RBSE Solutions for Class 7 Social Science Chapter 3 Water are part of RBSE Solutions for Class 7 Social Science. Here we have given Rajasthan Board RBSE Class 7 Social Science Chapter 3 Water.
|Number of Questions Solved||42|
Rajasthan Board RBSE Class 7 Social Science Chapter 3 Water
Exercise from text book
Choose the correct options :
(1) Water Day is celebrated on :
(a) 25 March
(b) 22 March
(c) 15 March
(d) 10 March
(b) 22 March
(2) Von Lake is in which country?
Fill in the Blanks :
(1) Natural water is getting ………… due to human activities.
(2) In …………. of Meghalaya in India receives maximum rainfall in the world.
(3) Rainwater when gets collected and stored on the rocks below ground is called ………….
(4) Salty water is also known as ……………..
2. Mawsynram and Cherrapunji
3. underground water
4. hard water/saline water.
What is roof top water conservation?
Roof top water conservation is a technique by which water is collected from roof top through pipes and is stored in ground water tank or in a sink for future usage as per requirement. This technique is best suited for areas which receive less or sporadic rainfall.
Write the various sources of water.
The main sources of water on the surface of earth are rivers, lakes, wells, annicus, groundwater, etc.
Why ancient civilizations developed near shores of water bodies?
The ancient civilizations mainly developed near shores of water bodies because these water bodies not only provided drinking water but were also the source of water for agriculture, trade, transportation and security. This is the reason that the major cities and towns of world developed on the shores of rivers, lakes and coast of sea.
What problems do we face by careless use of underground water?
Underground water is the main source of fresh and clean water. This underground water is reached through wells and boreholes and drawn on earth surface by machines. Further this water is made available for daily use. If underground water is not used carefully the following problems may arise :
- Continuous lowering of the level of underground water.
- Due to limitless usage of underground water its availability may decrease.
- Since underground water is the basis of water activities on earth’s surface, therefore its irrational use may cause problems to agriculture, industries, vegetation, creatures and to humans itself. As the moisture of soil will reduce and it will become unsuitable for agriculture.
What is the difference between fresh and salty water?
Only fresh water is useful for humans, crops and vegetation and all living organisms. On the other hand, salty water is unsuitable for humans, crops and vegetation and all living organisms. Water is salty due to dissolved sodium chloride, calcium, magnesium salts and other particles.
What is water pollution? Suggest measures for its control.
Natural water is pure, when unwanted substance gets dessolved into this pure natural water it becomes inappropriate for human consumption and it is called polluted water. Unwanted particles get dissolved in water due to human activities. The polluted water is unsuitable not only for humans but also for cattle, water creatures, plants and trees.
Water pollution can only be stopped when along with efforts at administrative level, individual level efforts are also involved. It is highly important to make people aware of water pollution, its causes and controlling methods.
Individual Efforts :
- Making people aware and informing them about the methods of controlling water pollution.
- To prohibit bathing, washing clothes and bathing animals in public water bodies.
- To minimize the use of chemical fertilizers and pesticides.
Administrative Efforts :
(i) To prevent the sewage water getting mixed with clean water bodies. The sewage water should be cleaned and made re-usable.
(ii) The non-biodegradable waste should not be disposed off in water bodies rather it should be dumped on unusable and barren lands.
(iii) Strong laws should be made against industrial units and individuals who create pollution.
(iv) It is necessary to create mass awareness about water pollution with the help of television and radio broadcast.
In order to control water pollution in India Water Pollution Prevention and Control Act was enacted in 1974 and Environment Protection Act was enacted in the year 1986. The Ganga and the Yamuna are considered to be most polluted rivers in India. To clean river Ganga, the Indian government started the “Ganga Action Plan” and “Namami Gange” projects.
Activities from textbook
Let us do (Page 22)
List the main civilizations of the world by looking at the map of ancient civilization.
2. Africa ………..
3. North America …………
4. South America ……….
1. Asia :
- Indus Valley Civilization
- Huang Ho Valley Civilization
- Mesopotamia Civilization
2. Africa- Nile Valley Civilization
3. North America- Maya, Aztec Civilization
4. South America- Inca Civilization.
Let us do (Page 23)
List other cities lying on the water sources by studying map of world. You can take help of your teacher.
Cities Situated Near River
|2.||Allahabad||Ganga and Yamuna||India|
Cities Situated Near Ocean Coast
|7,||New York||Atlantic Ocean||U.S.A|
|8.||San Fransisco||Pacific Ocean||U.S.A|
Cities Situated Near Lakes
Find out your city/village is situated near which source of water and list other sources of water near your village/city.
