Very Short Answer Questions

Q1. Name the means which help to communicate with several people simultaneously.
Ans: Mass Communication.

Q2. What is compact settlement?
Ans: Compact settlements are basically found in the plains. In this type of settlement the built-up area is compact and inter-house distance is small. Here the population is more.

Q3. Write any two benefits of railways.
Ans: Following are the two benefits of railways:
(a) Railways is the fastest and the cheapest means of land transportation.
(b) Electric engines used in railways are fast and eco-friendly and don't cause pollution.

Q4. Which is the fastest but most expensive means of transport?
Ans: Airways is the fastest but most expensive means of transport.

Q5. Name any two means of personal and mass communication.
Ans: Following are the means:
(a) Personal Communication: Telephones, emails, Post, etc.
(b) Mass communication: Television, Radio, Newspaper, etc.

 

Short Answer Questions

Q6. Name the different types of settlements.
Ans:

Q7. Define the term 'Communication'.
Ans: Communication is the process of conveying messages (sending or receiving) and ideas to others. With the development of technology humans have devised new and fast modes of communication.

Q8. Which developments have changed the world into a global village?
Ans. Development in the different means of communications (i.e personal and mass communication) has changed the world into a global village.

 

Long Answer Questions

Q9. Explain the different means of transport.
Ans: The different means of transport are:

ROADWAYS
• The most commonly used means of transport are the roads. Especially, for short distances. Roads can be metalled (Pucca) and unmetalled (Kutcha).
• Roads are the best means to link the rural and urban places across the country.
• The plains have a dense network of roads because it is easy to construct roads in plain than in the mountains.

RAILWAYS
• Railways is the fastest and the cheapest means of land transportation.
• Diesel and electric engines have largely replaced the steam engines. Electric engines are fast and eco-friendly and don't cause pollution.
• Indian railway network is well developed. It is the largest in Asia.

WATERWAYS
• Waterways are the oldest and the cheapest means of transportation to carry heavy and bulky goods from one country to another.
• Waterways are mainly of two types – Inland waterways and sea routes.

AIRWAYS
• This is the fastest & most comfortable means of transportation and also the most expensive due to high cost of fuels.
• It is the only mode of transport to reach the most remote and distant areas especially where there are no roads and railways. Helicopters are extremely useful in most inaccessible areas.
• Air Services are of two types: - (1) Domestic Airways: Fly within the boundaries of a country. (2) International Airways: Fly abroad and connects major cities of the world.

Q10. Distinguish between (i) Rural and Urban Settlement (ii) Personal and Mass Communication
Ans:
(i) Rural and Urban Settlement

(ii) Personal and Mass Communication

Q11. Why do we need means of communication? What are its two categories? What is there importance?
Ans: Communication is the process of conveying messages (sending or receiving) and ideas to others. With the development of technology humans have devised new and fast modes of communication.
Two categories of communication are: Personal and Mass Communication.
Importance of communication system can hardly be over estimated. Communication systems, such as TV, radio, mobile phones, etc, are the basic necessities' of modern society. Over the last few decades, the importance of communication is being increasingly recognized the face of in disaster and its management. A number of countries have setup Disaster Management Information System according to their needs. A good and effecting communication system can help in averting and reducing the impact of disasters.

 

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Human beings depended entirely on nature for food, clothing and shelter; but with time they learnt new skills to grow food, build homes and develop better means of transport and communication.  In this way they modified the environment where they lived.

Settlement:

1.  Earlier man lived a nomadic life, moving from one place to another in search of food and shelter, later man invented agriculture and started leading a more settled life.

2.  The settlements grew near the river valleys as water was available and land was fertile. With the development of trade, commerce and manufacturing, human settlements became larger.

What is settlement?

Ans: It is a place where people build their homes and interact with each other, carrying out various occupational activities which help making life more comfortable.

