The importance of Water 2020

Sources Of Water

        Water is an important part of our lives. We cannot live without water. Plants, birds and animals also need water to live. We need water for our daily use. We need it for drinking, washing, cooking, bathing and cleaning. Water is also used to produce electricity. The farmer also needs water to plough the fields. We get water from the rain. Rainwater fills up the lakes and rivers. We get drinking water from streams, lakes, ponds or from under the grounds through wells and tube wells. This water is stored in tanks and reservoirs.

Do you know ....!!!

           When it is very hot, the heat dries up the rivers and lakes. The water goes up in the sky as water vapors. These drops of water form clouds. This water from the clouds comes down as rain.  Rainwater goes deep into the ground. We dig wells at proper places to get this water. Too much rain leads to floods, It carries away houses, crops and animals. Dams and forests help us to control floods.  Too little rain leads to drought. During this period there is shortage of water.

       As in some cities, we too, get our water supply from lakes. Water is stored in a place called a reservoir from where it is carried to different places through water pipes. It finally reaches our homes and comes out through our water taps.

Water Purification : Water comes to our homes from several sources. This water may be impure. ' Treatment of water' is therefore necessary. The water stored in trunks and reservoirs is filtered and disinfected to make it germ free and  pure before it reaches our homes. 

Learning Outcome :To understand the uses and preservation of water.

 The importance of Water 

        People need Water not only for drinking but also for Cooking and cleaning. We need Water for agriculture and industry as well. 

Water is very important in our lives.

Plants need water.::  We Water our potted plants. Farmers water the crops in their fields. Could these plants live without Water ?

Thus, we see that plants, like animals, need water.

Use Your brain power !

    The trees in the forests also need water to grow. From where do they get the water they need ? Rainwater seeps into the Soil. Roots of plants spread deep into the soil. These roots absorb the water that has seeped into the soil.

Do you Know ? 

      Some plants, like bulrushes, grow only in water. We can try our best to grow them in soil, but they cannot survive there. The lotus, water chestnut and hyacinth are also plants that grow in water.

Living things need water: There is water in the bodies of living things That is why the body keeps working properly. We get thirsty when there is a lack of water in our body. Many villages have a common source of water from which water is taken for use at home. Certain birds and plants are commonly found near such sources. We need water not only for drinking but also for cleaning, cooking growing crops and for industry, too. The roots of plants go deep into the soil and absorb water.

Always remember - (Everyone Should take care to keep the public source of water clean. It is each one's responsibility to do so.)

Where does Water Come From ?
Where does all this Water Come From ?
     The answer to this question is - rain. All the water that we get comes from rain.

• When it rains, some water flows over the ground giving rise to rivulets, streams and rivers.
• Some water collects in low lying areas. Thus, lakes are formed.
• A flowing river is sometime blocked by building a wall. This is called a dam. When it doesn't rain, the water from the dam can be used.
• Some rainwater seeps into the ground. To obtain this water, we dig wells. This water can also be taken out by using hand-pumps and bore-wells.
• Sometimes, water in the ground comes out in the form of springs.

       Some Sources of water are formed naturally. However, places like wells and dams are man-made. If rainfall decreases, the water stored in these places also decreases. 

How is a river Formed and how does it flow ?  

     Rain also falls on high places like mountains. This rainwater flows downhill. Numerous rivulets of water flowing downhill join together to form a river. A river flows down mountains and plateaus, through valleys and over plains.                   

Water bodies : Flowing water and stores of water are examples of water bodies. Springs, Streams, rivers, lakes, reservoirs, creeks, seas and oceans are all water bodies.

Landforms : Due to the high and low levels of land at different places, land gets different forms. Mountains, peaks, hills, hillocks, plateaus, plains, passes and valleys are some of the landforms.

Do you Know where a spring comes from ?
Rainwater seeps into the ground. It seeps deep into the ground through cracks in the soil and rocks. Even under the ground, it flows from a higher level to lower levels. This groundwater comes out of the ground in some places. This is what we call a spring. All the water we get is rainwater. Rivers, lakes and springs are all formed because of the rain. Rivers start in high places like mountains and flow downhill. It is necessary to collect rainwater.

The Importance of Keeping Water Safe :
          Just as food is an important need of our body, so is water an equally important need. The water which we drink must be clean and safe. Then only our health will be safe. So, individually we should take care that the water does not get polluted.

1. Causes of water pollution :

1. Washing clothes near a river or lake.
2. Bathing cattle and animals in the river.
3. Waste products from the factories and gutters dumped into the river.
4. Accumulation of water in ponds for a long time.
5. Drinking water left open.

Diseases like dysentery, cholera, jaundice, etc. are caused by drinking impure water.  

    To avoid this, water should be safely purified and used. 

    Different methods are given below for purifying polluted water :

2. Purification of polluted water :
(1) To filter the Water : Always filter the water. If you fold cotton cloth two folds or three folds and filter the water, then all the mud and the minute insoluble particles get stuck to the cloth. Besides, you get a ready-made filter in the market which you can use to filter the water. Fix this filter to the tap to get pure water.

Methods of Filtering Water

(2) To make the Water Clear : Keep the water in a vessel for a sufficiently long time without moving it, till all the mud particles and grains have settled at the base of the vessel. Then remove the water Slowly from above and use it. If alum is swirled in water, mud particles settle down quickly and the water becomes clear.

(3) To boil the Water : When the monsoon arrives the rivers are flooded. At that time the water gets muddy and polluted. So this water must be filtered and made clear. Then it Should be boiled at least for 20 minutes.

