──────────────────────────────────────────────────────── IN-TEXT QUESTIONS ────────────────────────────────────────────────────────
Question:
“What will happen if the Sun is not visible for a few days?
(1) We may have to depend on artificial lighting during the day.
(2) …
(3) …”
Answer (sample ideas):
• If there is no sunlight, plants cannot make food and might start to weaken.
• We would have to use more electric lights during the daytime, which uses more energy.
• It would become colder.
• Many living things would struggle to survive without the warmth and light from the Sun.
Question:
“Look at this forest. What could happen if we keep cutting down trees from a large forest area? Can you make a story or a role play?”
Answer (sample ideas):
• If we keep cutting trees, many animals lose their homes, and the soil can get washed away (soil erosion).
• It may become harder to get fresh air and water.
• Fewer trees mean less rainfall and more warming of the area.
• Eventually, the place can become barren and lifeless.
Question:
“Whose statement about the cow’s energy is correct and why? Is the cow directly getting energy from the Sun, or is it through the grass?”
Answer:
• The cow gets energy from eating the grass.
• However, the grass itself needs sunlight to grow and make food.
• So, ultimately, the Sun is the main source of energy for all living things, but the cow gets it indirectly through plants.
──────────────────────────────────────────────────────── ACTIVITY QUESTIONS ────────────────────────────────────────────────────────
Activity 11.1 (Let us experience)
Question:
“Take a deep breath, then hold it for as long as you can. How long can you hold your breath? How do you feel when you hold your breath?”
Answer:
• We usually cannot hold our breath for very long because our body needs oxygen.
• Holding our breath makes us feel uncomfortable or dizzy after some time.
• This shows that oxygen in the air is very important for our survival.
Activity 11.2 (Let us make and decorate)
Question:
“Make a paper pinwheel (firki) by cutting and folding a square piece of paper. Blow air on it or run around. What do you observe?”
Answer:
• The pinwheel rotates when air (wind) moves against its blades.
• We see that moving air can cause movement, like a windmill.
• This demonstrates that wind has energy.
Activity 11.3 (Let us find out)
Question:
“In Table 11.1, list daily activities where water is used and often wasted. Suggest ways to reduce water wastage.”
Answer (sample):
• Hand washing: Turn off the tap while soaping hands.
• Brushing teeth: Use a mug instead of running water.
• Washing utensils: Use a tub or a sink filled with water rather than letting water run continuously.
• Gardening: Water plants in the early morning or late evening to reduce evaporation.
• By following these tips, we save water for future use.
Activity 11.4 (Let us investigate)
Question:
“Collect soil samples from different places. Guess what is in them, then observe color and texture with your eyes and possibly a magnifying lens. Are your guesses correct?”
Answer (sample):
• Soil from a garden might look dark and have pieces of roots.
• Soil from near a construction site might have small stones or sand.
• Under a magnifying lens, you might see tiny bits of gravel or plant matter.
• Different places have different soil types and colors because of what is in them.
Activity 11.5 (Let us conduct a survey)
Question:
“Survey vehicles in your neighborhood. Which types of vehicles do you see, and what fuels do they use?”
Answer (sample):
• Cars, motorbikes, scooters → mostly petrol.
• Buses, trucks → mostly diesel.
• Some autos/cars → CNG (Compressed Natural Gas) or electric.
• This shows we use different fuels, many of which are fossil fuels.
Activity 11.6 (Let us make a list of natural resources used)
Question:
“List different daily activities and the natural resource used. For example: Washing clothes → Water, etc.”
Answer (sample):
• Washing clothes → Water.
• Making clay toys → Soil (clay).
• Having breakfast → Food from plants/animals, water used for cooking.
• Collecting firewood → Forest trees.
• By making such lists, we see that we depend on air, water, soil, plants, animals, and minerals every day.
──────────────────────────────────────────────────────── EXERCISE QUESTIONS (“Let us enhance our learning”) ────────────────────────────────────────────────────────
Question:
“Fig. 11.9 shows items related to natural resources. Match them with their jumbled names (ocrk, refost, ndiw, atwre). Classify them as renewable or non-renewable.”
Answer:
• ocrk → rock (non-renewable)
• refost → forest (renewable)
• ndiw → wind (renewable)
• atwre → water (renewable)
Question:
“State whether these statements are True (T) or False (F). If false, correct them:
(i) Nature has all the resources to meet human needs.