 

TYPES OF SETTLEMENTS

 

Settlements can be classified into two types: - Temporary or Permanent Settlements

 

Permanent Settlements can be classified into two types: - Rural and Urban settlements

 

Rural Settlements can be classified into two types: -  Isolated and Compact Settlements

 

TRANSPORT

Transport is the means by which people and goods move from one place to another.In the early days it took a great deal of time, to travel long distances. People had to walk and used animals to carry their goods.Invention of the wheel made transport easier. With the passage of time different means of transport developed to a great extent.

 

MEANS OF TRANSPORTATION

 

ROADWAYS

• The most commonly used means of transport are the roads. Especially, for short distances. 
• Roads can be metalled (Pucca) and unmetalled (Kutcha).
• Roads are the best means to link the rural and urban places across the country.
• In developed countries road network is very good.
• The plains have a dense network of roads because it is easy to construct roads in plain than in the mountains.
• In India we have National Highways connecting all major cities of the country. 
• There are state highways and district roads which connects all cities and towns.
• Manali-Leh highway in the Himalayan Mountains is one of the highest roadways in the world.

 

RAILWAYS

• Railways is the fastest and the cheapest means of land transportation.
• Diesel and electric engines have largely replaced the steam engines.
• Electric engines are fast and eco-friendly and don't cause pollution.
• Factors responsible for the construction of railway lines: - Relief Features, Climatic Conditions, Density of Population and availability of resources.
• Railway network is more developed in the plains than in the mountiains.
• Indian railway network is well developed. It is the largest in Asia.

 

WATERWAYS

• Waterways are the oldest  and the cheapest means of transportation to carry heavy and bulky goods from one country to another.
• Waterways are mainly of two types – inland waterways and sea routes.
• Inland Waterways: Navigable rivers and lakes are used as inland waterways. Some of the important inland waterways are the Ganga-Brahmaputra  river system, the Great Lakes in North America and the river Nile in Africa.
• Sea routes and oceanic routes are mostly used for transporting merchandise and goods from one country to another. These routes are connected with the ports. Some of the important ports of the world are Singapore and Mumbai in Asia, New York, Los Angeles in North America, Rio de Janerio in South America, Durban and Cape Town in Africa, Sydney in Australia, London and Rotterdam in Europe.
• Important Sea Routes of the world: North Atlantic Route which connects North America with Europe. Mediterranean Sea – Indian Ocean connecting Europe-East Africa-South Asia-Cape of Good Hope-Australia
• Major sea ports of India: - Mumbai, Kandla, Kochi, Chennai, Vishakhapatnam, Kolkata.

 

AIRWAYS

• This is the fastest & most comfortable means of transportation and also the most expensive due to high cost of fuels.
• Air traffic is adversely affected by bad weather like fog and storms, etc.
• It is the only mode of transport to reach the most remote and distant areas especially where there are no roads and railways.
• Helicopters are extremely useful in most inaccessible areas and in time of calamities for rescuing people and distributing food, water, clothes and medicines.
• Some of the important airports are Delhi, Mumbai, New York, London, Paris, Frankfurt and Cairo.
• Air Services are of two types: - (1) Domestic Airways: Fly within the boundaries of a country. (2) International Airways: Fly abroad and connects major cities of the world.

 

 

COMMUNICATION

• Communication is the process of conveying messages (sending or receiving) and ideas to others. 
• With the development of technology humans have devised new and fast modes of communication.
• The invention of printing press, radio, television, development of satellites, radar and computers has greatly revolutionized the communication system.
• Satellites have helped in oil exploration, survey of forest, underground water, mineral wealth, weather forecast and disaster warning.
• Postal and telegraph services, telephones, e-mails, etc are personal means of communication.
• Through Newspapers, magazines, radio, television, films, etc. Communication can be done with large no. Of people. This is known as Mass Communication.
• Mass Communication can provide both education and entertainment.
• Wireless telephonic communications through cellular phones have become very popular today.
• Internet not only provides us with worldwide information and interaction but has also made our lives more comfortable.
• Now, we are a large global society, The world.

