Maharashtra Board Class 6 Geography Solutions Chapter 6 Importance of Oceans

Class 6 Geography Chapter 6 Importance of Oceans Textbook Questions and Answers

A. Find the odd man out:

Question 1.
Shell, fish, crab, ship
Answer:
ship

Question 2.
Arabian Sea, Mediterranean Sea, Dead Sea, Caspian Sea
Answer:
Dead Sea

Question 3.
Sri Lanka, India, Norway, Peru
Answer:
Sri Lanka

Question 4.
Southern Ocean, Indian Ocean, Pacific Ocean, Bay of Bengal
Answer:
Bay of Bengal

Question 5.
Natural gas, salt, gold, manganese
Answer:
Natural gas

B. Write the answers:

Question 1.
Which items does man get from the oceans?
Answer:
Salt, fish, shells and other products, minerals like iron, lead, cobalt, sodium, manganese, chromium, zinc, mineral oil and natural gas are the items man gets from oceans.

Question 2.
Why It is economic to carry out transport by water ways.
Answer:

• Waterways is a cost-effective, fuel efficient and relatively more environment friendly means of transportation.
• Large scale transport of goods can be carried out with the help of ships, trawlers, boats, etc. at a low cost.
• So it is economic to carry out transport by waterway.

Question 3.
Why There is a difference in the climate of regions close to the oceans and regions far away from the oceans.
Answer:
(i) The oceans influence the climatic condition of a place. Coastal areas are cooler and wetter than regions away from the ocean.

(ii) There is a difference in the maximum and minimum temperature with the difference being less in coastal region (nearness to the sea) while it is more in the region far away from the sea (continentality).

(iii) The temperature in coastal areas remains equable due to the mixing of vapour released through evaporation of water from these water bodies into air. This vapour absorbs and stores the heat released from the land.

Question 4.
Which continents are located along the coast of the Pacific Ocean?
Answer:
Asia, Australia, North America and South America are the continents located along the coast of the Pacific Ocean.

Activity:

Colour the different oceans on an outline map of the world and prepare an index for the map. (See inside front cover, figure B.)

Project:

Group work: Make five groups. Each group should collect some information and pictures of one ocean. With the help of the information collected, each group should make a poster and make presentation.

Class 6 Geography Chapter 6 Importance of Oceans InText Questions and Answers

Think a little!

Question 1.
Where does the water flowing through the rivers go in the end?
Answer:
The water flowing through the rivers goes into the oceans in the end.

Question 2.
Are there volcanic eruptions in the seas?
Answer:
Yes, volcanic eruptions take place in the seas.

Question 3.
What would have happened if man had not discovered sea routes?
Answer:

• If there were no sea routes, we would lose out on the most economic option of transportation.
• Large scale transport of goods would become inconvenient.
• International trade too would suffer.

Use your brain power!

Question 1.
Where did all this water on the earth come from?
Answer:
While some scientists believe that water was created due to the impact of comets there are others who believe that Earth’s waters have existed since the birth of planet earth.

Find out:

Question 1.
Collect information about how a natural pearl is formed.
Answer:

• Natural pearls form when an irritant- usually a parasite and not the proverbial grain of sand – works its way into an oyster, mussel, or clam.
• As a defense mechanism, a fluid is used to coat the irritant.
• Layer upon layer of this coating called ‘nacre’ is deposited until a pearl is formed.

Question 2.
Which oceanic organism develops in it?
Answer:
The oceanic organism oyster develops in it.

Question 3.
In which sea is it found in India?
Answer:
The Arabian Sea.

What will you do?

Question 1.
Different marine animals like the blue whale, turtle, starfish, etc. appear before you in your dream and complain to you. They say, “You humans are not allowing us to live properly. You throw the waste and chemicals that you do not want into our house. The youngsters in our house are falling ill due to this. Some are getting killed. You must think about this situation and remove the pollution from the seas.” Now tell what you will do.
Answer:
“Environmental problems begin with people as the cause and end with people as the victims.” Different ways to remove pollution from sea are:

• Creating awareness amongst people.
• Organising a clean-up operation.
• Insisting that government take steps to prevent marine pollution caused due to waste disposal.
• Following the principle of recycling waste and proper treatment of sewage before its disposal into water bodies.
• Generating a sense of responsibility amongst the citizens.

Can you do it?

