Chapter 1: Food: Where Does It Come From? Intext Question Q1. Do you find that all living beings need the same kind of food? Answer: No, all living beings do not need the same kind of food. Different animals eat different kinds of food: • Herbivores eat only plants (e.g., cow, deer). • Carnivores eat only animals (e.g., lion, tiger). • Omnivores eat both plants and animals (e.g., humans, dogs). ________________________________________ Exercise Questions Q1. Name five plants and their parts that we eat. Answer: Plant Name Part Eaten Rice Seed Potato Stem Carrot Root Spinach Leaves Cauliflower Flower Q2. Match the items in Column A with those in Column B. Column A (Food Items) Column B (Source) Milk, Curd, Paneer (iii) Animals Spinach, Cauliflower (ii) Plants Eggs (iii) Animals Chicken, Meat, Fish (iii) Animals Rice, Wheat (ii) Plants Q3. Fill up the blanks with the words given: (herbivore, plant, milk, sugarcane, carnivore) (a) Tiger is a ____. (b) Deer eats only plant products and so, is called ____. (c) Parrot eats only ____ products. (d) The ____ that we drink, which comes from cows, buffaloes and goats is an animal product. (e) We get sugar from ____. Answer: (a) carnivore (b) herbivore (c) plant (d) milk (e) sugarcane


Chapter 2: Components of Food
Intext Questions Q1. Given below are the nutrients, functions, and deficiency diseases.
Fill the blanks. Nutrient Function Deficiency Disease 1. Carbohydrates Provides energy ———————— 2. Proteins ———————— Kwashiorkor 3. Fats ———————— ———————— 4. Vitamin C ———————— Scurvy 5. Vitamin D Helps bones to use calcium ———————— 6. Iron ———————— Anaemia Answer: Nutrient Function Deficiency Disease 1. Carbohydrates Provides energy — 2. Proteins Body-building and growth Kwashiorkor 3. Fats Energy storage and warmth — 4. Vitamin C Helps to heal wounds and resist infections Scurvy 5. Vitamin D Helps bones to use calcium Rickets 6. Iron Formation of hemoglobin in blood Anaemia ________________________________________ Exercise Questions (Page 13) Q1. Name the major nutrients in our food. Answer: The major nutrients in our food are: • Carbohydrates • Proteins • Fats • Vitamins • Minerals In addition, roughage (dietary fibers) and water are also essential components of food. ________________________________________ Q2. Name the following: (a) The nutrients which mainly give energy to our body. (b) The nutrients that are needed for the growth and maintenance of our body. (c) A vitamin required for maintaining good eyesight. (d) A mineral that is required for keeping our bones healthy. Answer: (a) Carbohydrates and fats (b) Proteins (c) Vitamin A (d) Calcium ________________________________________ Q3. Name two foods each rich in: (a) Fats (b) Starch (c) Dietary fibre (d) Protein Answer: (a) Fats – Ghee, Butter (b) Starch – Rice, Potato (c) Dietary fibre – Whole grains, Fruits (d) Protein – Pulses, Milk ________________________________________ Q4. Tick (✓) the statements that are correct. 1. By eating rice alone, we can fulfill the nutritional requirement in our body. 2. Deficiency diseases can be prevented by eating a balanced diet. 3. Balanced diet for the body should contain a variety of food items. 4. Meat alone is sufficient to provide all nutrients to the body. Answer: • 1. ✗ • 2. ✓ • 3. ✓ • 4. ✗ ________________________________________ Q5. Fill in the blanks: (a) ______________ is caused by deficiency of Vitamin D. (b) Deficiency of ______________ causes a disease known as beriberi. (c) Deficiency of Vitamin C causes ______________. (d) Night blindness is caused due to deficiency of ______________ in our food. Answer: (a) Rickets (b) Vitamin B1 (c) Scurvy (d) Vitamin A Chapter 3: Fibre to Fabric – NCERT Solutions ________________________________________ Exercise Questions (Page 20) ________________________________________ Q1. Classify the following fibres as natural or synthetic: Nylon, Wool, Cotton, Silk, Polyester, Jute Answer: • Natural fibres: Wool, Cotton, Silk, Jute • Synthetic fibres: Nylon, Polyester ________________________________________ Q2. State whether the following statements are True or False. If false, correct them. (a) Yarn is made from fibres. (b) Spinning is a process of making fibres. (c) Jute is the outer covering of coconut. (d) The process of removing seed from cotton is called ginning. (e) Weaving of yarn makes a piece of fabric. (f) Silk fibre is obtained from the stem of a plant. (g) Polyester is a natural fibre. Answer: (a) True (b) False – Spinning is a process of making yarn from fibres. (c) False – Coir (not jute) is the outer covering of coconut. (d) True (e) True (f) False – Silk fibre is obtained from silkworms, not from plants. (g) False – Polyester is a synthetic fibre. ________________________________________ Q3. Fill in the blanks: (a) Plant fibres are obtained from __________ and __________. (b) Animals fibres are __________ and __________. Answer: (a) Cotton and Jute (b) Wool and Silk ________________________________________ Q4. From which parts of the plant cotton and jute are obtained? Answer: • Cotton is obtained from the fruit of the cotton plant (cotton bolls). • Jute is obtained from the stem of the jute plant. ________________________________________ Q5. Name two items that are made from coconut fibre. Answer: Two items made from coconut fibre: • Ropes • Mats ________________________________________ Q6. Explain the process of making yarn from fibre. Answer: The process of making yarn from fibres is called spinning. In spinning, fibres from a mass of cotton or wool are drawn out and twisted. This brings the fibres together to form a long and strong thread called yarn. . ________________________________________ Chapter 4: Sorting Materials into Groups – NCERT Solutions ________________________________________ Exercise Questions (Page 28) Q1. Name five objects that can be made from wood. Answer: Table, Chair, Door, Bat, Pencil ________________________________________ Q2. Select those objects from the following which shine: Glass bowl, Plastic toy, Steel spoon, Cotton shirt Answer: Glass bowl, Steel spoon ________________________________________ Q3. Match the objects with the materials they are made of: Object Material Book Paper Tumbler Glass Chair Wood Toy Plastic Shoes Leather ________________________________________ Q4. State whether the statements are True or False: (a) Stone is transparent. (b) A notebook has lustre. (c) Chalk dissolves in water. (d) A piece of wood floats on water. (e) Sugar does not dissolve in water. (f) Oil mixes with water. (g) Sand settles down in water. (h) Vinegar dissolves in water. Answer: (a) False (b) False (c) False (d) True (e) False (f) False (g) True (h) True ________________________________________ Q5. Given below are the names of some objects and materials: Water, basketball, orange, sugar, globe, apple, and earthen pitcher Group them as: (a) Round-shaped: Basketball, Orange, Globe, Apple (b) Eatables: Orange, Sugar, Apple, Water (c) Made of metal: None from the list (d) Made of clay: Earthen pitcher Chapter 5: Separation of Substances – NCERT Solutions ________________________________________ Exercise Questions (Page 36) ________________________________________ Q1. Why do we need to separate different components of a mixture? Give two examples. Answer: We need to separate components of a mixture to: 1. Remove harmful or non-useful substances (e.g., removing stones from rice). 2. Obtain useful components (e.g., separating butter from milk). ________________________________________ Q2. What is winnowing? Where is it used? Answer: Winnowing is the method of separating lighter components (like husk) from heavier components (like grain) using wind. Used in: Agriculture to separate husk from grain after threshing. ________________________________________ Q3. How will you separate husk or dirt particles from a given sample of pulses before cooking? Answer: By handpicking – manually removing husk or dirt particles from the pulses. ________________________________________ Q4. What is sieving? Where is it used? Answer: Sieving is a method of separating fine particles from bigger ones using a sieve. Used in: • Separating flour from impurities • Construction (separating sand from gravel) ________________________________________ Q5. How will you separate sand and water from their mixture? Answer: 1. Sedimentation – Let sand settle at the bottom. 2. Decantation – Pour clear water gently. 3. Filtration – Further filter water using a filter paper for better purity. ________________________________________ Q6. Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it? Answer: Yes. Add water: • Sugar dissolves, flour does not. • Filter the mixture. • Evaporate the filtrate to get sugar. ________________________________________ Q7. How would you obtain clear water from a sample of muddy water? Answer: • Allow mud to settle (sedimentation). • Decant the clean water. • Use filtration if needed. ________________________________________ Q8. Fill in the blanks: (a) The method of separating seeds of paddy from its stalks is called __________. (b) When milk, cooled after boiling, is poured on a piece of cloth the cream is left behind on it. This process of separating cream from milk is an example of __________. (c) Salt is obtained from seawater by the process of __________. (d) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clean water was then poured off from the top. This process is called __________. Answer: (a) Threshing (b) Filtration (c) Evaporation (d) Decantation ________________________________________ Q9. True or False: (a) A mixture of milk and water can be separated by filtration. (b) A mixture of powdered salt and sugar can be separated by winnowing. (c) Separation of sugar from tea can be done with filtration. (d) Grain and husk can be separated by the process of decantation. Answer: (a) False (b) False (c) False (d) False ________________________________________ Q10. Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to it. Should you use a tumbler made of plastic or glass? Why? Answer: We should use a glass or plastic tumbler because: • Glass and plastic do not react with acidic lemon juice. • Metal may react and spoil the taste. Chapter 6: Changes Around Us – NCERT Solutions ________________________________________ Exercise Questions (Page 40) ________________________________________ Q1. To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed? Answer: Yes, this change can be reversed by unfolding the dress back to its original length. ________________________________________ Q2. You accidentally dropped your favorite toy and broke it. This is a change you did not want. Can this change be reversed? Answer: No, the broken toy cannot be brought back to its original form. It is an irreversible change. ________________________________________ Q3. Some changes are listed below. For each change, write in the blank column whether the change can be reversed or not. Change Can be Reversed (Yes/No) The sawing of a piece of wood No The melting of ice candy Yes Dissolving sugar in water Yes Cooking of food No Ripening of a mango No Souring of milk No ________________________________________ Q4. A drawing sheet changes when you draw a picture on it. Can you reverse this change? Answer: If the drawing is done with a pencil, it can be erased and reversed. But if done with a pen or colors, it cannot be reversed completely. ________________________________________ Q5. Give examples to explain the difference between changes that can or cannot be reversed. Answer: Reversible Change Irreversible Change Melting ice to water Burning paper Folding a paper Tearing a paper Stretching a rubber band Cooking rice ________________________________________ Q6. A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilized. Can this change in POP be reversed? Answer: No, once Plaster of Paris hardens after drying, it cannot be reversed to its original form. It is an irreversible change. ________________________________________ Q7. A bag of cement lying in the open gets wet due to rain during the night. The next day, the sun shines brightly. Do you think the changes, which have occurred in the cement, can be reversed? Answer: No, the cement reacts with water and sets into a hard mass. This is a chemical change and cannot be reversed. Chapter 7: Getting to Know Plants – NCERT Solutions ________________________________________ Exercise Questions (Page 49) ________________________________________ Q1. Correct the following statements and rewrite them: (a) Stem absorbs water and minerals from the soil. (b) Leaves hold the plant upright. (c) Roots conduct water to the leaves. (d) The number of petals and sepals in a flower is always equal. (e) If the sepals of a flower are joined together, its petals are also joined together. (f) If the petals of a flower are joined together, then the pistil is joined to the petal. Answer: (a) Root absorbs water and minerals from the soil. (b) Stem holds the plant upright. (c) Stem conducts water to the leaves. (d) The number of petals and sepals in a flower is not always equal. (e) If sepals are joined together, it does not mean petals are also joined. (f) If petals are joined, it does not mean pistil is joined to them. ________________________________________ Q2. Draw a leaf, label its parts (midrib, vein, leaf blade). Answer: (Draw a leaf and label:) • Midrib: The central thick vein • Veins: The network of thin lines • Leaf blade: The broad green surface (You can draw this in your notebook or use a diagram from your textbook.) ________________________________________ Q3. Can you find a plant in your house or neighborhood which has a long but weak stem? Write its name. Answer: Yes, plants like money plant, pumpkin, and cucumber have long but weak stems. ________________________________________ Q4. What is the function of a stem in a