 

 

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Very Short Answer Questions

Q1. What do you mean by natural vegetations?
Ans: Plants which grow naturally without any human interference, covering a large area is known as natural vegetation.

Q2. Name the factors on which growth of vegetation depends.
Ans: Rainfall, Temperature, Relief, Soil & its fertility, height above sea level, Sunshine, Drainage, etc.

Q3. Why are the trees in Evergreen forests remain green all round the year?
Ans: In the Evergreen forests there is no particular dry season, the trees do not shed their leaves altogether. Thus, these forests remain green all round the year.

Q4. What makes Camel an essential animal for the desert dwellers?
Ans: Camel is the most important animal of the deserts also known as the Ship of the desert. Camels have special body features which help them to survive in extreme conditions. Camels can survive for many days without water.

Q5. Why are several plants, animals and birds becoming endangered species?
Ans: Human activities like deforestation, agriculture, mining, hunting, industrialization, modernization, etc. have destroyed several ecosystems to meet their demands, making several plants, animals and birds becoming endangered species.

 

Short Answer Questions

Q6. Distinguish between (i) Evergreen and Deciduous Forests (ii) Tropical and Temperate Grasslands
Ans.
(i) Evergreen and Deciduous Forests

(ii) Tropical and Temperate Grasslands

Q7. Why do softwood trees have great commercial value?
Ans. Softwood trees have great commercial value because the wood is used for manufacturing paper and newsprint. The wood is also used for making furniture, matchstick, plywood and sports goods. Infact, 80% of the world timber comes from softwood trees.

Q8. How do shrubs and some trees survive in hot deserts?
Ans. Shrubs and trees found in the hot deserts have some special characteristics. Vegetation cover includes thorny bushes, cacti and few short trees. These have long roots, thick stems, waxy leaves and thorns which help the vegetation to survive in such harsh climatic conditions.

Q9. Why is there very limited vegetation in the Ladakh region?
Ans. Ladakh region is like a cold desert, there is snow cover through the year. The extremely cold conditions do not allow the growth of vegetation on a large scale. Thus, we find very limited vegetation in these regions.

 

Long Answer Questions

Q10. Describe the main characteristics of tropical rain forests.
Ans. Characteristics of the tropical rain forests are as follows:
(a) These regions are hot and receive heavy rainfall throughout the year.
(b) As there is no particular dry season, the trees do not shed their leaves altogether. This is the reason they are called evergreen.
(c) Maximum varieties of trees are found. Trees are tall with large trunks.
(d) The thick canopies of the closely spaced trees do not allow the sunlight to penetrate inside the forest even in the day time. Thus, grass is not found in these forests.
(e) Hardwood trees like rosewood, teak, sal, ebony, and mahogany are the common trees found here.
(f) Here the population found is very less. Due to dense forests commercial exploitation of these forests has not be possible, making them economically backward.
(g) Large variety and most colourful animals are found here.
(h) Monkey, Ape, Birds, Hippopotamus, snake, python, Frog, Crocodile, etc. Anaconda, world's largest snake is also found in these areas.

Q11. Where are Mediterranean forests located? Highlight the main characteristics of the trees found here.
Ans. Mediterranean forests are found on the western margins of continents in the warm temperate regions, in areas around Mediterranean Sea, Central Chile, South-West USA, Australia, Africa.
Some of the main characteristics of the trees found here are:
(a) Mediterranean trees adapt themselves to dry summers with the help of their thick barks and wax coated leaves which help them reduce transpiration. Also, here the plants have long tap roots to reach underground water, called "Xerophytic Plants".
(b) Mediterranean regions are known as 'Orchards of the world' for their fruit cultivation.
(c) Citrus fruits such as oranges, figs, olives and grapes are commonly cultivated here because people have removed the natural vegetation in order to cultivate what they want to.

Q12. Why do the trees in the Coniferous forests have conical shape?
Ans. Chir, pine, cedar, etc. are the important variety of trees found in these forests. These trees are tall, straight and conical shaped with needle shaped leaves. The conical shapes of these trees are best suited to the climatic conditions as it allows the snow to slide down the leaves and branches of these trees.

