The Chapter “Latitude and Longitude” from Class 6 Social Science Chapter 2, prescribed by the Board of Secondary Education Manipur (BOSEM), teaches you about the following topics.
📀 Basic Concept of the Globe
📀 Building concept on Latitude and Longitude
📀 Types of Zones
Chapter Name: Globe-The Latitudes and Longitudes
Subject: Social Science
Lesson: 2
Class: 6
Board: Board Of Secondary Education Manipur (BOSEM/BSEM)
Contents: Chapter, Questions and Answers, Important points to Remember.
Chapter 2: Globe-The Latitudes and Longitudes
The Model of the Earth
We have seen many photographs of the earth. It is spherical in shape. But a model will give us a more realistic view of the sphere. That is why the small model of the earth is known as the globe. Being a three-dimensional model, it can be seen and comprehended easily.
A glove gives us a clear vision of the shape of the earth. It shows the north and the south poles, latitudes and longitudes, oceans and continents etc. Thus, a globe is almost similar to the real Earth. Now the question arises as to how to handle a globe. It is very simple. A globe can be handled or moved with the left hand towards the right because our earth rotates from west to east in the anti-clockwise.
Formerly, globes were not convenient to carry around. Nowadays, folding globes which can be inflated are available. They are made of plastic and can be kept in our pockets. Some globes show relief features like mountains, plateaus and plains, you can even feel them by your hands.
You can rotate a globe just like the Earth does. The north-south lines of a globe are tilted because the axis of the earth is inclined at an angle of 66 ½ to its orbital plane. Because of its inclination, we enjoy different seasons on the earth.
However, a globe has some disadvantages. As the globe represents the whole earth, the details of a region cannot be shown on it. For example, if you want to know about your state, the district or the town in which you live, a globe is of no use. In such cases, we depend on maps.
It is difficult to locate places on a sphere like the Earth. Luckily, we have two reference points on the earth’s surface. They are the North Pole and the South Pole. These are the end points of the axis of the earth. They act as basic points of reference for locating a place. If you have a globe, just keep it in front of you. The top of the globe is the north pole and the bottom is the south pole.
Rotate the globe slowly and draw a line midway between the north pole. Rotate the globe slowly and draw a line midway between the north pole and the south pole till it becomes a full circle. This is the largest circle we can draw on a globe. Because the centre of this circle is the centre of the globe. Such a circle is called a great circle. The imaginary circular line running halfway between the poles is known as the equator. It divides the globe into equal halves.
The northern half is called the northern hemisphere and the southern half is called the southern hemisphere.
We know that a circle has 360. Since the globe is a sphere, it is also 360. If we go from the equator to the pole, we can cover ¼th of a circle i.e., 90. Thus the north pole is located 90 degrees north of the equator. We call it 90 degrees N. likewise; the South Pole is located at 90-degree south of the equator. The value of the equator is 0 degrees.
Latitudes
From the figure, we see that the angular distance from the equator to the north pole or the south pole is 90 degrees. So, we can draw 90 parallels of latitude at an interval of 1 degree in the northern and southern hemispheres. The imaginary line is drawn on the globe parallel to the equator.
Since these lines are parallel to each other, they are known as parallels of latitudes. Note that parallels of latitudes become smaller and smaller as we go from the equator towards the poles. Thus the latitude of the north pole or south pole becomes a point. Find out the number of latitudes drawn at 1-degree intervals from pole to pole including the equator.
Latitude is the angular distance of a place north or south of the equator. It is measured from the centre of the earth. In the figure, the angular distance of the Imphal from the equator is 25 degrees. This angle is formed at the centre of the earth. It means the latitude of Imphal is 25 degrees north.
It is necessary to write the letters N or S with the values of the latitude. It helps us to know the location of a place north or south of the equator. For example, Imphal(Manipur) and Pretoria (South Africa) are located at 25-degree latitude. However, Imphal lies in the northern hemisphere while Pretoria is in the southern hemisphere. So, we write 25degree N for Imphal and 25degree S for Pretoria.
Latitudes and heat zones
We know that the equator(0°), the north pole (90° N) and the south pole (90° S) are the important latitudes. Besides these, we have four other important latitudes. They are the Tropic of Cancer (23 ° 30’N), the Tropic of Capricorn (23°30’S), the Arctic Circle (66 degree30’N) and the Antarctic Circle (66° 30’S)
The tropic of cancer is important because, on the 21st of June, the sun is overhead at this latitude. Likewise, on 22nd December the sun is overhead at the tropic of Capricorn. The region between these two latitudes is the hottest on the earth. Therefore, it Is known as the Torrid Zone.
The areas between the Tropic of Cancer and the Arctic Circle and the Tropic of Capricorn and the Antarctic Circle are neither too hot nor too cold. They are called temperate zones. The north temperate zone is in the northern hemisphere while the south temperate zone is in the southern hemisphere.
The regions between the Arctic Circle and the North Pole in the northern hemisphere and the Antarctic Circle and the South Pole in the southern hemisphere are very cold. So, they are known as frigid zones.
Longitudes
Several imaginary lines are also drawn vertically by joining the two poles of the earth. They are called meridians of longitude. On a globe, you can see that they form semi-circles. The longitude which passes through Greenwich Observatory near London is called the prime meridian. It is numbered 0 degrees.
The semi-circle directly opposite to the prime meridian (on the other side of the earth) is 180-degree longitude. East of the prime meridian up to 180 degrees is known as the eastern hemisphere while west of the prime meridian up to 180 degrees is called the western hemisphere. We write the letter E with the values of meridians for the eastern hemisphere and W with the values of meridians for the western hemisphere. It should be noted that 180-degree longitude is both E and W.
