Keywords To Remember
- Water Vapour – The gaseous form of water present in the air.
- Condensation – The process by which water vapour in the air cools down and changes back into liquid form.
- Precipitation – Any form of water (rain, snow, sleet, or hail) that falls from clouds to the Earth’s surface.
- Infiltration – The process of water seeping into the ground through soil and rocks.
- Groundwater – Water that fills the spaces in soil and rock layers underground.
- Water Table – The upper level of groundwater in the soil and rocks below the Earth’s surface.
- Aquifer – An underground layer of water-bearing rock or material from which groundwater can be drawn.
- Rainwater Harvesting – The method of collecting and storing rainwater for reuse, especially to replenish groundwater.
- Drip Irrigation – A method of watering plants by delivering water slowly and directly to the roots, minimizing wastage.
- Sprinkler Irrigation – A method of irrigating fields by spraying water through overhead pipes like artificial rain.
- Sewage – Wastewater that contains waste materials from homes, schools, hospitals, industries, etc.
- Sewerage System – A network of pipes that carries sewage away from homes and buildings to a treatment facility.
- Water Scarcity – A situation where the demand for water exceeds the available amount during a certain period.
- Usable Water – Freshwater that is safe and available for human consumption and daily use.
- Deforestation – Cutting down of trees, which leads to less rainfall, more soil erosion, and lower groundwater levels.
- Greenhouse Effect – A process by which heat is trapped in the Earth’s atmosphere due to gases like carbon dioxide, causing global warming.
- Global Warming – An increase in Earth’s average temperature due to the buildup of greenhouse gases.
- Non-point Source Pollution – Pollution that comes from many sources rather than a single outlet, like runoff from fields or streets.
- Potable Water – Water that is clean and safe enough to be drunk by humans.
- Contaminated Water – Water that contains harmful substances, making it unsafe for drinking or usage.
- Water Conservation – The practice of using water efficiently to reduce unnecessary water usage.
- Surface Water – Water found on the surface of the earth in lakes, rivers, ponds, and reservoirs.
- Evaporation – The process by which water changes from a liquid to a gas or vapour due to heat.
- Recycle – Reuse of treated wastewater for other purposes such as gardening or industrial processes.
- Purification – The process of cleaning water by removing harmful substances or organisms.
- Open Drains – Uncovered drainage systems that often lead to environmental and health problems.
- Waste Water Management – The process of treating and managing wastewater to reduce pollution and make it reusable or safe for disposal.
- Over-extraction – Drawing too much water from natural sources like rivers, lakes, or aquifers faster than it can be replenished.
- Water Pollution – The contamination of water bodies due to waste, chemicals, or harmful substances.
- Leaching – The removal of dissolved substances from soil or waste by the percolation of water.
Something To Know
A. Fill in the blanks.
- About __________ of water is present in oceans and seas.
Answer – 97%
- Only 0.3 per cent of fresh water available for use is present in rivers. __________ and __________.
Answer – lakes and streams
- Ground water is drawn from wells, __________ and __________.
Answer – tubewells and handpumps
- Use of __________ and __________ for irrigation reduces wastage of water.
Answer – sprinklers and drip irrigation
- Tie network of pipes which carries waste water to water treatment plant is called __________ .
Answer – sewerage system
B. Write True or False for the following statements.
- About 97 per cent of water on earth is fresh water and is good for human use.
Answer – False
- Water occurs in its solid form in glaciers and ice caps.
Answer – True
- Farmers rely on ground water for irrigating their crops when there in no rain.
Answer – True
- Deforestation increases the level of groundwater.
Answer – False
- More use of ground water causes decrease in water table.
Answer – True
C. Tick (✓) the correct option.
- Ocean water is unfit for drinking as it is—
- Ocean water is unfit for drinking as it is—
very salty
too clean
tasteless
generally frozen
Answer – very salty
2.’Rain water harvesting’ can help us to conserve—
sea water
rain water
fresh water
pond water
Answer – very salty
- On the earth, the percentage of water, that is fresh and readily available for use, is, nearly–
99.7
97%
3%
0.3%
Answer – very salty
- One of the important factors, that can lead to a scarcity of water, is—
excessive rainfall
deforestation
afforestation
processing of sea water
Answer – very salty
- ‘Waste water’ is also called—
sewage
water table
potable water
salty water
Answer – very salty
D. Answer the following questions in brief.
- Name the three forms in which water exists on the earth.