 

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Meaning of Natural Vegetation: Natural vegetation refers to a plant community which has grown naturally without human aid and has been left undisturbed by humans for a long time.

Thus, cultivated crops and fruits, orchards form part of vegetation but not natural vegetation.

The type and thickness of natural vegetation varies from place to place because of the variation in these factors. Natural vegetation is generally classified in to three broad categories as follows:

(a) Forests: Which grow where temperature and rainfall are plentiful to support a tree cover. Depending upon these factors, dense and open forests are grown.
(b) Grasslands: Which grow in the region of moderate rain.
(c) Desert Shrubs: Thorny shrubs and scrubs grow in the dry

 

Factors affecting the natural vegetation and wildlife:

1. Rainfall & Temperature
2. Relief
3. Soil & its fertility
4. Slope of land
5. Sunshine
6. Drainage

 

Types of Natural Vegetations:

 

FORESTS

Tropical Rainforests:
These forests are also called Tropical Evergreen.

Location:

• Forests found near the Equator (10° North to 10° South) in Amazon & Zaire Basin and Southeast Asia.

Climate:

• These regions are hot and receive heavy rainfall throughout the year.

Characteristics:

• As there is no particular dry season, the trees do not shed their leaves altogether. This is the reason they are called evergreen.
• Maximum varieties of trees are found. Trees are tall with large trunks.
• The thick canopies of the closely spaced trees do not allow the sunlight to penetrate inside the forest even in the day time. Thus, grass is not found in these forests.
• Hardwood trees like rosewood, teak, sal, ebony, and mahogany are the common trees found here.
• Here the population found is very less. Due to dense forests commercial exploitation of these forests has not be possible, making them economically backward.

Wildlife:

• Large variety and most colourful animals are found here.
• Monkey, Ape, Birds, Hippopotamus, snake, python, Frog, Crocodile, etc. Anaconda, world's largest snake is also found in these areas.

 

Tropical Deciduous Forests:
These forests are also called Monsoon Forests.

Location:

• Forests found in large part of India, Northern Australia and in Central America.

Climate:

• These regions are warm and receive rainfall less than 200 cms.

Characteristics:

• These regions experience seasonal changes. Trees shed their leaves in the dry season to conserve water.
• Trees like sandalwood, teak, sal, ebony, bamboo, etc. are the common trees found here.
• Forests are not very dense thus; commercial exploitation of these forests is possible.

Wildlife:

• Tigers, lions, elephants, langoors and monkeys are the common animals of these regions.

 

Temperate Evergreen Forests:

• These forests are also called Mixed Forests.

Location:

• Forests found in South-eastern parts of USA, Australia, Brazil and China.

Climate:

• These regions have cool winters and receive rainfall throughout the year.

Characteristics:

• They comprise both hard and soft wood trees like oak, pine, eucalyptus, etc.
• They look like Tropical Forest in thickness and variety.
• Timber (wood) from these forests is used for commercial purpose.

Wildlife:

• Deer, Wolves, Bears, Wild Boar, Foxes, Squirrels, Badgers, Skunks, Owls, Finches, etc. are the common animals of these regions.

 

Temperate Deciduous Forests:
Location:

• As we go towards higher latitudes, there are more temperate deciduous forests. These are found in the north eastern part of USA, China, Japan, New Zealand, etc.

Climate:

• These regions have cool winters and receive moderate rainfall.

Characteristics:

• Trees shed their leaves in autumn season and remain leafless through winters.
• The common trees are oak, ash, beech, etc.
• Forests are not very dense thus; commercial exploitation of these forests is possible.

Wildlife:

• Deer, foxes, wolves are the animals commonly found. Birds like pheasants, monals are also found here.

 

Mediterranean Forests:

 Location:

• Found in areas around Mediterranean Sea, Central Chile, South-West USA, Australia, Africa.

Climate:

• These regions have hot & dry summers and mild & wet winters.

