Importance of Oceans | Class 6 | Geography | Chapter 6 | Part 1 | Maharashtra State Board
Importance of Oceans | Class 6 | Geography | Chapter 6 | Part 2 | Maharashtra State Board
In this video, you will learn about the significance of oceans and their vast areas, including their influence on climate and the resources they provide. We will explore the role of oceans in transporting goods and conduct some experiments to illustrate their properties. You will discover why ocean water is salty and learn about the factors contributing to its salinity, as well as the process of creating salt pans. We will also guide you on how to calculate the range of temperature in the oceans. Lastly, we will address some of the challenges facing our oceans and the importance of protecting them for future generations.
Questions & Answers
A. Find the odd man out.
1. Shell, Fish, Crab, Ship.
Ans. Ship is manmade. All other things are naturally found in oceans.
2. Arabian Sea, Mediterranean Sea, Dead Sea, Caspian Sea.
Ans. The salinity of the Dead sea is ten times greater compared to other seas.
3. Sri Lanka, India, Norway, Peru.
Ans. Peru is to the south of the equator. All other given nations are to the north of the equator.
4. Southern Ocean, Indian Ocean, Pacific Ocean,Bay of Bengal.
Ans. Bay of Bengal is a bay. All other are oceans.
5. Natural gas, Salt, Gold, Manganese.
Ans. Natural gas is a gas. All others are solid minerals.
B. Writes the answers.
1. Which items does man get from the oceans?
Ans. Man gets the following items from the oceans.
Mineral like iron, lead, cobalt, sodium, manganese, chromium, zinc, etc.
Precious items like pearls and corals and ornamental item like shells.
Mineral oil and natural gas.
Food items like prawns, clams, crabs, serfish, mackerel, pomfret, Indian shark, Indian salmon, etc. and medical plants.
2. Why is it economic to carry out transport by waterways?
Ans.
By waterways, bulky materials like coal, crude oil, raw materials, metallic materials, food grains, etc. can be transported with ease.
Water transport carried out along ocean currents, accelerates the speed of ships and also saves fuel to a considerable extent. Therefore, it is economic to carry out transport by waterways.
3. Why is there a difference in the climates of regions close to the oceans and regions far away from the oceans?
Ans.
In the regions close to the oceans, because of the heating of sea water, water vapour gets mixed in the air.
This water vapour holds the heat in the air and the air remain humid.
Humid air leads to less amount of difference in the day and night temperature. Therefore, regions close to the oceans have an equal climate.
In the regions far away from the oceans, the amount of water vapour is extremely less. As its effect, the air remains dry.
Dry air leads to a sharp different in the day and night temperature. Therefore, regions far away from oceans have an extreme climate. In this way. There is a difference in the climates of regions close to the oceans and regions far away from the oceans.
4. Which continents are located along the coast of the Pacific Ocean?
Ans. Asia, Australia, North America and South America are the continents located along the coast of the Pacific Ocean.
E X T R A
A. Fill in the blanks.
The proportion of salts is quite low in drinking water.
The hydrosphere includes all the water bodies that exist on Earth.
Salinity is expressed in terms of mils (particles per thousand) .
The surface of the Earth is occupied by 70.8% water.
The average salinity of oceanic water is 35‰ .
B. Answer in one sentence.
1. Which sea is known to have the maximum salinity?
Ans. The Dead Sea is known to have the maximum salinity, that is 332‰.
2. What are planetary winds?
Ans. Winds that blow due to pressure differences in the pressure belts are called planetary winds.
3. Mention two things that cause pollution of oceanic waters.
Ans. a) Exploitative fishing.
b) Materials thrown out from the ships are the two things that cause pollution of oceanic water.
C. Answer in Brief.
1. Which natural resources does man get from the ocean?
Ans.
There is abundant aquatic life in the oceans.
From the microscopic planktons to huge whales, different types of living things are found in the oceans.
We get fish from rivers, lakes and seas.
We get minerals like lead, cobalt, sodium, manganese, chromium, zinc etc from the ocean floor.
We also get mineral oil and natural gas.
We get precious items like pearls, corals or ornamental items like shells, as also medicinal plants from the seas.
2. Why is it economic to carry out transport by waterways?
Ans.
Ocean currents are quite important in water transport.
As far as possible, water transport is carried out along ocean currents.
They accelerate the speed of the ships and also save fuels to a considerable extent.
Water transport is conducted on a much higher scale as compared to other modes of transport.
Hence, for transport of bulky materials like coal, crude oil, raw materials, metallic minerals, food grains etc. water transport is given preference.
3. Why is there a difference in the climate of regions close to the oceans and regions far away from the oceans?
Ans.
The main reason for this is the mixing of vapour released through evaporation of water from these water bodies into air. This vapour in the air absorbs and stores the heat released from the land. Hence, the temperature in coastal areas remain equable.
The cold currents moving towards the equatorial region make the temperature of coastal areas in that zone milder whereas the warm currents coming in the colder regions cause temperatures in coastal areas to rise.
The oceans have a vast expanse, therefore huge amounts of vapours get created. This process goes on continuously. From this vapour, the Earth gets rainfall. Oceans are the source of rains and the water cycle.
4. Which continents arc located along the coast of the Pacific Ocean?
Ans. The continents of North America , South America, Asia and Australia are located along the coast of Pacific Ocean.
D. Give Reasons.
1. Pollution of oceanic waters is a major issue in recent times.
Ans.
In order to fulfil his requirements, man undertakes many activities.
These lead to the production of huge amounts of different types of waste.
These waste materials cause pollution.
Some coastal regions are proving to be death traps for aquatic animals. As a result, many aquatic animals are under the threat of being extinct. Eg. the blue whale, some types of sea turtles, dolphins etc.
Thus, pollution of oceanic waters is a major and serious issue that has developed in recent times.
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