I live in Ajmer city and Aanna Sagar lake is situated in my city. Apart from this the other water sources situated close to my city are Foy Sagar lake, Pushkar and Narayan Sagar dam which fulfil the requirement of water in the region.
Let us do (Page 24)
How many oceans are there on the earth? List them.
The earth has only four oceans, namely :
- Pacific Ocean
- Atlantic Ocean
- Indian Ocean
- Arctic Ocean
Find out the availability of water per verson by observing the following map.
|Country/Region||Availability of Fresh Water (Cubic meter/ person/year)|
|1.||North and North-East Africa, Arabian peninsula, Afghanistan, Pakistan, etc.||0-1000|
|2.||India, some countries of Midwestern Asia, Mid Europe,
The south-central African countries in Sahara Desert, South Africa etc.
|3.||China, Japan, North and South Korea, Vietnam, Thailand, Mid-Eastern Africa, Britain, France, Italy, Greece, etc., European Countries etc. situated north of Mediterranean sea||1700-5,000|
|4.||Mongolia, Eastern isles, Middle eastern Africa, South Central Africa, United States of America, Alaska, Middle and South Eastern South America, etc.||5000-15,000|
|5.||Siberia, Eastern Europe, Australia, Brazil, countries of mid-eastern South America, Central Africa, Madagascar, etc.||15000
|6.||Finland, Western part of central Africa, Andes mountain region of western part of South America, Canada and different islands situated in its north.||50,000
Let us do (Page 25)
What is the source of water at your home/school ?
Groundwater is mainly used at our home and in our school. With the help of well, hand-pump, and machine groundwater is raised and through tap it is made available for use.
List the modes of with drawing underground water.
At present, modern techniques of submersible pumps, wells etc. are used to bring groundwater on surface. Conventional techniques like wells, ponds, hand-pump are also used to draw underground water.
Let us do (Page 26)
Discuss in class the state of polluted rivers and underground water resources with the help of the map below.
Due to urbanization and industrialization various rivers and much of groundwater has got intensively polluted. This level of pollution can be understood in terms of highly polluted, polluted and moderately polluted. Even groundwater has got polluted due to various industrial and agricultural activities.
Let us do (Page 27)
List the reason for pollution in water bodies nearby your places? Discuss the effect of using polluted water on organism in your class.
The reasons for water pollution nearby my place are as follows :
- Dumping of solid waste and chemicals from factories directly into water bodies.
- Dumping of solid waste from homes into water bodies.
- By the use of chemical fertilizers, insecticides and other medicines in agriculture.
- Washing clothes and bathing domestic animals in water bodies.
- Open defecation.
Bad-effect : Polluted water is harmful for water organims and plants. It is the cause of many diseases. It has an unfavourable effect on land and water organisms. It reduces the amount of dissolved oxygen in water which is the cause of death of many water organisms. The dissolved pollutants are also harmful for crops.
Let us do (Page 28)
Collect information from newspaper, magazines and internet about water conservation in Rajasthan, India and the world.
In the year 2016 the Rajasthan government started the Chief Minister Water Swavlamban Campaign which is the biggest water conservation project in India. Similar to this many water conservation projects have started in the world because the water available on earth which is suitable for consumption is very little.
Make a list of water sources in your places which are using from ancient times.
(iv) Canals etc.
Was any water source constructed in your district in ancient times? If yes, then collect information about it.
I live in Ajmer, and in my district Anna Sagar lake was constructed by Chauhan dynasty king Arnoraja in 1137 AD. Jahangir built the Daulatabagh near this lake, presently known as Subhash Udyan.
Other important questions
(A) Multiple Choice Questions
Nile Valley Civilization is related to which continent?
(d) North America
Udaipur city is situated on the shores of which river?
What is water conservation?
(a) Adequate use of water
(b) To consider the future use of water
(c) To reduce wastage of water
(d) All the above
(d) All the above
What is the main reason for reduction of water resources?
(a) Increase in usage of water
(b) Lack of water conservation
(d) All these
(d) All these
What is known as the Blue gold of future?
(c) Clean water
(c) Clean water
Out of the total water available on earth what is the percentage of water suitable for drinking?
Chicago is situated near which lake?
(a) Lake Superior
(c) Michigan lake
(d) Ontario lake
(c) Michigan lake
(B) Fill in the Blanks
1. ………is the main basis of Life.
