Samacheer Class 6 Social Science - Land and Oceans

1. A. A Strait
2. B. An Isthmus
3. C. An Island
4. D. A Trench

B. Fill in the blanks
The world’s largest continent is …………….
……………. is the mineral-rich plateau in India.
The largest ocean is …………….
Deltas are ……………. order landforms ……………..
The Island continent is …………….
Asia
Chotanagpur Plateau
The Pacific ocean
Third
Australia
C. Circle the odd one out

D. Match the following

1. – b
2. – a
3. – d
4. – e
5. – c
E. (i) Consider the following statements
1. Plains are formed by rivers.
2. The ‘South Sandwich Trench’ is found in the Indian Ocean.
3. Plateaus have steep slopes.
Choose the correct answer using the codes given below.
(a) 1 and 3
(b) 2 and 3
(c) 1, 2 and 3
(d) 2 only
(a) 1 and 3
(ii) Consider the following statements
Statement I : Mountains are second order landforms.
Statement II : The Mariana Trench is the deepest trench in the world.
Which of the statement(s) is/are true?
(a) I is true; II is wrong
(b) I is wrong; II is true
(c) Both the statements are true
(d) Statements I and II are wrong.
(c) Both the statements are true
F. Answer in a word

North America: On the west by the Pacific Ocean, on the east by Atlantic ocean and on the north by Arctic ocean
South America: On the west by the Pacific Ocean, on the east by Atlantic ocean.
H. Distinguish between

Mountains
A landform that rises over 600 meters above its surroundings and has steep slopes is called a mountain.
Example: Himalayas
Plateaus
Plateaus are the elevated portions of the Earth that have flat surfaces bounded by steep slopes. The elevation of plateaus maybe a few hundred metres or several thousand metre.
Example: Chotanagpur Plateau

First-order landforms:
Continents and oceans are grouped as first-order landforms.
The vast landmasses on Earth are called Continents and huge water bodies are called Oceans.
There are seven continents in the world. They are Asia, Africa, North America, South America, Antarctica, Europe and Australia.
The five oceans are the Pacific, Atlantic, Indian, Southern, and Arctic Oceans.
Second-order landforms:
Mountains, Plateaus, and Plains are grouped as second-order landforms.
A landform that rises 600 meters above its surroundings and has steep slopes is called a mountain. Example:
The Himalayas, the Rocky Mountains, and the Andes.
Plateaus are the elevated portions of the Earth that have flat surfaces bounded by steep slopes. Example:
Tibetan plateau and Deccan plateau.
Plains are flat and relatively low-lying lands. These plains are used extensively for agriculture. Example: Indo – Gangetic plain.
Third-order landforms:
Third-order landforms are formed on mountains, plateaus, and plains mainly by erosional and depositional activities of rivers, glaciers, winds, and waves.
Example: Valleys, beaches, and sand dunes.

Ocean:
An ocean is a vast expanse of water.
Oceans are very deep.
Example: The Pacific Ocean
Sea:
A sea is a water body partially or fully enclosed by land.
Seas are not so deep as oceans
Example: The Arabian sea

Plains are flat and relatively low-lying lands.
Plains are formed by rivers and their tributaries and distributaries.
Plains are used extensively for agriculture due to the availability of water and fertile soil.
Plains are most suitable for human inhabitation. Hence, they are highly populated.

The Pacific Ocean is the largest and deepest ocean on Earth.
It covers about one-third of the Earth’s total area.
It is bounded by Asia and Australia in its west and North America and South America in its east.
On its apex is the Bering Strait. It connects the Pacific Ocean with the Arctic Ocean.
The deepest point Mariana Trench is located in the Pacific Ocean.
A chain of volcanoes is located around the Pacific Ocean.

Oceans are the first order landform.
71% of the earth’s surface is covered with water.
Oceans influence man in various ways, from the climate he experiences to the food he eats.
Oceans are a major source of salt, valuable minerals, petroleum, pearls, and diamonds.
Ocean currents affect the climate of neighbouring areas.
Ocean trade plays an important role in the world economy.
Ocean currents can be converted into electricity.
J. Picture Study

Deposition

K. (i) Activity (Activity to be done by students)
Trip to the nearby area to appreciate the physical features of any kind of landform.
Conduct a quiz on landforms and oceans.
(ii) Activity

Bay: Hudson Bay, Bay of Bengal, Bay of Biscay
Gulf: the Persian Gulf, Gulf of Kutch, Gulf of Mannar
Island: Srilanka, Australia, Maldives
Straits: Palk strait, Bering strait, Magellan strait

A sea in the east of India – Bay of Bengal
Continents in the west of Atlantic Ocean – North America, South America
Continents in the south of Arctic Ocean – Europe, Asia
A strait between India and Sri Lanka – Palk strait
Oceans which surround Australia – Indian ocean, Pacific ocean
Find out the Isthmusses – Isthmus of Panama, Isthmus of Avalon, Isthmus of La Dune