Question 1.
Sameer and Sania are playing a game of showing the waterways on a map of the world. Their routes are going in opposite directions. One of the following the eastern route while the other is making a route that takes to the west.

From Mumbai port some goods are to be taken to London in UK. On a map of the world, show at least two such routes with a pencil.
Write down the names of the ports of different nations that fall on the route followed by each.

Ports on the route followed by Sameer:

Answer:

• JNPT – India
• Nish tun – Yemen
• Salal – Oman
• Port of Berbera – Somalia
• Port of A1 Qusayr – Egypt
• Port of Said – Egypt Suez
• port – Egypt
• Port of Tenes – Algeria
• Port of Tunis – Tunisia
• Port of Bone facia – France
• Port of Aguilas – Spain
• Port of Adra – Spain
• Port of Gibraltar – Gibraltar
• Port of Sines – Portugal
• Swange Pier – UK
• Whitstable harbour – UK
• Purfleet Thames Terminal – UK
• Port of London – UK

Ports on the route followed by Sania:

• Port of Mergui – Myanmar
• Port of Ramong – Thailand
• Port of Krueng Raya – Indonesia, etc.

Question 2.
Which of the routes you feel is shorter? That of Sameer’s or Sania’s?
Answer:
Sameer’s route is shorter.

Question 3.
Which oceans does one have to pass through if one follows Sameer’s route or Sania’s route?
Answer:
If one follows Sameer’s route one has to pass through the Indian Ocean and North Atlantic Ocean. If Sania’s route is taken she has to pass through the Pacific and North Atlantic Ocean.

Question 4.
What are Panama and Suez? For what purpose were they constructed?
Answer:

• Panama and Suez are the canals in the sea built for commercial purpose.
• It helped in saving time, money and energy and gave a fillip to international trade due to the shorter distance and easy accessibility.

Question 5.
Have they been used in Sameer’s and Sania’s routes?
Answer:
Yes, Suez Canal is used in Sameer’s route while Panama Canal is used in Sania’s route.

Class 6 Geography Chapter 6 Importance of Oceans Additional Important Questions and Answers

Fill the blanks choosing the correct alternatives from the brackets:

Question 1.
The ______ includes all the water bodies like oceans, seas, rivers and their tributaries, lakes, reservoirs and also ground water that exist on the earth.
(lithosphere, atmosphere, hydrosphere)
Answer:
hydrosphere

Question 2.
Total global water 97.7% is contained in ______ (lakes, oceans, seas)
Answer:
oceans

Question 3.
The ocean with an area 166,240,977 sq. km is the _______ ocean. (Indian, Atlantic, Pacific)
Answer:
Pacific

Question 4.
All rivers flowing from mountains or hilly areas finally meet in the ________.(lakes, seas, oceans)
Answer:
oceans

Question 5.
Salinity is expressed in terms of ______.(mils, ml, gms)
Answer:
mils

Question 6.
The average salinity of oceanic water is _______.(80%, 332%, 35%)
Answer:
35%

Question 7.
The salinity of the Dead Sea is _____.(332 %, 35%, 60%)
Answer:
332 %

Question 8.
About ________ of the surface of the earth is occupied by water. (90%, 95%, 70.8%)
Answer:
70.8%

Question 9.
Salt as a substance is obtained by constructing ______. (sea bed, salt pan, river bunds)
Answer:
salt pan

Question 10.
________ is conducted on a much higher scale as compared to the other modes of transport. (Water transport, Air transport, Road transport)
Answer:
Water transport

Question 11.
Pollution of _________ water is caused due to oil spills. (river, lake, oceanic)
Answer:
oceanic

Question 12.
Winds blowing due to pressure difference in the belts is called ______. (planetary winds, oceanic winds, minerals)
Answer:
planetary winds

Match the pairs correctly:

Question 1.

Oceans	The area in sq. km
(1) Pacific	(a) 20,327,000
(2) Atlantic	(b) 73,426,163
(3) Indian	(c) 166,240,977
(4) Southern	(d) 13,224,479
(5) the Arctic	(e) 86,557,402

Answer:
1 – c
2 – e
3 – b
4 – a
5 – d

Find the odd man out:

Question 1.
Pearls, corals, diamonds, medicinal plants
Answer:
diamonds

Question 2.
Spain, Norway, Japan, India
Answer:
India

Question 3.
Blue whale, sea turtles, seerfish, dolphins
Answer:
seerfish

Name the following:

Question 1.
Water bodies which are a part of the . hydrosphere.
Answer:
Oceans, seas, rivers and their tributaries, lakes, reservoirs, ground water.
Question 2.
Percentage of global waters contained in oceans.
Answer:
97.7%

Question 3.
Two aquatic animals found in the ocean.
Answer:

• Microscopic planktons
• Huge whales

Question 5.
Places where volcanic eruptions occur.
Answer:

• Land
• Ocean

Question 6.
Two minerals obtained from the sea.
Answer:

• Phosphates
• Sulphates

Question 7.
Two uses of marine animals.
Answer:

• Production of fertilisers
• Production of pharmaceuticals

Question 8.
Two countries with coastline which largely depends on the sea for their livelihood.
Answer:

• Seychelles
• Mauritius

Question 9.
The controller of global temperature and source of rains.
Answer:
Oceans.

Question 10.
The beginning and end of the water cycle takes place here.
Answer:
Oceans.

Question 11.
Two minerals obtained from the ocean floor.
Answer:

• Cobalt
• Sodium

Question 12.
Precious items obtained from the seas.
Answer:

• Pearls
• Corals

Question 13.
Mode of transport used for large scale transportation of goods.
Answer:

• Ships
• Trawlers

Question 14.
Two actions by man which has lead to large scale pollution in oceanic waters.
Answer:

• Oil spills
• Exploitative fishing

Answer the following in one sentence each:

Question 1.
What happens when aquatic animals die?
Answer:
When aquatic animals die, their remains accumulate in the oceans.

Question 2.
What enters the ocean with the rain water?
Answer:
Sediments from eroded lands, trees and bushes flowing with water, dead remains, etc. enter the ocean with the river water.

Question 3.
What happens when the dead remains in the ocean decompose?
Answer:
When the dead remains in the oceans decompose it releases various minerals and salts in the ocean water.

Question 4.
Where do we find maximum salinity?
Answer:
The Dead Sea is known to have the maximum salinity of 332%.

Question 5.
How is salt obtained?
Answer:
Salt as a substance is obtained by constructing salt pans in the coastal areas.

Question 6.
Which is one of the ancient occupations of human beings and what is the major purpose of his activity?
Answer:
Fishing is one of the ancient occupation and the major purpose of this activity is to obtain food.

Question 7.
How does the earth get rainfall?
Answer:
The oceans have a vast expanse, therefore huge amounts of vapour get created and this process goes on continuously and from this vapour the earth gets rainfall.

Question 8.
How is pollution caused in oceanic water?
Answer:
In order to fulfill his requirements, man undertakes many activities that lead to the production of huge amounts of different types of waste materials which cause pollution.

Question 9.
Write anyone cause of pollution of oceanic waters.
Answer:
Cutting of mangroves forests in coastal areas is one of the main cause of pollution in oceanic waters.

Question 10.
How does oceanic pollution affect the aquatic animals?
Answer:
Due to oceanic pollution many aquatic animals are under the threat of being extinct. For example, the blue whale, some types of sea turtles, dolphins, etc.

Question 11.
Which items does man get from the oceans?
Answer:
Salt, fish, shells and other products, minerals like iron, lead, cobalt, sodium, manganese, chromium, zinc, mineral oil and natural gas are the items man gets from oceans.

Question 12.
Which continents are located along the coast of the Pacific Ocean?
Answer:
Asia, Australia, North America and South America are the continents located along the coast of the Pacific Ocean.

Give geographical reasons for the following statements:

Question 1.
The ocean water is saltier than drinking water.
Answer:

(i) In drinking water, the proportion of salts is quite low. Water from oceans and seas has a greater amount of salt. Hence it tastes salty.

(ii) Volcanic eruptions leads to increase in the level of salts and minerals in ocean water.

(iii) Volcanic eruptions takes place in the oceans. During volcanic eruptions different minerals, ashes, salts and gases are added to the water. This increases the level of salts and minerals in ocean water.

(iv) Due to continuous evaporation of oceanic water, the proportion of salt increase.

Question 2.
The temperature in coastal areas remains equable.
Answer:

(i) In regions close to the oceans, seas or large reservoirs, there is not much of a difference in the temperature throughout the day.

(ii) The main reason for this is the mixing of vapour released through evaporation of water from these water bodies into air.

(iii) This vapour in the air absorbs and stores the heat released from the land.

(iv) Hence, the temperature in coastal regions remain equable.

