Samacheer Kalvi 6th Science Term 3 Solutions Chapter 2 Pdf
Tamilnadu Board Samacheer Kalvi 6th Science Term 3 Solutions Chapter 2: Tamilnadu State Board Solution Class 6 Science Term 3 Chapter 2 – Water.
Samacheer Kalvi 6th Science Term 3 Solutions Chapter 2: Overview
|
Board |
Samacheer Kalvi |
| Class |
6 |
|
Subject |
Science |
| Chapter |
2 |
|
Chapter Name |
Water |
Samacheer Kalvi 6th Science Term 3 Solutions Chapter 2 Pdf
I.) Choose the correct answer .
1.) Around 97% of water available on earth Is ______ water.
a.) Fresh
b.) pure
c.) Salty
d.) polluted
Answer:Salty
Solution: About 97% of the Earth’s water is found in Oceans and seas. This water is Salty and is unfit for human consumption.
2.) Which of the following is not a part of Water cycle?
a.) Evaporation
b.) condensation
c.) Rain
d.) distillation
Answer: Distillation
Solution: Evaporation, condensation and rain are all part of the water cycle but distillation is a process of purifying water.
3.) Which of the following processes add Water vapour to the atmosphere?
i.) Transpiration
ii.) Precipitation
iii.) Condensation
iv.) Evaporation
a.) ii and iii
b.) ii and iv
c.) i and iv
d.) i and ii
Answer:i and iv
Solution: Plants through the process of transpiration release water vapours in the atmosphere. And evaporation is a process through which liquid turns into gaseous state.
4.) About 30% of the fresh water is found In?
a.) Glaciers
b.) Ground water
c.) Other sources of water
d.) 0.3%
Answer: Ground water
Solution: About 68% of the freshwater is found in glaciers, 0.3% in rivers, lakes and ponds and about 30% as ground water.
5.) Using R.O. (Reverse Osmosis) plant At home eliminates lot of non-potable Water. The best way to effectively Use the expelled water of R.O. plant is _______
a.) Make the expelled water go and Seep near the bore well
b.) Use it for watering plants
c.) To drink the expelled water after Boiling and cooling
d.) To use for cooking as the water is Full of many nutrients
Answer: Use it for watering plants.
Solution: Reverse osmosis is a process ofpurifying contaminated water. The expelled contaminated water can be use effectively by watering plants.
II.) Fill in the blanks
1.) Only__0.3____ percent of natural water Is available for human consumption.
2.) The process of changing water into its Vapour is called __evaporation______ .
3.) ____Dam______ Is built on rivers to regulate Water flow and distribute water.
4.) Water levels in rivers increase greatly During __raining______ .
5.) Water cycle is also called as ___hydrologicalcycle_____.
III.) True or False. If False, give the Correct statement
1.) Water present in rivers, lakes and Ponds is unfit for use by human beings.
Answer: Water present in rivers, lakes and Ponds is fit for use by human beings.
2.) Seas are formed when the water table Meets the land surface.
Answer:Ponds are formed when the water table Meets the land surface.
3) The evaporation of water takes place Only in sunlight.
Answer: False, the evaporation of water also takes place in the absence of sunlight.
4.) Condensation results in the formation Of dew on grass.
Answer: True
5.) Sea water can be used for irrigation as Such.
Answer: False, seawater cannot be used for irrigation as such.
IV.) Match the following
Answer:
| Flood | Increased rainfall |
| Surface water | Lake |
| Sun light | Evaporation |
| Cloud | Water vapour |
| Frozen water | Pole |
V.) Arrange the following statements In correct sequence
1.) These vapours condense to form tiny Droplets of water.
2.) The water droplets come together to Form large water droplets.
3.) The heat of the sun causes evaporation Of water from the surface of the earth, Oceans, lakes, rivers and other water Bodies.
4.) The large water droplets become Heavy and the air cannot hold them, Therefore, they fall as rains.