Characteristics:

• Mediterranean trees adapt themselves to dry summers with the help of their thick barks and wax coated leaves which help them reduce transpiration. Also, here the plants have long tap roots to reach underground water, called "Xerophytic Plants".
• Mediterranean regions are known as 'Orchards of the world' for their fruit cultivation.
  Citrus fruits such as oranges, figs, olives and grapes are commonly cultivated here because people have removed the natural vegetation in order to cultivate what they want to.

Wildlife:

• There isn't much wildlife here.

 

Coniferous Forests:
These forests are also called "Taiga Forest".

Location:

• Found in the higher latitudes (50° – 70°) of Northern hemisphere.

Climate:

• These regions have cool & short summers and cold & long winters. These forests are also seen in the higher altitudes. Norway, Sweden, Finland, Russia and Canada.

Characteristics:

• Forests consist of tall, softwood evergreen trees.
• Limited species of trees are found. These trees are evergreen and grow apart from each other.
• Trees are conical shaped with needle shaped leaves and trees are found in large groups.
• Chir, pine, cedar are the important variety of trees in these forests. Lumbering is the common activity. Soft wood is used for manufacturing paper.

Wildlife:

• Fur-bearing animals like Silver fox, mink, and polar bear are the common animals found here.

 

GRASSLANDS

Tropical Grasslands:

 These grasslands are also known as "Savannas in Africa" and "Campos in Brazil".

Location:

• Found within Tropical zone (i.e. between Tropic of Cancer and Tropic of Capricorn).

Climate:

• These regions have hot & long summers and mild & short winters. Receives light rainfall in summers.

Characteristics:

• The grass can grow very tall, about 3 to 4 metres in height, which is also known as "Elephant Grass".
• Near river banks and water holes trees are found, which are deciduous in nature, e.g. Acacia, baobab, etc.
• Climatic conditions in these grasslands do not support rich agriculture and animal rearing. Economically, these grasslands are backward.

Wildlife:

• Lions, Tigers, Leopards, Elephants, Giraffes, Zebras, etc. are the species of animals found here. Birds like Ostrich, Emu, Cassowary, etc. can also be seen.

 

Temperate Grasslands:

These grasslands are also known as "Prairies in North America", "Pampas in South America", "Downs in Australia", "Velds in South Africa" and "Steppes in Europe".

Location:

• These are found in the mid- latitudinal zones and in the interior part of the continents. Central Asia from Black Sea to Central Russia, North Central USA and Southern Canada, South-East Australia and Southern Africa, Argentina.

Climate:

• These regions have warm & moist summers and cold & snowy winters.

Characteristics:

• The grass found here is short and juicy, which is suitable for cattle feed.
• Maize and wheat are grown in large amount, that's why this area is also known as "Bread Basket" of world.

Wildlife:

• Herbivores like Wild Ass, Antelopes, and Horses. Kangaroos in Australia. Carnivores like Rodents and Reptiles are also found.

 

DESERTIC SCRUBS

Tropical Deserts:

Location:

• Located on the western margins of the continents between 15° – 30° North & South of Equator. Biggest desert, Sahara in North Africa is hot desert while Ladakh in India is cold desert.

Climate:

• These regions have hot & dry summers and receive very less rainfall.

Characteristics:

• Plants found are very less with succulent stems, long roots and leaves are reduced to spines.
• Nature has been very kind, at some places "Oasis" is found in deserts with palm trees surrounding them.

Wildlife:

• Camel is the most common animal found in these deserts. Wild Yak, Hyena, Scorpion, fox, jackal, etc. are also found.

 

Tundra Regions:

Location:

• Tundra means barren land. Located in North Canada, North Russia, North Sweden and Finland islands in Arctic Ocean.

Climate:

• These regions have long & very cold winters and very short and cold summers.
• Land is always frozen

Characteristics:

• Trees are not found; as trees don't grow below 10° C. Very less vegetation is found.
• Mosses, Lichens and some shrubs grow here.
• Economically underdeveloped.

