82.5 degree.
We have seen that 15 degree for 1 hour and 15 degree for 1 hour. So to do 82.5 degree, it takes 5.5 hours. And India is on the eastern side.
This is the eastern longitude. In India, sunrise is before Greenwich. So, we have to add 5.5 hours to the time of Greenwich Meridian. So, if it is 12 o'clock on Greenwich Meridian, sorry, then it will be 5.5 or 5.30 pm. The time issue of Chai Bagan.
When the British were in India, 150 years ago, they had created a time zone for the North-Eastern region. This is called Chai Bagan time zone. Chai Bagan is known for tea planters. In North East India, when there were European tea planters, this was a different time zone.
Why was this a different time zone? The reason for this is that our... The time difference between the standard meridian and the northeastern states is around 1 hour. The time difference between the northeastern states and Gujarat is around 2.5 hours. So, for the convenience of European tea planters, the British government made a different time zone, the Chai Bagan time zone, which was one hour ahead of the Indian Standard Time.
Government rejected this idea and brought India in one time zone. There was a valid reason behind it because in India there were not many communication lines, there were not many transportation lines, there was a lot of illiteracy. and poverty, then that administrative would have been very challenging to deal in a different time zone.
So at that time the Indian government rejected it. But around 2000, again in these states, there was a demand for a different time zone. In 2007, Department of Science and Technology conducted a feasibility study to find out if the time zone is feasible or not.
After the study, it was concluded that it would be very administrative challenging and the government rejected the demand. This was the whole issue in the news in 2014 because in January 2014, the CM of Assam declared that no matter what happens, the central government should not approve. We will apply for the Chai Bagan time zone.
This issue is burning. Nothing has happened since then. I don't know when they will start applying for it. Maybe the central government will approve it.
And two time zones will be created in India. I want you to track this news. It is a burning issue.
It is not that there are not many time zones. There are multiple time zones in many countries. Russia has 8 time zones.
If it has a longitudinal extent, then it can be convenient. But a country with a horizontal length, like Sri Lanka, cannot be selected. I have asked some questions related to time zones.
If 12 noon at Greenwich Meridian, what is the time at 75 degrees? Now, we will find the difference first. Greenwich is 0 degree, 75 degree.
Difference is 75 degree. 15 degree is to 1 hour, so 75 degree. 5 hours. Now, this is on the eastern side. So, we have to add 12 plus 5, 5 degrees.
Let us take an example from the western side. If 12 noon at GMT, what is the time at 30 degree west? Difference is 30?
Yeah, very smart people. to 1, towards, we'll minus them. minus 2, 10m. Now a tricky question, now that is not so easy. If it is 10am in Indian Standard Time, then what would be the local time at Silong or East Longitude?
9.30am, 10.30am, 12.22am or 9.22am? I will give you a hint that this is the Indian Standard Time. So, before that reference, we will find the time of Greenwich Maridons.
And from the time of Greenwich Maridons, we will calculate the difference of 92 degrees. I suggest you to calculate this yourself when you go home. The answer will be B.
I want to give you some map based exercises from here. I will add some location based questions in every lecture. So that a foundation gets created when I take world geography. So from now on, at last, you will learn some of the questions.
So that the questions are familiar to the students. So that the questions are familiar to the students. So that the questions are familiar to the students.
So that the questions are familiar to the students. So that the questions are familiar to the students. So that the questions are familiar to the students.
So that the questions are familiar to the students. So that the questions are familiar to the students. So that the questions are familiar to the students.
So that the questions are familiar to the students. So that the questions are familiar to the students. So that the questions are familiar to the students. So that the questions are familiar to the students.
So that the questions are familiar to the students. This question is asked, through which one of the following groups of countries does equator pass? Which country passes equator? Brazil, Zambia, Malaysia, B, Colombia, Kenya, Indonesia, C, Brazil, Sudan and Malaysia, D, Venezuela, Ethiopia and Indonesia.
Now, Brazil is a country like equator and tropic of capricorn. I have given you a hint, you should open your atlas and practice it yourself. If you get the answer here, you will not be interested in opening your atlas. I will tell you that Zambia is an African country, Malaysia and Asia. Colombia is a South American country.
Kenya is an African country. Indonesia is an Asian country. Sudan is an African country. Venezuela is a South American country. Ethiopia is an African country.
The second is... is the exercise which of the following cities nearest to the equator Colombo Jakarta Manila or Singapore? Singapore.
That's correct. Colombia is the city of Sri Lanka, Jakarta, Indonesia's capital, Manila, capital of Philippines and Singapore. But still, I want you to...
You can see the locations of all these stations in the Atlas. You can see how far away and near the equator is. Pralim 2008 question. Which one of the following straits is the nearest to the International Dateline? Now, strait means a narrow waterway.
So, this is the narrow waterway of Pralim 2008. water body which connects two big water bodies. They can be two big seas or two oceans. We call a narrow water body as a strait. Now, which of these options is the strait which is closest to the international deadline? Malacca strait, Bering strait, the state of Florida and the state of Gibraltar.
That is Bering strait. I had told you that the narrow water body between Russia and Alaska is called Bering strait. Let's study all these states in detail.
This is the Southest Asian region. Near India, this is Manmiyar. This is Thailand.
This is called Malayan Palancula. This thin neck is called Isthmus of Kra. This is part of Thailand.
This is Sumatra Island of Indonesia. This is Java Island. These are Bali Islands and other small islands. The water body between Sumatra Island and Malin Palansula is called the state of Malacca. And here is Singapore.