Answer – Solid (ice), Liquid (water), and Gaseous (water vapour).
- Give the meaning of the term ‘water table’.
Answer – The top level of ground water is called the water table.
- Name two methods of drawing out ground water.
Answer – Tubewells and handpumps.
- Name two activities which lead to the formation of sewage.
Answer – Bathing and washing clothes.
- State any two precautions that can help avoid the ‘choking of drains’.
Answer – (i) Do not throw food waste or plastic in drains.
(ii) Avoid pouring oil or grease down the drain.
E. Answer the following questions
- How is increase in population responsible for shortage of water?
Answer – Increase in population raises the demand for water, but the water resources remain limited, leading to a shortage.
- Discuss, in brief, how ‘rain water harvesting’ can be done.
Answer – Rainwater can be collected in underground tanks or open containers. It is then allowed to seep into the soil to replenish groundwater.
- Discuss any two causes that lead to a decrease in ground water level.
Answer – (i) Overuse of ground water for farming and domestic use.
(ii) Reduced rainfall due to deforestation.
- How can ‘better management of water resources’ help in conservation of water?
Answer – It ensures water is used wisely and wastage is minimized through techniques like rain water harvesting and proper maintenance of water systems.
- Write, in brief, about the basic details and the role of the ‘sewerage system’.
Answer – It is a network of pipes that carries sewage away from homes and offices to treatment plants where it is cleaned before being released into rivers or seas.
Value Based Question
The school had invited a noted speaker for a talk on ‘Our Environment’. The speaker first gave many suggestions and ideas that could help in improving the environment. She, then, went on to say that though water exists in all its three forms in nature it is the liquid form of water that is most ‘liked’ by all forms of life. In the same way, she said that our habits and activities can be in many ‘forms’ but we should make greater use of only those ‘forms’ that are more liked by the environment.
- Suggest at least two ‘habits’ or ‘values’ that can help in having a better environment.
Answer – (i) Turning off the tap while brushing teeth.
(ii) Planting more trees to maintain ecological balance.
- Write five daily-life related activities’ that usually require the use of water in its liquid form.
Answer – (i) Bathing
(ii) Cooking
(iii) Washing clothes
(iv) Cleaning utensils
(v) Drinking
Something To Do
- Make posters related to water shortage and water conservation and display them in the school.
Answer – Posters can have slogans like “Save Water, Save Life”, “Every Drop Counts”, and “Harvest Rain, Save Tomorrow”.
- On the map of India, indicate the places where there is generally—
(a) heavy rainfall
(b) medium rainfall
(c) practically no rainfall
Answer – (a) Heavy rainfall – Mawsynram, Cherrapunji (Meghalaya)
(b) Medium rainfall – Mumbai, Delhi
(c) Practically no rainfall – Jaisalmer (Rajasthan)
- Try to find out the ‘water related problems’ faced by people living in different regions. Take the help of newspaper clippings, encyclopaedia or internet.
Answer – In Rajasthan: water scarcity due to desert conditions.
In Kerala: water contamination during floods.
In Maharashtra: over-dependence on ground water leads to drought.
In urban areas: sewage mixing with drinking water due to broken pipelines.
Additional Questions And Answers – 01
Fill in the Blanks (with Answers)
- Water in the gaseous form is called __________.
Answer: water vapour - __________ is a traditional method of storing rainwater.
Answer: Rainwater harvesting - The water cycle is also known as the __________ cycle.
Answer: hydrological - __________ is the process of removing salt from sea water.
Answer: Desalination - Water becomes polluted when __________ are released into water bodies.
Answer: harmful chemicals - __________ helps in replenishing ground water.
Answer: Infiltration - The process of water seeping into the ground is called __________.
Answer: percolation - Water that is safe for drinking is called __________.
Answer: potable water - __________ is the main source of water for lakes and rivers.
Answer: Rainfall - __________ is the level below which the ground is saturated with water.