Question 3.
It is economic to carry out transport by water ways.
Answer:

• Waterways is a cost-effective, fuel efficient and relatively more environment friendly means of transportation.
• Large scale transport of goods can be carried out with the help of ships, trawlers, boats, etc. at a low cost.
• So it is economic to carry out transport by waterway.

Question 4.
There is a difference in the climate of regions close to the oceans and regions far away from the oceans.
Answer:
(i) The oceans influence the climatic condition of a place. Coastal areas are cooler and wetter than regions away from the ocean.

(ii) There is a difference in the maximum and minimum temperature with the difference being less in coastal region (nearness to the sea) while it is more in the region far away from the sea (continentality).

(iii) The temperature in coastal areas remains equable due to the mixing of vapour released through evaporation of water from these water bodies into air. This vapour absorbs and stores the heat released from the land.

Question 5.
Oceans act as the controller of global temperature.
Answer:

(i) Winds move the oceanic water in the form of currents.

(ii) Ocean currents move from the equatorial region to polar regions and from polar regions to the equatorial region.

(iii) This leads to the redistribution of heat on the earth.

(iv) The cold currents moving towards the equatorial region making the temperature of coastal areas in that zone milder whereas the warm currents coming in the colder region cause the temperature in coastal areas to rise. Hence, the oceans act as the controller of global temperature.

Answer the following questions in brief:

Question 1.
What are planetary winds?
Answer:

• Equatorial regions receives perpendicular sunrays.
• As a result these areas get more heat whereas the polar regions receive highly slant rays.
• This differential heating creates imbalance in the temperature of air in different parts leading to formation of belts of high and low pressure on earth.
• Winds blow1 due to the pressure differences in these belts. These winds are called Planetary Winds.

Question 2.
Write in brief about oceanic transport.
Answer:

• Oceans have provided us the most economic option of transportation.
• Large scale transportation of goods is carried out with the help of ships, trawlers, boats, etc.
• International trade is carried out on a large scale using waterways.
• Countries like Spain, Norway, Japan have a good coastline due to which goods are transported by ocean routes, making these countries important.

Question 3.
How do ocean currents aid water transport?
Answer:

• 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 fuel to a considerable extent.

Question 4.
List the causes that lead to large scale pollution of oceanic water.
Answer:
The causes that lead to large scale pollution of oceanic water are:

• Oil spills.
• Releasing the waste produced in the coastal cities into the seas.
• Materials thrown out from ships.
• Exploitative fishing.
• Cutting of mangrove forests in coastal areas.
• Disasters caused by the water mines.
• Sewage released by industries and cities.
• Excavation carried out in the seas.

Do it yourself!

Question 1.
Calculate the difference between the mean maximum and minimum temperature and write in the last column

Place	Country	Mean Max. Temp. °C	Mean Min. Temp. °C	Range of Temperature
Beijing	China	18.4	08.4	10
Istanbul	Turkey	18.0	10.0	08		_______
Madrid	Spain	19.0	09.0	10
New York66	United States	16.3	08.3	08		________
Denver	United States	16.2	02.2	14
Kabul	Afghanistan	14.7	05.2	09.5		________
Baghdad	Iraq	30.4	14.7	15.7

Question 2.
Highlight the rows for the places having a range of temperatures over 10°C with red colour, other rows in blue colour (Refer the above table)
Question 3.
Find the locations of these places from an atlas. (Students activity)
Question 4.
Which places are closer to the oceans? Tell whether the range of temperature at these
places is l ess or more?
Answer:
Istanbul and New York are closer to the oceans. These places which are closer to the oceans have lesser range of temperature.

Question 5.
What might be the main reason leading to differences in the temperature range in different places?
Answer:
The main reason leading to differences in temperature range in different places is because of the location of the place on the planet earth. Other factors like latitude, altitude, atmosphere, ocean currents, planetary winds etc. too have their impact.

Question 6.
In which thermal zone are all these places located?
Answer:
All these places are located in the temperate thermal zone.

Question 7.
Which places are fai away from the oceans?
Do these places have a greater or smaller temperature range?
Answer:
Istanbul, Denver, Kabul and Baghdad are far away from the ocean as these places have a greater temperature range.

Question 8.
Mention the places having the smallest and greatest temperature ranges.
Answer:
Istanbul and New York have the smallest temperature range while Baghdad has the greatest temperature range.

Question 9.
Draw a graph for the above data. Use a proper colour scheme.
Answer: