CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
UNIT IV - WATER ON LAND
CONTENT
Water
Its Importance
Nature and Source of Water
Fresh and Saline Water
Hydrological Cycle
Definition & Process
Its Processes
Three processes
o Evaporation
o Condensation
o Precipitation
Importance of Water Cycle
Water as a Renewable Resource
Conservation of Water
Need For conservation
Water Related Issues
Scarcity of Potable Water
Pollution of water
Case Studies
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Water on Land – An Overview
When Neil Armstrong saw the earth from the moon, it appeared blue. This is because water
covers more than two-third of the earth’s surface and rest is covered by land. All the water
bodies on the earth are together called the hydrosphere. 97% of the water on the earth is salt
water found in seas and oceans. Only three percent is fresh water found in streams, lakes,
rivers, glaciers etc. Water is one of nature's most important gifts to mankind. Essential to life,
abundance of water on earth has entitled it ‘watery planet’.
Nature of Water
Water is the only substance that occurs at ordinary temperatures in all three states of matter:
solid, liquid, and gas. As a solid, ice, it forms glaciers, frozen lakes, snow, hail, and frost. It is
liquid as rain and dew, and it covers three-quarters of the earth's surface in swamps, lakes,
rivers, and oceans. Water also occurs in the soil and beneath the earth's surface as a vast
groundwater reservoir. As gas, or water vapour, it occurs as fog, steam, and clouds .
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CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Saline Water - Water containing a large amount of dissolved salts is called saline water. Seas
and Oceans are the largest water bodies in which 97.3 per cent of the total water is found are
saline in nature. This water cannot be used for drinking or irrigation due to its high salt content
but we can obtain common salt and many other chemicals by evaporating sea water. On an
average salinity of ocean water is 35 parts per thousand.
Do you know?
Dead Sea is without any means of outflow, the primary mechanism of water to leave the lake is
by evaporation which can be quite high in a desert. The result is that the water of Dead Sea has
the highest salinity and density. This makes easier for the swimmers to float in the Dead Sea as
the saline water is denser than the ordinary water. The water is ideal for locating evaporation
ponds for extraction of table salt.
Dead Sea, Evaporation Pond
(Source: EXACT)
Do You Know?
Water is called the “universal solvent” because it dissolves more substances than any other
liquid. This means that wherever water goes, either through the ground or through our bodies, it
takes along valuable chemicals, minerals, and nutrients.
Water Cycle
Water moves continuously among hydrosphere, atmosphere and lithosphere. This never ending
cycle of movement of water from land to sky and back to land (from liquid to vapour and back to
liquid) is also called Hydrological cycle. The processes responsible for this cyclic movement of
water are evaporation, condensation and precipitation. Even though water is constantly changing
states the total amount of water on the earth remains constant. The Sun is the energy force that
forms the cycle.
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CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Condensation
Precipitation
Transpiration
Evaporation
Runoff
Infiltration
The Hydrological Cycle
Evaporation: The process by which water changes into water vapour or gas is known as
evaporation. Water can change from one form to another by absorbing or giving out heat. It
evaporates continuously from oceans and other water bodies on the land surface. The rate of
evaporation is highest on hot windy and dry days. Warm air can hold more water vapour than
cold air. The return of water vapour into the atmosphere by plants is called transpiration. This
occurs mainly from surface of leaves.
Evaporation is a continuous process, but the air cannot keep holding endless amount of water
vapour. At a particular temperature the air can hold only a certain amount of water vapour .When
the air contains as much water vapour as it can hold at a given temperature it is said to be
saturated.
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Evaporation
Do it Yourself
Experiment - Record Evaporation
1. Pour coloured water into a saucer and mark around the surface of the water. Leave
the bowl in a warm place for few hours.
2. Do you observe water level dropping?
3. Now place the bowl in a cool place?
4. Record your observations-Will the effect be same? If yes -why and if not then why
not?
Do You Know?
The plants also ‘sweat’………
But plants transpire. Transpiration is the process
by which plants lose water out of their leaves
and contribute to the water cycle.
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Condensation
It is the process of change of water from its gaseous form (water vapour) into its liquid form. It
takes place in the atmosphere when warm air rises cools and loses its capacity to hold water
vapour .The air gets saturated. When the temperature of the saturated air falls, the air is no longer
able to hold the moisture it is carrying the excess water vapour changes into tiny droplets of
water.
Condensation is the process that creates clouds, and so is important for the formation of rain and
snow. Condensation also leads to the formation of fog, mist and dew. The two most important
pre-requisites for condensation to occur are
i) the saturated air and
