29 Apr 2022

Samacheer kalvi 6th Science Term 3 Unit 2 Answers

Samacheer Kalvi 6th Science Term 3 Unit 2 Book Back Question and Answers/Solutions:

Samacheer Kalvi 6th Standard New Science Book Back 1 Mark and 2 Mark Question & Answers PDF uploaded and available below. Class 6 New Syllabus 2021 to 2022 Book Back Question & Answer solutions available for both English and Tamil Medium. Class 6 Science  Book Term 3 Unit 2 Water Answers/Solutions are provided on this page. 6th Std Science Book is of 1st Term, 2nd Term consists of 7 units and 3rd Term consists of 6 units. All Units/Chapters of Term 1st, 2nd, 3rd Social Book Back One, and Two Mark Solutions are given below.

Check Unit wise and  6th New Science Book Back Question and Answers Guide/Solutions PDF format for Free Download. English, Tamil, Maths, Science, and Social Science Book Back Questions and Answers available in PDF. Check Science Book Back Solutions below. See below for the Samacheer Kalvi 6th Science Term 3  Unit 2 Book Back Answers PDF:




Samacheer Kalvi 6th Science Book Back Chapter 2 Term 3 Answers/Solutions Guide PDF:

Science Subject 1 Mark and 2 Mark Solutions Guide PDF available below. Click the Download option to download the book back 1 Mark & 2 Mark questions and answers. Take the printout and use it for exam purposes.

6th Science – Term 1 Unit 2

Water

I. Choose the appropriate answer:

1. Around 97% of water available on earth is _______ water.
(a) fresh
(b) pure
(c) Salty
(d) polluted
Answer:
(c) Salty

2. Which of the following is not a part of water cycle?
a. evaporation
b. condensation
c. rain
d. distillation
Answer:
d. distillation

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:
(c) i and iv

4. About 30% of the freshwater is found in?
a. glaciers
b. groundwater
c. other sources of water
d. 0.3%
Answer:
b. groundwater

5. Using R.O. plant at home eliminates a 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:
(b) use it for watering plants

II. Fill in the blanks:

  1. Only _______ percent of natural water is available for human consumption.
  2. The process of changing water into its vapour is called _______
  3. _______ is built on rivers to regulate water flow and distribute water.
  4. Water levels in rivers increase greatly during _______
  5. Water cycle is also called as _______

Answer:

  1. 0.3
  2. Evaporation
  3. Dam
  4. Raining
  5. Hydrological cycle

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:
False. 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:
False. Ponds are formed when the water table meets the land surface.

3. The evaporation of water takes place only in sunlight.
Answer:
True.

4. Condensation results in the formation of dew on grass.
Answer:
True.

5. Sea water can be used for irrigation as such.
Answer:
False. Sea water cannot be used for irrigation as such.





IV. Match the following :

1. Flood Lake
2. Surface water Evaporation
3. Sunlight Water vapour
4. Cloud. Pole
5. Frozen water Increased rainfall

Answer:

1 – v; 2 – i; 3 – ii; 4 – iii; 5 – iv

V. Arrange the following statements in the 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:

  1. The heat of the sun causes evaporation of water from the surface of the earth, oceans, lakes, rivers and other water bodies.
  2. Water vapour is also continuously added to the atmosphere through transpiration from the surface of the leaves of trees.
  3. Higher up in the atmosphere, the air is cool.
  4. These vapours condense to form tiny droplets of water.
  5. These droplets floating in the air along with the dust particles form clouds.
  6. Warm air carrying clouds rises up.
  7. The water droplets come together to form large water droplets.
  8. 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 : __________ :: Surface water : lakes
Answer:
Tube wells

VII. Give Very Short Answer:

1. Name four different sources of water.
Answer:
Rivers, wells, lakes, glaciers, ponds etc.

2. How do people in cities and rural areas get water for various purposes?
Answer:
In city, people get water from water tanks, hand pipes and bore wells.
In rural area, people get water from wells, canals, ponds and rivers.

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:
The cooled surface of bottle cools the air around it and the water vapour of the air condenses. So after some time a puddle of water can be noticed around the bottle.

4. We could see clouds almost every day. Why doesn’t it rain daily?
Answer:

  1. The millions of tiny droplets do not collide with another to form larger droplets.
  2. The air around the clouds is not cool.

5. Name the places where water is found as ice.
Answer:
Polar ice-caps, Ice sheets and glaciers in Artie region arid Antarctica.

6. How do aquatic animals manage to live in Arctic and Antarctic Circle?
Answer:
In Arctic and Antarctic circle, water in lakes and ponds will be frozen and a solid layer of ice is formed on the surface of water. Still aquatic animals living under the ice do not die. This is because the floating layer of ice acts as a protective coat and does not permit heat to escape from water. So as the surface water alone turns to ice, the aquatic animals manage it.

7. What are the types of rainwater harvesting?
Answer:
There are two types of rainwater harvesting.

  1. Collecting water from where it falls.
  2. Collecting rainwater by constructing bunds.

VIII. Give Short Answer:

1. Differentiate between surface water and groundwater.
Answer:
Surface water:

  1. Water present on the surface of the earth.
  2. Ex : River, lake, ponds, streams or freshwater.

Groundwater:

  1. Water present beneath earth’s surface in soil.
  2. Ex : open wells, tube wells (or) hand pumps, Spings etc.

2. Write a few slogans of your own on the topic “Save Water”?
Answer:

  1. “To a thirsty man, a drop of water is worth more than a sack of gold”.
  2. “Water covers 2/3 of the surface of the earth. But only 0.002% is drinkable. Save water”
  3. “Save water to secure your future”
  4. “Don’t make nature cry, keep your water clean”
  5. “Store water for dry days”.

3. About 71% of earth’s surface is covered with water, then why do we face scarcity of water?
Answer:
About 71% of the earth’s surface is covered with water and even then we face scarcity of water. Reasons:

  1. 97% of total water is found in seas and oceans, which is salty and not fit for human consumption.
  2. Only 3% found is the freshwater and that too available in polar ice caps and glaciers.
  3. Out of 3% fresh water, only 0.3% is available to us as surface water, in lakes, rivers, and swamps.

4. Give a reason for the following statement – Sewage should not be disposed of in rivers or oceans before treatment.
Answer:

  1. Sewage should not be disposed of in rivers or oceans before treatment.
  2. If we dispose of sewage before treatment the rivers and oceans will be polluted.
  3. Aquatic animals and species will die due to pollution.
  4. We can not use the river water for our day to day life.

5. The freshwater available on earth is only 3%. We cannot increase the amount of water. In that case, how can sustain the water level?
Answer:

  1. The sewage water treatment is to be adopted.
  2. Decrease the usage of pesticides, insecticides, and fertilizers in agriculture.
  3. Protect forest and trees.
  4. Adopt drip irrigation and sprinkler irrigation in agriculture.
  5. Rainwater harvesting should be implemented in every building.
  6. Create awareness about the impact of throwing wastes into the water bodies.

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