plant? Answer: Functions of a stem: 1. Supports branches, leaves, flowers, and fruits 2. Transports water from roots to other parts 3. Transports food from leaves to other parts 4. Stores food in some plants (e.g., potato) Chapter 8: Body Movements – NCERT Solutions ________________________________________ Exercise Questions (Page 56) ________________________________________ Q1. Fill in the blanks: (a) Joints of the bones help in the __________ of the body. (b) A combination of bones and cartilages forms the __________ of the body. (c) The bones at the elbow are joined by a __________ joint. (d) The contraction of the __________ pulls the bones during movement. Answer: (a) Movement (b) Skeleton (c) Hinge (d) Muscles ________________________________________ Q2. Indicate ‘True’ or ‘False’ among the following sentences: (a) The movement and locomotion of all animals is exactly the same. (b) The cartilages are harder than bones. (c) The finger bones do not have joints. (d) The forearm has two bones. (e) Cockroaches have an outer skeleton. Answer: (a) False (b) False (c) False (d) True (e) True ________________________________________ Q3. Match the items in Column I with those in Column II: Column I Column II Upper jaw (iii) Fixed joint Fish (iv) Streamlined body Ribs (v) Protect the heart Snail (vi) Muscular foot Cockroach (ii) Legs Answer: • Upper jaw → Fixed joint • Fish → Streamlined body • Ribs → Protect the heart • Snail → Muscular foot • Cockroach → Legs ________________________________________ Q4. Answer the following: (a) Why can our elbow not move backward? Answer: Our elbow has a hinge joint, which allows movement only in one direction—like the hinge of a door. So, it cannot move backward. Chapter 9: The Living Organisms – Characteristics and Habitats – NCERT Solutions ________________________________________ Exercise Questions (Page 64) ________________________________________ Q1. What is a habitat? Answer: A habitat is the natural home or environment of a living organism where it gets food, water, shelter, and suitable conditions to survive. ________________________________________ Q2. How are cactus adapted to survive in a desert? Answer: Cactus adaptations for desert survival: • Spines instead of leaves reduce water loss. • Thick, fleshy stem stores water. • Stem performs photosynthesis. • Roots spread wide to absorb water quickly. ________________________________________ Q3. Fill in the blanks: (a) The presence of specific features, which enable a plant or an animal to live in a particular habitat, is called __________. (b) Animals living on land are called __________ animals, whereas those living in water are called __________ animals. (c) Frogs can live both on land and in water, so they are called __________. (d) Some organisms like __________ do not grow from seeds. Answer: (a) Adaptation (b) Terrestrial, aquatic (c) Amphibians (d) Mushrooms ________________________________________ Q4. Which of the things in the following list are living? Plough, Mushroom, Sewing machine, Radio, Boat, Water, Hyena, Dog, Tree, Wind Answer: Living things: Mushroom, Hyena, Dog, Tree ________________________________________ Q5. Give reasons: (a) Water is important for all living organisms. Answer: Water is essential because: • It helps in digestion and transportation of food. • Maintains body temperature. • Needed for photosynthesis in plants. • Acts as a habitat for aquatic life. (b) Dolphins and whales breathe through nostrils located on the top of their heads. Answer: They breathe through blowholes (nostrils) on top of their heads so they can breathe while mostly submerged in water. ________________________________________ Q6. List common characteristics of living things. Answer: Common characteristics of living things: 1. Need food and water 2. Grow 3. Respond to stimuli 4. Breathe 5. Reproduce 6. Excrete waste 7. Move (some externally, some internally) ________________________________________ Q7. Explain why speed is important for survival in the grasslands for animals like deer. Answer: In grasslands, deer must run fast to escape predators (like lions or tigers). Their speed helps them survive by avoiding danger. Chapter 10: Motion and Measurement of Distances – NCERT Solutions ________________________________________ Exercise Questions (Page 73) ________________________________________ Q1. Give two examples each of modes of transport used on land, water, and air. Answer: • Land: Bus, Bicycle • Water: Boat, Ship • Air: Aeroplane, Helicopter ________________________________________ Q2. Fill in the blanks: (a) One metre is __________ cm. (b) Five kilometre is __________ m. (c) Motion of a child on a swing is __________. (d) Motion of the needle of a sewing machine is __________. (e) Motion of wheel of a bicycle is __________. Answer: (a) 100 (b) 5000 (c) Periodic (d) Oscillatory (e) Circular ________________________________________ Q3. Why can a metre scale not be used to measure the length of a curved line? Answer: A metre scale is straight and rigid, so it cannot bend along the curves. Hence, it can’t accurately measure a curved line. ________________________________________ Q4. What is the use of a thread in measuring the length of a curved line? Answer: A thread is flexible and can be bent along the curve. After placing it along the curved path, it can be straightened and measured with a scale. ________________________________________ Q5. Arrange the following lengths in their increasing order: 1 metre, 1 centimetre, 1 kilometre, 1 millimetre Answer: 1 millimetre < 1 centimetre < 1 metre < 1 kilometre ________________________________________ Q6. The distance between Radha’s home and her school is 3250 m. Express this distance in km. Answer: Distance in km = 3250 ÷ 1000 = 3.25 km ________________________________________ Q7. While measuring the length of a knitting needle, the reading of the scale at one end is 3.0 cm and at the other end is 33.1 cm. What is the length of the needle? Answer: Length = 33.1 cm − 3.0 cm = 30.1 cm ________________________________________ Q8. Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on. Answer: Similarities Differences Both show circular motion Bicycle moves forward, fan is fixed Bicycle involves linear motion too ________________________________________ Q9. Why can you not use a simple scale to measure the length of a curved line? Which instrument is best suited for this? Answer: A simple scale is straight and cannot bend to follow a curved line. A thread or divider with a ruler is best suited. Chapter 11: Light, Shadows and Reflections – NCERT Solutions ________________________________________ Exercise Questions (Page 83) ________________________________________ Q1. Rearrange the boxes given below to make a sentence that helps us understand opaque objects. ☐ allow ☐ light ☐ do ☐ not ☐ objects ☐ opaque ☐ through ☐ to ☐ pass Answer: Opaque objects do not allow light to pass through. ________________________________________ Q2. Classify the objects or materials given below as opaque, transparent, or translucent: Air, Water, Glass, Wood, Steel, Fog, Paper, Butter paper Answer: • Opaque: Wood, Steel, Paper • Transparent: Air, Water, Glass • Translucent: Fog, Butter paper ________________________________________ Q3. Can you see a shadow of an object in a completely dark room? Answer: No, shadow is formed only when light is present. In a completely dark room, there is no light, so no shadow is formed. ________________________________________ Q4. A ball is placed in the middle of a room. Can its shadow be formed in more than one direction at the same time? Answer: Yes, if there are more than one light sources around the ball, multiple shadows can be formed in different directions. ________________________________________ Q5. Can you form a shadow with a transparent object? Why not? Answer: No, a transparent object does not block light, so it does not form a shadow or forms a very faint one. ________________________________________ Q6. What kind of change occurs when your body casts a shadow? Answer: When light is blocked by your body, it creates a dark region on the opposite side called a shadow. It’s a temporary and reversible change. ________________________________________ Q7. What are the conditions required to form a shadow? Answer: To form a shadow, three things are needed: 1. Source of light 2. Opaque object 3. Surface on which the shadow is cast ________________________________________ Q8. How are shadows different from images? Answer: Shadow Image Formed when light is blocked Formed by reflection or refraction Only dark in color Shows exact color and details No detailed features Has clear details Requires a screen May not need a screen (mirror) Chapter 12: Electricity and Circuits – NCERT Solutions ________________________________________ Exercise Questions (Page 90) ________________________________________ Q1. Fill in the blanks: (a) A device that is used to break an electric circuit is called a __________. (b) An electric cell has __________ terminals. Answer: (a) switch (b) two ________________________________________ Q2. Mark ‘True’ or ‘False’ for the following statements: (a) Electric current can flow through metals. (b) Instead of metal wires, a jute string can be used to make a circuit. (c) Electric current can pass through a sheet of thermocol. Answer: (a) True (b) False (c) False ________________________________________ Q3. Explain why the bulb would not glow in the arrangement shown below. Answer: The bulb will not glow because the circuit is not complete. The terminals of the cell are not connected properly, or the material used to join them may not be a conductor. ________________________________________ Q4. Complete the drawing shown below to indicate where the free ends of the two wires should be joined to make the bulb glow. Answer: The free ends of the wire should be connected: • One to the positive terminal of the cell • Other to the negative terminal This will complete the circuit, and the bulb will glow. ________________________________________ Q5. What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them. Answer: A switch is used to open or close a circuit. It helps to turn ON or OFF electrical gadgets. Examples: Television, Fan, Iron, Refrigerator, Mixer grinder ________________________________________ Q6. Would the bulb glow after completing the circuit shown in the figure below if instead of safety pins we use an eraser? Answer: No, because an eraser is an insulator and does not allow electricity to pass through. The circuit remains incomplete. ________________________________________ Q7. Would the bulb glow in the circuit shown below? Answer: If the wires are connected properly and materials are conductive, then the circuit is complete and the bulb will glow. ________________________________________ Q8. Using the ‘conductor or insulator’ activity done in class, name 5 objects each that conduct electricity and 5 that do not. Answer: • Conductors: Copper wire, Iron nail, Aluminium foil, Steel spoon, Graphite • Insulators: Plastic scale, Rubber, Wood, Glass, Cloth ________________________________________ Q9. What are conductors and insulators? Answer: • Conductors are materials that allow electric current to pass through them. Example: Copper, Iron • Insulators are materials that do not allow current to pass through them. Example: Plastic, Rubber Chapter 13: Fun with Magnets – NCERT Solutions ________________________________________ Exercise Questions (Page 97) ________________________________________ Q1. Fill in the blanks: (a) Artificial magnets are made in different shapes such as __________, __________ and __________. (b) The materials which are attracted towards a magnet are called __________. (c) Paper is not a __________ material. (d) In olden days, sailors used to find direction by suspending a piece of __________. (e) A magnet always has __________ poles. Answer: (a) bar, horse-shoe, cylindrical (b) magnetic materials (c) magnetic (d) magnet (e) two ________________________________________ Q2. State whether the following statements are True or False. (a) A cylindrical magnet has only one pole. (b) Natural magnets were discovered in Greece. (c) Similar poles of two magnets repel each other. (d) Maximum iron filings stick in the middle of a bar magnet when brought near them. (e) Bar magnets always point towards North–South direction. Answer: (a) False (b) True (c) True (d) False (e) True ________________________________________ Q3. It was observed that a pencil sharpener gets attracted by both the poles of a magnet although its body is made of plastic. Name a material that might have been used to make some part of it. Answer: The blade of the sharpener is likely made of iron or steel, which are magnetic materials. ________________________________________ Q4. Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks. Column I Column II N – N Repulsion N – S __________ S – N __________ S – S __________ Answer: Column I Column II N – N Repulsion N – S Attraction S – N Attraction S – S Repulsion ________________________________________ Q5. Write any two properties of a magnet. Answer: 1. A magnet has two poles: North and South. 2. Like poles repel each other, unlike poles attract each other. ________________________________________ Q6. Where are poles of a bar magnet located? Answer: Poles of a bar magnet are located at its two ends – one end is the North Pole, and the other is the South Pole. ________________________________________ Q7. A bar magnet is cut into two pieces. Will both the pieces work as magnets? Draw a diagram to show the poles. Answer: Yes, both pieces will become magnets and will have both North and South poles. Diagram (Text Description): If a bar magnet is cut into two, each piece becomes: [N——S] → Cut → [N——S] & [N——S] ________________________________________ Q8. Consider the following situations: (a) A magnet is brought near a compass. (b) Iron nails are kept near a magnet. (c) Two similar magnets are brought close to each other. What do you observe in each case? Answer: (a) The compass needle deflects due to magnetic field. (b) Iron nails get attracted to the magnet. (c) If like poles face each other, they repel; if unlike poles, they attract. Chapter 14: Water – NCERT Solutions ________________________________________ Exercise Questions (Page 103) ________________________________________ Q1. Fill in the blanks: (a) The process of changing water into its vapour is called __________. (b) The process of changing water vapour into water is called __________. (c) No rainfall for a year or more may lead to __________ in that region. (d) Excessive rains may cause __________. Answer: (a) evaporation (b) condensation (c) drought (d) flood ________________________________________ Q2. State for each of the following whether it is due to evaporation or condensation: (a) Water drops appear on the outer surface of a glass containing cold water. (b) Steam rising from wet clothes while they are ironed. (c) Fog appearing on a cold winter morning. (d) Blackboard dries up after wiping it. (e) Steam rising from a hot girdle when water is sprinkled on it. Answer: (a) Condensation (b) Evaporation (c) Condensation (d) Evaporation (e) Evaporation ________________________________________ Q3. Which of the following statements are "true"? (i) Water vapour is present in air only during the monsoon. (ii) Water evaporates into air from oceans, rivers, and lakes but not from the soil. (iii) The process of water changing into its vapour is called evaporation. (iv) The evaporation of water takes place only in sunlight. (v) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler. Answer: (i) False (ii) False (iii) True (iv) False (v) True ________________________________________ Q4. Suppose you want to dry your school uniform quickly. Would spreading it near an anghithi or heater help? If yes, how? Answer: Yes. The heat from the anghithi or heater increases the rate of evaporation. Warm air absorbs more water vapour, so the clothes dry faster. ________________________________________ Q5. Take out a cooled bottle of water from the refrigerator and keep it on a table. After some time, you notice water droplets on the outer surface of the bottle. Why? Answer: The water vapour present in the air condenses on the cold surface of the bottle, forming water droplets. ________________________________________ Q6. To clean your spectacles, you often breathe out on glasses to make them wet. Explain why they become wet. Answer: Our breath contains water vapour. When we breathe out on cool glasses, the vapour condenses, forming a thin film of moisture. ________________________________________ Q7. How are clouds formed? Answer: Water from oceans, rivers, and other sources evaporates and rises. In the upper atmosphere, it cools and condenses to form tiny water droplets. These droplets gather to form clouds. ________________________________________ Q8. When does a drought occur? Answer: A drought occurs when there is no rainfall for a long time, leading to scarcity of water for drinking, farming, and daily use. Chapter 15: Air Around Us – NCERT Solutions ________________________________________ Exercise Questions (Page 110) ________________________________________ Q1. What is the composition of air? Answer: Air is a mixture of gases. The major components of air are: • Nitrogen (about 78%) • Oxygen (about 21%) • Carbon dioxide, argon, water vapour, and other gases (about 1%) ________________________________________ Q2. Which gas in the atmosphere is essential for respiration? Answer: Oxygen is essential for respiration. ________________________________________ Q3. How will you prove that air supports burning? Answer: Take a burning candle and cover it with a glass jar. After some time, the flame goes out. This shows that something in air (oxygen) supports burning. Once it is used up, the flame goes out, proving air supports burning. ________________________________________ Q4. How will you show that air is dissolved in water? Answer: • Take some water in a pan and heat it slowly. • Before boiling, you will see tiny bubbles forming on the inner surface of the pan. • These bubbles are air that was dissolved in water, coming out when heated. ________________________________________ Q5. Why does a lump of cotton wool shrink in water? Answer: A lump of cotton contains air in between its fibres. When dipped in water, the air escapes and the fibres get soaked, so it