ii) the availability of a surface on which water vapour condenses.
The most common surface over which water vapour condenses are the dust particles floating in
the air.
Condensation – Formation of Clouds
Clouds: When warm and moist air rises upwards, it cools and the air gets saturated. When the
temperature of the air falls further, the water vapour condenses on the dust particles into water
droplets. At times the temperature is so low that the water vapour changes into ice crystals.
These droplets or crystals are so light that they float in the atmosphere. These visible masses of
water droplets or ice crystals are called clouds.
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Precipitation
Clouds that are formed contain millions of tiny droplets of water. Some of these droplets fall
very slowly, while some are carried by the air currents. The moving droplets cling onto each
other and become larger in size. The droplets further grow in size and become so heavy to float
in the air. Then they fall as rain. When the ice crystals in the clouds grow in size, they fall as
snow. The falling of the condensed water vapour is called as precipitation.
Rain drops on a leaf
Rain Showers
Water that falls on the land in the form of rain, collect in ponds, lakes or rivers that carry it back
to the oceans.
Thus the never ending movement of water continues and is also referred to as the Hydrological
Cycle.
Importance of the Water Cycle
It is because of the water cycle that water is constantly recycled, and because of this the
amount of water on the Earth always remains the same.
The natural supply of water varies from place to place and season to season because of the
processes that make the water cycle.
Water is essential for life and water cycle is nature’s way of ensuring that the natural supply
of fresh water is maintained.
Today, when natural sources of water are being polluted due to over population,
urbanization, industrial effluents, chemical fertilizers etc., the importance of water cycle
becomes immense as it involves processes that add fresh water to this earth.
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CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Humans and world’s unique biodiversity both depend on clean continuous availability of
fresh water which is made possible by water cycle.
All the water that we use also forms a part of the water cycle. The waste water coming out of
our homes, factories etc., flow into the rivers and then finally into the oceans and seas. The
heat of the sun makes water evaporate from the seas, lakes and rivers and the cycle continues.
Do it Yourself
Make a list of role/use of water in 12 hours of your day.
Try to put them in order of priority
Conclude- Can you live without water.
Conservation of Water
Fresh water is a renewable resource, yet the world's supply of clean, fresh water is steadily
decreasing. Water demand already exceeds its supply in many parts of the world due to the
pressure of growing population. The world is heading towards a freshwater crisis mainly due to
its mismanagement. This crisis is already evident growing in many parts of the world, varying in
scale and intensity depending on the time of the year, climate, and location. The causes of water
pollution vary. Agricultural runoff carrying fertilizers, pesticides, insecticides etc., add pollutants
into river, lakes, ponds and underground sources. Petroleum products and other contaminants
from urban and rural areas, leaking sewer lines, discharge of industrial wastes into water bodies
etc., are the major culprits of polluting then fresh water sources.
All this makes conservation of water a major concern. Recognising the importance of water
resource for the planet’s future, the United Nations General Assembly proclaimed the year 2003
as the ‘International Year of Fresh Water’. Deliberate efforts have been taken since then to raise
awareness, motivate people and mobilise resources in order to manage water resources available
on the earth’s surface.
"Water is probably the only natural resource to touch all aspects of human civilization from agricultural and industrial development to the cultural and religious values
embedded in society."
- Koichiro Matsuura, Director General, UNESCO
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CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Conservation of water in different sectors is essential since water is necessary for the growth of
plants, industries, domestic consumption, maintaining temperature etc. A depleting water table
and a rise in salinity due to overuse of chemical fertilizers and pesticides has made matters
serious. Various methods of water harvesting and recharging have been and are being applied all
over the world to tackle the problem.
Think about it………..
As per a study a dripping tap can waste up to 6 litres of water in a
day. Every day, we take about four-fifths of the world’s
fresh water that is stored in the rivers and in the rocks
underground.........Can we afford it??
Rainwater Harvesting – A Technique to Conserve Water
Rainwater harvesting essentially means collecting rainwater on the roofs of building and storing
it underground for later use. Not only does this recharging arrest groundwater depletion, it also
raises the declining water table and can help augment water supply. This has become a very
popular method of conserving water especially in the urban areas.
A Common Technique to Conserve Water
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Case Study - Rainwater harvesting:
A Success Story
Once Cherrapunji was famous because it
received the largest volume of rainfall in
