WATER CLASS 7 CBSE

 

WATER CLASS 7 CBSE

A. Tick (✓) the correct option.

1. Which process of the water cycle includes the transformation of a liquid into gas?
• b. evaporation
2. What percentage of the world's water supply is freshwater?
• a. 3%
3. Which of the following consumes the most water?
• c. agriculture
4. Pay more if your supply of water is wasted. It can be imposed as ______________ .
• a. Pay fine
5. Which of the following methods contributes to water scarcity in India?
• c. managing industrial waste into rivers and lakes
6. Which of the following statements is true about water conservation?
• b. Trees prevent runoff of soil erosion by holding roots with their leaves.

B. Use the given words to solve the crossword.

• (Across)
1. Name of the trees over wind
• DRAIN (This one is a bit of a stretch, as "drain" isn't directly related to trees over wind, but given the provided words, it is the best fit.)
2. Planting trees is called
• RAIN (Again, a stretch. They meant to use afforestation, but given the words, rain is the best fit.)
• (Down) 3. Process of clouds called * PRECIPITATION 4. Away must to protect. * WATER

C. State whether the following statements are TRUE or FALSE. Correct the false ones.

1. Soil erosion control helps in reducing silts, nutrients into the lakes and rivers.
• TRUE
2. Deforestation causes floods due to the population of solid silts in rivers.
• FALSE. Deforestation causes floods because trees no longer absorb rainwater, leading to increased runoff and soil erosion.
3. Developing a method for water harvesting by providing water storage tanks is a modern method.
• TRUE
4. Treating the water before release into canals, rivers and lakes may keep the environment and large benefits.
• TRUE
5. Treating the water before release into canals and help to conserve it.
• TRUE

D. Answer the correct word to fill in the blanks.

1. Open and check the area that forest already is cut people it harmful is ____________.
• DEFORESTATION
2. The more water between all particles between the air and particles between rocks will filled with water is called the __________.
• WATER (This is a poorly worded description of groundwater.)
3. ____________ of flowing streams is shown as __________.
• dam (and I am guessing the second blank is also dam. the sentance is very poorly worded.)
4. Applying flowing of water supply also by directing flow to the roots of the plants is called __________.
• IRRIGATION
5. Can cause a huge amount of water which use to generate __________.
• paper (Again, very poorly worded, but it is the only remaining option. They are most likely talking about a hydroelectric dam)

E. Answer each of the following in brief.

1. Describe three states in water.
• Solid (Ice): Water in its solid state, ice, forms when water molecules lose energy and slow down, arranging themselves into a rigid crystalline structure. Ice can take many forms, such as ice cubes, snow, glaciers, and frost. It occupies more volume than liquid water, which is why ice floats.
• Liquid (Water): In its liquid state, water molecules have enough energy to move freely past one another, giving water its fluidity. It takes the shape of its container and is found in rivers, lakes, oceans, and as rain. Liquid water is essential for all living organisms.
• Gas (Water Vapor): Water vapor is the gaseous state of water, formed when liquid water evaporates or when ice sublimates. Water vapor is invisible and is a component of the Earth's atmosphere. Condensation of water vapor forms clouds.
2. List three purposes for water is used for the human body.
• Hydration: Water is the primary component of bodily fluids and is essential for maintaining proper hydration. It helps transport nutrients, oxygen, and waste products throughout the body. Dehydration can lead to fatigue, headaches, and other health problems.
• Digestion: Water is crucial for the digestive process. It helps break down food, allowing nutrients to be absorbed into the bloodstream. Water also helps move waste through the digestive system, preventing constipation.
• Temperature Regulation: Water plays a vital role in regulating body temperature. When the body gets too hot, it releases sweat, which evaporates and cools the skin. Water also helps distribute heat throughout the body, maintaining a stable internal temperature.
• Joint Lubrication: Water helps lubricate joints, allowing for smooth movement.
• Waste Removal: Water helps the kidneys to filter waste from the blood.
3. List two sources of water.
• Surface Water: Surface water refers to water found on the Earth's surface, including rivers, lakes, ponds, reservoirs, and oceans. It is replenished by precipitation and runoff. Surface water is a readily accessible source of water for human use, but it is also susceptible to pollution.
• Groundwater: Groundwater is water that seeps into the ground and accumulates in aquifers, which are underground layers of permeable rock, sediment, or soil. It is replenished by rainwater that infiltrates the soil. Groundwater is accessed through wells and springs and is an important source of drinking water, especially in areas with limited surface water resources.
4. The unequal populations between the water table of many parts of India, give reasons.
• Uneven Rainfall Distribution: India's rainfall patterns are highly variable, with some regions receiving abundant rainfall during the monsoon season and others experiencing prolonged dry periods. This leads to unequal replenishment of groundwater aquifers.
• Over-extraction of Groundwater for Agriculture: Agriculture is the largest consumer of water in India, and the over-extraction of groundwater for irrigation has led to a significant decline in the water table in many areas, particularly in regions with intensive agriculture.
• Urbanization and Industrialization: Rapid urbanization and industrialization have increased the demand for water, leading to increased groundwater extraction. Urban areas often have limited recharge capacity due to paved surfaces and reduced infiltration.
• Varying Soil Types and Geology: The geology and soil types in different regions of India influence the rate of groundwater recharge and storage. Some areas have soils that allow for rapid infiltration, while others have impermeable layers that restrict groundwater flow.
• Deforestation: The removal of trees reduces the amount of rainwater that infiltrates the soil, leading to decreased groundwater recharge.
5. Define an Aquifer.
• An aquifer is an underground layer of permeable rock, sediment, or soil that can store and yield significant quantities of groundwater. It is characterized by its ability to transmit water through its pore spaces or fractures. Aquifers are typically saturated with water, and the upper surface of the saturated zone is called the water table. Aquifers are vital sources of freshwater for drinking, irrigation, and industrial use.

G. Long answer questions

1. The water table has gone down considerably in recent times. What are the reasons for the depletion of groundwater?
• Over-extraction for Agriculture: Modern agriculture relies heavily on groundwater for irrigation. As populations grow, so does the demand for food, leading to increased pumping of groundwater. In many regions, this extraction far exceeds the natural replenishment rate of aquifers.
• Increased Urbanization: Rapid urbanization leads to the construction of more buildings, roads, and infrastructure, which reduces the area available for rainwater to seep into the ground and recharge aquifers. Urban areas also have higher water demands for domestic and industrial use, further depleting groundwater resources.
• Deforestation: Trees play a crucial role in the water cycle. They help rainwater infiltrate the soil and replenish groundwater. Deforestation reduces this infiltration capacity, leading to increased runoff and decreased groundwater recharge.
• Climate Change: Changes in rainfall patterns, such as prolonged droughts and more intense but less frequent rainfall events, can significantly impact groundwater availability. Droughts reduce the amount of water available to recharge aquifers, while intense rainfall events may lead to increased runoff rather than infiltration.
• Industrial Use: Many industries rely on groundwater for various processes, including cooling, cleaning, and manufacturing. Unregulated or excessive industrial extraction can contribute to groundwater depletion.
• Inefficient Water Management: Leaky pipes, inefficient irrigation systems, and other forms of water wastage contribute to increased demand for groundwater, further exacerbating depletion.
2. Drought and irrigation are two sides of the same coin; justify.
• Droughts are periods of prolonged dry weather, characterized by low rainfall and reduced water availability. This naturally leads to a scarcity of water for agriculture, forcing farmers to rely on irrigation to maintain crop production.
• Irrigation, the artificial application of water to land for agriculture, is often a necessary response to droughts. However, excessive or unsustainable irrigation practices can have detrimental effects on water resources.
• Over-reliance on irrigation can lead to the depletion of groundwater aquifers and surface water sources, which can exacerbate drought conditions in the long term. If more water is pulled from the ground than can be replaced, then the next drought will be even worse.
• Furthermore, inefficient irrigation methods can lead to water wastage through evaporation and runoff, further contributing to water scarcity.
• Therefore, while irrigation provides a temporary solution to drought-induced water shortages, it can also contribute to the long-term depletion of water resources, creating a vicious cycle.
3. State any two reasons for the scarcity of water in India.
• Uneven Rainfall Distribution: India experiences a highly variable monsoon season, with some regions receiving excessive rainfall and others experiencing prolonged dry spells. This uneven distribution leads to water scarcity in areas with low rainfall, while other areas may experience floods.
• Over-extraction of Groundwater: Rapid population growth and agricultural intensification have led to the over-extraction of groundwater in many parts of India. This has resulted in a significant decline in the water table, making it more difficult and expensive to access groundwater resources.
4. Describe four ways of saving water.
• Rainwater Harvesting: This involves collecting and storing rainwater for later use. Rainwater can be collected from rooftops and other surfaces and stored in tanks or underground reservoirs. This method helps to replenish groundwater supplies and reduce reliance on municipal water sources.
• Efficient Irrigation Practices: Implementing water-saving irrigation techniques, such as drip irrigation and sprinkler irrigation, can significantly reduce water wastage in agriculture. These methods deliver water directly to plant roots, minimizing evaporation and runoff.
• Fixing Leaks: Leaky pipes and faucets can waste significant amounts of water. Regularly checking and repairing leaks in homes, businesses, and municipal water systems can help to conserve water.
• Water Conservation Habits: Adopting water-saving habits in daily life, such as taking shorter showers, turning off the tap while brushing teeth, and using water-efficient appliances, can collectively make a significant difference in water conservation. Promoting public awareness and education about water conservation is also essential.