(4) To store the Water : The Water which is stored should always be covered. Water does not become stale soon. So if the water is covered, then it can be utilized for the next day too.

3. The Use of Water : The water vessel should have a tap. The water in the glass should be filled from the tap.

If the vessel does not have a tap, then use a ladle to take the water. Do not hold the glass with your fingers and dip it in the vessel.

4. Water Vessels : The vessels used for storing water should be scrubbed and cleaned daily. If possible scrub and wash the vessels minutely once a week and keep them for drying in the sun.   

Height above sea - level (ASL) : Height above mean sea-level. This is knows as altitude Considering the mean sea-level to have zero height, the heights of all other locations is measured as above or below sea - level.

High tide and low tide: The rise or fall in the level of sea waters caused by the combines effect of centrifugal force associated with sea water and he gravitational pull of the moon and the sun. The rise in the level is called high tide and the fall is called low tide.

 River 

Catchment areas : Area of a river basin. The areas from where the water gets collected into a river is called the catchment area of the river. This term is also used with reference to a dam or a bund indicating the area from which water gets collected in the reservoirs.

   A river is a stream of water that flows through a channel in the surface of the ground. The passage where the river flows is called the river bed and the earth on each side is called a river bank. A river begins on high ground or in hills or mountains and flows down from the high ground to the lower ground, because of gravity. A river begins as a small stream, and gets bigger the farther it flows.

         A river is the path that water takes as it flows downhill towards the ocean. Rivers can be long or short, wide or narrow and they often join together on their way downstream to make bigger rivers. Lots of animals live in or by rivers and people often  find them a good place to live too. Rivers can be used for lots of good thing, like sailing boats on them to trade goods with other towns on the river, and farming on land that has been made fertile by the river, but when there are heavy rains and the river is very full they can be dangerous, rivers do a lot of damage when they flood.

         The start of a river is called the source or head water. The part of the river that is near the source is called a young river. A young river is often in v-shaped river bed, and flows quickly downhill over stones, and around big rocks. Young rivers often have lots of small waterfalls and rapids. As the rivers travel downhill they begin to erode the ground taking small bits of soft rock and soil

       The source of a river may be a spring, often on a hill, mountain, glacier, or another high place. A spring is water that flows out from under the ground. The source of a river may be a lake where lots of water from small streams gathers when it rains or snows. A river may begin in mountains where there is snow. The melting snow runs together to from a small stream that runs down the mountain. As more little streams run in, the  main stream gets bigger, until it from a river.

Some rivers flow from hills where there is no snow, but lots of rain.

Some rivers only flow after there has been rain near the has water.

Sea - level : The level of sea waters keeps on oscillating due to the tides, waves, etc. The mean of high and low tide determiners the mean sea - level at a place in coastal area. All height values in the region are measured with reference to the mean sea - level. As the tidal range of different places can vary the mean sea - level of a selected station is take as the standard mean sea - level for the region. For India mean sea level at Chennai is considered as the standard mean sea - level.

     The middle part of a river is called a mature river. A mature river makes a riverbed that is U- shaped. It might be very  deep and run fast. Is sweeps over small rocks and boulders, and makes big turns around hills and mountains It is much wider than a young river, but not as wide as an old river. To cross over a mature river, people use bridges. Many cities and towns are built on the banks of mature rivers. Many farms that keep animals such as dairy cows, horses and sheep are along mature rivers because the animals can drink from the  river every day.

        A  river usually ends by flowing into an ocean, a lake or a bigger river. The place where the river flows out into a bigger body of water is called the mouth of the river.

         As a river flows towards its mouth, the countryside around the river often changes from hilly to flat. As it flows over the flat land the river becomes wider and slower. A wide slow river is called an old river. An old river often floods across the land after there is lots of rain at the headwaters. An old river slowly builds up its banks on either side; the high banks are called levees. An old river often meanders [twists and turns], and sometimes, after a flood, it leaves lakes behind which are called ox- bows or billabongs. old river are the most useful type of river for growing crops. Corn rice, fruit, cotton, hay, tobacco and sugar are some of the crops that are grown near old rivers.

          The shape of the mouth depends on the conditions of the sea where it flows. If there is a strong tide where the river meets the sea, the river from an estuary. An estuary is a wide, funnel-like mouth of the river. The fresh water of the river mixes slowly with the salt water, becoming brackish water - somewhat salty water. Many kinds of fish, clams, mollusk and other sea life live at estuaries. Many of the world's largest cities and  harbors are at estuaries.

         Where a river flows out to the sea, it sometimes flows very slowly through sandy or muddy land, making lots of little islands as it flows. The main stream of the river gets broken into many parts that spread out into a triangle shape like the Greek letter delta. When this happens, it is called the delta of the river. Deltas are often places that are not good for towns or farms but are very good for birds and other wildlife and fishing. Deltas are often made onto wildlife reserves. Not all rivers have deltas. There are deltas on the Nile River, the Amazon, River, the Mekong River, the Mississippi River and the Danube River.

      Some rivers flow underground through caves. Underground rivers from in places where there are lots of cracks in the rocks above, so that in rainy weather, the water runs downs and collects in small underground streams. Sometimes the underground water trickles or gushes out of the ground to form a small spring of water. In other places, where there are caves, the small underground streams run together to form a river. The river can sometimes run through deep wide underground caverns. While many underground rivers flow gently, some underground rivers flow fast and have rapids, particularly after heavy rain. Many underground rivers flow  out through a cave mouth to become an ordinary river.