Answer: Water table
Multiple Choice Questions (MCQs)
- The main source of ground water is:
Rivers
B. Lakes
C. Rainwater
D. Oceans
Answer: C. Rainwater - The process of water turning into vapour is called—
Freezing
B. Evaporation
C. Precipitation
D. Condensation
Answer: B. Evaporation - Water table is—
A table made of water
B. Top level of sea water
C. Level below ground where water is available
D. A container of water
Answer: C. Level below ground where water is available - The underground layer through which water moves easily is called—
Aquifer
B. Glacier
C. Spring
D. Cloud
Answer: A. Aquifer - Which of the following can cause water pollution?
Afforestation
B. Sprinkler system
C. Oil spills
D. Rainwater harvesting
Answer: C. Oil spills
True/False Statements
- Rainwater harvesting increases ground water level.
Answer: True - All water on Earth is fit for drinking.
Answer: False - Rivers and lakes are examples of surface water.
Answer: True - Pollution does not affect the water table.
Answer: False - Glaciers are a source of fresh water.
Answer: True - Leaving the tap running while brushing helps save water.
Answer: False - Water exists in only two forms in nature.
Answer: False - Plants help in maintaining the water cycle.
Answer: True
Short Answer Questions
- What is desalination?
Answer: Desalination is the process of removing salt from seawater to make it fit for human use. - Why is water considered a renewable resource?
Answer: Because it is naturally recycled through the water cycle. - How do trees help in increasing ground water levels?
Answer: Trees promote infiltration of rainwater into the ground, thus recharging groundwater. - Name two sources of surface water.
Answer: Rivers and lakes. - What is meant by infiltration?
Answer: It is the process of water seeping into the soil.
Competency-Based Questions (Reasoning & Assertion)
- Assertion: Water conservation is important.
Reason: It helps ensure availability of water for future generations.
Answer: Both assertion and reason are correct, and reason is the correct explanation. - Assertion: Deforestation improves the ground water level.
Reason: Trees absorb water and prevent it from seeping into the ground.
Answer: Both assertion and reason are incorrect. - Assertion: Groundwater levels are falling in many areas.
Reason: Over-extraction and less recharge cause water table to fall.
Answer: Both assertion and reason are correct, and reason is the correct explanation. - Assertion: Use of drip irrigation helps in conserving water.
Reason: It delivers water directly to the roots.
Answer: Both assertion and reason are correct, and reason is the correct explanation.
High Order Thinking Skill (HOTS) Questions
- Why is water called a universal solvent?
Answer: Because it can dissolve more substances than any other liquid, making it essential for chemical reactions in living beings. - What would happen if there were no water cycle?
Answer: Water would not be naturally replenished, leading to scarcity of fresh water, affecting life on Earth. - How can you design a model for rainwater harvesting in your school?
Answer: By connecting roof drains to an underground storage tank and using filters to clean the collected water.
Long Answer Questions (50–60 words each)
- Explain how human activities are responsible for the falling water table.
Answer: Excessive use of groundwater for agriculture, industries, and domestic purposes without allowing it to recharge leads to a falling water table. Activities like deforestation, urbanization, and blocking natural recharge zones worsen the problem, reducing the amount of water that seeps into the ground. - What are the advantages of using sprinkler and drip irrigation methods?
Answer: Sprinkler and drip irrigation reduce water wastage by delivering water directly to plants’ roots or evenly on fields. These methods use less water compared to traditional ones, promote better yield, and are especially useful in areas with water scarcity. - Describe the water cycle with its main stages.
Answer: The water cycle consists of evaporation (water turns into vapour), condensation (vapour cools to form clouds), precipitation (rain or snow), and collection (water gathers in rivers or lakes). Some water seeps into the ground (infiltration), replenishing the groundwater. - How does pollution affect water bodies and human health?
Answer: Pollutants from industries, sewage, and agricultural runoff contaminate water bodies, making the water unfit for use. It can spread diseases like cholera and typhoid, harm aquatic life, and disrupt ecosystems, endangering both the environment and human health.
Additional Questions And Answers – 02
Fill in the Blanks Questions and Answers
- Question: Water exists on Earth in three forms: solid, liquid, and ______ form.
Answer: Water exists on Earth in three forms: solid, liquid, and gaseous form. - Question: About ______ per cent of water on Earth is present in oceans and seas.
Answer: About 97 per cent of water on Earth is present in oceans and seas. - Question: Only ______ per cent of water on Earth is fresh water suitable for human use.
