Extra Questions for Class 7 Science Chapter 16 Water A Precious Resource
Extra questions for Class 7 Science Chapter 16 Water A Precious Resource with answers is given below. Our subject expert prepared these solutions as per the latest NCERT textbook. These questions will be helpful to revise the all topics and concepts. CBSE Class 7 extra questions are the most simple and conceptual questions that are prepared by subject experts for the students to study well for the final exams. By solving these extra questions, students can be very efficient in their exam preparations.
Water A Precious Resource Class 7 Science Extra Questions and Answers
Very Short Extra Questions and Answer
1. List the main sources of underground water.
Answer: Springs, tubewells, handpumps, etc.
2. What is water management?
Answer: Minimum wastage of water is called water management.
3. When is water day celebrated?
Answer: 22 March is celebrated as the world water day.
4. What is ground water?
Answer: The water found below the water table is called groundwater.
5. What is infiltration?
Answer: The process of seeping of water into the ground is called infiltration.
6. Why do we celebrate world water day?
Answer: We celebrate water day every year to attract the attention of everybody towards the importance of conserving water.
7. What is aquifer?
Answer: At places the groundwater is stored between layers of hard rock below the water table. This is known as an aquifer.
8. What are the main processes involved in the water cycle?
Answer: The main processes involved in the water cycle are evaporation, transpiration, condensation, precipitation, runoff, and percolation.
9. Why is the water cycle important?
Answer: The water cycle is important because its process provides Earth with the natural, continual water supply all living things need in order to survive.
10. What is the source of groundwater?
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.
Short Extra Questions and Answers
1. How is water supplied in town?
Answer: Most towns and cities have water supply system maintained by the civic bodies. The water is drawn from nearby lakes, rivers, ponds or wells. The water is supplied through a network of pipes.
2. What is rainwater harvesting?
Answer: Most of the water that we get as rainfall just flows away. This is a waste of precious natural resource. The rainwater can be used to recharge the groundwater. This is referred to as water harvesting or rainwater harvesting.
3. You have been asked to maintain a garden. How will you minimise the use of water?
Answer: We can use drip irrigation to minimise the use of water. Drip irrigation is a technique of watering plants by making use of narrow tubings which deliver water directly at the base of the plant.
4. There are ten tube wells in a lane of fifty houses. What could be the long term impact on the water table?
Answer: The water table does not get affected as long as we draw as much water as is replenished by natural processes. However, water table may go down if the water is not sufficiently replenished.
5. How can farmer use water economically?
Answer: A farmer using water in the field can also use water economically by using drip irrigation technique. Drip irrigation is a technique of watering plants by making use of narrow tubings which deliver water directly at the base of the plant.
6. How increasing industries are responsible for depletion of water table?
Answer: Water is used by all the industries. Almost everything that we use needs water somewhere in its production process. The number of industries is increasing continuously. Water used by most of the industries is drawn from the ground.
Long Extra Questions and Answer
1. 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.
2. What will consequences if water is not available to plants?
Answer: Plants need water to get nutrients from the soil to prepare their food. If water is not available to plants, the green character of the planet shall be lost. This may mean the end of all life, for a world without plants shall mean no food, no oxygen, not enough rain, and innumerable other problems.
3. Why are we left only tiny fraction of water for use even if about 71 % of the earth surface is covered with water?
Answer: 71% of the earth’s surface is covered with water. Almost all the water on the earth is contained in the seas and oceans, rivers, lakes, ice caps, as groundwater and in the atmosphere. However, most of this water is not fit for human consumption. The water that is fit for use is fresh water.
4. Explain the three form of water that exists in nature.
Answer: Water exists in three forms: solid, liquid and vapour. 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.
5. From where do people in villages get water?
Answer: Many villages do not have water supply system. There people fetch water directly from the sources. Often women and children have to walk several kilometres to fetch water. The children suffer a lot. They cannot attend school regularly since they spend hours in fetching water. A large number of people draw water from wells, tube wells or hand pumps.
6. List some methods to conserve water.
Answer: Methods to conserve water are:
- Repairing leaking supply pipes and taps.
- Judicially using water while brushing teeth, shaving, bathing, washing and during many other activities.
- Water harvesting
- Drip irrigation
7. Can we keep on drawing water from under the ground? How will it affect the water table?
Answer: Water drawn from under the ground gets replenished by seepage of rainwater. The water table does not get affected as long as we draw as much water as is replenished by natural processes. However, water table may go down if the water is not sufficiently replenished.
8. What are the reasons for lowering of the water table?
Answer: This may happen due to many reasons. Increase in population, industrial and agricultural activities are some common factors affecting water table. Scanty rainfall is another factor that may deplete the water table. Yet another factor affecting water table could be deforestation and decrease in the effective area for seepage of water.
9. Why is distribution of water uneven in our country?
Answer: India is a vast country and the rainfall is not the same everywhere. Some regions have excessive rains while some others have very little rainfall. Excessive rains cause floods, whereas the absence of rains results in droughts. Therefore, some regions in our country may have floods while others may suffer from droughts at the same time.
10. Write a note on water table.
Answer: If we dig deeper and deeper, 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.
The water table varies from place to place, and it may even change at a given place. The water table may be at a depth of less than a metre or may be several metres below the ground.
11. How increasing agricultural activities are responsible for depletion of water table?
Answer: A majority of farmers in India depend upon rains for irrigating their crops. Irrigation systems such as canals are there only in a few places. Even these 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.
12. How increasing population is responsible for depletion of water table?
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, on the one hand we are consuming more groundwater, and on the other we are allowing lesser water to seep into the ground. This results in depletion of water table.
13. Make a sketch showing groundwater and water table. Label it.
Answer:
14. How does water on the earth has been maintained for millions of years?
Answer: Water on the earth has been maintained for millions of years by various processes which make the water cycle. When water circulates through the water cycle it can be found in all the three forms, i.e., solid, liquid and gas—at any given time somewhere on the earth. 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. The continuous cycling of water among its three forms keeps the total amount of water on the earth constant even when the whole world is using it.
15. Explain the factors responsible for the depletion of water table.
Or
Why water is getting scarce?
Answer: Factors responsible for the depletion of water table are:
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.
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: A majority of farmers in India depend upon rains for irrigating their crops. Irrigation systems such as canals are there only in a few places. Even these 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.
Mismanagement of water resources: Leakage in water supply pipes and a lot of water gushing out of the pipes leads to wastage of precious water. Mismanagement or wastage may take place at the level of individuals also. Due to lack of water harvesting techniques water did not get replenished. Thus, results in depletion of water table.