Samacheer Kalvi Class 6 Science Solutions Term 3 Chapter 2 Water

Tamilnadu Samacheer Kalvi 6th Science Solutions Term 3 Chapter 2 Water

Samacheer Kalvi 6th Science Water Text Book Back Questions and Answers

I. Choose the correct Answer:

Question 1. Around 97% of water available on earth is water.
(a) fresh
(b) pure
(c) salty
(d) polluted
Answer: (c) salty
In simple words: Most of the water on Earth, about 97%, has salt in it. This means it is salty water, like the water found in oceans.

🎯 Exam Tip: Remember the approximate percentages of fresh and salt water on Earth to answer similar questions accurately.

Question 2. Which of the following is not a part of the water cycle?
(a) evaporation
(b) condensation
(c) rain
(d) distillation
Answer: (d) distillation
In simple words: The water cycle includes evaporation, condensation, and rain, but distillation is a way to purify water, not a natural part of Earth's water movement. Distillation is a man-made process, not a natural one.

🎯 Exam Tip: Clearly understand the natural processes involved in the water cycle: evaporation, condensation, precipitation, and collection.

Question 3. Which of the following processes add water vapour to the atmosphere?
(i) Transpiration
(ii) Precipitation
(iii) Condensation
(iv) Evaporation
(a) ii and iii
(b) ii and iv
(c) i and iv
(d) i and ii
Answer: (c) i and iv
In simple words: Transpiration (from plants) and evaporation (from water bodies) both turn liquid water into gas, sending water vapour into the air. This adds moisture to our atmosphere.

🎯 Exam Tip: Differentiate between processes that add water vapor (evaporation, transpiration) and those that remove it (condensation, precipitation).

Question 4. About 30% of the freshwater is found in?
(a) glaciers
(b) groundwater
(c) other sources of water
(d) 0.3%
Answer: (b) groundwater
In simple words: A large portion, around 30%, of the world's freshwater is stored underground in aquifers, known as groundwater. It is an important source of drinking water.

🎯 Exam Tip: Remember the main reservoirs for freshwater, especially the significant amounts found in glaciers and groundwater.

Question 5. Using R.O. plant at home eliminates lot of non-potable water. The best way to effectively use the expelled water of R.O. plant is ..........
(a) make the expelled water go and seep near the bore well
(b) use it for watering plants
(c) to drink the expelled water after boiling and cooling
(d) to use for cooking as the water is full of many nutrients
Answer: (b) use it for watering plants
In simple words: The leftover water from an R.O. purifier is usually not good for drinking, but it can be safely used to water plants. This helps to save water and use resources wisely.

🎯 Exam Tip: Focus on practical and environmentally friendly ways to reuse rejected water from R.O. purifiers, especially for non-drinking purposes like gardening.

II. Fill in the Blanks

Question. Fill in the blanks with the correct words.
1. .......... percent of natural water is available for human consumption.
2. The process of changing water into its vapour is called ............
3. .......... is built on rivers to regulate water flow and distribute water.
4. Water levels in rivers increase greatly during ............
5. Water cycle is also called as ............
Answer:
1. 3%
2. Evaporation
3. Dam
4. Rainy days
5. hydrological cycle
In simple words: Only a small part of Earth's water can be used by people. Water turns into vapor through evaporation, and dams help control river water. Rivers rise during rainy days, and the water cycle is also known as the hydrological cycle.

🎯 Exam Tip: Understand the key terms related to water resources and the water cycle, including the small percentage of usable freshwater and the names of processes.

III. True or False. If False, give the correct statement.

Question 1. Water present in rivers, lakes and ponds is unfit for use by human beings.
Answer: False – Water present in rivers, lakes and ponds is fit for use by human beings.
In simple words: It is not true that water in rivers, lakes, and ponds cannot be used by humans. These are actually important sources of water for people, often after some treatment.

🎯 Exam Tip: Always provide the correct statement when asked to justify a 'False' answer in true/false questions.

Question 2. Seas are formed when the water table meets the land surface.
Answer: True
In simple words: This statement is correct. Seas are large bodies of saltwater, and their formation is not directly linked to the water table meeting the land surface.

🎯 Exam Tip: Understand the difference between large ocean bodies and local groundwater tables, as they are not directly related in sea formation.

Question 3. The evaporation of water takes place only in sunlight.
Answer: False – The evaporation of water takes place in any source of heat.
In simple words: Evaporation can happen whenever there is heat, not just from the sun. Any warm temperature can make water turn into vapor.

🎯 Exam Tip: Remember that evaporation is a continuous process that occurs at all temperatures where water is present, even if it's slower without direct sunlight.

Question 4. Condensation results in the formation of dew on grass.
Answer: True
In simple words: This statement is correct. When water vapor in the air cools down and turns back into liquid water droplets on surfaces like grass, it forms dew.

🎯 Exam Tip: Connect the process of condensation with common atmospheric phenomena like dew and fog formation.

Question 5. Seawater can be used for irrigation as such.
Answer: False – Seawater cannot be used for irrigation as such.
In simple words: Seawater contains too much salt, which is harmful to most plants. Therefore, it cannot be used for watering crops without being treated first to remove the salt.

🎯 Exam Tip: Emphasize why direct use of seawater for irrigation is detrimental to agriculture due to its high salt content.

IV. Match the following

Question. Match the following items correctly.

🎯 Exam Tip: Carefully read each item in both columns and identify the best logical connection. If you are unsure, try eliminating options.

V. Arrange the following statements in the correct sequence

Question. Arrange the following statements in the correct sequence to describe the water cycle.
1. These vapours condense to form tiny droplets of water.
2. The water droplets come together to form large water droplets.
3. The heat of the sun causes evaporation of water from the surface of the earth, oceans, lakes, rivers and other water bodies.
4. The large water droplets become heavy and the air cannot hold them, therefore, they fall as rains.
5. Water vapour is also continuously added to the atmosphere through transpiration from the surface of the leaves of trees.
6. Warm air carrying clouds rises up.
7. Higher up in the atmosphere, the air is cool.
8. These droplets floating in the air along with the dust particles form clouds.
Answer:
1. The heat of the sun causes evaporation of water from the surface of the earth, oceans, lakes, rivers and other water bodies.
2. Water vapour is also continuously added to the atmosphere through transpiration from the surface of the leaves of trees.
3. These droplets floating in the air along with the dust particles form clouds.
4. Warm air carrying clouds rises up.
5. Higher up in the atmosphere, the air is cool.
6. These vapours condense to form tiny water droplets of water.
7. The water droplets come together to form large water droplets.
8. The large water droplets become heavy and the air cannot hold them, therefore, they fall as rains.
In simple words: The sun heats water, causing it to evaporate. Plants also release water vapor. This vapor rises, cools, and forms tiny droplets around dust, creating clouds. These small droplets join to make bigger ones, which then fall as rain when they become too heavy for the air to hold.

🎯 Exam Tip: To sequence events, identify the starting point (e.g., sun's heat), then trace the logical flow of processes in the water cycle step by step.

VI. Analogy:

Question 1. Population explosion : Water scarcity : : Recycle : ..........
Answer: Water management
In simple words: Just as more people lead to less water, recycling is a way to manage water resources better. It helps control how much water we use and need.

🎯 Exam Tip: In analogies, identify the relationship between the first pair of words (cause-effect, problem-solution) and apply it to the second pair.

Question 2. Groundwater : ........... : : Surface-water: Lakes
Answer: Wells
In simple words: Just as lakes are examples of surface water, wells are places where we get groundwater. Wells access the water that is stored underground.

🎯 Exam Tip: Recognize the different sources of water – surface (lakes, rivers) and underground (wells, borewells).