Answer: Only 3 per cent of water on Earth is fresh water suitable for human use. - Question: Fresh water in rivers, lakes, and streams constitutes only ______ per cent of all fresh water.
Answer: Fresh water in rivers, lakes, and streams constitutes only 0.3 per cent of all fresh water. - Question: In cities, water is supplied through a network of pipes maintained by ______ agencies.
Answer: In cities, water is supplied through a network of pipes maintained by civic agencies. - Question: The top level of ground water is called the ______ table.
Answer: The top level of ground water is called the water table. - Question: Ground water is drawn using wells, tubewells, or ______ pumps.
Answer: Ground water is drawn using wells, tubewells, or hand pumps. - Question: The decrease in rainfall is due to factors like deforestation and increase in ______ activity.
Answer: The decrease in rainfall is due to factors like deforestation and increase in construction activity. - Question: An increase in population leads to a higher ______ for water, causing scarcity.
Answer: An increase in population leads to a higher demand for water, causing scarcity. - Question: Cutting trees increases the level of ______ dioxide gas, contributing to global warming.
Answer: Cutting trees increases the level of carbon dioxide gas, contributing to global warming. - Question: The phenomenon that traps the sun’s energy due to carbon dioxide is called the ______ House Effect.
Answer: The phenomenon that traps the sun’s energy due to carbon dioxide is called the Green House Effect. - Question: ______ water harvesting involves collecting rain water to replenish ground water.
Answer: Rain water harvesting involves collecting rain water to replenish ground water. - Question: Using ______ irrigation can reduce water wastage in agriculture.
Answer: Using drip irrigation can reduce water wastage in agriculture. - Question: Water used in daily activities like washing clothes becomes ______ water.
Answer: Water used in daily activities like washing clothes becomes waste water. - Question: Waste water from homes and industries is called ______.
Answer: Waste water from homes and industries is called sewage. - Question: The network of pipes that carries sewage to treatment plants is called the ______ system.
Answer: The network of pipes that carries sewage to treatment plants is called the sewerage system. - Question: Open drains can become a breeding ground for ______ that cause diseases.
Answer: Open drains can become a breeding ground for mosquitoes that cause diseases. - Question: Contaminated ground water can cause diseases like cholera, typhoid, and ______.
Answer: Contaminated ground water can cause diseases like cholera, typhoid, and jaundice. - Question: We should not throw ______ oil in the drain as it hardens and blocks pipes.
Answer: We should not throw cooking oil in the drain as it hardens and blocks pipes. - Question: Chemicals thrown in drains kill ______ micro-organisms that purify water.
Answer: Chemicals thrown in drains kill friendly micro-organisms that purify water.
Multiple Choice Questions and Answers
- Question: In which form is water NOT present on Earth?
a) Solid
b) Liquid
c) Gaseous
d) Plasma
Answer: d) Plasma - Question: What percentage of water on Earth is present in oceans and seas?
a) 50%
b) 75%
c) 97%
d) 3%
Answer: c) 97% - Question: How much of Earth’s water is fresh water suitable for human use?
a) 97%
b) 3%
c) 50%
d) 0.3%
Answer: b) 3% - Question: What percentage of fresh water is readily available in rivers, lakes, and streams?
a) 2%
b) 0.7%
c) 0.3%
d) 97%
Answer: c) 0.3% - Question: Who supplies water in cities through a network of pipes?
a) Farmers
b) Civic agencies
c) Schools
d) Factories
Answer: b) Civic agencies - Question: What is the top level of ground water called?
a) Ground water
b) Water table
c) Sewerage system
d) Rain water
Answer: b) Water table - Question: How is ground water typically accessed?
a) Through rivers
b) Using wells and tubewells
c) From glaciers
d) From oceans
Answer: b) Using wells and tubewells - Question: What is one major reason for the decrease in rainfall?
a) Increase in rainfall
b) Deforestation
c) Decrease in population
d) Better irrigation
Answer: b) Deforestation - Question: How does an increase in population affect water availability?
a) It decreases demand
b) It increases demand
c) It increases supply
d) It has no effect
Answer: b) It increases demand - Question: What gas increases due to deforestation, contributing to global warming?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Hydrogen
Answer: c) Carbon dioxide - Question: What phenomenon is caused by the trapping of sun’s energy due to carbon dioxide?