Wildlife:

• Most common animal found in these area are Penguins, Polar Bears, Musk, Ox, Wolf, etc.

 

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Very Short Answer Questions

Q1. What are streams of water moving in a definite pattern called?
Ans: Streams of water moving in a definite pattern are called Ocean Currents.

Q2. What are the giant waves caused by earthquakes on ocean floors called?
Ans: Tsunami giant waves caused by earthquakes on ocean floors.

Q3. What are the three movements of ocean water?
Ans: Waves, Tides and Ocean Currents are the three movements of ocean water.

Q4. Define the term Salinity.
Ans: The amount of salt in the ocean water is called salinity.

 

Short Answer Questions

Q1. What is the hydrological cycle?
Ans. The process by which water continually changes its form and circulates between lithosphere, atmosphere and hydrosphere is known as the Water Cycle or the Hydrological Cycle. It is a never ending process.

Q2. Is water a renewable resource?
Ans. Yes, water is called as a renewable resource because it can be used again and again. Water changes its form, due to heat water evaporates, when cools it condenses to form clouds and then through precipitation water comes back to the earth, this is a continuous process.

Q3. What does the word 'Tsunami' means?
Ans. An earthquake, a volcanic eruption or underwater landslides can shift large amounts of ocean water. As a result a huge tidal wave called tsunami originates.
Tsunami is a Japanese word that means "Harbour waves" as the harbours get destroyed whenever there is tsunami. The term "Tsunami" has been derived from: - "Tsu" – Harbour and "Nami" – Waves. Meaning huge tidal waves.

Q4. Explain why warm ocean currents are less dense than cold ocean currents.
Ans. Warm ocean currents are less dense than the cold ocean currents because the warm ocean currents originate near the equator and move towards the poles. Due to high temperature, moisture content in the air becomes very less making the warm currents rise the temperature over land surface. Whereas, cold ocean currents blow from Poles towards the equator. Here the temperature is less and moisture content is more, making these currents more dense than the warm currents

 

Long Answer Questions

Q1. What are the different types of tides and how are they caused? How are tides useful?
Ans. The tides are broadly classified into two types: Spring Tides and Neap Tides.
• During the full moon and new moon days, the sun, the moon and the earth are in the same line and the tides are highest. These tides are called spring tides. It is high tide when water covers much of the shore by rising to its highest level.
• But when the moon is in its first and last quarter, the ocean waters get drawn in diagonally opposite directions by the gravitational pull of sun and earth resulting in low tides. These tides are called neap tides. It is low tide when water falls to its lowest level and recedes from the shore.

Tides help us in the following ways:
• High tides help in navigation. This helps the ships to arrive at the harbour more easily.
• The high tides also help in fishing.
• Tides are also helpful in generating electricity.

Q2. How are ocean currents different from waves? Which factors are responsible for giving rise to ocean currents?
Ans.

Factors affecting the Ocean Currents: -
1. Planetary Winds.
2. Rotation of the Earth
3. Variation in the temperature
4. Density of ocean water
5. Shapes of the coastlines

Q3. Suggest measures to conserve water. When do we celebrate 'World Water Day'?
Ans. Some of the important ways to conserve water are:
1. Decrease of water pollution: Discharge of untreated sewage, agriculture chemicals & industrial effluents.
2. Proper irrigation method.
(a) Sprinklers can be used to irrigate very large area.
(b) Drip irrigation can be used in dry regions, where evaporation is very high.
3. Water Harvesting Method: This water can be used for cleaning, washing, gardening, etc.
4. Water conservation in the home.
• Check faucets and pipes for leaks.
• Check your toilets for leaks.
• Use your water meter to check for hidden water leaks.
• Install water-saving shower heads and low-flow faucet aerators.
• Put plastic bottles or float booster in your toilet tank.
• Insulate your water pipes.
• Take shorter showers.
• Turn off the water after you wet your toothbrush.
• Use your dishwasher and clothes washer for only full loads.
• When washing dishes by hand, don't leave the water running for rinsing.

'World Water Day' is celebrated on 22 March every year.

Q4. Give reasons:
(a) Ocean currents are important. How?
(b) Tides are very useful. How?
Ans.
(a) Following are the importance of ocean currents:
• Warm and cold currents help in controlling the climatic conditions of the world.
• Ocean currents help in navigation.
• ocean currents are important to the distribution of the world's sea life.
• Ocean currents also act as the convectional source of energy.

(b) Tides are very useful, following are the different ways:
• High tides help in navigation. This helps the ships to arrive at the harbour more easily.
• The high tides also help in fishing.
• Tides are also helpful in generating electricity.

Q5. The ocean currents are broadly divided into warm and cold currents. Why are they called so? What makes them warm and cold?
Ans. The ocean currents are broadly divided into warm and cold currents. These currents get influence by the temperature conditions of an area. The warm ocean currents originate near the equator and move towards the poles. Warm currents rise the temperature over land surface.
Whereas, the cold currents carry water from polar or higher latitudes to tropical or lower latitudes. Cold currents reduces the temperature of the coastal areas.
Movement of these currents make them warm or cold. The general circulation of ocean currents is clockwise in the Northern Hemisphere and anti-clockwise in the Southern Hemisphere.

 

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Some Facts and Figures of Water:

• TWO-THIRD OF THE EARTH'S SURFACE IS COVERED WITH WATER.
• Earth is also known as "Watery Planet", because 71% of the earth's surface is covered with water and only 29% is land.
• World Water Day is celebrated on 22 March.

 

Distribution of Water:

1. 97% of the total volume of water is covered by Seas and Oceans

2. 3% as fresh water available on earth.

    (a) Out of 2% of the fresh water available, nearly 70% is in the form of "ICE" and is found in glaciers in Antarctica, Greenland, mountain regions, etc.

    (b) Only 1% of water is fit to use. It is found as underground water, surface water in rivers and lakes and also, water vapors' in the Atmosphere.

 

Water is available in three forms:

1. Water vapor's

2. Water in ocean, lakes & rivers

3. Ice in the glaciers & ice caps

 

HYDROLOGICAL CYCLE

• The fresh water is continuously being renewed and recharged through hydrological cycle.
• The sun's heat causes evaporation of water vapour.
• When the water vapour cools down, it condenses and forms clouds.
• From there it may fall on the land or sea in the form of rain, snow or sleet which is known as precipitation.
• The process by which water continually changes its form and circulates between oceans, atmosphere and land is known as the Water Cycle or the Hydrological Cycle.

 

Usage of Water:

1. Drinking                                         2. Bathing                                           3. Washing

4.  Cooking                                        5. Irrigation                                         6. Construction, etc.

7. Water used in Industries                  8. Generating Electricity

 

PROBLEM OF WATER AVAILABILITY

• Water is available in abundance and is renewable. Then why we suffer from water scarcity?
• Water is not evenly divided around the world. Some places have lots and others have very little. Water supply is a big problem in some countries like, Africa, West Asia, South Asia, etc.

According to Mr. Falkenmark (a Swedish Expert), Water Stress Indicator, a country or region is said to experience "water stress" when annual water supplies drop below 1,700 cubic metres per person per year. At levels between 1,700 and 1,000 cubic metres per person per year, periodic or limited water shortages can be expected. When water supplies drop below 1,000 cubic metres per person per year, the country faces "water scarcity".

 

CONSERVATION OF WATER

Some of the important ways to conserve water are: -

1.  Decrease of water pollution:- Discharge of untreated sewage, agriculture chemicals & industrial effluents.

2.  Proper irrigation method.

     (a) Sprinklers can be used to irrigate very large area.

     (b) Drip irrigation can be used in dry regions, where evaporation is very high.

3.  Water Harvesting Method: This water can be used for cleaning, washing, gardening, etc.

4.  Water conservation in the home.

• Check faucets and pipes for leaks.
• Check your toilets for leaks.
• Use your water meter to check for hidden water leaks.
• Install water-saving shower heads and low-flow faucet aerators.
• Put plastic bottles or float booster in your toilet tank.
• Insulate your water pipes.
• Take shorter showers.
• Turn off the water after you wet your toothbrush.
• Use your dishwasher and clothes washer for only full loads.
• When washing dishes by hand, don't leave the water running for rinsing.

 

MOVEMENT OF OCEAN WATER OR OCEAN CIRCULATION

• March 22 is celebrated as World Water Day.
• Ocean water keeps moving continuously. It is never still.
• The movements that occur in oceans can be broadly categorized as:Waves, Tides and Currents.

 

WAVES

• When the water on the surface of the ocean rises and falls alternately, they are called waves.
• During a storm, the winds blowing at very high speed form huge waves.
• These may cause tremendous destruction.An earthquake, a volcanic eruption or underwater landslides can shift large amounts of ocean water. As a result a huge tidal wave called tsunami.
• Tsunami is a Japanese word that means "Harbour waves" as the harbours get destroyed whenever there is tsunami. The term "Tsunami" has been derived from: - "Tsu" – Harbour and "Nami" – Waves. Meaning huge tidal waves.

 

TIDES

• The rhythmic rise and fall of ocean water twice in a day is called a tide.
• It is high tide when water covers much of the shore by rising to its highest level.
• It is low tide when water falls to its lowest level and recedes from the shore.
• During the full moon and new moon days, the sun, the moon and the earth are in the same line and the tides are highest. These tides are called spring tides.
• But when the moon is in its first and last quarter, the ocean waters get drawn in diagonally opposite directions by the gravitational pull of sun and earth resulting in low tides. These tides are called neap tides.
• High tides help in navigation.
• This helps the ships to arrive at the harbour more easily.
• The high tides also help in fishing.
• Also, the rise and fall of water due to tides is being used to generate electricity in some places.

 

OCEAN CURRENTS

The horizontal movement of ocean water in the form of streams flowing constantly in definite directions is known as Ocean Currents.

 

Factors affecting the Ocean Currents: -

1.  Planetary Winds

2.  Rotation of the Earth

3.   Variation in the temperature

4.  Density of ocean water

5.  Shapes of  the coastlines

 

• The ocean currents may be warm or cold.
• The warm ocean currents originate near the equator and move towards the poles.
• The cold currents carry water from polar or higher latitudes to tropical or lower latitudes.
• The ocean current influence the temperature conditions of the area.
• The place where warm and cold currents meet, dens fog is produced, reducing the visibility and thus, making it difficult for navigation. But at the same time these are the best fishing grounds of the world.
• The general circulation of ocean currents is clockwise in the Northern Hemisphere and anti-clockwise in the Southern Hemisphere.

 

 

CASE STUDY

(TSUNAMI IN THE INDIAN OCEAN ON 26 DECEMBER 2004)

• Tsunami or the harbour wave struck havoc in the Indian Ocean on the 26 December 2004.
• The wave was the result of the earthquake that had its epicenter close to the western boundary of Sumatra in Indonesia.
• The magnitude of the earthquake was 9.0 on the Richter scale.
• Tsunami affected the coastlines of South and Southeast Asian countries. India, Indonesia, Sri Lanka, Thailand, etc were some of the countries where destruction was maximum.
• Tsunami travelled at a speed of about 800km. per hour and completely washed away some of the islands in the Indian ocean.
• The Indira point in the Andaman and Nicobar islands that marked the southernmost point of India got completely submerged. In India, the worst affected were the coastal areas of Andhra Pradesh, Tamil Nadu, Kerala, Puducherry and the Andaman and Nicobar Islands.
• The earthquake-induced tsunami resulted in at least 1.8 lakh dead, 500,000 injuries, and damages that exceeded $10 billion. Also, it is estimated that 5 million people lost their homes or access to food and water.
• Relief work was carried out at a great speed. All types of helps were received from all the corners of the world. Serious efforts were made by the government and non-government agencies to bring back life of the leftovers on track.

 

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