Grade 5 Q&A: Chapter 16: Water

Concept Questions

Q1: What happens when other substances get mixed with water?

Answer: When other substances get mixed with water, it becomes impure. Some substances float, making the water look unclean or muddy, while others dissolve and are invisible.

Q2: When is water said to be polluted?

Answer: Water is said to be polluted if the substances that have got mixed with it are harmful for living things.

Q3: How does waste water from cities and towns pollute water bodies?

Answer: Waste water from cities and towns, containing many kinds of impurities (some dissolved, some not), is collected and let into water bodies. This sewage water can carry disease-spreading micro-organisms, leading to pollution.

Q4: Why is it compulsory for factory owners to treat waste water before letting it out?

Answer: It is compulsory for factory owners to treat waste water before letting it out because industrial waste water is likely to contain poisonous substances. If let out as is, it pollutes water bodies, making them dangerous and unusable for drinking or other purposes.

Q5: How does flowing river water get purified naturally to some extent?

Answer: Flowing water of rivers gets purified to some extent by natural processes, such as dilution and aeration, which help break down impurities.

Q6: What happens if large quantities of impurities get mixed with river water, exceeding natural purification capacity?

Answer: If large quantities of impurities get mixed with river water, the natural process of purification cannot keep pace. This reduces the proportion of oxygen dissolved in the water, which is a threat to aquatic living things.

Q7: Name the four main processes used for water purification at water-works before it is supplied to a town or city.

Answer: The four main processes are: Settling, Oxygenation, Filtration, and Chlorination.

Q8: Explain the 'Settling' process in water purification.

Answer: In the settling process, water from the water source is allowed to stand in large tanks. Alum is often used to help the impurities settle down at the bottom.

Q9: Explain the 'Oxygenation' process in water purification.

Answer: Oxygenation involves allowing air and water to mix with the help of pumps. This causes oxygen from the air to dissolve in the water, aiding in purification.

Q10: Explain the 'Filtration' process in water purification.

Answer: Filtration involves passing water through a filtration machine (or layers of sand, coal, and cloth in a simple filter) to remove suspended impurities, making the water appear clean.

Q11: Explain the 'Chlorination' process in water purification.

Answer: Chlorination involves mixing chlorine in the water. Chlorine is a chemical that kills the germs present in the water, making it safe for drinking.

Q12: What is a 'famine'?

Answer: A famine is a condition that occurs when it does not rain for a very long period of time, leading to a drought. The water level falls in rivers, wells, lakes, bunds, and dams, some of which may even go dry. The land also dries up, causing scarcity of water, foodgrain, and fodder for humans, animals, and agriculture.

Q13: What is 'water management'?

Answer: Water management refers to taking steps to ensure that rainwater will be available even in the period after the rainy season. This involves stopping rainwater from flowing away, making it seep into the ground, or collecting it in tanks to meet the whole year's need for water.

Q14: Name two methods used to make rainwater seep into the soil.

Answer: Two methods are building smaller reservoirs and contour bunding (constructing bunds or bandharas to stop the water of smaller streams).

Q15: What is the benefit of rainwater percolating into the soil?

Answer: As rainwater percolates into the soil, the groundwater storage increases, trees get water, wells get enough water, and the land can be cultivated.

Application-Based Questions

Q16: You collect rainwater directly in a clean container and also rainwater flowing over the ground. What difference would you see and why?

Answer: The rainwater collected directly would appear cleaner, while the water flowing over the ground would likely be muddy and contain rubbish. This is because the water flowing over the ground picks up impurities like soil, dust, and other waste, making it impure.

Q17: If a place experiences a very long period without rain, what would be the effect on the life of the people there?

Answer: If it did not rain for a very long period, the people would suffer from severe water scarcity. Rivers, wells, and other water sources would dry up, leading to a lack of drinking water, no water for agriculture, and scarcity of food and fodder for animals. This would cause immense hardship and potentially force people to migrate.

Q18: Your class is visiting a lake far from the city, and arrangements need to be made for drinking water. What solution would you suggest?

Answer: I would suggest carrying purified bottled drinking water for the entire class. Alternatively, if there's a reliable source nearby, we could carry portable water filters or boil the water to make it safe.

Q19: You see an empty bottled water bottle. Why should you crush it before throwing it into a garbage bin?

Answer: You should crush the empty bottle to prevent it from being reused by unscrupulous individuals who might refill it with unpurified water and sell it. This practice can spread water-borne diseases and poses a serious health risk to consumers.

Q20: Soil in a garden gets washed away with water due to the slope of the land. What's the solution?

Answer: To prevent soil from washing away, one solution is to implement **contour bunding** or build small bunds/terraces along the slope. Planting grass or other vegetation with strong root systems can also help hold the soil in place and allow water to seep into the ground.

Higher-Order Thinking Questions

Q21: "Water is life. Use it judiciously." Explain the deeper meaning of this statement in the context of environmental science.

Answer: This statement emphasizes that water is fundamental for all life on Earth, not just for human survival but for entire ecosystems. "Use it judiciously" means to use it wisely, carefully, and without waste, recognizing its finite nature and the interconnectedness of water systems. Environmentally, it implies that irresponsible water use (e.g., pollution, excessive extraction) can disrupt natural water cycles, deplete resources, harm aquatic life, and lead to widespread environmental degradation, ultimately threatening the very existence of life on the planet. It calls for sustainable water management practices.

Q22: How should roads and footpaths be built to make rainwater seep into the ground, contributing to water management?

Answer: To make rainwater seep into the ground, roads and footpaths should be built with permeable materials or designs that allow water to infiltrate rather than run off. This can include: * **Permeable Pavement:** Using porous asphalt, pervious concrete, or interlocking pavers with gaps filled with sand/gravel. * **Rain Gardens/Swales:** Incorporating vegetated depressions alongside roads and footpaths to collect and absorb runoff. * **Tree Pits:** Designing tree pits along sidewalks to capture and infiltrate rainwater. * **Sloping and Drainage:** Directing runoff towards green spaces or infiltration areas rather than storm drains that lead to rivers.

Q23: Why is it necessary to stop rainwater and make it seep into the ground, even in areas with regular rainfall?

Answer: It is necessary to stop rainwater and make it seep into the ground even in areas with regular rainfall for several reasons: * **Groundwater Recharge:** It recharges underground aquifers, which are vital sources of drinking water and irrigation, especially during dry periods. * **Preventing Runoff & Flooding:** It reduces surface runoff, preventing soil erosion and minimizing the risk of urban flooding. * **Sustaining Vegetation:** Increased groundwater supports trees and plants, contributing to local ecosystems. * **Ensuring Year-Round Supply:** By storing water underground, it ensures a continuous supply even after the rainy season, reducing dependence on external sources.

Q24: The chapter mentions that the government temporarily moves people and animals from famine-stricken areas to safe places and sets up fodder camps. Discuss the social and ethical responsibilities behind these actions.

Answer: These actions reflect a strong social and ethical responsibility to protect vulnerable populations and ensure their basic needs are met during natural disasters. * **Social Responsibility:** Governments have a duty to protect their citizens and livestock. Moving people to safe places and providing food/fodder prevents starvation, disease, and social unrest. * **Ethical Responsibility:** It's an ethical imperative to provide humanitarian aid to those suffering, especially when their survival is threatened by circumstances beyond their control. It demonstrates compassion and the value placed on human and animal life. * **Community Welfare:** These measures also help maintain social order and prevent the collapse of communities by providing temporary relief and support.

Q25: How does the information on bottled drinking water (date of bottling, expiry date, crushing the bottle) relate to responsible consumption and public health?

Answer: This information is crucial for responsible consumption and public health: * **Date of Bottling/Expiry:** Ensures consumers know the water's freshness and safety. Consuming water past its expiry date can pose health risks due to potential bacterial growth or degradation of the plastic. * **Crushing the Bottle:** Prevents the bottle from being reused for unhygienic refilling and resale. This directly safeguards public health by preventing the spread of water-borne diseases from contaminated or improperly handled water sold in reused bottles. It also reduces waste and promotes recycling.

References

1. Maharashtra State Board Environmental Studies (Part One) Standard Five Textbook (2015 Edition) - Chapter 16: Water, pages 77-81.
2. Maharashtra State Board 5th Standard Environmental Studies Syllabus.
3. Balbharati Environmental Studies Part 1 Textbook.