a) Photosynthesis
b) Green House Effect
c) Rain water harvesting
d) Sewerage system
Answer: b) Green House Effect - Question: What is the process of collecting rain water to replenish ground water called?
a) Sewerage system
b) Rain water harvesting
c) Deforestation
d) Global warming
Answer: b) Rain water harvesting - Question: Which irrigation technique helps reduce water wastage?
a) Flood irrigation
b) Drip irrigation
c) Manual irrigation
d) Rain irrigation
Answer: b) Drip irrigation - Question: What is waste water from daily activities called?
a) Fresh water
b) Ground water
c) Sewage
d) Rain water
Answer: c) Sewage - Question: What system carries sewage to waste water treatment plants?
a) Water table
b) Sewerage system
c) Rain water harvesting
d) Ground water system
Answer: b) Sewerage system - Question: What can open drains become a breeding ground for?
a) Fish
b) Mosquitoes
c) Plants
d) Birds
Answer: b) Mosquitoes - Question: Which disease can be caused by contaminated ground water?
a) Malaria
b) Cholera
c) Dengue
d) Flu
Answer: b) Cholera - Question: Why should cooking oil not be thrown in the drain?
a) It purifies water
b) It hardens and blocks pipes
c) It attracts mosquitoes
d) It increases rainfall
Answer: b) It hardens and blocks pipes - Question: What do chemicals in drains kill that helps purify water?
a) Mosquitoes
b) Fish
c) Friendly micro-organisms
d) Plants
Answer: c) Friendly micro-organisms - Question: What should be done to avoid wastage of water at home?
a) Leave taps running
b) Turn off the tap while brushing teeth
c) Throw chemicals in drains
d) Use a pipe to water plants
Answer: b) Turn off the tap while brushing teeth
True/False Questions and Answers
- Question: Water exists on Earth in three forms: solid, liquid, and gaseous.
Answer: True - Question: 97% of Earth’s water is fresh water suitable for human use.
Answer: False (97% is in oceans and seas, not fresh water.) - Question: Only 3% of water on Earth is fresh water.
Answer: True - Question: Fresh water in rivers, lakes, and streams is 0.3% of all fresh water.
Answer: True - Question: In cities, water is supplied by farmers through pipes.
Answer: False (It is supplied by civic agencies.) - Question: The water table is the top level of ground water.
Answer: True - Question: Ground water is accessed using wells and tubewells.
Answer: True - Question: Deforestation contributes to a decrease in rainfall.
Answer: True - Question: An increase in population decreases the demand for water.
Answer: False (It increases the demand.) - Question: Cutting trees reduces the level of carbon dioxide in the atmosphere.
Answer: False (It increases the level.) - Question: The Green House Effect can lead to global warming.
Answer: True - Question: Rain water harvesting helps replenish ground water.
Answer: True - Question: Drip irrigation increases water wastage in agriculture.
Answer: False (It reduces wastage.) - Question: Waste water from daily activities is called sewage.
Answer: True - Question: The sewerage system carries fresh water to homes.
Answer: False (It carries sewage to treatment plants.) - Question: Open drains can breed mosquitoes that cause diseases.
Answer: True - Question: Contaminated ground water can cause diseases like cholera.
Answer: True - Question: Cooking oil should be thrown in the drain to purify water.
Answer: False (It hardens and blocks pipes.) - Question: Chemicals in drains kill friendly micro-organisms that purify water.
Answer: True - Question: Turning off the tap while brushing teeth helps save water.
Answer: True
Short Questions and Answers
- Question: Name the three forms of water on Earth.
Answer: Solid, liquid, and gaseous. - Question: What percentage of Earth’s water is in oceans and seas?
Answer: 97%. - Question: How much of Earth’s water is fresh water?
Answer: 3%. - Question: What percentage of fresh water is in rivers, lakes, and streams?
Answer: 0.3%. - Question: Who supplies water in cities?
Answer: Civic agencies. - Question: What is the water table?
Answer: The top level of ground water. - Question: How is ground water accessed?
Answer: Using wells and tubewells. - Question: What is one cause of decreased rainfall?
Answer: Deforestation. - Question: How does population growth affect water demand?
Answer: It increases demand. - Question: What gas increases due to deforestation?