          A river begins at a source ( or more often several sources), follows a path called a course and ends at a mouth or mouths. The water in a river is usually confined to a channel, made up of a stream bed between banks. In larger rivers there is often also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be very wide in relation to the size of the river channel. This distinction between river channel and floodplain can be blurred, especially in urban areas where the floodplain of a river channel can become greatly developed by housing and industry. Rivers can flow down mountains, through valleys (depressions) or along plains, and can create canyons or gorges.

        The term upriver (Or upstream) refers to the direction towards the source of the river, i.e. against the direction of flow. Likewise, the term downriver (Or downstream) describes the direction towards the mouth of the river, in which the current flows. The term left bank refers to the left bank in the direction of flow, right bank to the right.

        The river channel typically contains a single stream of water, but some rivers flow as several interconnecting streams of water, producing a braided river. Extensive braided rivers are now found in only a few regions worldwide, [citation needed] such as the South island of New Zealand. They also occur on peneplains and some of the larger river deltas. Anastomosing rivers are similar to braided rivers and are quite rare. They have multiple sinuous channels carrying large volumes of sediment. There are rare cases of river bifurcation in which a river divides and the resultant flows ending in different seas. An example is the bifurcation of  Nero dime River in Kosovo.

      A river flowing in its channel is a source of energy that acts on the river channel to change its shape and form . In 1757, the German hydrologist Albert Brahms empirically observed that the submerged weight of objects that may be carried away by a river is proportional to the sixth power of the river flow speed. This formulation is also sometimes called Airy law. Thus, if the speed of flow is doubled, the flow would dislodge objects with 64 times as much submerged weight. In mountainous torrential zones, this can be seen as erosion channels through hard rocks and the creation of sands and gravels from the destruction of larger rocks. A river valley that was created from a U- shaped glaciated valley, can often easily be identified by the V-shaped channel that it has carved. In the middle reaches where river flows over flatter land, meanders may from through erosion of the river banks and deposition on the inside of bends. Sometimes the river will cut off a loop, shortening the channel and forming an oxbow lake or billabong. Rivers that carry large amounts of sediment may develop conspicuous deltas at their mouths. Rivers whose mouths are in saline tidal waters may form estuaries.

         Throughout the course of the river the total volume of water transported downstream will often be a combination of the free water flow together with a substantial volume flowing through sub-surface rocks and gravels that underlie the river and its floodplain (called the hyporheic zone). For many rivers in large valleys, this unseen component of flow may greatly exceed the visible flow.

Water:

1) Water is needed for survival of every living organism. Amount of water needed for every organism depends on its size of the body. For smooth functioning of our body we need 3 to 4 liters of water daily.

2) Hydrogen gas upon burning in air can form water.

3) Water is available in three different states in nature. Water is a colorless, tasteless and odorless liquid. Since many substances can dissolve in it, it is also called universal solvent.

4) There is high proportion of water in blood of the animals and the sap of the plants. 

5) It is said that 'Water is life' because no living thing can survive without water.

6) For drinking purpose only very small quantity of water is left on the earth.

7) Water in liquid form is used by every living organism.

8) In solid state it turns into ice. 

9) In gaseous state it is a vapors.

10) Boiling point and condensation point of the water is 100・C. 

11) The melting point and freezing point of water is O ・c.

12) Many substances can dissolve in water, therefore it is called universal solvent.

Water cycle and uses of water :

1) All the water on earth is regulated through the water cycle.

2) Sun's heat evaporates water from the oceans. These water vapor's condense after reaching the sky and fall back on the earth in the form of rains. Rainwater creates fresh water sources on the earth.

3) Natural sources of water : Streams, rivers, ponds, springs and lakes, etc.

4) Man-made sources of water : Wells bore-wells, bunds and dams on the rivers.

5) Uncontrolled use of water : Increasing population, industry and farming all are responsible for excessive use of water. Water scarcity is thus an grave problem.

Water is life : Living organisms cannot survive without water. The blood of the animals and sap of the plants also have high proportion of water. Therefore, water is said to be life.

• There are many aquatic organisms in the marine waters ( Water of the seas and oceans). Of some of these are edible varieties such as fish, crab, prawn, bivalves, oysters, lobsters, etc.
• Fishery is an important occupation of coastal people which is entirely dependent on seas.
• Salt, iodine and some other minerals are obtained from the sea water.
• The valuable jewels such as corals and pearls are obtained from some of the marine. animals.
• Transport of goods and cargo is done via sea routes.
• Due to evaporation of sea water. the water cycle remains operative. Monsoon rains, weather patterns and cycle of seasons all are possible due to oceans.
• In some countries , potable and usable water is obtained from sea water through a process called desalination. All these facts explain to us that though sea water is salty, it is useful.

About 71% of the earth's surface :

       Though 71% of the earth's surface is covered with the water, most of this water is not usable and potable.  2) 97% of this water is salty water of the sea. This water cannot be used for agriculture or for drinking. cooking, etc. 3) Some fresh water is in frozen state. 4) Due to tremendous increase in the population the demand for water is also rising.  5) Due to global warming there are droughts and this results in lack of water. 6) Due to all these reasons there is always a water shortage even though the 71% of earth's surface is occupied by water.

Using Water :

     We must use water sparingly. 2) Use the methods of blocking water and helping it to percolate in the ground. 3) Store the water wherever possible, especially one should practices rainwater harvesting. 4) Water should be rescued again and again. 5) Water never becomes stale, so it should never be thrown.