All the meridians of longitude are equal in length. They all converge at the poles. The distance between two meridians decreases as we go from the equator to the poles.
On a globe, you will see that parallels of latitude and the meridians of longitude form a network. The network is called Grid. These horizontal and vertical lines meet at every point on the earth’s surface. The meeting point of parallels and meridians helps us to locate a place on the earth.
Longitude and time
The word meridian comes from the Latin word maridies meaning midday. All places on the same meridian of longitude have midday at the same time. When the sun is overhead at the longitude where we are, we call it noon or midday. This is our local time. The sun cannot be overhead at two meridians at a time. So, the local time measures from the noon of the overhead sun varies from one meridian to another.
The earth takes 24 hours to complete a full turning on its axis, which means that the earth turns through 260° in 24 hours i.e., 15 degrees in one hour or 1 degree in 4 minutes. Thus for 15 degrees of longitudinal differences, the time difference will be 1 hour. A place located at 15 degrees east of Greenwich will have sunrise one hour ahead of Greenwich time. Similarly, a place located at 15 degrees west of Greenwich will have sunrise one hour later than Greenwich time.
Accordingly, the earth is divided into 24-hour time zones of one hour each. So when it is noon at Greenwich (0degree) it is 6 p.m. at 90degree E, 6 a.m. at 90-degree W, and midnight at 180 degrees and so on. Large countries like Russia and the United States have several time zones, each differing from the adjacent one by an hour.
Our country extends from 68 degrees 7’E to 97degree 25’E longitudes. There is a longitudinal difference of about 30 degrees between the eastern and the western parts of the country. It means that when the local time is 12 noon at Arunachal Pradesh it will be only 10 a.m. in Gujarat. This will create problems for the people to function.
Therefore, the local time of a central meridian of India is taken as the standard time for the whole country. The standard meridian of India is 82 degrees 30’E. the local time of this meridian is followed all over the country. This is known as Indian Standard Time (IST).
Important Points to Remember for Globe-The Latitudes and Longitudes
| 💡 The small spherical model of the Earth is known as the globe |
| 💡 A globe can be handled or moved with the left hand towards the right because our earth rotates from west to east in the anticlockwise direction |
| 💡 We enjoy different seasons on the Earth as the axis of the Earth is inclined at an angle of 66 ½ degrees to its orbital plane. |
| 💡 The imaginary circular line running halfway between the pole is known as the equator |
| 💡 The value of the equator is 0 degree |
| 💡 Latitude is the angular distance of a place north or south of the equator |
| 💡 The five major parallels of latitudes from north to south are called the Arctic Circle., the Tropic of Cancer, the Equator, the Tropic of Capricorn, and the Antarctic Circle |
| 💡 On a map where the orientation of the map is either due north or due south, latitude appears as horizontal lines |
| 💡The parallels of latitude divide the earth into different heat zones. There are three types of heat zones 1. Torrid zone 2. Temperate zone and 3. Frigid zone |
| 💡 The torrid zone: The torrid zone lies between the Tropic of Cancer and the Tropic of Capricorn which is also called the tropical zone |
| 💡 The temperate zone: There are two temperate zones: 1. The north temperate zone: Lies between the Tropic of Cancer and the Arctic Circle. 2. The southern Temperate zone: Lies between the tropics of Capricorn and the Antarctic Circle. |
| 💡 In the temperate zones the four seasons, spring, summer, autumn, and winter are clearly felt |
| 💡 The frigid zone: There are two frigid zones. 1. The north frigid zone: lies between the Arctic Circle and the North Pole. 2. The south frigid zone: Lies between the Antarctic Circle and the South Pole. |
| 💡 The longitude of a place is the angular distance east or west of the prime meridian measured from the centre of the earth. |
| 💡 Meridians of longitude are imaginary lines drawn vertically by joining the two poles of the earth. |
| 💡 The longitude which passes through the Greenwich Observatory near London is called the prime meridian |
| 💡 All the meridians of longitude are equal in length. |
| 💡 The longitude of a place is the angular distance east or west of the prime meridian measured from the centre of the earth. |
| 💡 Local time is the time taken when the sun is overhead at the longitude that we call noon or midday |
| 💡 The standard meridian of India is 82degree30’E. The local time of this meridian is followed all over the country. This is known as Indian standard time. |
| 💡 The Indian standard time(IST) is 5 hours 30 minutes ahead of Greenwich mean time(GMT) |
| 💡 Most of the country has its own particular standard time, and it remains the same for the whole country. |
BOSEM Solutions For Class 6 Social Science: Globe-The Latitudes and Longitudes
Very short answer type questions.
Q1. What is meant by latitude?
Ans: latitude is the angular distance of a place north or south of the equator.
Q2. What is the angle of inclination of the Earth’s axis to its orbital plane?
Ans: The axis of the earth is inclined at an angle of 66 ½ degrees to its orbital plane.
Q3. On which day is the sun overhead at the tropic of cancer?
Ans: 21st June.
Short answer type question
Q1. How is the globe useful to us?
Ans: A globe gives us a clear vision of the shape of the earth. It shows the north and the south poles, latitudes and longitudes, oceans and continents etc.. The globe also shows relief features like mountains. Plateaus and plains.
Q2. What is a great circle?
Ans: When we rotate the globe slowly and draw a line midway between the north pole and the south pole till it becomes a full circle. This is the largest circle we can draw on a globe. Such a circle is called a great circle. The equator itself is a great circle.
Q3. Name the three heat zones of the earth.
Ans: The heat zones of the earth: Torrid zone, temperate zone, and frigid zone
Q4. What is the difference between local time and standard time?
Ans: When the sun is overhead at the longitude where we are, we call it noon or midday. This is our local time whereas standard time refers to the time that is officially used in a country. Standard time is recorded as per Greenwich Time.