5.) Water vapour is also continuously Added to the atmosphere through Transpiration from the surface of the Leaves of trees.
6.) Warm air carrying clouds rises up.
7.) Higher up in the atmosphere, the air is Cool.
8.) These droplets floating in the air along With the dust particles form clouds.
Answer:
3.) The heat of the sun causes evaporation Of water from the surface of the earth, Oceans, lakes, rivers and other water Bodies.
5.) Water vapour is also continuously Added to the atmosphere through Transpiration from the surface of the Leaves of trees.
7.) Higher up in the atmosphere, the air is Cool.
1.)These vapours condense to form tiny Droplets of water.
8.) These droplets floating in the air along With the dust particles form clouds.
6.) Warm air carrying clouds rises up.
2.) The water droplets come together to Form large water droplets.
4.) The large water droplets become Heavy and the air cannot hold them, Therefore, they fall as rains.
VI.) Analogy
1.) Population explosion : Water scarcity ::Recycle : ?
Answer: Water management
2.) Ground water : _______ :: SurfaceWater : lakes
Answer: Tubewells
VII.) Give very short answer
1.) Name four different sources of water
Answer: Lakes, tube wells, sea water and ponds are four different sources of water.
2.) How do people in cities and rural areas Get water for various purposes?
Answer: People in cities get water from water tanks, water supply, pipes
3.) Take out of cooled bottle of water from Refrigerator and keep it on a table. After Some time you notice a puddle of water Around it. Why?
Answer: A puddle of water can be noticed around the bottle as the surface of the bottle cools down the air in the surrounding and the water vapours of the air condenses.
4.) We could see clouds almost every day. Why doesn’t it rain daily?
Answer: Tiny water droplets present in million numbers do not collide everyday thereby forming large water droplets. The air surrounding the clouds are not always cool.
5.) Name the places where water is found As ice.
Answer: Places where water is found as ice are glaciers, ice-caps, ice sheets etc.
6.) How do aquatic animals manage to live In Arctic and Antarctic Circle?
Answer: The Aquatic animals manage to live in Arctic and Antarctic circle as the surface of the ice act as a protective layer that prevents the heat present from escaping.
7.) What are the types of rain water Harvesting?
Answer: There are two types of Rainwater harvesting:
- To collect rainwater where it falls.
- To construct bund for collecting Rainwater.
VIII.) Give short answer
1.) Differentiate between surface water And ground water.
Answer:Surface water refers to the water present on the earth surface. Example- lakes, rivers, ponds etc.
Ground water refers to the water that is present beneath the surface of the earth. Example- hand pumps, tube wells etc.
2.) Write a few slogans of your own on the Topic “Save Water”.
Answer:
- Save water, to save lives.
- If you want to survive, don’t make the earth water deprived.
- Save water today, to secure your tomorrow.
3.) About 71% of earth’s surface is covered With water, then why do we face scarcity Of water?
Answer: We face water scarcity because:
- About 97% of earth’s water is found in the oceans and seas. This water is salty and hence not fit for use.
- Only about 3% of earth’swater is freshwater that too are in the form of glaciers and polar ice caps. Only 0.3% of this freshwater is fit for human consumption that is found in rivers, lakes and swamps.
4.) Give reason for the following statement – Sewage should not be disposed of in Rivers or oceans before treatment.
Answer: Without treatment, sewage should not be disposed off in water bodies. Disposing without treatment will lead to water pollution. As a result, aquatic plants and animals would die because of polluted water. Also we will not be able to use the water for our day to day activities.
5.) The fresh water available on earth Is only 3%. We cannot increase the Amount of water. In that case, how can Sustain the water level?
Answer: The following measures can be adopted to sustain the water level:
- Rainwater harvesting should be adopted to store rain water and using it for later use.
- Irrigation methods like drip irrigation and sprinkle irrigation should be adopted in agriculture.
- Deforestation
- Treatment of sewage water.
- The use Pesticides, Insecticides and fertilizers in agriculture should be minimised.