Answer: Carbon dioxide. - Question: What is the Green House Effect?
Answer: Trapping of sun’s energy by carbon dioxide. - Question: What is rain water harvesting?
Answer: Collecting rain water to replenish ground water. - Question: Name one irrigation technique that saves water.
Answer: Drip irrigation. - Question: What is waste water from daily activities called?
Answer: Sewage. - Question: What system carries sewage to treatment plants?
Answer: Sewerage system. - Question: What can breed in open drains?
Answer: Mosquitoes. - Question: Name one disease caused by contaminated ground water.
Answer: Cholera. - Question: Why should cooking oil not be thrown in the drain?
Answer: It hardens and blocks pipes. - Question: What do chemicals in drains kill?
Answer: Friendly micro-organisms. - Question: Name one way to save water at home.
Answer: Turn off the tap while brushing teeth.
Competency-Based Questions and Answers (Reasoning and Assertion)
- Question: Assertion (A): Only 0.3% of fresh water is readily available in rivers, lakes, and streams.
Reason (R): Most fresh water is trapped in glaciers, ice caps, and ground water.
Answer: Both A and R are true, and R is the correct explanation of A. The document states that 97% of water is in oceans, and of the 3% fresh water, most is in glaciers (2%) and ground water (0.7%), leaving only 0.3% in rivers, lakes, and streams for easy access. - Question: Assertion (A): Deforestation contributes to water scarcity.
Reason (R): Cutting trees reduces rainfall, increasing reliance on ground water.
Answer: Both A and R are true, and R is the correct explanation of A. Deforestation decreases rainfall by increasing carbon dioxide levels, as trees use this gas in photosynthesis. Reduced rainfall forces farmers to rely on ground water, depleting its levels and causing water scarcity, as explained in the document. - Question: Assertion (A): Rain water harvesting helps conserve water.
Reason (R): It collects rain water to replenish ground water.
Answer: Both A and R are true, and R is the correct explanation of A. Rain water harvesting involves collecting rain water in tanks to seep into the soil, replenishing ground water, as mentioned. This reduces wastage and ensures more water availability, directly contributing to water conservation efforts. - Question: Assertion (A): The sewerage system is essential for waste water management.
Reason (R): It carries sewage to treatment plants for purification.
Answer: Both A and R are true, and R is the correct explanation of A. The sewerage system transports waste water from homes and industries to treatment plants, where it is purified before being released into rivers or seas, ensuring proper waste water management and preventing environmental contamination, as per the document. - Question: Assertion (A): Open drains can cause diseases like malaria.
Reason (R): They become a breeding ground for mosquitoes.
Answer: Both A and R are true, and R is the correct explanation of A. Open drains, as noted, breed mosquitoes due to stagnant water, which can lead to diseases like malaria. This connection highlights the health risks of poor waste water management and the need for proper drainage systems. - Question: Assertion (A): Ground water is decreasing due to increased population.
Reason (R): More people increase the demand for water, depleting resources.
Answer: Both A and R are true, and R is the correct explanation of A. The document explains that population growth increases water demand, while availability decreases due to over-extraction of ground water for irrigation and daily needs, leading to a significant reduction in ground water levels, causing scarcity. - Question: Assertion (A): Cooking oil should not be thrown in the drain.
Reason (R): It attracts mosquitoes that cause diseases.
Answer: A is true, but R is false. Cooking oil should not be thrown in the drain because it hardens and blocks pipes, as stated in the document, not because it attracts mosquitoes. Blocked pipes can disrupt the sewerage system, leading to stagnant water, which indirectly causes other issues like mosquito breeding. - Question: Assertion (A): Global warming can increase sea levels.
Reason (R): It causes melting of glaciers and ice caps.
Answer: Both A and R are true, and R is the correct explanation of A. Global warming, driven by the Green House Effect from increased carbon dioxide, melts glaciers and ice caps, as mentioned. This increases water levels in seas and oceans, potentially flooding large areas of Earth’s surface, illustrating a direct consequence of global warming. - Question: Assertion (A): We should use water judiciously at home.
Reason (R): Turning off taps while brushing teeth saves water.
