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Online Education for Class 7 Science Chapter 16 Extra Questions and Answers Water: A Precious Resource
Class 7 Science Chapter 16 Extra Questions Question 1.
When is the World Water Day celebration?
Answer:
22 March.
Water Class 7 Questions And Answers Question 2.
What is minimum limit of water prescribed by United Nations?
Answer:
The amount of water recommended by the United Nations for drinking, washing, cooking and maintaining proper hygiene is a minimum of 50 litres per person per day.
Water A Precious Resource Class 7 Extra Questions And Answers Question 3.
How much of earth’s surface is covered by water?
Answer:
About 71%.
Class 7 Science Water Extra Questions Question 4.
How much water (by percentage) is available for us to use?
Answer:
Roughly 0.006%.
Water: A Precious Resource Class 7 Extra Questions And Answers Question 5.
Where is solid form of water present in the earth?
Answer:
The solid form, snow and ice, is present as ice caps at the poles of the earth, snow-covered mountains and glaciers.
Water A Precious Resource Class 7 Questions And Answers Question 6.
How is water present in the atmosphere?
Answer:
As water vapour.
Water Class 7 Extra Questions Question 7.
What is Baril?
Answer:
Bawri is the traditional way of collecting water.
Ncert Class 7 Science Chapter 16 Extra Questions Question 8.
Which year was observed as International Year of Freshwater and why?
Answer:
Year 2003 was observed as the International Year of Freshwater to make people aware of this dwindling natural resource.
Ncert Solutions For Class 7 Science Chapter 16 Extra Questions Question 9.
Where is most of the water in earth contained?
Answer:
Almost all the water on the earth is contained in the seas and oceans, rivers, lakes, ice caps, as groundwater and in the atmosphere.
Extra Questions Of Water Class 7 Question 10.
Give two tips to save water.
Answer:
- Turn off taps while brushing.
- Mop the floor instead of washing.
Class 7 Water Extra Questions Question 11.
What could be the effect of scarcity of water?
Answer:
Without water, no animals and plants can survive. The green character of the planet shall be lost. For a world without plants shall mean no food, no oxygen, not enough rain, and innumerable other problems. This may mean the end of all life.
Ch 16 Science Class 7 Extra Questions Question 12.
How is water distributed on the earth in its three forms?
Answer:
The solid form, snow and ice, is present as ice caps at the poles of the earth, snow-covered mountains and glaciers.
- Liquid water is present in oceans, lakes, rivers, and even underground.
- The gaseous form is the^ water vapour present in the air around us.
Class 7 Science Ch 16 Extra Questions Question 13.
Write some methods to save water.
Answer:
Scarcity of water can be tackled only through its judicious use. We cannot create water but can save water. Here are some tips for saving water :
- While brushing teeth or shaving turn off the water tap until it is time to rinse.
- Use a bucket of water while washing dishes instead of washing them under the tap.
- Never put water down the drain when there may be another use for it such as watering a plant in the garden or cleaning.
- Verify that your home is leak-free. Repair any leakage.
- Use minimum water for bath. If there is shower in the bathroom, use the ultra-low-flow version and take short showers.
- Avoid the installation of ornamental water features (such as fountains) unless the water is recycled.
- Report all significant water losses \(broken pipes, open hydrants, etc.) to the property owner or authorities.
- Do not pollute water.
Water: A Precious Resource Class 7 Questions And Answers Question 14.
How is increasing population responsible for depletion of groundwater?
Answer:
- Increasing population creates demand for construction of houses, shops, offices, roads and pavements. This decreases the open areas like parks and playgrounds. This, in turn, decreases the seepage of rainwater into the ground.
- Moreover, a huge amount of water is required for construction work. Often groundwater is used for this purpose.
- So, we are not only consuming more groundwater, but we also are allowing lesser water to seep into the ground. This results in depletion of water table.
Extra Questions On Water Class 7 Question 15.
Explain the factors responsible for the depletion of water table.
Answer:
There are three main causes of depletion of water table:
- Increasing population: Increasing population creates demand for construction of houses, shops, offices, roads and pavements. This decreases the open areas like parks and playgrounds. This, in turn, decreases the seepage of rainwater into the ground. Along with consumption of water increases.
- Increasing industries: Water is used by all the industries. The number of industries is increasing continuously. Water used by most of the industries is drawn from the ground.
- Agricultural activities: These irrigational systems may suffer from lack of water due to erratic rainfall. Therefore, farmers have to use groundwater for irrigation. Population pressure on agriculture forces increasing use of groundwater day by day. This results in depletion of water table.
Class 7 Chapter 16 Science Extra Questions Question 16.
Explain how groundwater is recharged?
Answer:
The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called infiltration. The groundwater thus gets recharged by this process.
Multiple Choice Questions
1. Which of the following is a correct statement?
(i) Earth has limitless freshwater resource
(ii) Water conservation is just wasteful employment.
(iii) Freshwater reserves are limited and need to be conserved.
(iv) Oceans on the earth are great source of freshwater.
Answer:
(iii) Freshwater reserves are limited and need to be conserved.
2. Which of the following are reserves of freshwater, which can be used readily?
(i) Oceans
(ii) Frozen glaciers, ice caps and perma¬nent snow
(iii) Seas
(iv) Lakes and rivers.
Answer:
(iv) Lakes and rivers.
3. The water sources that can be used by us are present in quantity on the earth.
(i) enormous
(ii) adequate
(iii) scanty
(iv) more than adequate
Answer:
(iii) scanty.
4. Wells, tube wells or hand pumps get water from :
(i) oceans
(ii) sea
(iii) groundwater
(iv) river.
Answer:
(iii) groundwater.
5. The process of changing water from liquid state to its vapour state is known as :
(i) condensation
(ii) evaporation
(iii) transpiration
(iv) precipitation.
Answer:
(ii) evaporation.
6. Choose the correct one out of the following Statements :
(i) Amount of water in rivers and lakes remain constant.
(ii) Amount of water in oceans remains constant.
(iii) Amount of water in ice caps remains constant.
(iv) Amount of water on earth remains constant.
Answer:
(iv) Amount of water on earth remains constant.
7. In which of the following ways industries do not harm the water resources?
(i) Excess use of water for industrial purposes.
(ii) Discharging industrial waste in water bodies.
(iii) Extracting electric energy from hydel energy.
(iv) Disturbing ecological setup.
Answer:
(iii) Extracting electric energy from hydel energy.
8. Which of the following regions receives highest rainfall in our country?
(i) Eastern ghats and north-west regions
(ii) Western ghats and north-east regions
(iii) The great plain
(iv) Deccan region
Answer:
(ii) Western ghats and northeast regions.
Keywords:
→ Aquifer: At some places, the groundwater is stored between layers of hard rock below the water table. This is knowñ as an aquifer.
→ Depletion: To lessen.
→ Drip irrigation: Drip irrigation is a technique of watering plants by making use of narrow tubings which deliver water directly at the base of the plant.
→ Water table: If we dig deep, we would reach a level where all the space between particles of soil and gaps between rocks are filled with water. The upper limit of this layer is called the water table.
→ Groundwater: The water found below the water table is called groundwater.
→ Infiltration: The process of seeping water into the ground is called infiltration.
→ Recharge: Replenish.
→ Water harvesting: The rainwater can be collected and used to recharge the groundwater. This is referred to as water harvesting or rainwater harvesting.