This state is the most important state of this region. Because this is the most important sea line of communication. Sea line of communication means that the trade of the whole world is passing through this line.
Now look at the countries like China, South East Asia, Korea or Japan. trade between Asia and Africa is passed through East Asia. Even India and Gulf countries, African countries, all their trade that is connected to East Asia is passed through East Asia.
This is a very important trade for trade and communication. Now, in this region of Southeast Asia, the incidence of maritime piracy is increasing. The number of pirates that are found in the region is increasing. They capture industrial or trade vessels through gun points and demand booty or ransom. So, maritime piracy is very damaging for industry and trade.
Due to maritime piracy, there are many questions on the safety of the state of Malacca. That is why our warships are patrolling near this area to ensure that the state of Malacca is safe. The second state is Florida. This is the United States and Mexico.
The tip is the Florida state. The islands that pass through this state are called the Greater Antilles and the Lesser Antilles. The countries like Cuba, Haiti, and the Dominican Republic are located here. The Indian state is the northernmost state in the world. The line between these two states is called the state of Florida.
It is connecting Gulf of Mexico to Atlantic Ocean. Now, this Gulf of Mexico is very important sea because from here, sulfur is found. Sulfur is a mineral that is rarely found on land or on the continent. But in the Gulf of Mexico, an abundance amount of sulfur is found.
So, that is why the Gulf of Mexico has a lot of sulfur. There are many industrial cities in USA and the trade of their import export passes through this trade. State of Gibraltar.
Here you can see the entire Mediterranean Sea. This is North Africa and this is Europe. Now when we want to go to the Mediterranean Ocean, we have to pass through this trade. And this is the state of Gibraltar.
It is the access and inlet to the Mediterranean Sea. And this is the sea. The entire trade of the country will be passed from here.
Even the Gulf countries have made pipelines so that they can pass through the Mediterranean Sea and export their oil from the USA and Western European countries. Because if the Arab countries want to export oil from the USA, they will have to travel all over Africa. This is the very shortage route. They have made petroleum pipelines there. And from here, they...
The entire petroleum of this region is exported to Western European countries and American countries. The entire European trade of this region is also dependent on this trade. If you look at the political map of this trade, you will see that here is a country called Spain and here is Morocco.
We think that the Gibraltar trade is between Spain and Morocco. But it is not. This trade is between the two countries.
This land is occupied by the UK since the colonization time. This is why the state of Gibraltar is the overseas territory of the UK. The Gibraltar area is also in the news. The reason is that the Spanish government has merged this region with its mainland country.
After the independence of India, the government merged the two regions with its mainland country. The Spanish government merged the two regions with its mainland country. The Spanish government wants to merge Gibraltar into their mainland country.
But the UK is also in front of them. The Spanish government is trying to negotiate with the UK. In 2002, the Spanish government started secret talks with the UK. The UK and Spain decided to rule the UK together.
Then a referendum was held. The team is asked a question whether they agree or not. The answer is given by the public.
This is called referendum. They were asked whether they accept the combined rule of both the countries. The public of Gibraltar rejected this question with 98% of votes. Even now, the rule of UK is there. In 2014, the Spanish government used force.
The government used force. They put restrictions on food, petrol and energy supplies that reach Gibraltar. So that they are pressured to surrender and merge into Spain. There were many protests, the UK intervened and then the situation cooled down.
But still, the rule of the UK is in Gibraltar. We have to remember that Gibraltar is under the occupation of the UK, not under Spain or Morocco. You ask a question, please answer it.
Prelim 2009 Consider the following countries 1. Australia 2. Namibia 3. Brazil 4. Chile Through which of the above does the topic of Capricorn pass? I had told you that Brazil is a country where Capricorn and Equator pass But we should first study the options of the question Only one 2,3,4,1,2,3,4 1, 2 and 3 and 1, 2, 3, 4 all of them. At last, please open and study.
Today we have studied fundamentals, longitudes, latitudes, reason for seasons on earth, right, about time zones. I am giving you some self-study. If you... Now see, NCIT is our fundamental.
We should not skip it at any cost. 8 to 12 standard geography, our NCIT, our old NCIT. you have to study it.
There is no substitute for it. If there is no foundation, then building cannot be created. This is not only applicable for geography, it is applicable for every subject.
You have to study NCERT for geography also. If you will study NCERT Classics Chapter 2, then you will be able to study longitude, latitude and time zones. In map, I want you to open your atlas.
So, how to study Greenwich Meridian and IST? When you open the world So, what you can do in the political map is that you can draw the lines of Greenwich Meridian with any color pen so that they look different from the whole map. And then you can see which cities are coming near and then locate it.
In this way, you can also do equator, topic of cancer, Capricorn, you can draw the whole line in different colors with the same pen and draw it and separate it so that when you open the atlas, your mind will be clear. you will get a chance to see that line again. In Indian Standard Time also, you can find that 2.5 degree line and draw a separate line and see which other cities are near to that line.
You can also draw a line for India by taking India's political map and see which states are passing the topic of cancer. Hey buddy, what are you thinking? We think this is a very easy question and we neglect it. But when we get options like this, we feel it is difficult to decide whether Chhattisgarh is coming or not. Whether Jharkhand is passing or not.
So, we have that line. We have a different highlighter. And study the map in this way.
I want to start the hardcore geography from here. And this is called geomorphology.