Answer: Both A and R are true, and R supports A but is not the complete explanation. Using water judiciously, as emphasized, involves actions like turning off taps while brushing, which saves water. However, A also implies broader conservation efforts, like fixing leaks, to ensure sustainable water use for future generations, as per the document. - Question: Assertion (A): Waste water should not mix with rain water.
Reason (R): Rain water can be harvested for daily use.
Answer: Both A and R are true, and R is the correct explanation of A. The document advises harvesting rain water instead of letting it mix with waste water, as rain water can be collected in tanks for daily needs, preserving its purity and ensuring more usable water, enhancing water management efforts.
High Order Thinking Skills (HOTS) Questions and Answers
- Question: Why might the small percentage of fresh water in rivers and lakes pose a challenge for human use, and what does this suggest about the need for alternative water sources?
Answer: Only 0.3% of fresh water in rivers and lakes is readily available, while most is in glaciers or ground water, making it insufficient for growing populations. This suggests alternative sources like rain water harvesting and waste water recycling are crucial to meet demand, ensuring sustainable water use and reducing dependency on limited natural freshwater bodies. - Question: How does deforestation contribute to water scarcity through global warming, and what does this indicate about the interconnectedness of environmental systems?
Answer: Deforestation increases carbon dioxide, enhancing the Green House Effect and global warming, which melts glaciers, raising sea levels but not usable water, while reducing rainfall. This interconnectedness shows how environmental systems—trees, air, and water—rely on each other, indicating that disrupting one, like forests, impacts water availability, necessitating holistic conservation strategies to maintain balance. - Question: Why might rain water harvesting be a sustainable solution to water scarcity, and what does this reveal about the role of community participation in water management?
Answer: Rain water harvesting collects water to replenish ground water, reducing wastage and ensuring long-term availability, making it sustainable. It reveals community participation is vital, as collective efforts in harvesting, reducing waste, and maintaining systems like tanks ensure effective water management, empowering communities to address scarcity and sustain resources for future generations collaboratively. - Question: How does the sewerage system contribute to public health, and what does this suggest about the importance of infrastructure in environmental management?
Answer: The sewerage system carries sewage to treatment plants, preventing contamination of ground water and reducing diseases like cholera, as open drains breed mosquitoes causing malaria. This suggests robust infrastructure is essential in environmental management, ensuring clean water, reducing health risks, and maintaining hygiene, highlighting the need for investment in effective waste water systems. - Question: Why might the Green House Effect exacerbate water scarcity, and what does this indicate about the long-term impacts of human activities on water resources?
Answer: The Green House Effect, worsened by deforestation, causes global warming, melting glaciers into oceans, reducing fresh water while decreasing rainfall due to higher carbon dioxide levels. This indicates human activities like tree cutting have long-term impacts, depleting usable water resources, underscoring the need for sustainable practices to mitigate climate change and preserve water for future generations. - Question: How does population growth exacerbate water scarcity, and what does this reveal about the balance between resource use and replenishment?
Answer: Population growth increases water demand for daily needs and agriculture, while over-extraction of ground water outpaces replenishment due to reduced rainfall, causing scarcity. This reveals the imbalance between resource use and replenishment, highlighting the need for sustainable practices like rain water harvesting and efficient irrigation to ensure water availability matches the growing demand. - Question: Why might open drains pose a greater risk in urban areas, and what does this suggest about the challenges of waste water management in cities?
Answer: Open drains in urban areas breed mosquitoes due to stagnant water, increasing diseases like malaria, and can contaminate ground water, causing health issues like cholera. This suggests waste water management in cities faces challenges like population density and infrastructure gaps, necessitating better sewerage systems and public awareness to prevent health risks and ensure clean surroundings. - Question: How does drip irrigation address water scarcity in agriculture, and what does this indicate about the role of technology in sustainable water use?
Answer: Drip irrigation delivers water directly to plant roots, minimizing wastage compared to flood irrigation, conserving water in agriculture amid scarcity. This indicates technology plays a critical role in sustainable water use, offering efficient methods to maximize limited resources, reduce dependency on ground water, and support farming, ensuring food security while preserving water for other needs. - Question: Why might throwing chemicals in drains disrupt waste water treatment, and what does this reveal about the importance of public responsibility in environmental health?