VII. Give Very Short Answer

Question 1. Name four different sources of water.
Answer: Rivers, wells, lakes, glaciers, ponds, etc.
In simple words: Water can be found in many natural places like flowing rivers, underground wells, still lakes, huge glaciers of ice, and small ponds.

🎯 Exam Tip: When listing sources, try to include a variety from different environments (surface, underground, frozen) to show comprehensive knowledge.

Question 2. How do people in cities and rural areas get water for various purposes?
Answer: People get water from wells, canals, tanks, ponds, rivers, water tanks, hand pipes for various purposes.
In simple words: People get water from different places depending on where they live. In villages, they might use wells, ponds, or rivers, while in cities, they often get water from large tanks and hand pumps.

🎯 Exam Tip: Consider both natural sources and human-made systems that supply water to different types of communities.

Question 3. Take out of cooled bottle of water from refrigerator and keep it on a table. After some time you notice a puddle of water around it. Why?
Answer: The cooled surface of the bottle cools the air around it and the water vapour of the air condenses. So after some time, a puddle of water can be noticed around the bottle.
In simple words: The cold bottle makes the air around it cool. The water vapor in that air then turns into tiny water droplets, which collect as a puddle around the bottle. This is like how clouds form.

🎯 Exam Tip: Explain this phenomenon using the concept of condensation: warm, moist air touching a cold surface causes water vapor to change back into liquid.

Question 4. We could see clouds almost every day. Why doesn't it rain daily?
Answer: When the air around the clouds is cool, the clouds then only rain comes. That is the reason why we can't get rain daily.
In simple words: Clouds only release rain when the air around them is cold enough. If the air isn't sufficiently cool, the water droplets in the clouds remain in the air and do not fall as rain.

🎯 Exam Tip: Explain that rain requires specific atmospheric conditions, particularly sufficient cooling and particle size, not just the presence of clouds.

Question 5. Name the places where water is found as ice.
Answer: Polar ice-caps, Ice sheets, and glaciers in Arctic region and Antarctica.
In simple words: Water is found as ice in very cold places such as the North Pole (Arctic region) and South Pole (Antarctica), where huge amounts of ice are stored as polar ice-caps, ice sheets, and glaciers.

🎯 Exam Tip: Focus on the coldest regions of the Earth (polar areas) when asked about places where water is predominantly found in its solid, frozen state.

Question 6. How do aquatic animals manage to live in Arctic and Antarctic Circle?
Answer: Floating layer of ice acts as a protective coat and does not permit heat to escape from water. So aquatic animals manage to live in Arctic and Antarctic circle.
In simple words: In very cold places like the Arctic and Antarctic, a layer of floating ice covers the water. This ice acts like a blanket, keeping the heat inside the water and stopping it from getting too cold, which helps aquatic animals survive.

🎯 Exam Tip: The insulating property of ice is crucial for aquatic life in polar regions, as it prevents the water beneath from freezing solid and losing heat.

Question 7. What are the types of rainwater harvesting?
Answer: There are two types of rainwater harvesting.
1. Collecting water from where it falls.
2. Collecting rainwater by constructing bunds.
In simple words: Rainwater harvesting involves two main ways to collect rain: one is to catch water right where it lands, like on rooftops, and the other is to build small dams (bunds) to collect flowing rainwater.

🎯 Exam Tip: When describing rainwater harvesting, include both methods: direct collection from surfaces and storing runoff from the ground.

VIII. Give Short Answer

Question 1. Differentiate between surface water and groundwater.
Answer:

🎯 Exam Tip: Clearly distinguish between water visible on the Earth's surface and water stored beneath it, providing examples and relative amounts for each.

Question 2. Write a few slogans of your own on the topic “Save Water”.
Answer:
1. “To a thirsty man, a drop of water is worth more than a sack of gold".
2. "Water covers 2/3 of the surface of the earth. But only 0.002% is drinkable. Save water"
3. "Save water to secure your future"
4. "Don't make nature cry, keep your water clean”
5. "Store water for dry days".
In simple words: These slogans remind us that water is very precious, especially the small amount that is safe to drink. They encourage us to protect water, keep it clean, and save it for future use.

🎯 Exam Tip: Create slogans that are short, impactful, and clearly convey the importance of water conservation. Use facts if they enhance the message.

Question 3. About 71% of earth's surface is covered with water, then why do we face scarcity of water?
Answer: 71% of the earth's surface is covered with water. The freshwater will be only 3%. It remains the same. But the water useful for plants, animals, and men is increasing day by day. So we face water scarcity.
In simple words: Even though Earth has a lot of water, most of it is salty ocean water. Only a tiny portion (about 3%) is fresh water, and the amount of fresh water available is not increasing, while the need for it is growing, leading to water shortages.

🎯 Exam Tip: Explain that water scarcity is due to the small proportion of usable freshwater and the increasing demand from a growing population, not a lack of water overall.

Question 4. Give reason for the following statement – Sewage should not be disposed of in rivers or oceans before treatment.
Answer: Sewage contains harmful and toxic chemicals. They can disturb the ecosystem of the living animals, in the rivers or oceans. So it should be treated effectually before disposing into rivers or oceans.
In simple words: Sewage water has bad chemicals that can harm plants and animals living in rivers and oceans. To protect these environments, all sewage must be cleaned before it is released into natural water bodies.

🎯 Exam Tip: Emphasize the ecological impact of untreated sewage on aquatic ecosystems and the necessity of treatment for environmental protection.

Question 5. The freshwater available on earth is only 3%. We cannot increase the amount of water. In that case, how can sustain the water level?
Answer:
1. The sewage water treatment is to be adopted.
2. Decrease the usage of pesticides, insecticides, and fertilizers in agriculture.
3. Protect forest and trees.
4. Adopt drip irrigation and sprinkler irrigation in agriculture.
5. Rainwater harvesting should be implemented in every building.
6. Create awareness about the impact of throwing wastes into the water bodies.
In simple words: To keep enough water, we must clean dirty water, use fewer harmful farm chemicals, protect forests, use smart watering methods like drip irrigation, collect rainwater, and teach people not to pollute water. These actions help us manage the limited freshwater we have.

🎯 Exam Tip: Focus on a multi-pronged approach to water sustainability, including pollution control, efficient use, conservation, and public awareness.

IX. Answer in detail

Question 1. What is potable water? List down its characteristics.
Answer: The water which is fit for drinking by human beings is called potable water.
Characteristics:
1. It is transparent.
2. It is odourless and colourless.
3. It is harmless or free from disease-causing bacteria.
In simple words: Potable water is water that is safe for people to drink. It should be clear, have no smell, no color, and be free from any germs that can make us sick.

🎯 Exam Tip: When defining potable water, include both its safety for consumption and its physical characteristics, especially clarity and freedom from harmful agents.

Question 2. Who is known as waterman of India? Browse the net and find the details about the award, the waterman received for water management. State the findings by drafting a report.
Answer: The 'Waterman of India' is Dr. Rajendra Singh. He is a well-known water conservationist and environmentalist from Alwar district, Rajasthan.
Awards:
1. He gets the Ramon Magsaysay award for community leadership in 2001.
2. In 2005, he got the Jamnalal Bajaj Award for Science and Technology for rural development.
3. In 2008, The Guardian named him amongst its list of 50 people who could save the planet.
4. In 2015, he won the Stockholm Water Prize. He runs an NGO called 'Tarun Bharat Sangh' (TBS), which was founded in 1975.
5. In 2016, he was bestowed with Ahimsa Award by the Institute of Jainology based in UK.
In simple words: Dr. Rajendra Singh is called the 'Waterman of India' because he has done great work in saving water. He has received many important awards, like the Ramon Magsaysay award and the Stockholm Water Prize, for his efforts in water conservation.

🎯 Exam Tip: When discussing prominent figures, mention their key contribution and significant recognitions or awards received for their work.

Question 3. What is rainwater harvesting? Explain in a few sentences how it can be used in houses.
Answer: Rainwater harvesting: Direct collection and use of rainwater are called rainwater harvesting.
There are two types of rainwater harvesting.
(a) Collecting water from where it falls.
Example: Collecting water from the rooftops of the houses or buildings (Roof water harvesting).
(b) Collecting flowing rainwater.
Example: Collecting rainwater by constructing ponds with bund.
In simple words: Rainwater harvesting means collecting and storing rainwater directly. In houses, rain falling on rooftops can be collected in tanks for later use. Also, small barriers can be built to gather rainwater that flows over the ground.

🎯 Exam Tip: Define rainwater harvesting clearly and provide practical examples of how it can be implemented in urban (rooftop) and rural (pond/bund) settings.

X. Questions Based on Higher Order Thinking Skills.

Question 1. When there is no pond or lake in an area, will there be the formation of clouds possible in that area?
Answer: When there is no pond or lake in an area, the formation of clouds will be possible. Transpiration from the aerial parts of all plants and trees will evaporate water and it will form clouds.
In simple words: Yes, clouds can still form even without ponds or lakes. Plants and trees release water vapor into the air through a process called transpiration. This water vapor can then rise and form clouds.

🎯 Exam Tip: Remember that evaporation from water bodies is one source of atmospheric moisture, but transpiration from plants is another significant contributor to cloud formation.

Question 2. To clean the spectacles, people often breathe out on glasses to make them wet. Explain why do the glasses become wet.
Answer: When we breathe out, the hot air comes out from our mouth which gets condensed and changed into tiny water droplets, and glasses become wet.
In simple words: When you breathe on glasses, the warm, moist air from your breath touches the cooler glass surface. This causes the water vapor in your breath to cool down and turn into tiny liquid water droplets, making the glasses wet.

🎯 Exam Tip: Explain this everyday phenomenon using the scientific principle of condensation, where warm, moist air cools on a surface and forms liquid droplets.

XI. Crossword

Question. Solve the crossword clues for "Down".
1. A method of water conservation.
2. Process of getting water vapour from seawater.
6. Water stored in dams is used for the generation of ............
Answer:
1. CONSERVATION
2. DESALINATION
6. ELECTRICITY
In simple words: Water conservation is saving water. Desalination turns seawater into fresh water. Water in dams makes electricity.

🎯 Exam Tip: For crossword clues, think of keywords related to the topic and how they might fit into the given letter spaces.

Question. Solve the crossword clues for "Across".
3. .......... is a large body of non-potable water found in nature.
4. In summer, the body loses water as ............
5. Plants undergo ............ and contribute to the water cycle.
Answer:
3. OCEAN
4. SWEAT
5. TRANSPIRATION
In simple words: A huge body of salty water is an ocean. In hot weather, our body releases water as sweat. Plants give off water vapor through transpiration, which is part of the water cycle.

🎯 Exam Tip: Use the lengths of the words and any intersecting letters from the "Down" clues to help deduce the "Across" answers.

XII. Observe the given graph carefully and answer the questions.

Question 1. Observe the given graph showing water content in various food items and answer the questions.
1. What percentage of water is seen in fish?
2. Name the food item that has the maximum amount of water in its content.
3. Name the food item that has a minimum amount of water in its content.
4. The human body consists of about .......... percentage of water.
5. Specify the food item that can be consumed by a person when he / she is suffering from dehydration.
Answer:
1. Fish – 70%
2. Watermelon
3. Fish
4. 60%
5. watermelon, pineapple
In simple words: From the graph, fish has 70% water. Watermelon has the most water, and fish has the least among the options shown. The human body is about 60% water. If you are dehydrated, watermelon and pineapple are good choices to get water.

🎯 Exam Tip: Read bar graphs carefully by checking the y-axis (percentage) and x-axis (items) to accurately extract information for each question.