Our Need for Water

      We find water in rivers, lakes, wells and seas. We get drinking water from the wells, the rivers and the lakes. Similarly rivers, lakes and the sea give u water, fish and salt, All these are natural resources from water.

This happens, doesn't it ?

• Sometimes, tears flow from our eyes.
• Our mouth waters when we see a tamarind pod.
• Our nose runs when we have a cold.
• When we get a cut, it bleeds.

What does this tell us ?

       Tears, saliva, water running from the nose and blood are present in our body. They are substances that flow. They contain water.
Try this : (Do this under adult supervision.) Take a small piece of cucumber. Grate it. Squeeze it hard. Take a slice of lemon. Squeeze it hard, too.
What do you see?
Juice flows out of the grated cucumber and the lemon slice. 
What does it tell us?
There is water in a cucumber and a lemon.

Why do we feel thirsty ?

We need water if our body has to function properly.

    Water keeps our blood thin. Water helps to digest our food. Unwanted substances leave our body through urine. We must have enough water in our body at all times. When there is a lack of water in our body, we get thirsty. Like us, other living things, too, need water.

A public source of water

         In many villages, cows, buffaloes and goats come to the river or pond to drink water. Grass and other bushes can be seen growing near the waterhole. Animals bathe themselves in it. Birds like the lapwing, Kingfisher and egret can also be seen around the water source. People from the village wash their clothes in it. They carry water to use at home.

What's the solution ?

The water in the public source has to be kept clean.

Do you know ?

         People who keep animals provide drinking water to them without fail. We know that these animals, too, get thirsty. But there are thousands of other animals. We do not realize that they, too, need water.  Ants, Honey bees, Crabs, Scorpions, and all other animals need water.

       Wild animals also need water. They come to a waterhole in the forest when they are thirsty. So, people, too, go there in order to sight the wild animals.

The importance of water: People need water not only for drinking but also for cooking and cleaning. We need water for agriculture and industry as well. 

Water is very important in our lives.

Try this .

• Take two potted plants of equal growth.
• Label them as 1 and 2.
• Every morning, for the next five days, water only Plant 1. Do not water Plant 2.

What do you see ?

• Plant 2, which was not watered, slowly dries up.

    Plant 1 looks fresh and green.

What does this tell us?

• Plants need water to live

Plants need water.

      We water our potted plants. Farmers water the crops in their fields.

        Could these plants live without water ?

         Thus, we see that plants, like animals, need water.

Use your brain power !

• The trees in the forests also need water to grow. From where do they get the water they need ?
• Rainwater seeps into the soil. Roots of plants spread deep into the soil. These roots absorb the water that has seeped into the soil.

Do you know ?

      Some plants, like bulrushes, grow only in water. We can try our best to grow them in soil, but they cannot survive there. 

     The lotus, water chestnut and hyacinth are also plants that grow in water. 

Use your brain power!

• Why do we need to water a garden more often in summer ? 
• Why is water in ponds and wells much reduced in summer ?

Always remember- 

     Everyone should take care to keep the public source of water clean. It is each one's responsibility to do so.

What's the solution ?

• In summer, animals have to wander around in search of water. You have to provide water for these thirsty animals.

Think and tell !

1. In summer, why do we eat plenty of fruits like watermelons and cucumbers ?
2. Watch how a pumpkin is cooked. Where does all the water in which it cooks, come from ?

Where does water come from ?

Can you tell ?

   Where does all this water come from ?

The answer to this question is - rain. All the water that we get comes from rain.

• When it rains, some water flows over the ground giving rise to rivulets, streams and rivers.
• Some water collects in low lying areas. Thus, lakes are formed.
• A flowing river is sometimes blocked by building a wall This is called a dam. When it doesn't rain, the water from the dam can be used.
• Some rainwater seeps into the ground. To obtain this water, we dig wells. This water can also be taken out by using hand-pumps and bore-wells.
• Sometimes, water in the ground comes out in the form of springs.

             Some sources of water are formed naturally. However, places like wells and dams are man-made. If rainfall decreases, the water stored in these places also decreases. You can see such water sources in your locality, taluka or district.

How is a river formed and how does it flow ?

• Rain also falls on high places like mountains. This rainwater flows downhill.
• Numerous rivulets of water flowing downhill join together to form a river.
• A river flows down mountains and plateaus, through valleys and over plains.    

Water bodies : Flowing water and stores of water are examples of water bodies. Springs, streams, rivers, lakes, reservoirs, creeks, seas and oceans are all water bodies.

Land forms : Due to the high and low levels of land at different places, land gets different forms. Mountains, peaks, hills, hillocks, plateaus, plains, passes and valleys are some of the land forms.

Do you know where a spring comes from ?

       Rainwater seeps into the ground. It seeps deep into the ground though cracks in the soil and rocks. Even under the ground, it flows from a higher level to lower, levels, This groundwater comes out of the ground in some places. This is what we call a spring

Try this :

          Take three bottles of the same shape. Fill one bottle to the brim with water. Imagine that you are the only one using all this water. This means you can use all  the water in the bottle. Now fill the second bottle with water. Imagine that another student from your class will also use this bottle with you. Divide the water equally into two parts. Now see how mush  water you get. Is this water less or more than the amount you had the first time ? Now fill the third bottle. Imagine that four other children in the class besides you will use this water. Now you will have to divide the water in the bottle into five equal parts. Now see how much your share of the water is. Is the amount of water you have this time less or more than the first two times ?

Think about why this happened.

What's the solution ?

