NCERT Solutions For Class 7 Geography Social Science Chapter 5 Water - Free PDF

Geography - Class 7

Our Environment

Chapter 5: Water

Question 1:Answer the following questions.

(i) What is precipitation?

Answer:When any liquid or frozen water that forms in the atmosphere, falls back to the earth, this process is called precipitation. It comes in many forms like rain, snow, or sleet.

(ii) What is water cycle?

Answer:The process by which water continually changes its form and circulates between oceans, atmosphere, and land is known as the water cycle.

(iii) What are the factors affecting the height of the waves?

Answer:The factors affecting the height of the waves are:

  • The winds blowing at the high speed.
  • an earthquake
  • volcanic eruptions
  • underwater landslides.
(iv) Which factors affect the movement of ocean water?

Answer:The factors that affect the movement of ocean water are:-

  • Warm and cold currents
  • Temperature
  • Winds
  • gravitational pull of the Sun and the Moon.
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(v) What are tides and how are they caused?

Answer:The rhythmic rise and fall of ocean water twice a day is called a tide.

  • It is high tide when water covers much of the shore by rising to its highest level.
  • It is low tide when water falls to its lowest level and recedes from the shore.
  • The strong gravitational pull exerted by the sun and the moon on the earth’s surface causes the tides.
(vi) What are ocean currents?

Answer: Ocean currents are streams of water flowing constantly on the ocean surface in definite directions. The ocean currents may be warm or cold.

Question 2:Give reasons.

(i) Ocean water is salty.

Answer:The water of the oceans is salty or saline as it contains a large amount of dissolved salts. Most of the salt is sodium chloride or the common table salt that we eat. Salt in the ocean comes from the rocks on land. When the rain falls on the land, it contains dissolved carbon dioxide from the air. This acidic rain breaks down the rocks and carries the salts and minerals to the oceans and rivers.

(ii) The quality of water is deteriorating.

Answer:The quality of water is deteriorating day by day because of the following reasons:-

  • Throwing garbage and other waste material in the water.
  • Chemicals released from industries into the water.
  • Toxic and hazardous wastes.
  • Pollution of groundwater.

Question 3:Tick the correct answer.

(i) The process by which water continually changes its form and circulates between oceans, atmosphere and land

(a) Water cycle

(b) Tides

(c) Ocean currents

(ii) Generally the warm ocean currents originate near

(a) Poles

(b) Equator

(c) None of these

(iii) The rhythmic rise and fall of ocean water twice in a day is called

(a) Tide

(b) Ocean current

(c) Wave

Answer:

(i). (a) Water cycle

(ii). (b) Equator

(iii). (a) Tide

Question 4:Match the following.

(i) Caspian Sea (a) Largest lake
(ii) Tide (b) Periodic rise and fall of water
(iii) Tsunami (c) Strong seismic waves
(iv) Ocean currents (d) Streams of water moving along definite paths
(e) Water cycle

Answer:

(i) Caspian Sea (a) Largest lake
(ii) Tide (b) Periodic rise and fall of water
(iii) Tsunami (c) Strong seismic waves
(iv) Ocean currents (d) Streams of water moving along definite paths

Question 5:For Fun:

Be a Detective

The name of one river is hidden in each of the sentences below. Spot it.
Example: Mandira, Vijayalakshmi and Surinder are my best friends.

Answer:Ravi

(a) The snake charmer’s bustee, stables where horses are housed, and the piles of wood, all caught fire accidentally. (Hint: Another name for River Brahmputra)
(b) The conference manager put pad, material for reading and a pencil for each participant. (Hint: A distributary on the Ganga-Brahmputra delta)
(c) Either jealousy or anger cause a person’s fall (Hint: Name of a juicy fruit!)
(d) Bhavani germinated the seeds in a pot (Hint: Look for her in West Africa)
(e) “I am a zonal champion now” declared the excited athlete. (Hint: The river that has the biggest basin in the world)
(f) The tiffin box rolled down and all the food fell in dusty potholes. (Hint: Rises in India and journeys through Pakistan)
(g) Malini leaned against the pole when she felt that she was going to faint. (Hint: Her delta in Egypt is famous)
(h) Samantha mesmerised everybody with her magic tricks. (Hint: London is situated on her estuary)
(i) “In this neighbourhood, please don’t yell! Owners of these houses like to have peace. Warned my father when we moved into our new flat”. (Hint: colour!)
(j) ‘Write the following words’, Marc! “On”, “go”, “in”……….. said the teacher to the little boy in KG Class. (Hint: Rhymes with ‘bongo’) Now make some more on your own and ask your classmates to spot the hidden name. You can do this with any name: that of a lake, mountains, trees, fruits, school items, etc.

Answer:

(a)Teesta

(b) Padma

(c) Orange

(d) Niger

(e) Amazon

(f) Indus

(g) Nile

(h) Thames

(i) Yellow

(j) Congo

Intext Questions:

  • Why is water important for us?
  • Suggest some ways in which water can be conserved.
  • (a) in your home

    (b) in your school

    Answer:Water is the most important and essential resource of our life. Human beings cannot survive without water. It is used for drinking, cooking, washing, cleaning, bathing, irrigation etc.

    (a) at home:

    1. Look out for leaky taps, dripping water from shower heads, rusting pipes and signs of water damage
    2. Don't keep the tap running the entire time you're brushing your teeth or washing your hands.
    3. if you notice that your toilet is constantly running, try replacing the flapper.
    4. Rainwater harvesting.

    (b) at school:

    1. Detect and repair leaks at schools so that wastage of water will get reduce.
    2. Put signs near the basins to remind students to turn off taps as soon as they wash their hands.
    3. Raise awareness of the importance of water by creating colorful posters on water use and water saving.
    4. Encourage students to use refillable water bottle and educate them to pour leftover water onto the garden.