Answers to all "Let us enhance our learning" questions of Chapter 11, Nature's Treasures (NCERT Class 6 Science, Curiosity, 2026-27): natural resources, renewable and non-renewable resources, air, water, forests, fossil fuels, solar energy, pollution and conservation. All 16 questions are answered, with the key answer highlighted.
Fig. 11.9 shows items related to natural resources (a tap with water, a windmill, a forest, a rock). Match them with their jumbled-up names (ocrk, refost, ndiw, atwre). Write the names of these resources and classify them as renewable or non-renewable.
Solution
Item
Jumbled name
Resource
Type
Tap with running water
atwre
Water
Renewable
Windmill
ndiw
Wind
Renewable
Forest
refost
Forest
Renewable
Rock
ocrk
Rock (minerals)
Non-renewable
Water (atwre), wind (ndiw), forest (refost): renewable; rock (ocrk): non-renewable.
State 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.
Solution
(i) T. Nature provides enough for everyone's needs (though not for everyone's greed, so we must use resources wisely).
(ii) F. Machines are made by humans (human-made resources); they are not found in nature.
(iii) T
(iv) T
(i) T (ii) F: machines are made by humans (iii) T (iv) T
Fill in the blanks: (i) A fuel that is commonly used in two-wheelers like scooters or bikes is ___ (a) kerosene (b) petrol (c) diesel (d) LPG. (ii) An example of a renewable resource is ___ (a) coal (b) water (c) natural gas (d) petrol.
Why do we say that petroleum is a non-renewable resource?
Solution
Petroleum was formed from the remains of tiny plants and animals buried deep under the Earth (mostly under the sea) for millions of years. Once we use it up, it cannot be replaced within a human lifetime, and its stock is limited. So it is non-renewable.
It takes millions of years to form and its stock is limited, so once used up it cannot be replaced soon.
It is difficult to regrow forests. Justify this statement.
Solution
Trees take many years (often decades) to grow big; a forest with tall trees, bushes and grasses takes even longer to develop.
A natural forest is a home for many plants, animals, insects and microorganisms that depend on each other; planting a few trees cannot quickly replace this variety of life.
When a forest is cut, its fertile top soil is often washed away, so new plants grow poorly.
So although forests are renewable, regrowing a forest is slow and difficult; it is much better to protect the forests we have.
Trees take many years to grow, a forest's rich variety of life cannot be replaced quickly, and the soil is often lost after cutting, so forests regrow very slowly.
Make a list of five daily activities in which you use natural resources. Suggest ways by which you can reduce their use.
Solution
Activity
Resource used
How to reduce its use
Bathing and brushing
Water
Use a bucket instead of a shower; close the tap while brushing
Cooking food
LPG (natural gas) or wood
Cover pans while cooking, use a pressure cooker, use solar cookers
Travelling to school
Petrol, diesel
Walk, cycle, use the school bus or share rides
Using lights and fans
Electricity (from coal)
Switch off when not needed, use LED bulbs and daylight
Writing in notebooks
Paper (from trees)
Use both sides of the paper, reuse old notebooks, recycle paper
E.g. bathing (water), cooking (gas), travel (petrol), lights and fans (electricity), notebooks (paper); reduce by saving water, switching off lights, walking or cycling, and reusing paper.
In the illustration, food is being cooked (in a solar cooker). (i) What type of energy is being used for cooking? (ii) Name one benefit and one drawback of using this type of energy for cooking.
Solution
(i) Solar energy (energy from sunlight).
(ii) Benefit: it is free, renewable and does not pollute the air (no smoke).
Drawback: it cannot be used at night or on cloudy or rainy days, and it cooks slowly.
(i) Solar energy (ii) Benefit: free, renewable, no smoke. Drawback: cannot be used at night or on cloudy days, and is slow.
Explain two ways in which human activities pollute the air. Propose one action which can help in reducing air pollution.
Solution
Two ways:
Burning fuels in vehicles, factories and power plants releases smoke and harmful gases (like carbon monoxide).
Burning garbage, crop stubble and firewood produces smoke and fine dust particles. (Bursting firecrackers and construction dust also pollute the air.)
One action: use public transport, cycles or walking instead of private vehicles (or plant more trees, which clean the air; or do not burn waste but compost or recycle it).
Burning fuels in vehicles and factories, and burning garbage or crop stubble, pollute the air; using public transport or cycling (and planting trees) helps reduce it.
A family uses solar panels to generate electricity, a gas stove to cook food and a windmill for pumping water from a well. What would happen if there were no sunlight for a week?
Solution
The solar panels would not produce electricity, so the family would have no power (unless they had stored electricity in batteries or used the main supply).
The gas stove would still work, because it uses LPG, not sunlight.
The windmill would still pump water as long as the wind blows (wind does not stop just because the sky is cloudy for a week).
The solar panels would stop producing electricity; the gas stove would still work; the windmill would work as long as the wind blows.
There is an increasing demand for trees to meet the requirements of industries and for housing. Therefore, trees are being felled. Is it justified? Discuss and prepare a brief report.
Solution
Report: "Felling trees for development: is it justified?"
Why trees are cut: wood is needed for furniture, paper and construction, and land is needed for houses, roads and industries as the population grows.
Problems caused: loss of homes for birds and animals, less oxygen and more pollution and heat, less rainfall, soil erosion, floods and landslides, and climate change.
Conclusion: cutting trees on a large scale is not justified, because the harm to the environment is serious and lasts for a long time. Some cutting may be necessary, but it should be balanced by:
planting more trees than are cut (afforestation) and protecting natural forests;
using wood from planted forests, and recycling paper and wood;
using other materials (bamboo, metal, recycled plastic) where possible;
following the laws that protect forests and building on already cleared land.
Large-scale felling is not justified: it destroys habitats, causes pollution, soil erosion and less rain. Needs should be met through planting more trees than are cut, recycling, using alternatives and protecting natural forests.
Propose a plan to use less water in your school. What steps would you take to make this plan happen and how would it help the environment?
Solution
"Save Every Drop" plan:
Form a student water team to check taps and pipes every week and report leaks for repair.
Put up reminder posters near taps ("Close the tap!") and fit taps that close automatically.
Use buckets and mugs for cleaning instead of running hoses.
Use the water left in bottles and from washing hands or vegetables to water the school garden.
Set up rainwater harvesting from the school roof into a tank or a recharge pit.
Hold awareness talks and a "water-saving champion" competition between classes.
Benefits: less water is drawn from wells and rivers, groundwater is recharged, less energy is used to pump water, and students learn habits that save water at home too.
Fix leaks, put up reminders, use buckets, reuse leftover water for plants, harvest rainwater and run awareness drives; this saves water, recharges groundwater and builds good habits.