       Rahul and Saguna drink water. After playing, they wash their hands and feet, they bathe every morning and wash their plates after eating. However, they use too much water while doing these things. Their mother scolds them. They wonder how they should use water carefully.

     What good ideas can you give them for using water carefully ?

Use your brain power !

• If rainwater is collected and stored, can it be used later ?        How will you store rainwater ?
• If human beings begin to use all the water for themselves, what will happen to other living things ?

Do you know ?

    Pipelines are used to carry water from distant wells, lakes and water tanks to our homes. In some areas, water is also supplied through tankers. 

More about Water 

      Take some clean water in a glass. Look at its color. What color is it ?
         Smell a fragrant flower. Did you like the smell ?
Now smell the water. Does it have a smell ?
         Taste a ripe mango or chikoo or guava.
How does the ripe fruit taste ?
Now taste the water. How does it taste ?
What does this t ell us ? Pure water has no color, taste or smell.

New terms :

Transparent : If you can see through a substance, it is said to be transparent.

Opaque : If you cannot see through a substance, it is said to be opaque.

Try this.

(This should be done with adult supervision.)

• Light a candle and stand it on a table.
• Look at it through a cardboard.
• Now look at the same candle through a glass pane. What do you find ?
• You cannot see the flame through the cardboard. But you can see it through the glass. What does that mean ?
• The cardboard is opaque, but glass is transparent.
• Now look at the candle through a glass of water. What do you find ?
• The candle can be seen through the water in the glass, as well.

What does this mean ?

Water, too, is transparent.

Pure water

Has no color, Has no smell, Has no taste, Is transparent.

Try this. 

• Take some wheat or jowar flour and some water. Take two dishes and two glasses.
• Put a little flour in one of the dishes.
• Pour some water in the other dish.
• Now put some flour in one of the glasses.
• And put some water in the other glass.

What do you see ?

• A small heap of flour is formed in the dish. A heap of flour is formed in the glass as well. The water, however, takes the shape of the plate or the glass.

What does this tell us ?

Water takes the shape of the container into which you pour it.

Water does not have a shape of its own. That is why, it spreads when it spills on the floor.

Use your brain power !

• We can see the bottom of a pool of water only if the water is clean. Why?
• While carrying a bucket of water down a slope, the bucket fell and the water was Spilt. Will the water form a heap? Or, will it flow away?

More about water

• It takes the shape of its container.
• It spreads on a flat surface.
• It flows down a slope.

The three states of water.

Try this.

Place a few ice cubes in a glass. See what happens to them after a while.

Try this. (Do this experiment with the permission of an adult and under his/her supervision.)

       Heat some water on a burner. What do you see after some time?

        The water begins to boil. Keep it boiling for some time and observe it. What do you see? There is less water in the beaker. Why is there less water than before?

          Using tongs, hold a steel plate in the steam coming from the water only for a few moments and remove it. What do you see on the underside of the plate? Droplets of water have formed on it.

Where did these droplets come from ?

     When water becomes very cold, it freezes. That is, it turns into ice. When ice is left uncovered, it gets heat from the air around it. It melts. That is, it forms water. When water gets enough heat, it turns into vapour.
     The boiling water in the experiment turned into vapors. That is why, the water in the beaker was reduced.
      As steam cools, it turns into water. The plate held in the steam was cool. So, the steam that collected on its underside cooled down and droplets of water were formed.

New terms :
State : the form in which a substance may be found.
Water vapour :the form in which water is held in the air.

     The water we use every day is its liquid state. Ice is its solid state Vapour is the state of water in which it is a gas. Water vapour is the gaseous state of water.

The three states of water

• Solid state       (Ice)
• Liquid state    (Water)
• Gaseous state (Water vapour)

Try this.

Have some fun

• Take a glass. Wipe it dry inside and outside with a clean piece of cloth.
• Place five or six ice cubes in the glass.

What do you see ?

• It is no surprise if the glass becomes wet on the inside. But, you see that the outside of the glass has also become moist. Isn't that strange ?

What does this tell us ?

        The air around the glass contains water vapors. When we put ice cubes in the glass, the glass becomes cold. That makes the air around the glass cold, too. The water vapor in the air also cools and forms very tiny droplets of water. They make the glass moist.

Try this.
(This should only be done under adult supervision.)

• When chapatis have been made and the griddle is still very hot, sprinkle a few drops of water on it. What do you see?
• The drops sprinkled on the griddle become round like beads and disappear even as you watch.

What does this tell us ?

• The griddle is very hot. The heat from the griddle changes the water into water vapors all at once.

Use your brain power !

• Why do wet clothes on the clothesline become dry after some time?

Try this.

• Take water in a glass.
• Add a pinch of salt to the water. Stir it with a spoon.

What do you see ?

• You do not see the salt in the water any more. With the spoon, place a drop of this water on your tongue. You find that it tastes salty.

What does this tell us?

• The water was salty. It means that the salt is still there in the water though we cannot see it. In other words, the salt has dissolved in the water.

Some substances dissolve in water.

Use your brain power !

• Several substances dissolve in water. Name some of them.

Do you know ?

    Water has to be frozen to make ice. Many people have refrigerators in which ice can be made. In factories, ice is made in large quantities. Ice candy or ice fruit is made by freezing water to which sugar, fruit juice and color have been added.

• Water has no color, smell or taste. Water is transparent.
• Water takes the shape of the container in which it is kept.
• Water spreads on a flat surface. It flows down a slope.
• Water is found in three states : solid, liquid and gaseous.
• Several substances dissolve in water.

