8th Standard Social, GEOGRAPHY, CHAPTER-11
THE EARTH – OUR LIVING PLANET
EXERCISES
I. Fill in the blanks with suitable words:
1 The total geographical area of the Earth is 510 million Sq. Kms.
2 The shape of the Earth is Geoid.
3 The equatorial and polar diameters of the Earth is 12756 and 12714 Kms.
4 The 230.30l North latitude is called as Tropic of Cancer.
5 The Indian Standard Time is based on 820.30l East longitude.
II Answer the following questions briefly:
6. Why is the Earth called ‘Living Planet’?
Answer: The Earth is the home for all forms of life like plants, animals and human beings because of its suitable distance from the Sun, range of temperature, life supporting gases, atmosphere, water cycle etc. So the Earth is called ‘Living Planet’.
7 Why are the Northern and Southern hemispheres called Land and Water Hemispheres?
Answer: The Northern Hemisphere has 60% of land and 40% of water. Therefore it is called the ‘Land Hemisphere’. On the other hand there is 81% of water and 19% of land in the Southern Hemisphere and so it is called the ‘Water Hemisphere’.
8 What are latitudes and longitudes?
Answer: Latitude is an imaginary line which joins all the places which have the same angular distance north or south of the equator. The imaginary lines that intersect equator at right angle joining the north and south are called longitudes.
9 Mention the difference between local time and standard time.
Answer: The time according to the longitude of a place or according to the position of Sun at that place is known as the Local time. In order to avoid confusion many countries follow uniform time throughout the country. Such uniform time is based on the central meridian of the country or the meridian on which the most important city is located. This uniform time which is followed throughout a country is called Standard Time of that country.
10 What is the International Date Line?
Answer: Line passing through 1800 meridian diametrically opposite to the G.M.T was adopted as the point where circumnavigators should make adjustments. This line is supposed to pass Pacific Ocean along the 1800 meridian but makes short detours in order to avoid land masses. This is known as the International Date Line.
III Define the following:
11. Unique planet 14. Continents
12. Size of the Earth 15. Prime Meridian
13. Geoid 16. Indian Standard Time
11. Unique planet: The Earth is the home for all forms of life like plants, animals and human beings because of its suitable distance from the Sun, range of temperature, life supporting gases, atmosphere, water cycle etc. So the Earth is called ‘Unique Planet’.
12. Size of the Earth: The Earth is the fifth largest planet in the Sun’s family. The diameter of the Earth is approximately 4 times greater than the Moon and it is around 107 times less than that of the Sun. The total geographical area of the Earth is 510 million sq kms.
13. Geoid: The Earth is spherical in shape. The Earth’s shape is often described as Geoid, which literally means ‘Earth shaped’, or ‘Oblate Spheroid’. The Earth is flattened at the poles and bulged at the equator. The Equatorial diameter of the Earth is 12756 kms and the Polar diameter is 12714 kms Equatorial circumference – 40,076 kms and Polar circumference – 40,008 kms. The difference of 42 kms in diameter is the proof for regarding the earth as Geoid.
14. Continents: The land bodies of the Earth are known as Continents. The continents are land masses of large size. There are seven continents, namely Asia, Africa, North America, South America, Antarctica, Europe and Australia. The continents are land masses of large size. Asia is the largest continent in the world while Australia is the smallest continent.
15. Prime Meridian: Lines of longitude are called Meridians (‘meri’-mid and ‘dian’-day) because all places along the same meridian of longitude experience noon or mid-day at the same time. The meridian passing through Greenwich (England) has been chosen as Prime Meridian.
16. Indian Standard Time: In India, 820.30l East longitude is considered as the Standard Meridian of the country. It passes through Prayagraj of Uttar Pradesh. The time based on this Meridian is called the Indian Standard Time (IST). It is 5 hours and 30 minutes ahead of G.M.T.
IV Terms to Remember :
1. Living Planet 4. Antarctic circle
2. Equator 5. Zonal Time
3. Arctic circle 6. International date line
1. Living Planet: The Earth is the home for all forms of life like plants, animals and human beings because of its suitable distance from the Sun, range of temperature, life supporting gases, atmosphere, water cycle etc. So the Earth is called ‘Living Planet’.
2. Equator: Equator is the 00 latitude. Latitude is an imaginary line which joins all the places which have the same angular distance north or south of the equator. It is measured in degrees. The Equator (00) is the longest line of latitude known as the Great circle. It is equal to the circumference of the Earth.