(ii) Machines are a resource found in nature.
(iii) Natural gas is a non-renewable resource.
(iv) Air is a renewable resource.”
Answer:
(i) True.
(ii) False. Machines are made by humans, so they are human-made resources.
(iii) True.
(iv) True.
Question:
“Fill in the blanks with the best option:
(i) A fuel commonly used in two-wheelers:
(a) Kerosene (b) Petrol (c) Diesel (d) LPG
(ii) An example of a renewable resource:
(a) Coal (b) Water (c) Natural gas (d) Petrol”
Answer:
(i) (b) Petrol
(ii) (b) Water
Question:
“Classify the following as renewable or non-renewable: coal, natural gas, forests, minerals.”
Answer:
• Renewable → Forests
• Non-renewable → Coal, natural gas, minerals
Question:
“Why do we say petroleum is a non-renewable resource?”
Answer:
• It takes millions of years to form beneath the earth from dead plants and animals.
• We cannot make more petroleum quickly. Once used up, it will not be replaced in a short time.
Question:
“It is difficult to regrow forests. Justify.”
Answer:
• Trees take many years to grow fully.
• A forest is not just trees; it is also many different plants, animals, and insects living together.
• Restoring that entire system is very slow.
Question:
“Make a list of five daily activities where you use natural resources. Suggest ways to reduce their use.”
Answer (sample):
• Bathing (water) → Take shorter baths, use buckets instead of a shower.
• Lighting rooms (electricity) → Switch off lights when not in use.
• Using vehicles (fossil fuels) → Walk or cycle for short distances.
• Cooking (fuel) → Use efficient stoves or solar cookers.
• Cooling rooms (fan/AC) → Use fans more, AC only when necessary.
Question:
“List four activities that are possible because of the presence of air.”
Answer (sample):
• Breathing for humans, animals, and plants.
• Flying kites.
• Rotating windmills.
• Birds flying in the sky.
Question:
“How can you help increase the green cover in your locality?”
Answer (sample):
• Plant more trees in parks and empty spaces.
• Water saplings regularly and protect them from animals.
• Organize tree-planting drives in your community and school.
Question:
“In the given illustration, food is being cooked.
(i) What type of energy is being used?
(ii) Give one benefit and one drawback of using this type of energy.”
Answer (sample):
• (i) If they are using firewood or coal, that comes from forests/fossil fuels.
• (ii) Benefit: It is a common and cheap method of cooking. Drawback: It causes a lot of smoke, which can lead to air pollution and breathing problems.
Question:
“Cutting down trees on a large scale impacts soil quality. Why?”
Answer:
• Tree roots hold the soil together and prevent it from washing away.
• Without trees, soil can be easily carried away by water or wind, causing erosion.
Question:
“Explain two ways human activities pollute the air. Propose one action to reduce air pollution.”
Answer (sample):
• Burning fossil fuels in vehicles and factories → smoke, harmful gases.
• Burning garbage or crop stubble → releases pollutants into the air.
• One action: Encourage using public transport or plant more trees to clean the air.
Question:
“A family uses solar panels, a gas stove, and a windmill. What if there is no sunlight for a week?”
Answer:
• The solar panels cannot generate electricity without sunlight.
• They would still have gas for cooking, and the windmill might work if there is wind, but they lose the solar power source.
Question:
“Fill in the blanks with (fossil fuels, forest, air, petroleum, coal, water, non-renewable resource).”
Answer (sample fill):
• “Natural Resources → Renewable Resources → (forest, air, water), Non-renewable Resources → (coal, petroleum). Fossil fuels include coal and petroleum. A forest is a renewable resource if we care for it properly. Fossil fuels are a non-renewable resource.”
Question:
“There is an increasing demand for trees to meet requirements of industries and housing. Trees are being cut. Is it justified? Prepare a brief report.”
Answer (sample ideas):
• Cutting trees can be harmful if we do not replant them.
• We need to balance development with conservation.
• We should plant new trees to replace the ones cut down.
Question:
“Propose a plan to use less water in your school. What steps would you take, and how would this help the environment?”
Answer (sample plan):
• Steps: Fix leaking taps; use buckets instead of hoses for cleaning; place awareness posters.
• Impact: Saves water for future use, ensures more water is available to plants and people, reduces wastage.