the world. It still does but ironically,
experiences acute water shortages. This
is mainly the result of extensive deforestation and because proper methods of conserving rainwater are
not used. There has been extensive soil erosion and often, despite the heavy rainfall and its location in the
green hills of Meghalaya, one can see stretches of hillside devoid of trees and greenery. People have to
walk long distances to collect water.
In the area surrounding the River Ruparel in Rajasthan, the story is different - this is an example of
proper water conservation. The site does not receive even half the rainfall received by Cherrapunji, but
proper management and conservation have meant that more water is available than in Cherrapunji.
The water level in the river began declining due to extensive deforestation and agricultural activities
along the banks and, by the 1980s, a drought-like situation began to spread. Under the guidance of some
NGOs (non-government organizations), the women living in the area were encouraged to take the
initiative in building johads (round ponds) and dams to hold back rainwater. Gradually, water began
coming back as proper methods of conserving and harvesting rainwater were followed. The revival of the
river has transformed the ecology of the place and the lives of the people living along its banks. Their
relationship with their natural environment has been strengthened. It has proved that humankind is not
Measures to
Water
in Day
to Day
the Some
masterCommon
of the environment,
butConserve
a part of it.
If human
beings
putSituations
in an effort, the damage caused by us
can be undone.
Some of the simple steps have been listed below that can contribute to water conservation.
You can make a difference by saving even a small amount of water as every drop counts.
Do not leave the tap water running while you are brushing your teeth or soaping your face.
When washing the car, use water from a bucket and not a hosepipe.
Avoid flushing the toilet unnecessarily. Put a brick or any other device that occupies space to
cut down on the amount of water needed for each flush.
Do not throw away water that has been used for washing vegetables, rice or dals¾use it to
water plants or to clean the floors, etc
Use sprinklers in gardens for watering plants.
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CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Form a group of water-conscious people and encourage your friends and neighbours to be
part of this group. Promote water conservation in community newsletters and on bulletin
boards of your school.
Each Drop Counts - Conserve Water
Role Play
We need to change people's attitudes as the most important step in the direction of
finding solutions to the issues of water conservation. Discuss and plan simple steps
which can help in this direction.
Create an awareness campaign in your school and neighbourhood in the form of a
street play.
Water Related Issues
Looking into the importance of water as resource and limited availability of fresh water, number
of water related issues have come to a forefront in various world forums. With water becoming
increasingly scarce, national conflicts are expected to rise. Industry, agriculture, and citizens are
in competition for the resource that is so desperately needed for further development. National
tensions over the distribution of water can quickly escalate into discord between groups
dependent on a shared resource.
Water tensions are brewing over shared rivers and basins in many countries around the world.
Over 200 bodies of water are shared by two or more countries or areas. Strife over water is
plaguing countries to including the Middle East, Eastern Europe, and South East Asia. Of
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
particular concern for this case is the dispute between Tamil Nadu and Karnataka, two states in
India, over access to the water of River Cauvery.
Case Study – Global Water Problems
Water shortage has a severe impact on local people and on the potential development.
The UN World Water Development Report (WWDR, 2003) from the World Water
Assessment Program indicates that, in the next 20 years, the quantity of water available to
everyone is predicted to decrease by 30%. 40% of the world's inhabitants currently have
insufficient fresh water for minimal hygiene. More than 2.2 million people died in 2000 from
waterborne diseases (related to the consumption of contaminated water) or drought. In 2004,
the UK charity Water Aid reported that a child dies every 15 seconds from easily preventable
water-related diseases.
In accordance with the principles adopted at the International Conference on Water and the
Environment (Dublin, January 1992), it was agreed that "fresh water is a finite and vulnerable
resource, essential to sustain life, development and the environment". Water is a resource which is
absolutely necessary for the sustained development of a state. Regrettably, the statistics regarding the
availability of fresh water in the world are staggering. It is estimated that 1 billion people do not have
access to clean water, and 1.7 billion do not have sanitation.
"No single measure would do more to reduce disease and save lives in the developing world
than bringing s There are more than one billion people particularly in North Africa and
Western and South Asia, who lack access to a steady supply of clean water. Safe water and
adequate sanitation to all."
- UN Secretary General Kofi Annan
There are more than one billion people particularly in North Africa and Western and South
Asia, who lack access to a steady supply of clean water.

