Case Study Questions Class 6 Science Chapter 14 Water
CBSE Class 6 Case Study Questions Science Water. Important Case Study Questions for Class 6 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Water.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Study Questions Class 6 Science Water
Case study 1
Heating is essential to convert water into its vapour. Water vapours so formed become a part of the air and cannot usually be seen. Water changes into its vapour also from the fields, roads, rooftops and other land areas.Let’s understand with the help of an activity thatfrom where water gets the heat it needs to evaporate.Take two similar plates. Place one of the plates in sunlight and keep the other under shade. Now, pour equal amount of water in each of the plates. You can use a cap of a bottle to measure water. Make sure that water does not spill over. Observe the two plates after every 15 minutes. You’ll observe that water from the plate kept under sunlight disappeared first and faster than the one kept under the shade.
During the daytime, sunlight falls on the water in oceans, rivers, lakes and ponds. The fields and other land areas also receive sunlight. As a result, water from all these places continuously changes into vapour. However, the salts dissolved in the water are left behind.
From the above activity we found that water also disappeared from the plate kept in the shade, although it took more time. During the daytime all the air surrounding us gets heated. This warm air provides heat for evaporation of water in the shade. Thus, evaporation takes place from all open surfaces of water. As a result, water vapour gets continuously added to air. However, evaporation of water is a slow process. That is why we rarely notice its loss from a bucket full of water. In sunlight, evaporation takes place faster. On heating water on a burner, its evaporation takes place even faster.
Que. 1) Water can be converted into vapours through …………………………………………………………………………….………..
(a) Adding Salt
(b) Evaporation
(c) Heating
(d) All of the above
Que. 2) Evaporation of water is a …………………………………………………………………………………. process under sunlight.
(a) Slow
(b) Fast
(c) Long
(d) None of the above
Que. 3) Which of the following is a source of water?
(a) Ocean
(b) Lake
(c) River
(d) All of the above
Que. 4) Explain how water in riverchanges to vapour? Name the source of heat present here?
Que. 5) What makes water disappear from a bucket kept in the shade?
Answer Key
Que.1. c) Heating
Que.2. b) Fast
Que. 3. d) All of the above
Que. 4) Answer:Water bodies like oceans, rivers and lakes receive sunlight during the day time as a natural source of heat. As a result, in the presence of constant heat, water from these bodies continuously changes into vapour.
Que. 5) Answer: Due to the presence of sunlight during the day time, all the air in our surrounding gets heated. This heat helps in the evaporation of water in open surfaces. When a bucket full of water is kept in shade, the heat in the surrounding air slowly but continuously changes water into vapours.
Case study 2
Plants need water to grow. Plants use a part of this water to prepare their food and retain some of it in their different parts. Remaining part of this water is released by the plants into air, as water vapour through the process of transpiration. Water vapour enters the air through the processes of evaporation and Transpiration.
Take a glass half filled with water. Wipe the glass from the outside with a clean piece of cloth. Add some ice into the water. Wait for one or two minutes. Observe the changes that take place on the outer surface of the glass. You’ll notice water drops appear on the outer side of the glass.The cold Surface of the glass containing iced water, cools the air around it, and the water vapour of the air condenses on the surface of the glass.
The process of condensation plays an important role in bringing water back to the surface of earth. As we go higher from thesurface of the earth, it gets cooler. Whenthe air moves up, it gets cooler andcooler. At sufficient heights, the airbecomes so cool that the water vapourpresent in it condenses to form tinydrops of water called droplets. It is thesetiny droplets that remain floating in airand appear to us as clouds.It so happens that many droplets of water come together to form largersized drops of water. Some drops of water become so heavy that they begin to fall. These falling water-drops are, what we call rain. In special conditions, it may also fall as hail or snow. Thus, water in the form of vapour goes into air by evaporation and transpiration, forms clouds, and then comes back to the ground as rain, hail or snow.