IX.) Answer in detail
1.) What is potable water? List down its Characteristics.
Answer: The water that is fit for drinking purposes are called potable water. It’s characteristics include:
- It has no colour, it is transparent.
- It has no odour.
- It is free from germs and bacteria.
- The amount of salts and minerals should be as per the body need.
2.) Who is known as waterman of India? Browse the net and find the details About the award, the waterman Received for water management. State The findings by drafting a report.
Answer:Dr Rajendra Singh from Alwar district of Rajasthan, well known as a water conservationist is called as the Waterman of India. In 1975 he also started a NGO as ‘Tarun Bharat Sangh’ .
He won many awards for his contribution to water conservation and environment.
- In 2001, he got the Ramon Magsaysay award for community leadership.
- The Jamnalal Bajaj award for science and technology was awarded to him in 2005 for his contribution to rural development.
- By 2008, he was among the 50 people who could save the planet in the guardian list.
- He was awarded the Stockholm water prize in 2015.
- The UK based Institute of Jainology bestowed him with Ahimsa award in 2016.
3.) What is rainwater harvesting? Explain in a few sentences how it can be used in houses.
Answer:Rainwater harvesting refers to the direct collection and use of rain water.It is usually stored in rooftops or other such surfaces at houses. This stored water from rain can be used in garden and crop irrigation, watering livestock, laundry, and flushing toilets etc.
X.) Question based on Higher Order Thinking Skills
1.) When there is no pond or lake in an area, will there be formation of clouds possible in That area?
Answer:The formation of clouds will be possible in area with no ponds or lake as water vapour that form clouds can also be released through the process of transpiration by plants.
2.) To clean the spectacles, people often breathe out on glasses to make them wet. Explain Why do the glasses become wet.
Answer:When we exhale, water vapours along with water carbon dioxide are also released. Water vapours get collided with the surface of the glasses when we breathe out onto it and get condensed , thereby making the glasses of spectacles wet.
XI.) CROSSWORD
DOWN
- A method of water conservation.
- Process of getting water vapour from sea water.
6.Water stored in dams is used for generation of .
ACROSS
- Is a large body of non-potable water found in nature.
- In summer, the body loses water as .
- Plants undergo and contribute to water cycle.
Answer:
Down:
- Recycling
- Evaporation
- Electricity
Across:
- Ocean
- Sweat
- Transpiration
XII.) (1). Observe the given graph carefully and answer the questions.
a.) What percentage of water is seen in fish?
Answer: In fishes , 70% of water is seen.
b.) Name the food item that has maximum amount of water in its content.
Answer: Watermelon has the maximum amount of water in its content.
c.) Name the food item that has minimum amount of water in its content.
Answer: Fish has the minimum amount of water in its content.
d.) Human body consists of about percentage of water.
Answer: Human body consists of about 60% of water.
e.) Specify the food item that can be consumed by a person when he / she is suffering fromDehydration.
Answer: Watermelon can be consumed by a person when he/she is suffering from Dehydration.
(2) Look at the map of Tamil Nadu showing annual rainfall and answer The questions given Below.
a.) Identify the districts that get onlyLow annual rainfall in Tamil Nadu.
Answer: Districts with low annual rainfall are Dharmapuri, erode, madurai, Sivagangai, Ramanathapuram, karur, Dindigul, Perambalur, Trichy, and Tanjore.
b.) identify the districts that get a Medium annual rainfall in Tamil Nadu.
Answer: Districts with medium annual rainfall are Krishnagiri, Vellore, Thiruvannamalai, Salem, namakkal, Ariyalur, Thiruvarur, virudhunagar, Tuticorin, Thiruvallur, kanchipuram, chennai vizhuppuram.
c.) State the districts that enjoy high Annual rainfall in Tamil Nadu.
Answer: Districts that enjoy high Annual rainfall are theni, Coimbatore, Nilgiri, thirunelveli, kanyakumari, Nagapattinam, Cuddalore.
