GSEB Class 7 Science Solutions Chapter 16 Water A Precious Resource

 

Question 1. Mark 'T' if the statement is true and 'F' if it is false:
(a) The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. (T/F)
(b) Water shortage is a problem faced only by people living in rural areas. (T/F)
(c) Water from rivers is the only source for irrigation in the fields' (T/F)
(d) Rain is the ultimate source of water. (T/F)
Answer:
(a) True
(b) False
(c) False
(d) True
In simple words: Groundwater stores a lot more fresh water than all the rivers and lakes combined. Water scarcity affects everyone, not just people in villages. Rivers are not the only way to water farms, and rain is the main origin of all water.

Exam Tip: Remember key facts about water distribution and global water issues, as these are common points for true-false questions.

 

Question 2. Explain how groundwater is recharged.
Answer: Groundwater refills through a process called infiltration. Infiltration means water slowly seeps from rivers and lakes into the empty spaces and tiny cracks deep down in the earth.
In simple words: Groundwater is refilled when water from rivers and lakes soaks into the ground through small gaps and cracks. This process is called infiltration.

Exam Tip: Use terms like "infiltration" and "seeping" to accurately describe the replenishment of groundwater.

 

Question 3. There are ten tubewells in a lane of fifty houses. What could be the long-term impact on the water table?
Answer: The long-term impact on the water table will depend on how quickly underground water gets refilled. If only five families share each tubewell, the water used for everyday household needs might not significantly lower the water table. However, if there is not enough rain, the water taken out by these families will not be replaced, and the water table will eventually go down.
In simple words: The water table's future depends on rain. If rain is scarce, the water used by 50 houses from ten tubewells won't get refilled, and the water level will drop.

Exam Tip: When discussing water table impact, always consider both consumption and replenishment rates, especially rainfall.

 

Question 4. You have been asked to maintain a garden. How will you minimize the use of water?
Answer: To reduce water waste, we can employ drip irrigation, which delivers water directly to the plant's roots. We should also inspect water pipes for any leaks and set up small collection pits for rainwater harvesting. The water gathered from rain would then be used later.
In simple words: Use drip irrigation for plants, fix any pipe leaks, and collect rainwater in pits to use later. This helps save water.

Exam Tip: Focus on practical, sustainable methods for water conservation in gardening, such as drip irrigation and rainwater harvesting.

 

Question 5. Explain the factors responsible for the depletion of the water table.
Answer: Many factors contribute to the reduction of the water table:
1. Increasing population: With more people each day, there's a greater need for building homes, shops, offices, and roads. This reduces open spaces like parks and playgrounds, which means less rainwater can soak into the ground.
2. Increasing industries: Every industry requires water. As the human population grows, the number of industries also goes up, which certainly boosts water usage.
3. Lack of water conservation techniques: The primary source of water on Earth and for underground water is rain. If rainwater were properly collected, it could raise the groundwater level. However, this is often neglected due to a lack of effective water-saving methods.
4. Agricultural activities: India is a nation that relies on farming. The amount of land used for crops has increased, leading to higher water consumption for agriculture. Irregular rainfall has also caused more reliance on groundwater, further accelerating its depletion.
In simple words: The water table drops because of more people needing more water and buildings, more factories using lots of water, not enough ways to save rainwater, and increased farming that uses groundwater.

Exam Tip: When listing factors, provide clear, concise explanations for each point, demonstrating how they impact the water table.

 

Question 6. Fill in the blanks with the appropriate answers:
(a) People obtain groundwater through .......... and ............
(b) Three forms of water are .........., .......... and ..........
(c) The water-bearing layer of the earth is ..........
(d) The process of water seepage into the ground is called ..........
Answer:
(a) wells, hand pumps
(b) solid, liquid, gas
(c) aquifer
(d) infiltration
In simple words: People get groundwater from wells and hand pumps. Water exists as solid, liquid, and gas. The part of the Earth holding water is the aquifer. Water soaking into the ground is infiltration.

Exam Tip: Be precise with scientific terms when filling in the blanks. Review common vocabulary related to water resources.

 

Question 7. Which one of the following is not responsible for water shortage?
(a) The rapid growth of industries
(b) Increasing population
(c) Heavy rainfall
(d) Mismanagement of water resources
Answer: (c) Heavy rainfall
In simple words: Heavy rainfall actually helps to increase water supply, not cause a shortage. The other options like growing industries, more people, and poor water management all make water scarcity worse.

Exam Tip: Understand the factors that cause water scarcity and differentiate them from factors that improve water availability.

 

Question 8. Choose the correct option. The total water
(a) in the lakes and rivers of the world remains constant.
(b) under the ground remains constant.
(c) in the seas and oceans of the world remains constant.
(d) of the world remains constant.
Answer: (d) of the world remains constant.
In simple words: The total amount of water on Earth, across all its forms and locations, stays the same due to the water cycle. While water moves and changes states, the overall quantity does not change.

Exam Tip: Remember the principle of conservation of matter in the context of the water cycle; water merely changes form and location, its total quantity remains fixed.