3. Arctic circle: 660.30l North latitude is called Arctic Circle. The Arctic Circle is an imaginary line of latitude circling the Earth at approximately 66°33′44″ (66.5622°) north of the Equator. It’s one of the five major circles of latitude and marks the southernmost point where the sun can be seen for 24 hours during the summer solstice (around June 21st) and the northernmost point where the sun is not visible for 24 hours during the winter solstice (around December 21st).
4. Antarctic circle: 660.30l South latitude is called Antarctic Circle. The Antarctic Circle is located at 66°33′47.5″ south latitude. It is an imaginary line that encircles the Antarctic region, marking the boundary of the southernmost extreme of the Earth’s surface where at least one full day of 24 hours of daylight or darkness occurs during the year.
5. Zonal Time: In certain countries of the World, where the longitudinal extent is so large (more than 450 of longitude) that there is often a difference of three to four hours between one part and the other, the land surface is divided into Time Zones. The whole globe is divided into 24 such time zones so that the time in each zone differs from the other by only one hour.
6. International date line: The circumnavigation of the world brought a new problem in keeping the correct date and day in the week for the travellers. Therefore a line passing through 1800 meridian diametrically opposite to the G.M.T was adopted as the point where circumnavigators should make adjustments. This line is supposed to pass Pacific Ocean along the 1800 meridian but makes short detours in order to avoid land masses. This is known as the International Date Line because the date and day is changed whenever people cross this line by ships or aeroplanes.
V Activity:
- List out the countries of the Eastern hemisphere and Western hemisphere on the basis of longitudes.
Answer: The Eastern Hemisphere is defined as the half of the Earth east of the Prime Meridian (0° longitude) and west of the 180th meridian. It includes the majority of the world’s population.
The countries of the Eastern hemisphere as follows.
- Countries in Asia like China, India, Japan, Indonesia, Russia (eastern part), Saudi Arabia, Iran, Iraq, Turkey, Israel, South Korea, North Korea, Malaysia, and many more.
- Countries in Europe like Russia (western part), Germany, France, the United Kingdom, Italy, Spain, Greece, etc.
- Most African countries including Algeria, Egypt, Ethiopia, Nigeria, South Africa, etc.
- Australia, New Zealand, Papua New Guinea, and many island nations.
The countries of the Western hemisphere as follows.
- Countries in North America like Canada, United States, Mexico, Greenland, and various islands in the Caribbean and North Atlantic.
- Countries in Central America like Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama.
- Countries in South America like Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, and Venezuela.
- Countries in Caribbean like Antigua and Barbuda, Bahamas, Barbados, Cuba, Dominica, Dominican Republic, Grenada, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, and many smaller island nations.
- Parts of Europe and Africa: Western portions of countries like Spain, Portugal, Ireland, Iceland, and the United Kingdom are considered to be in the Western Hemisphere. Some countries like Algeria also have portions within the Western Hemisphere.
- Other Territories: Some islands in Oceania are also part of the Western Hemisphere.
Additional Questions and Answers:
- What are the other names of the Earth?
Answer: ‘Living Planet’, ‘Unique Planet’, ‘Watery Planet’, and ‘Blue Planet’ are the other names of the Earth.
- Name the Continents in the Earth.
Answer: There are seven continents in the Earth. They are Asia, Africa, North America, South America, Antarctica, Europe and Australia.
- What are Oceans? Which are the oceans in the Earth?
Answer: The large water bodies on the Earth are called oceans. There are four major oceans. They are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean and the Arctic Ocean.
- What is grid or graticule?
Answer: The horizontal lines are the lines of latitudes and the vertical ones are the lines of longitudes. These lines intersect each other at right angles and create a network called grid or graticule.
- Define ‘Great Circle’.
Answer: Latitude is an imaginary line which joins all the places which have the same angular distance north or south of the equator. It is measured in degrees. The Equator (00) is the longest line of latitude known as the Great circle.
- Name the important latitudes.
Answer: The important latitudes are as follows.
1. 00 latitude-Equator or Great Circle.
2. 230.30l North latitude – Tropic of Cancer.
3. 230.30l South latitude – Tropic of Capricorn
4. 660.30l North latitude – Arctic Circle.
5. 660.30l South latitude – Antarctic Circle.
6. 900 North – North pole.
7. 900 South – South pole