Que.1) Water enters the air through the processes of Transpiration and condensation.
a) True
b) False
Que.2) ………………………………………………………………………..…… are the tiny drops of water that are formed by the condensation of vapours present in air.
a) Droplets
b) Vapour
c) Clouds
d) None of the above
Que.3) Through the process of…………………………………………………………………………………… water comes back to the surface of the earth in the form of rain, hail or snow.
a) Transpiration
b) Evaporation
c) Condensation
d) All of the above
Que.4) Define the process of transpiration.
Que.5) Explain the important role played by the process of condensation?
Answer Key
Que.1. b) False
Que.2.a) Droplets
Que.3. c) Condensation
Que.4) Answer:The process through which plants release water into the air, in the form of vapours is called transpiration.
Que.5) Answer: Condensation helps in bringing back water to the surface of the earth. When water moves up as vapours through the processes of evaporation and transpiration, it gets cooler and cooler with increasing heights and at an ample height the vapour becomes so cool that water present in them condenses into tiny drops of water called droplets. It is these floating droplets of water that appear to us as clouds. With time, some of these droplets of water become so heavy that they begin to fall in the form of rain and sometimes as hail or snow.
Case study 3
Most of the water that falls on the land as rain and snow sooner or later goes back to the oceans.This happens in many ways.Snow in the mountains melts intowater. This water flows down themountains in the form of streams andrivers. Some of the water thatfalls on land as rain, also flows in theform of rivers and streams. Most of therivers cover long distances on land andultimately fall into a sea or an ocean.However, water of some rivers flowsinto lakes. The rainwater also fills up the lakes and ponds. A part of the rainwater gets absorbed by the ground and seems to disappear in the soil. Some of this water is brought back to the air by the process of evaporation and transpiration. The rest seeps into the ground. Most of this water becomes available to us as groundWater. Open wells are fed by ground water. Ground water is the source for many lakes as well. It is also this ground water which is drawn by a hand pumpor a tube well. The more hand pumps orTube wells that are used in an area, the deeper we need to dig to find this ground water. The loss in the level of ground water due to over use, is worrisome.
Water brought back to the surface of the earth by rain, hail or snow, goes back to oceans. Thus, water from the ocean and surface of the earth goes into air as vapour; returns as rain, hail or snow and finally goes back to the oceans. The circulation of water in this manner is known as the Water cycle. This circulation of water between ocean and land is a continuous process. This maintains the supply of water on land.
Que.1) Water cycle is a continuous process.
a) True
b) False
Que.2) ………………………………………………………………………….. water is drawn through Tube wells or hand pumps.
a) Rain
b) Lake
c) Ground
d) River
Que.3) …………………………………………………………………….…maintains the supply of water on land.
a) Rain
b)Transpiration
c)Ground water
d) Water cycle
Que.4) Explain the process of water cycle.
Que.5) How water from the ground is available to us?
Answer Key
Que.1. a) True
Que.2. c) Ground
Que.3. d) Water cycle
Que.4) Answer:Through the processes of Transpiration and evaporation water from oceans, rivers and lakes goes into the air as vapours. Then it returns in the form of rain, hail or snow through the process of condensation and finally goes back to the water bodies. This circulation of water is a continuous process known as the water cycle.
Que.5) Answer: Water is brought back to the surface of the earth in the form of rain. This rainwater flows back to the oceans and a part of it is absorbed by the soil. This absorbed water is available to us as ground water. It is this water which fills up open wells and lakes. It is usually drawn with the help of hand pumps or tube wells.
Case study 4
The time, duration and the amount of Rainfall varies from place to place. In Some parts of the world it rains throughout the year while there are Places where it rains only for a few days. In our country, most of the rainfall occurs during the monsoon season. Rains bring relief especially after hot summer days. The sowing of many crops depends on the arrival of monsoon. However, excess of rainfall may lead to many problems. Heavy rains may lead to rise in the level of water in rivers, lakes and ponds. The water may then spread over large areas causing floods. The crop fields, forests, villages, and cities may get submerged by water. In our country, floods caused extensive damage to crops, domestic animals, property and human life.