Always remember-

         We know that liquid water has many uses. But, the solid ice and the gaseous water vapors are also useful in many ways.

What's the solution?

     Due to the cold, the coconut oil in the bottle has frozen. We have to pour it out.

Think and tell.

1. During the rainy season, why do crisp biscuits become soft ?
2. Why does water become colored when crystals of potassium permanganate are added to it ?
3. When we add jaggery to water and stir it, why does the water taste sweet?
4. The mountain peaks in the Himalayas are always covered with snow and ice. What could be the reason for that ?

Collect samples of water from various sources such as water from a well, tap water, muddy water, water drawn with a hand-pump.

Observe the samples.

Caution : DO NOT DRINK OR TASTE THIS WATER.

Clean Water

 

       We must make sure that our water is clean and pure. We must drink only clean water. Water can be purified by boiling and filtering. Nowadays, water is also purified using electronic water filters. At home, water can be stored in clean vessels or clean pots. These must be covered with a clean plate or a clean cloth. A clean glass must be used for removing water from a vessel. We make the water impure by bathing. washing clothes and throwing water in the lakes and rivers. impure water leads to sickness and disease. We must not waste water. Use water only when it is needed. Water used for washing vegetables or grains can be used for watering plants.

         Clean and pure water is necessary for good health.

Learning Outcome :To acquire the knowledge of clean and pure water.

Water Safe For Drinking

Solution :

1) Some substances mix completely with water, these substances are said to be dissolved in water. 2) When a substances dissolves in water, then the mixture formed of water. This mixture is called a solution. Some substances do not dissolve in water, they do not form the solution. 3) The taste of solution is due to the substance which dissaves in the water. 4) ORS or Oral Rehydration Solution is the solution made by dissolving certain amount of salt and sugar in water. ORS is given to the patients suffering from loose motions or vomiting. 5) Saline given to the patients in hospitals is the salt solution containing  medicines. It is directly injected into the blood stream of the patient. 6) Saline and ORS are useful solutions. 7) Sea water is the natural solution of salt water. Therefore sea water is salty to teste. 8) Some substances from the ground dissolve in well water and hence taste of different wells' water is different.9) The carbon dioxide gas is dissolved under pressure to make soda water.

Floaters and sinkers :

1) The things which are lighter than water float on the surface of water.

2) The things which are heavier than water sink in water.

Settling :The process of allowing the heavier particles to settle down at the bottom of the container is called setting.

Methods to make the water transparent and clean :

1)Muddy or turbid water can be left undisturbed for some time. This makes the sediment settle down at the bottom of the container.

2) This water looks clean. If a piece of alum is swirled through the muddy water, the floating particles settle down. This makes water transparent. This method is called settling.

3) Filtering the water through four layers of fine cloth removes the sediment from the water. This method is called filtration.

Thus Summarizing :

Methods to make water clean and transparent

          _⬇ ____________________________⬇___________________________⬇__

       Settling

 Keeping the water                            Swirling of alum helps the                   Filtration

undisturbed and allowing                 floating particles to settle

it to settle                                                        down                                                                                                       

The water obtained by such processes may become clean and transparent but not safe and potable.

Water : Safe for drinking : Potable water :

1) Water used for drinking must be clean and safe. Only such potable water will not cause any health problem. Such water is tasteless, odourless and colourless.

2) To understand the quality of water we must see

             ___⬇_____________________________⬇__________________________⬇___

               Taste                                                  Colour                                            Odour

        If taste is bad                If there is colour to the water        If the water is foul smelling

• Such water should never be used.
• Even if water appears clean and transparent, it may not be safe and potable as there may be disease-causing germs in it.
• It is necessary to destroy the micro-organisms present in the water before using it.
• In rainy season diarrheic and gastritis outbreaks are common. To avoid this, water must be boiled.
• Boiling kills the harmful micro - organisms and thus our health is not affected.

Water For Every Household

Storage of Water : We constantly need water. So we store water in our homes. Earlier people used to store water into metal pots. These used to be either brass or copper pots. Some people also used earthen pots. There were different types and shapes among these pots. Nowadays, we use steel or plastic tanks in the house for storage of water.

Care of drinking water: 

1. In order to maintain our health and good hygiene, we must have safe drinking water. 
2. Contaminated water can cause diseases. Therefore water should be stored carefully.

The proper ways to store the water :

1. keeping the water containers covered with a well-fitting lid.
2. Using a long dipper to take out water.
3. To have a tap on the container.
4. Washing the containers well before raffling them again.

Supply of Water :

1. Water stored at one place can be supplied to several places by proper distribution.
2. For this purpose huge tanks are installed on the roofs or terraces of buildings.
3. With the help of pipes the water from these tanks is supplied to kitchens, toilets and bathrooms of different houses.
4. These tanks are made of either of cement or plastic.
5. There are taps fitted onto the pipes, this makes people use the water according to their needs.

Water for a human settlement :

1. The sources of water are lakes, rivers, reservoirs, etc.
2. From here water is brought near human settlements through the canals and pipes.
3. Here by the purification process, the water is made safe for drinking. Then the purified potable water is distributed to all houses.
4. The purification and distribution of water are two important steps in the water supply for human settlements.

Water tanks at a height :

1. When we want to lift water from a lower level to an upper level, we need force. For this force, pumps running on electricity or diesel are used.
2. Water is filled in the tanks which are built at a height. They are also called water towers. From here, the water is supplied to different parts of towns and cities.
3. The water purified in the water purification plant is stored in such water towers.
4. As per the need of people, water is released for some time from these tanks.
5. In some places there may be two to three common taps in an area where people can come and fetch water for their needs.
6. In some place people draw water from wells or borewells. Such water should be boiled before use. Ii is not purified and may cause health problems.