shrinks. ________________________________________ Q6. The layer of air around the earth is known as __________. Answer: The layer of air around the earth is known as the atmosphere. ________________________________________ Q7. The component of air used by green plants to make their food is __________. Answer: Carbon dioxide is used by green plants to make food through photosynthesis. ________________________________________ Q8. List five activities that are possible due to the presence of air. Answer: 1. Breathing by humans and animals (respiration) 2. Burning of fuels 3. Flying of birds and airplanes 4. Photosynthesis in plants 5. Movement of windmills and sailing boats ________________________________________ Q9. How do plants and animals help each other in the exchange of gases in the atmosphere? Answer: • Animals take in oxygen and give out carbon dioxide during respiration. • Plants take in carbon dioxide and release oxygen during photosynthesis. Thus, plants and animals help maintain the balance of oxygen and carbon dioxide in the atmosphere. Chapter 16: Garbage In, Garbage Out – NCERT Solutions ________________________________________ Exercise Questions (Page 117) ________________________________________ Q1. Which kind of garbage is not converted into compost by redworms? Answer: Garbage items like plastic, polythene bags, broken glass, aluminium foil, and metal objects are non-biodegradable and not converted into compost by redworms. ________________________________________ Q2. Have you seen any activity which is harmful to the environment? Answer: Yes. Examples include: • Burning of garbage, especially plastic, which releases toxic gases. • Throwing waste in water bodies, which pollutes water and harms aquatic life. • Littering in public places, which leads to land pollution. ________________________________________ Q3. Is garbage disposal the responsibility only of the government? Answer: No. Every citizen is responsible for proper disposal of garbage. We should: • Segregate waste into biodegradable and non-biodegradable. • Avoid using plastic bags. • Recycle and reuse items. • Keep our surroundings clean. ________________________________________ Q4. What do you do with the leftover food at home? Answer: • Minimize wastage by cooking only what is needed. • Leftover food can be: o Fed to animals. o Disposed in compost bins to make manure. o Shared with others when possible. ________________________________________ Q5. If you and your friends are given the choice of eating in a plastic plate or a banana leaf platter at a party, which one would you prefer and why? Answer: We would prefer a banana leaf platter because: • It is natural and biodegradable. • It does not cause pollution. • It can be composted easily. • Plastic is harmful to health and environment. ________________________________________ Q6. Write a poem on garbage. You can take the help of your elders, or teachers. Answer: Poem: “Let’s Clean Our Earth” Garbage here, garbage there, Lying scattered everywhere. Plastic bags and wrappers fly, Polluting land, water, and sky. Let us clean and segregate, Before it becomes too late. Compost the waste, reuse the best, Recycle things – that’s our test. Say no to plastic, loud and clear, Keep our earth fresh and dear. Together we can make a start, With love and care from every heart. ________________________________________ Q7. Write an article in your local newspaper on the harmful effects of plastic bags, suggesting alternatives. Answer: Article: “Say No to Plastic Bags” Plastic bags have become a serious threat to our environment. They do not decompose and remain in soil and water for hundreds of years. Animals often eat plastic unknowingly, which harms or kills them. Burning plastic releases toxic gases that pollute the air and affect health. We must switch to eco-friendly alternatives like: • Cloth bags • Jute bags • Paper bags • Banana or palm leaves Let’s make our community plastic-free by spreading awareness and adopting greener options. ________________________________________ Q8. Be a detective. Find out whether the garbage is properly disposed of at your home, school, and neighborhood. Prepare a list of things you find out. Answer: Observations as a Detective: Place Observation Proper Disposal? Home Kitchen waste put in dustbin, but mixed Mixed waste School Separate bins for dry and wet waste Yes Neighborhood Garbage thrown in open spaces and drains No Nearby Shop Uses plastic bags for everything No Conclusion: Awareness and waste segregation needs to improve. People must be encouraged to use dustbins, avoid plastic, and support composting.