Question 2. Look at the map of Tamilnadu showing annual rainfall and answer the questions given below.
a. Identify the districts that get only low annual rainfall in Tamilnadu.
b. Identify the districts that get a medium annual rainfall in Tamilnadu.
c. State the districts that enjoy high annual rainfall in Tamilnadu.
Answer:
a. northwest zone (Coimbatore, Erode, Namakkal, Karur)
b. Pudhukottai, Virthunagar, Sivagangai, Salem, Dindigul, Theni, Vellore.
c. Tirunelveli, Kanyakumari, Chennai, Vizhupuram, Thiruvallur, Kadalur, Nagapattinam
In simple words: Based on the rainfall map, areas like Coimbatore, Erode, Namakkal, and Karur receive low rain. Pudhukottai, Virthunagar, Sivagangai, Salem, Dindigul, Theni, and Vellore get medium rain. Districts such as Tirunelveli, Kanyakumari, Chennai, Vizhupuram, Thiruvallur, Kadalur, and Nagapattinam have high annual rainfall.

🎯 Exam Tip: Always refer to the map's legend to correctly interpret the different rainfall categories and then carefully locate and list the districts corresponding to each category.

I. Choose the best Answer:

Question 1. If the total water on earth be 100% the percentage of freshwater is ..........
(a) 97%
(b) 93%
(c) 3%
(d) 0.3%
Answer: (c) 3%
In simple words: Out of all the water on Earth, only a tiny part, just 3%, is fresh water. This small amount is what we need for drinking and other daily uses, making it very precious.

🎯 Exam Tip: Remember the critical percentages: most of Earth's water is salt water, and only a small fraction is freshwater, which is vital for life.

Question 2. .......... is a transparent, tasteless, odourless, chemical substance.
(a) Petrol
(b) Wax
(c) Water
(d) Kerosene
Answer: (c) Water
In simple words: Water is a clear liquid that has no taste or smell. It is made of chemicals, but it is natural and safe for us to use.

🎯 Exam Tip: When describing basic substances, use simple adjectives like 'transparent', 'tasteless', and 'odourless' to highlight their key properties.

Question 3. Which one is not an example of groundwater?
(a) hand pump
(b) borewell
(c) wetland water
(d) well
Answer: (c) wetland water
In simple words: Groundwater is water found under the earth's surface, like in wells or borewells. Wetland water is on the surface, not hidden underground.

🎯 Exam Tip: Understand the difference between surface water (like wetlands, lakes, rivers) and groundwater (like aquifers, wells, borewells) for clear definitions.

Question 4. Water from oceans, lakes, ponds, and rivers evaporates due to the heat of ..........
(a) Sun
(b) Pressure
(c) Atmosphere
(d) None of the options
Answer: (a) Sun
In simple words: The sun's heat is the main reason why water from different places like oceans and rivers changes into vapour and goes up into the air. This process is called evaporation.

🎯 Exam Tip: The sun is the primary energy source driving the water cycle, causing evaporation and influencing global weather patterns.

Question 5. .......... are wetlands where water bodies meet the sea.
(a) lake
(b) well
(c) estuary
(d) glacier
Answer: (c) estuary
In simple words: An estuary is a special wetland area where freshwater from a river meets saltwater from the sea. This mix creates a unique environment for many plants and animals.

🎯 Exam Tip: An estuary is a unique ecosystem where fresh and salt water mix, often serving as important breeding grounds for marine life.

II. True or False.

Question 1. Maximum surface water is stored in lakes.
Answer: True
In simple words: Lakes hold a very large amount of the water that is found on the surface of the Earth. These large water bodies store a significant portion of surface freshwater.

🎯 Exam Tip: Differentiate between the total volume of water and the accessible surface water, with lakes being major reservoirs for the latter.

Question 2. The oceanic volcanoes add salts to the sea.
Answer: True
In simple words: Volcanoes under the ocean release minerals and salts into the seawater. This is one way the ocean gets its salty taste.

🎯 Exam Tip: Remember that oceanic processes like volcanic activity and hydrothermal vents contribute to the chemical composition of seawater.

Question 3. Water is a non-transparent chemical.
Answer: False
Water is a transparent chemical.
In simple words: Water is actually clear, meaning you can see through it. It is not opaque or cloudy.

🎯 Exam Tip: Water is generally transparent in its pure state, allowing light to pass through, which is a key physical property.

Question 4. Transpiration takes place in rivers and lakes.
Answer: False
Transpiration takes place in plants.
In simple words: Transpiration is when plants release water vapour from their leaves into the air. It does not happen in rivers or lakes, which experience evaporation instead.

🎯 Exam Tip: Distinguish between transpiration (water loss from plants) and evaporation (water loss from open water bodies or soil).

Question 5. Nitrogen is used for the treatment of drinking water.
Answer: False
Chlorine is used for the treatment of drinking water.
In simple words: People use chlorine to clean drinking water, not nitrogen. Chlorine helps to kill germs and make the water safe.

🎯 Exam Tip: Chlorine is commonly used for disinfecting water due to its ability to kill bacteria and other harmful microorganisms.

III. Match the Following

Question 1. Match the following:
1. Roof of World
2. Wet lands
3. Freezing point of water
4. Water treatment
5. Estuary
a. 0°C
b. Chlorine
c. Coovam
d. Pichavaram
e. Himalayas
Answer:
1. Roof of World - (e) Himalayas
2. Wet lands - (d) Pichavaram
3. Freezing point of water - (a) 0°C
4. Water treatment - (b) Chlorine
5. Estuary - (c) Coovam
In simple words: We connect different things to their correct partners. For example, the freezing point of water is a specific temperature, and the Himalayas are known as the 'Roof of the World' because they are so high.

🎯 Exam Tip: Pay attention to specific geographical names and scientific definitions when matching, ensuring each item has only one correct pair.

IV. Analogy:

Question 1. Low rainfall: Water scarcity : : Recycling Water : ...........
Answer: Water Management
In simple words: When there is little rain, water becomes scarce. Similarly, recycling water is a part of managing our water resources well, helping us have enough.

🎯 Exam Tip: Analogies test your understanding of relationships; identify the cause-effect or part-whole relationship to find the matching pair.

Question 2. Frozen Water : Glaciers : : Surface Water : ..........
Answer: River
In simple words: Glaciers are large bodies of frozen water. In the same way, rivers are common examples of surface water, which is water found on top of the land.

🎯 Exam Tip: When forming analogies, connect the given terms based on their primary form or location, such as 'frozen water' to 'glaciers' and 'surface water' to 'rivers'.

Question 3. Evaporation : Sea : : .......... : Trees
Answer: Transpiration
In simple words: Evaporation is when water leaves the sea and goes into the air. Transpiration is a similar process where water leaves trees and goes into the air.

🎯 Exam Tip: Remember that while both are processes of water release, evaporation happens from water bodies, and transpiration specifically from plants.

Question 4. Filtering: Sand : : .......... : Ammonia
Answer: Disinfection
In simple words: Sand is used to filter water. Similarly, ammonia is sometimes used in water treatment for disinfection, which means cleaning it to kill germs.

🎯 Exam Tip: Recognize the specific roles of materials and chemicals in water purification processes, such as sand for filtration and ammonia for disinfection.

Question 5. Solid State : .......... : : Gaseous State : Vapour
Answer: Ice
In simple words: When water is in its gaseous state, it is called vapour. When water is in its solid state, it is called ice.

🎯 Exam Tip: Understand the different states of matter for water: solid (ice), liquid (water), and gas (vapour), and their common names.

V. Very Short Answer

Question 1. What is the composition of water?
Answer: Water is made up of two hydrogen atoms and one oxygen atom joined together. Its chemical formula is H2O. This combination is essential for life on Earth.
In simple words: Water is made from two parts hydrogen and one part oxygen. Its chemical name is H2O.

🎯 Exam Tip: For scientific definitions, state the main components and their ratio, along with the chemical formula if applicable.

Question 2. What is water?
Answer: Water is a clear, tasteless, and odourless chemical substance that appears almost colourless. It is essential for all known forms of life.
In simple words: Water is a clear liquid that has no taste or smell. It is a very important chemical that all living things need.

🎯 Exam Tip: Emphasize the key physical properties (transparent, tasteless, odourless) and its biological importance when defining water.

Question 3. What is saltwater?
Answer: Saltwater is water that contains more than 3% salt. We cannot drink or use this water directly because of its high salt content, which is harmful to our health and most plants. Special processes are needed to remove the salt.
In simple words: Saltwater is water with more than 3% salt. We cannot drink or use it as it is because it is too salty.

🎯 Exam Tip: Clearly state the defining characteristic (salt percentage) and the implications for use (undrinkable, harmful to most plants) when defining saltwater.

Question 4. What are the three stages in the water cycle?
Answer: The three main stages in the water cycle are evaporation, condensation, and precipitation. These stages continuously move water around the Earth.
In simple words: The water cycle has three main steps: water changing to vapour (evaporation), vapour turning into clouds (condensation), and water falling back down as rain or snow (precipitation).

🎯 Exam Tip: Listing the stages accurately is important; briefly explaining each stage in an exam will help score full marks.

Question 5. What is transpiration?
Answer: Transpiration is the process where plants lose water from their leaves into the atmosphere as water vapour. This process helps move water through the plant and cool it down.
In simple words: Transpiration is when plants release water from their leaves into the air as a mist.

🎯 Exam Tip: Clearly state that transpiration is specific to plants and involves the release of water vapour from their aerial parts.

VI. Long Answer Questions:

Question 1. Explain the three stages of the water cycle.
Answer: The water cycle is a continuous natural process that moves water between the Earth's surface and the atmosphere. It is also known as the hydrological cycle. The three main stages are:
1. **Evaporation:** The sun's heat causes water from oceans, lakes, ponds, and rivers to turn into water vapour. This vapour then rises into the air.
2. **Condensation:** As the water vapour rises higher, the air gets cooler. This cool air makes the water vapour change back into tiny water droplets. These droplets then come together to form clouds in the sky.
3. **Precipitation:** When many tiny water droplets in the clouds collide, they form larger, heavier water droplets. The air can no longer hold these heavy droplets, so they fall back to Earth as rain, snow, or hail. This completes the cycle.
In simple words: The water cycle constantly moves water. First, the sun heats water, turning it into vapour (evaporation). This vapour cools and forms clouds (condensation). Then, water falls from the clouds as rain or snow (precipitation).

🎯 Exam Tip: When explaining the water cycle, clearly define and describe each stage (evaporation, condensation, precipitation) and mention that it's a continuous process.

Question 2. How water is conserved by water management method?
Answer: Water management involves several methods to save water and use it wisely. These methods help ensure enough water for everyone and prevent pollution:
1. **Raising Awareness:** Informing people about the harmful effects of throwing waste into water bodies helps protect our water sources.
2. **Water Recycling:** Reusing water after separating pollutants helps to save fresh water. Treated wastewater can be used for non-drinking purposes.
3. **Reduced Chemical Use:** Using fewer chemical fertilizers and pesticides in farming prevents underground water from becoming polluted.
4. **Controlling Deforestation:** Protecting and planting trees helps maintain the water cycle and prevents soil erosion, which can affect water quality.
5. **Efficient Irrigation:** Using methods like drip irrigation and sprinkler irrigation in agriculture saves a lot of water by delivering it directly to plant roots.
In simple words: To save water, we should teach people not to pollute it, clean and reuse water, use fewer chemicals on farms, protect forests, and use smart watering methods like drip irrigation.

🎯 Exam Tip: When listing water conservation methods, include a variety of approaches covering pollution prevention, efficient use, and ecosystem protection.