Water Book Back Questions 6th Science Lesson 16
6th Science Lesson 16
16] Water
Book Back Questions with Answer and Do You Know Box Content
Do You Know?
Water while passing through layers of soil dissolves salts and minerals to a maximum extent. These salts and minerals have been deposited in seas and oceans for millions of years and are still being deposited. In addition, the oceanic volcanoes which are present inside, also add salts to the sea. Water with large amounts of dissolved solids is not portable or suitable for drinking. Such water is called saline water.
Water freeze at 0o Celsius at normal pressure. Every year March 22nd is observed as the world water day.
The Himalayas: The Himalayas contain ice caps, ice bergs and glaciers. Ten of Asia’s largest rivers flow from the Himalayas and more than a billion people’s livelihoods depend on those rivers.
Water, is measured in litre and millilitre. Gallon is also a measure of volume of liquids. 1 Gallon = 3.785 litre. Water level in the reservoirs is measured in TMC (One thousand million cubic feet). Water released from dams is measured in cusec (cubic feet/sec).
Aquatic animals: During winter, water in lakes and ponds in the cold countries 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 doesn’t permit heat to escape from water. So as the water at the surface alone turns to ice, it the existence of aquatic animals.
Koovam is an estuary! Estuaries are wetlands where water bodies meet the sea. It is a combination of fresh water from land meeting the salty seawater. Estuaries are home to unique plants and animal species.
Swamps are wetlands that are forested. They occur along large rivers or on the shores of large lakes. The water of a swamp may be freshwater, brackish water or seawater. Swaps are important for providing fresh water and oxygen to all life. Pichavaram Mangroves in Chidambaram, Muthupet mangrove wetland. Pallikaranai wetland in Chennai, Chembarambakkam in Kancheepuram is a few examples of swamps in Tamil Nadu.
Choose the best answers:
1. Around 97% of water available on earth is _______________ water.
(a) Fresh
(b) Pure
(c) Salty
(d) Polluted
2. Which of the following is not a part of water cycle?
(a) Evaporation
(b) Condensation
(c) Rain
(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
4. About 30% of the fresh water is found in?
(a) Glaciers
(b) Ground water
(c) Other sources of water
(d) 0.3%
5. Using R.O. (Reserve 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 pants
(c) To drink the expelled water after boiling and cooling
(d) To use for cooking as the water is full of many nutrients
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 ________________
State true or false. If false, correct the statement:
1. Water present in rivers, lakes and ponds is unfit for use by human beings.
2. Seas are formed when the water table meets the land surface.
3. The evaporation of water takes place only in sunlight.
4. Condensation results in the formation of dew on grass.
5. Sea water can be used for irrigation as such.
Match the following:
1. Flood – Lake
2. Surface water – Evaporation
3. Sun light – Water vapour
4. Cloud – Pole
5. Frozen water – Increased rain fall
Complete the analogy:
1. Population explosion: Water scarcity :: Recycle: _____________
2. Ground water: _______________ :: Surface water: lakes
Answers:
Choose the best answer:
1. Salty 2. Distillation 3. Transpiration and Evaporation 4. Ground water 5. Use it for watering plants
Fill in the blanks:
1. 0.3% 2. Evaporation 3. Dam 4. Raining season 5. Hydrological cycle
Say True or False:
1. False
Correct Statement: Water present in rivers, lakes and ponds is fit for use by human beings.
2. False
Correct Statement: Ponds are formed when the water table meets the land surface.
3. True
4. True
5. False
Correct Statement: Sea water cannot be used for irrigation because of its high salinity.
Match the following:
1. Increased rainfall 2. Lake 3. Evaporation 4. Water vapour 5. Pole
Complete the Analogy:
1. Water management 2. Tube wells