Water is valuable :

1. Water purification, storage and distribution are the processes that require a lot of money.
2. Electricity and diesel are used to run the machines for all the above processes.
3. Therefore, we should know that potable water is expensive substance and we must take care of this valuable resource.
4. We should not waste or contaminate the water.

Using water without wastage :

                                      Should not be thrown away.

              ↗   Should not allow taps leaking or running.

Water ✒  Reuse the water (water used for washing vegetables and fruits can be                                                        used  for gardening )

            ↘      Do not turn the tap fully.

 Storage Of Water

The need for storing rainwater :

       The rain is the only source of water for us. Not all the water that we receive is available for us to use easily.  Some of it flows over the ground in the form of rivers and rivulets and some water gets accumulated in ponds and lakes. This surface water we can se easily. Large amount of water seeps into the ground which is difficult to use. The rainy season lasts for three or four months. Along with us, all living beings use this water all the year round. Therefore, we need to save and use water carefully.

Old Water Stores (Traditional methods of water Storage ) :

         In our state, a variety of methods of storing water were existing in the olden days. These systems are rarely used these days. However, we can see their remains at many places. Wells, water tanks in forts, draw - wells, bunds, old reservoirs, old tanks, are the traditional methods of water storage. 

Wells : Wells are dug to obtain the rainwater that seeps into the ground.

Water tanks in forts : In the past, the hill forts had reservoirs and tanks dug into the stone for people who lived on the hill forts.

Draw - wells [Aad ] : In the past, draw - wells were dug to get drinking water, In order to get drinking water, small draw -wells were dug in the past. Water could be drawn from these wells by using containers' like, pots or buckets.

Bunds : Earthen or masonry bunds are built across rivers to store their water. Bunds are the small earthen walls built across the channel of a river.

old reservoirs : In the past, reservoirs were built in areas which received very less rainfall or in the areas which did not have a major river.

old tanks : Tanks were built in large cities to store water in the past.

Recent systems (Modern methods of water storage):

       Dams and borewells are the modern methods of water storage.

Dams : Water stored in dams is used for drinking. Cultivation, factories and generating electricity. 

Borewells : Nowadays, very deep and narrow borewells are dug with the help of electricity. The water from these wells is drawn with the help of electric pumps.

Panpoi [Drinking Water stands ]  Panpois are big clay jars of drinking water kept at some places. This water is provided free of charge to the people passing by. During  summer, Panpois  are very useful.

Earth And Its Living World

             On the surface of the earth, we find land in some places and water in others. The earth is surrounded by the atmosphere. There are living things on land, in water and in the air. The sun is the cause of many natural processes on the earth. Water, land and air constitute envelopes of the earth, namely, the hydrosphere, lithosphere and atmosphere. The biosphere spreads in all the other three spheres. The lithosphere and the hydrosphere The earth's crust is hard. It is mainly made of rock. When we travel in hilly regions, we see layers of soil and rock along road cuts. We see grassy expanses of land in some places and only sand in others. The land is covered with crops in some places and with forest in others. Sometimes we get to see the deeper layers of soil into which tree roots spread. At others we see rocks split apart by the tree roots. There are gentle mountain slopes as well as sheer cliffs of rock. All these land features are a part of the earth's lithosphere. Much of the earth's surface is occupied by water. The lithosphere extends under this water too. About a third of the surface of the earth consists of land. A vast continuous stretch of land is called a continent. The land on earth is divided into seven continents. They are Asia, Europe, Africa, North America, South America, Antarctica and Australia. Asia is the larges continent and Australia the smallest. The land is not even in all places. The unevenness gives different shapes to the land in different places. They are called landforms.  

            Two - thirds of the earth's surface is covered with water. Most of this water is in the oceans. Ocean water is salty. There are five oceans, namely, the Atlantic, Pacific, Arctic, the Southern Ocean and the Indian Ocean. The land along the margins of an ocean is called the coastal region. Water bodies of different shape and sizes are formed along the coast, for example, sea, bay, strait, gulf, creek, etc. These water bodies are part of the ocean.

Surface Water : There are many streams of water flowing over the land. This water is not salty but fresh. These streams of water may be rills, brooks, streams or rivers . Rills are the smallest and rivers , the biggest. Rills, brooks, streams join each other to from rivers Rivers which join to make a bigger river are called its  tributaries. In some places a river cascades down a sudden drop. This forms a 'waterfall'. All rivers eventually flow into the ocean. 

Lakes : A water body formed by water collecting naturally in a low - lying area of land is called a lake.

Water in the form of ice : Water particles in the clouds freeze and in cold regions, they come down in the form of snow. When layers of snow pile up on the ground, they form ice. When such layers of ice pile up in a low - lying area, they become enormous in size. This huge mass slips down a slope at a very slow speed. This is called a glacier. There are also huge blocks of ice floating in the sea. They are called icebergs. 

Groundwater : Besides these water bodies on the earth's surface, there is a lot of water stored in the underground layers of rock. It is called groundwater. We reach it by means of dug wells and bore wells. Many lakes and wells get water from underground springs. The water or ice tat occupies the earth's surface, groundwater and the water vapors in the atmosphere together form the earth's hydrosphere. 