2. Due to availability of water …………. is possible on the earth.
3. Air gets moisture due to water vapour from sea which is known as ………..
4. By consuming water which has chloride causes ……….. disease.
(C) Very Short Answer Type Questions
Briefly describe the usefulness of water?
Water is used for drinking, bathing, washing, irrigation and industrial purpose. It is also useful for maintaining the thermal balance of earth’s surface.
How can we say that water is multifaceted?
Water is important in our social, religious, political, cultural and trading purposes, therefore we can say water is multifaceted.
Describe the main reason for salinity of water.
The main reason for salinity of water are dissolved sodium chloride, and magnesium- calcium salts.
Where do you find flouride in water? What are its harmful effects?
Fluoride rich water is found in Rajasthan’s Shekhawati region and in Southern Rajasthan. Using this water for drinking purpose can lead to bone-related diseases.
What are the reasons for decrease in groundwater?
(1) Decrease in Rainfall.
(2) Increase in irrigation.
(3) Increase in Industrial demand
(4) Expolitation of water due to increasing population.
How are forests useful for rainfall?
Forests cause transpiration which results in rainfall. Therefore, area having large forest areas receive more rainfall.
At present what are the steps taken for water conservation?
(1) Construction of dams and canals.
(2) Constructions of anicuts.
(3) To clean polluted water and make it re-usable.
(4) Spreading awareness, etc.
(D) Short Answer Type Questions
Water is the foundation of life. Explain.
Humans, wildlife, plants and vegetation all depend on water. The earth is the only planet which has water, hence it has life. Water is the only substance which touches all the aspects of human civilization. It plays an important role in agricultural and industrial development. If water is removed from the Biosphere the Biosphere, will perish. Thus it can be said that water is life. So, we can say that it is because of water there is vegetation, wildlife, human civilization oceans, rivers, waterfalls, lake, wells, and atmosphere.
Describe the traditional ways of water conservation.
In ancient times, to reduce water shortage problem, the states and people cooperatively dug lakes, wells, baoli, etc. The rulers of Rajasthan played an important role in water conservation. They constructed different lakes from time to time and looked after them. They directed the path of rivers to the lakes to fulfil the purpose of water conservation.
How did the people of western Rajasthan get educated about water conservation?
The people of western Rajasthan learned to conserve every drop of water from honey bees. They also have a folk sing meaning, if the honeybees can make honey by collecting nectar from different flowers can’t we humans save water by collecting rainwater.
(E) Long Answer Type Questions
Describe the water cycle with the help of a diagram.
Rivers, lakes, ponds, oceans, groundwater are the main sources of water. These sources receive water from rainfall. Due to high temperature, the water from these sources evaporate; transpiration also occurs in plant. The air receives water vapor from oceans which we call humidity.
Watervapor laden air rises above and as the air rises, due to decrease in temperature with attitude, the vapour laden capacity of air reduces which futher result in condensation of vapour into water droplets and formation of clouds which flow from one plaice to another with the move of winds.
These clouds cause rainall, and through rains the water reaches the ocean. This whole process of evaporation, condensation and transformation of water into various forms and falling back on the earth to rejoin the water source is called water cycle.
The present conditions indicate acute water crisis in the future. Explain.
Presently, water pollution is increasing at a rapid rate due to increase in population and industrial development. Every one out of six person on the earth is struggling for clean water. The world population is supposed to increase to 9 billion by the year 2050. By that time more than half of the population would be facing water crisis.
According to a study, almost half of the population will be living in urban areas by the year 2020. It will be a tough challenge to provide clean water to the ever increasing urban population. At present there is a continuous increase in demand of clean water. However fresh water is continuously decreasing which has the following reasons.
- Increasing population.
- Global warming.
- Excessive exploitation of groundwater.
- Deforestation and reduction in rainfall.
- Excessive water requirement for commercial agriculture.
- Increase in Industrialization and urbanization.
- Modern lifestyle.
Describe the usefulness of traditional water sources and the threats upon them.
Traditional water sources are constructed according to physical and social conditions, such as wells, baolis, canals, lakes, and ponds etc. They are constructed to conserve water, increase the water table, level, irrigation and water supply. Presently, the population is increasing at a rapid rate due to which these traditional water sources are under danger; at some places people have taken over these tradational water sources for these personal use and at some places these sources are in a state of disrepair due to lack of maintenance.
These sources could have become the cure for the present water crises. Therefore, we can say that traditional water management system is an important part of our heritage and it is important to conserve it. These water conservation techniques can prove to be very efficient and useful.
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