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Class 6 Science: Nature's Treasures, 8 practice questions with answers

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These are 8 practice questions on Class 6 Science Chapter 11, Nature's Treasures, of the new NCERT textbook, Curiosity. Each has a worked answer and the textbook page it comes from. They cover the air around us, fresh and salty water, windmills, soil and rocks, fossil fuels, natural and human-made resources, and renewable and non-renewable resources. Try each one before you open the answer.

These questions are our own, drafted with AI help, and every answer was checked against the textbook page it cites, but no practising teacher has reviewed them yet. If you find a mistake, please tell us.

What the chapter says you need

Facts from the NCERT textbook (Curiosity: Textbook of Science for Grade 6, Chapter 11, printed pages 207 to 230):

Air, water and wind

Question 1. A small room holds about 300 litres of air. Using the chapter's figure for oxygen, about how many litres of that air are oxygen?

Answer: about 63 litres. Air is about 21% oxygen, which means 21 parts in every 100. 300 litres is 3 lots of 100, so the oxygen is about 3 × 21 = 63 litres. (Composition of air, page 209.)

Question 2. Riya says, "Water covers about two-thirds of the Earth, so most of the Earth's water is fresh water we can use." Find her mistake.

Answer: most of the Earth's water is salty sea water, not fresh water. Water does cover about two-thirds of the Earth's surface, but most of it is in the oceans and seas, and it is saline, so it is not fit for drinking, farming or industry. Fresh water is in ice sheets and snow, rivers, lakes and underground, and only a very small fraction of it is easily accessible. (Water, pages 211 and 212.)

Question 3. On a day with no breeze at all, would a windmill farm make electricity? Why?

Answer: no; with no moving air, the wings do not turn, so no electricity is made. A windmill farm uses the energy of the wind to generate electricity: the wind, which is moving air, rotates the wings of each windmill, just as it rotates a firki. On a day with no breeze there is no moving air to turn the wings. (Wind and windmills, page 210.)

Soil, rocks and fuels

Question 4. Sohan says, "Soil is everywhere, so it is a renewable resource." Find his mistake.

Answer: the chapter counts soil as non-renewable, because it takes thousands of years to form. Soil forms when rocks are broken apart by the Sun, water and living organisms over a very long time, thousands of years. A resource that is not replenished within a reasonable period of time is non-renewable, and the chapter lists soil with minerals, rocks, coal, petroleum and natural gas as non-renewable natural resources. Being found everywhere does not make it quick to replace. (How soil forms, page 219; renewable and non-renewable resources, page 224.)

Question 5. Suppose a forest and a granite hill were both used up. Which could nature replace sooner, and why?

Answer: the forest, because it is a renewable resource that can regrow, even though it takes many years; rocks take thousands to millions of years to form. It takes many years to grow a new forest or restore a lost one, but forests are renewable natural resources that nature renews. Rocks such as granite take thousands to millions of years to form, so they are non-renewable. (Forests, page 217; rocks, page 221; renewable and non-renewable resources, page 224.)

Question 6. One bus runs on diesel and another on CNG. Which is the cleaner fuel, according to the chapter?

Answer: CNG. Natural gas used as Compressed Natural Gas (CNG) is a cleaner fuel than petrol or diesel. When fossil fuels such as diesel are burnt, smoke and carbon dioxide are produced, which pollute the air. (Fossil fuels, pages 222 and 223.)

Natural resources and their care

Question 7. Kabir sorts four things into natural resources and human-made resources: a river, sunlight, a wooden chair and a solar panel. He puts the wooden chair with the natural resources because it is made of wood. Find his mistake.

Answer: the wooden chair is human-made, even though wood is natural. Resources we get from nature, such as the river and sunlight, are natural resources. Things people make from natural resources for their convenience, such as furniture and solar panels, are human-made resources. So the chair and the solar panel are human-made; the river and the sunlight are natural. (Natural and human-made resources, page 223.)

Question 8. What did the women of the Chipko movement do, and why?

Answer: they encircled and hugged the trees, to stop them being felled. The Chipko movement started in the early 1970s in Uttarakhand (then part of Uttar Pradesh). Local women took an active part, putting their arms round the trees to protect the forest. It is one example of how common people have worked to stop the cutting of trees. (Forests, page 217.)

Questions students ask

What is the difference between renewable and non-renewable resources? Renewable resources, such as air, water and forests, are renewed, replenished or restored by nature within a reasonable time. Non-renewable resources, such as minerals, soil, rocks, coal, petroleum and natural gas, are found in limited quantities and are not replenished within a reasonable time. (Pages 224 and 226.)

What are fossil fuels? Petroleum, natural gas and coal. They formed from the remains of microorganisms and plants buried deep inside the earth, over millions of years. Petrol, diesel and kerosene are obtained from petroleum. (Page 222.)

What is rainwater harvesting? Collecting and storing rainwater, for example in buildings and schools, for later use. Stepwells, called Bawadi in Rajasthan and Vav in Gujarat, are an old way of harvesting water. (Page 213.)

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Sources

All opened and read on 22 October 2026. Page numbers are the printed page numbers of the textbook; printed page = PDF page + 206.

The facts are from the textbook pages above. The questions and worked answers are our own. This guide is general information; follow your teacher and the textbook.