The Atmosphere : The envelope of air around the earth is called the atmosphere. As we go higher from the surface if the earth, the air in the atmosphere becomes rarer. The air consists of a mixture of gases, namely, nitrogen, oxygen, water vapour and carbon dioxide. There are some other gases too in the air in very small quantities. The layers of the atmosphere are named as the troposphere, stratosphere, mesosphere, ionosphere and exosphere. The layer that extends from the earth's surface  to a height f about 13 km is called the troposphere. The conditions in the troposphere change continuously. They affect the  living world to a great extent . The surface of the earth gets heated due to the heat it receives from the sun. Hence, the air nearest the surface is the hottest. As we go higher in the troposphere, it becomes cooler. Almost all the water vapour in the atmosphere is contained in the troposphere. That is why, all weather - related phenomena such as formation of clouds, rain, fog, winds and storms take place in the troposphere. The air on high mountains is rarer than the air near the earth's surface. Airplanes fly in the higher parts of the troposphere. There, the air is very rare. Therefore, arrangements have to be made to ensure that passengers get enough air for breathing.

               Beyond the troposphere, up t a height of about 50 km from the earth is the layer called the stratosphere,. In the lower part of the stratosphere, there is a layer of a gas called ozone. Ultraviolet rays coming from the sun are harmful for living things. But the ozone layer absorbs them and protects the living world from those rays. 

Condensation : the process of Vapour turning into water on cooling.

How does it rain ?

       Water on the earth evaporates continuously due to the heat of the sun. Water that has percolated into the soil also evaporates due to the heat and enters the atmosphere. As water vapour is lighter than air, it rises high up into the atmosphere. As it goes higher, it cools and condenses forming very fine droplets of water. The  droplets are so small and light that they float in the atmosphere forming clouds. These small droplets join together and form bigger drops which are heavy. They cannot float. Such drops of water fall down on the earth in the form of rain. This rainwater flows into rills, streams, rivers and finally into the sea. Ice in the snow - covered regions also melts due to the heat of the sun to finally flow into rivers. These processes of evaporation, condensation and rainfall go on in a  continuous cycle. This is knows as the water cycle in nature.

          There are innumerable kinds of living things on the earth. The varoius regions of the earth differ in many was. Some regions are always covered with ice while others have a hot climate. There are mountains in some places and plains in others. Some places have a lot of rainfall while others are dry deserts. There are salty seas and oceans and also freshwater lakes. The ocean is shallow near the coast but away from the coastline, the ocean can be several kilometers deep.

      When other substances get mixed with water, it becomes impure. Some of these substances float in the water. So, the water looks unclean or muddy. Some substances dissolve in the water and we cannot see them. If the substances that have got mixed with the water are harmful living things. We say that the water has becomes polluted. Rivers, lakes are our sources of water.

Disposal Of Waste Water : The waste water of a city or town is collected and let into a water body at a convenient location. The waste water from residential buildings as well as from factories and industries contains many kinds of impurities. Some of these dissolve in the water while some do not. Sewage water can carry micro- organisms that spread diseases. Waste water from industries is more likely to contain poisonous substances. If all this waste water is let into water bodies as it is, the water bodies becomes polluted and that is dangerous. Such water cannot be used for drinking or for any other purposes. That is why, it is compulsory for factory - owners to treat the water before letting it out. Similarly, sewage and other waste water of towns and cities is processed for purification before letting it into a water body. This helps to prevent pollution of water. Flowing water of rivers gets purified to same extent by natural processes also. Before water is supplied to a town or city, it is purified.

If large quantities of impurities get mixed with river water, the natural process of purification cannot keep pace. The proportion of oxygen dissolved in the water is reduced. And this is a threat to the aquatic living things. While travelling. We often buy bottled drinking water. The bottles are available at places like bus stands and railway stations. The date of bottling and the period for which the water can be safely used is printed on the bottle. It is important to read this information when buying a bottle. Once you have opened it, the water should not be kept for very long. The empty bottle must be crushed and thrown into a garbage bin, so that it cannot be reused.

Famine : Water evaporates continuously. That is why, places where it does not rain for a long time, experience a drought. At such places, the water level falls in rivers, wells, lakes, bunds and dams, some of theses' may even go dry. The land also dries up due to evaporation. Humans and animals suffer from scarcity of water. There is no water for agriculture. This condition is called a famine. A famine is a natural disaster. Grain and fodder become scarce during a famine. You may have read about a famine in our State, or country or in another part of the world. People living there have to face a lot of hardship. Animals and plants in those parts also suffer. The government temporarily moves people and animals from famine - stricken areas to safe places where they ca be provided with water, food grain and fodder. Fodder camps are set up to take care of dogmatic animals.

Water Management : Rain brings us water again and again. But, we get rain for only four months in a year. If rainwater is not stored, we will not have water for our daily needs after the rains. To meet the whole year's need for water, rainwater must be stopped. When it is stopped, it percolates into the soil. As the ground water storage increases, trees get water. Wells, too get enough water and the land can be cultivated. Several methods are used to make rainwater seep into the soil. Large dams can be built. But that , may not be possible in all places. In that event, the government and the people come together to undertake several works such as building smaller reservoirs, contour bunding, stopping the water of the smaller streams by constructing bunds or bandaris, etc. In some places, wells are dug in river beds to allow water to collects in them. Rainwater falling on roofs of houses is drained into large tanks placed beside the building. Using all such methods helps us to store as much water as possible. It is very important to use water carefully, to stop rainwater from flowing away, to make it seep into the ground or to collect it in tanks. Taking steps to ensure that rainwater will be available even in the period after the rainy season is called 'water management.'

Always Remember ___ Water is life. Use it judiciously.