Find the percentage of per capita consumption of water used by different regions of
the world and discuss need for careful water management.
In search of Potable Water........
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
Glossary

Condensation, the changing of water from a gas to a liquid

Dew: Condensation of water on the Earth's surface because of atmospheric cooling.

Evaporation, the changing of water from a liquid to a gas

Fog: Fog exists if the atmospheric visibility near the Earth's surface is reduced to 1
kilometre or less. Fog can be composed of water droplets, ice crystals or smoke particles.

Freezing: The change in state of matter from liquid to solid that occurs with cooling.
Usually used in meteorology when discussing the formation of ice from liquid water.

Humidity: A general term used to describe the amount of water vapour found in
the atmosphere.

Hydrosphere: The hydrosphere describes the waters of the Earth.

Infiltration, the process of water filling the porous spaces of soil

Percolation, groundwater moving in the saturated zone below the earth's surface

Precipitation, the process by which water molecules condense to form drops heavy
enough to fall to the earth's surface

Rain: A form of precipitation. It is any liquid deposit that falls from clouds in the
atmosphere to the ground surface. Rain normally has a diameter between than 0.5 and 5.0
millimetres.

Salinity: Concentration of dissolved salts found in a sample of water. Measured as the
total amount of dissolved salts in parts per thousand.

Surface runoff, the flowing of water over the land from higher to lower ground

Transpiration, the process by which moisture is carried through plants from roots to
leaves, where it changes to vapour and is released to the atmosphere
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
WORKSHEET-I
Name of the Student:
Class:
Section:
Forms of Water in Everyday Life
In our everyday life, water is present in various forms. Water can be solid, liquid or
gaseous in nature. Use these three terms to define the following forms of water and
state one characteristic of the given forms:
An Ice Cube: is a solid form that keeps our drinks cool on a hot day.
Rain: ______________________________________________________________
Steam: ____________________________________________________________
A snow flake: _______________________________________________________
A River: ___________________________________________________________
Frost: _____________________________________________________________
A glacier: __________________________________________________________
Dew: ______________________________________________________________
An Iceberg: ________________________________________________________
A Vapour: _________________________________________________________
A Waterfall: ________________________________________________________
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
WORKSHEET-II
Name of the Student:
Class:
Section:
PROCESSES OF THE WATER CYCLE
Complete the following with the words from the box:
Evaporation
On a warm, __________________ day, water in a glass of water seems to slowly disappear. This is
because the energy from the sun is _______________ the water up and turning the liquid water into
water ______________. This process is called ___________________. When the water
________________, it becomes an invisible gas in the _____________________. Evaporation takes
places all over the earth, but especially in the ________________ and ________________ where there
is lots of water.
Condensation
As the water vapor rises, it cools off and ______________________ into water _________________. If
the water vapor becomes extremely cold, it will form ice ________________ instead of water droplets.
As the water droplets or ice crystals grow bigger and more numerous, they form
___________________.
Precipitation
If water droplets or ice crystals become too _______________, they can’t stay in the air. They
_________________. Water droplets precipitate as ________________ and ice crystals precipitate as
_________________. Sometimes, the rain freezes before it hits the earth and precipitates as
_________________.
evaporation
sunny
precipitate
condenses
evaporates
clouds
vapor
atmosphere
heating
heavy
hail
lakes
droplets
snow
crystals
rain
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
WORKSHEET-III
Name of the Student:
Class:
Section:
Draw a well-labelled diagram of Hydrological Cycle and state its importance. (Any three)
Importance of Hydrological Cycle
1. ________________________________________________________________________
2. ________________________________________________________________________
3. ________________________________________________________________________
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
An Autobiography
A drop of water wants to describe its journey from oceans to back to its source. Can you help the
‘drop’ to pen down its account by using the given clues describing its journey?
Oceans, Sky, Clouds, Snow, Mountains, Melt, Rivers, Reservoirs, Treatment
plant, Tap, Washing vegetables, Domestic drain, Stream, River, Ocean
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
______________________________________________________________________________
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
WORKSHEET-IV
Name of the Student:
Class:
Section:
Study the given map on Risk of Water Shortage at the global level and answer the following
questions:
Risk of Water Shortage
1. Identify the high risk areas.
________________________________________________________________________
2.
What major factor according to you makes the above-mentioned region a high risk area?
________________________________________________________________________
3. Identify the no risk areas.
________________________________________________________________________
4. Looking at the world water scenario, in which continent would you like to settle down
and why?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
The water drop goes on a trip into the future. Two decades from now what do you think the drop
finds……….
How can you help to change the future?
20 Years from Now – World Situation
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
________________________________
Suggestive Measures to Avert the Crisis
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
____________________
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
WORKSHEET-V
Name of the Student:
Class:
Section:
22nd March is celebrated as World Water Day. Make a poster
to create awareness regarding importance and conservation
of water. Give a catchy slogan or write a short poem.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
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CBSE-i
CLASS VII GEOGRAPHY
STUDENTS’ MANUAL
REFERENCE AND LINKS

http://www.windows2universe.org/earth/Water/water_cycle.html

http://www.mbgnet.net/fresh/cycle/index.htm

http://www.enchantedlearning.com/subjects/ocean/Watercycle.shtml

http://www.sawse.org/Training.html

http://library.thinkquest.org/C004240/important.htm

http://science.nasa.gov/earth-science/oceanography/ocean-earth-system/ocean-watercycle/

www.tradenewswire.net/archives/9128

www.freewebs.com/mist-aszune/

http://vionnaswatching.wordpress.com/2011/09/15/morning-dew/

southeverett.org/2009/10/

planetgreen.discovery.com/.../water-iq-quiz/

http://www.examiner.com/energy-investment-in-baltimore/water-shortages-problemslead-to-solutions-profits

www.mlit.go.jp/.../01_worldwater/index.html

http://www.medindia.net/news/Interviews/Rain-Water-Harvesting-35311-1.htm

www.panasianbiz.com/.../

takepart.com

Google Images – Clip art.

Living Geography – two-canpublishing.com
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