Answer: Chemicals in drains kill friendly micro-organisms that purify sewage in treatment plants, disrupting the process and polluting water bodies. This reveals public responsibility is crucial in environmental health—improper disposal harms ecosystems and health, emphasizing the need for awareness and responsible actions to support waste water management and maintain clean, safe surroundings for communities. - Question: How does the decrease in rainfall affect both agriculture and urban water supply, and what does this suggest about the need for integrated water management strategies?
Answer: Decreased rainfall reduces water in rivers and lakes, impacting urban supply, while farmers over-rely on ground water, depleting it for agriculture. This suggests integrated water management strategies, like rain water harvesting, efficient irrigation, and fixing leaks, are essential to balance urban and agricultural needs, ensuring sustainable water use across sectors amid changing climatic conditions.
Long Questions and Answers (50-60 Words)
- Question: Describe the distribution of water on Earth and its availability for human use.
Answer: 97% of Earth’s water is in oceans, unsuitable for use. Only 3% is fresh water, with 2% in glaciers, 0.7% as ground water, and just 0.3% in rivers, lakes, and streams. This limited availability of fresh water poses challenges for human use, highlighting the need for conservation and alternative sources like rain water harvesting. - Question: Explain why water is scarce despite its abundance on Earth.
Answer: Water is scarce because 97% is salty ocean water, and of the 3% fresh water, most is in glaciers or ground water, not easily accessible. Only 0.3% is in rivers and lakes for use. Increasing demand, decreasing rainfall, and over-extraction of ground water further reduce availability, making water scarce despite its abundance. - Question: Discuss how deforestation contributes to water scarcity.
Answer: Deforestation reduces rainfall by increasing carbon dioxide, as trees use this gas for photosynthesis. Less rainfall decreases water in rivers and lakes, forcing reliance on ground water, which depletes rapidly. This scarcity affects agriculture and daily needs, showing how cutting trees disrupts the water cycle, leading to a shortage of usable water on Earth. - Question: Describe the process of rain water harvesting and its benefits.
Answer: Rain water harvesting collects rain water in underground tanks to seep into the soil, replenishing ground water, or in open tanks for daily use. It reduces wastage, ensures more water availability, and decreases reliance on depleting ground water. This sustainable method helps combat scarcity, supporting both household needs and agriculture efficiently. - Question: Explain the role of the sewerage system in waste water management.
Answer: The sewerage system carries waste water, or sewage, from homes and industries to treatment plants through a network of pipes. There, it is purified before being released into rivers or seas, preventing contamination of ground water and reducing health risks like cholera, ensuring clean surroundings through effective waste water management. - Question: Discuss the health risks associated with open drains.
Answer: Open drains breed mosquitoes due to stagnant water, causing diseases like malaria, and can contaminate ground water, leading to cholera, typhoid, and jaundice. These health risks arise from poor waste water management, as stagnant sewage spreads pathogens, highlighting the need for proper drainage systems to protect public health and maintain hygiene in communities. - Question: Explain how global warming impacts water availability.
Answer: Global warming, driven by the Green House Effect, melts glaciers and ice caps, increasing sea levels but not usable fresh water. It also reduces rainfall by altering climate patterns, decreasing water in rivers and lakes. This impacts agriculture and urban supply, exacerbating water scarcity and necessitating conservation efforts to ensure future availability. - Question: Describe how drip irrigation helps conserve water in agriculture.
Answer: Drip irrigation delivers water directly to plant roots through pipes, minimizing wastage compared to flood irrigation. It ensures efficient use of limited water, reducing the strain on ground water resources. This method conserves water, supports sustainable farming, and helps address scarcity, making it ideal for agriculture in water-stressed regions. - Question: Discuss the importance of not throwing chemicals in drains.
Answer: Throwing chemicals in drains kills friendly micro-organisms that purify sewage in treatment plants, disrupting the process and polluting water bodies. This can lead to environmental damage and health issues like waterborne diseases. Avoiding this practice ensures effective waste water treatment, maintaining clean water and healthy ecosystems, highlighting the need for responsible disposal. - Question: Explain how individuals can contribute to water conservation at home.
Answer: Individuals can conserve water by turning off taps while brushing teeth, fixing leaking taps, and watering plants with a mug instead of a pipe. Other ways include using a bucket for washing cars, reusing laundry water for cleaning, taking shorter showers, and collecting rain water, ensuring judicious use to preserve water for future generations.