While on the other hand, when it does not rain in a region for a year or more,the soil continues to lose water by evaporation and transpiration. Since it is not being brought back by rain, the soil becomes dry. The level of water in ponds and wells of the region goes down and some of them may even dry up. The ground water may also become scarce. This may lead to drought. In drought conditions, it is difficult to get food and fodder.
Que.1) Which of the following is difficult to get during drought conditions?
a) Water
b) Food
c) Fodder
d) All of the above
Que.2) In India, rainfall occurs during the …………………………………………………………………………………….. season.
a)Summer
b) Spring
c) Monsoon
d) Autumn
Que.3) Excessive rainfallcan lead to flood in a region.
a) True
b) False
Que.4) How can excessive rainfall affect human and other living beings?
Que.5) What happens when it does not rain for a long period of time?
Answer Key
Que.1. d) All of the above
Que.2. c) Monsoon
Que.3.a) True
Que.4) Answer: Excessive rainfall is dangerous as it may lead to rise in the water levels in river, lakes and ponds, resulting overflow of water in them. This water may then spread over an area causing floods in that region. Everything including villages and cities may get submerged in water. It destroys human properties, crops, domestic animals and even human lives.
Que.5) Answer: When it does not rain in a region for a long period of time, the soil continues to release water as vapours into the air through the processes of evaporation and transpiration, the absence of rain in a region affects the soil causing it to dry up that can lead to a condition called drought. In such a situation, water level in lakes and ponds goes down and the ground water may also become scarce leading to scarcity of water in that region. As a result, it becomes difficult to get food and Fodder to sustain lives.
Case study 5
Only a small fraction of water availableon the Earth is fit for use of plants,animals and humans. Most of the wateris in the oceans and it cannot be useddirectly. When the level of the groundwater decreases drastically, this cannotbe used any more. The total amount ofwater on Earth remains the same, but,the water available for use is very limitedand is decreasing with over usage.The demand for water is increasingday-by-day. The number of people usingwater is increasing with risingpopulation. In many cities, long queuesfor collection of water are a common site. Also, more and more wateris being used for producing food and bythe industries. These factors are leading to shortage of water in many parts of the world. Hence, it is very important that water is used carefully. We should take care not to waste water.
One way of increasing the availability of water is to collect rainwater and store it for later use. Collecting rainwater in this way is called rainwater harvesting. The basic idea behind rainwater harvesting is “catch water where it falls”. There are two techniques of rainwater harvesting:
1. Rooftop rainwater harvesting: In this system the rainwater is collected from the rooftop to a storage tank, throughpipes. This water may contain soilfrom the roof and need filteringbefore it is used. Instead of collectingrainwater in the tank, the pipes can go directly into a pit in theground. This then seeps into the soil to recharge or refill the groundwater.
2. Another option is to allow waterto go into the ground directlyfrom the roadside drains thatcollect rainwater.
Que.1) The basic idea behind Rainwater harvesting is ……………………………………………………………………………………..
a) Save water, save life
b) Stop wasting water
c)Catch water where it falls
d)Water is precious
Que.2) Water available for use is limited.
a) True
b) False
Que.3) Which of the following is a factor leading to shortage of water?
a) Rise in population
b) Wastage of water
c) Limited availability
d)All of the above
Que.4) What is rainwater harvesting?
Que.5) Explain the process of Rooftop Rainwater harvesting?
Answer Key
Que.1. c) Catch water where it falls.
Que.2. a) True
Que.3. d) All of the above
Que.4) Answer:The method of collecting rainwater and storing it for later use is known as Rainwater harvesting.
Que.5) Answer: Rooftop rainwater harvesting is a system where rainwater is collected through pipes from the rooftop to a tank to store it for later use. As it is collected from the rooftop the water may contain soil , so it needs to be filtered before using. Another alternate way to store this water is, to connect the pipes into a pit in the ground. This way the water will be refilled as ground water.