 

Question 9. Make a sketch showing groundwater and water table. Label it.
Answer: Here is a diagram illustrating groundwater and the water table with proper labels.

In simple words: This picture shows that the ground has water underneath it, called groundwater. The top level of this water is the water table. Rain and other water soak into the ground, refilling this groundwater, which is called recharge.

Exam Tip: Clearly label all essential components like the water table, aquifer, and groundwater, and show how recharge occurs through infiltration.

Extended Learning Activities And Projects

 

Question 1. Roleplay You are a water detective in your school. You have a team of six members. Survey the campus and make a note of the following:
(a) Total number of taps
(b) Number of taps leaking
(c) Amount of water wasted due to leakage
(d) Reasons of leakage
(e) Corrective measures are taken
Answer: As water detectives, our team completed a survey of the school campus. Here are our findings:
(a) Total number of taps: We found 35 taps located across various washrooms, science labs, and drinking water stations.
(b) Number of taps leaking: We identified 7 taps that had noticeable leaks, ranging from slow drips to steady trickles.
(c) Amount of water wasted due to leakage: Based on our estimates, these leaks are wasting approximately 50-70 liters of water per day.
(d) Reasons of leakage: The main reasons for the leaks appeared to be worn-out washers, loose fittings, and some older tap mechanisms that were corroded.
(e) Corrective measures are taken: We reported our findings to the school administration, who have arranged for the immediate repair of the leaking taps and planned for a regular maintenance check of all water fixtures. Awareness posters about water conservation will also be put up.
In simple words: Our team surveyed the school's water use. We found 35 taps, with 7 of them leaking, wasting about 50-70 liters daily due to old parts. We reported this, and the school will fix the leaks and put up water-saving posters.

Exam Tip: For observational questions, provide specific, realistic details for each point. Emphasize both identifying problems and suggesting practical solutions.

 

Question 2. Groundwater pumped out Try to find out if there are any hand pumps in your neighborhood. Go to the owner or the users of a few of these and find out the depth at which they struck water? If there are any differences, think of the probable reason. Write a brief report and discuss it in your class. If possible, visit a place where boring is going on to install a hand pump. Watch the process carefully and find out the depth of the water table at that place.
Answer: The water's depth relies on the local water table. Because water tables vary in depth from one location to another, hand pumps must be drilled to different depths accordingly.
In simple words: The depth where you find water depends on the water table in that area. Since the water table is not the same everywhere, hand pumps are dug to different depths.

Exam Tip: Emphasize that the water table's depth is not uniform and varies geographically due to factors like geology, rainfall, and extraction rates.

 

Question 3. Catching rainwater – Traditional methods Form groups of 4 to 5 students in the class and prepare a report on the various traditional ways of water harvesting. If possible, use the following web link: www.rainwaterharvesting.org.
Answer: There are many traditional methods for harvesting rainwater that have been used for centuries. These methods help to collect and store water for later use or to recharge groundwater. Some key examples include:
1. Ponds and Tanks: Creating small reservoirs or tanks to collect rainwater runoff from catchment areas. These can be used for irrigation, livestock, or domestic purposes.
2. Check Dams: Building small barriers across seasonal streams to slow down water flow and allow it to percolate into the ground, thus recharging aquifers.
3. Baoris/Stepwells: These are ancient stepwells that store water and allow access to groundwater. They also serve as community gathering places.
4. Rooftop Rainwater Harvesting: Collecting rainwater from rooftops using gutters and pipes, then storing it in underground tanks or using it to recharge wells.
These methods are very important for managing water resources, especially in regions with limited water availability.
In simple words: Traditional ways to collect rainwater include making ponds, building small check dams across streams, using stepwells (baoris), and gathering water from rooftops. These old methods help save water for later and refill underground water.

Exam Tip: When describing traditional water harvesting, name specific methods and explain their function clearly. Mention the purpose of each technique (e.g., storage, groundwater recharge).

 

Question 4. Conservation of water Carry out a campaign to conserve water at home and in the school. Design posters to remind others of the importance of water resources.
Answer: To conduct a successful water conservation campaign, we should educate other students on several important practices:

• Always turn off taps completely after using them.
• Take only the amount of drinking water you actually need to avoid wasting it by throwing away the excess.

Other measures include: Design posters that show people queuing to collect drinking water from a tap or a water pump, highlighting the value and scarcity of water.
In simple words: To save water, teach students to turn off taps after use and only take the water they need to drink. Also, make posters to show water is important and scarce.

Exam Tip: Provide actionable advice for water conservation. Campaigns should focus on both simple daily habits and visual reminders.

 

Question 5. Create a logo Hold a competition to create a logo or a symbol depicting water scarcity.
Answer: This activity requires a creative, hands-on approach. Students should design their own logos or symbols to represent water scarcity.
In simple words: You need to make your own logo or symbol that shows what water scarcity looks like.

Exam Tip: For creative tasks like logo design, focus on originality and clear visual communication of the theme (water scarcity).