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Class 6 Science: The Wonderful World of Science, 8 practice questions with answers

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These are 8 practice questions on Chapter 1, The Wonderful World of Science, of the new NCERT Class 6 Science textbook, Curiosity. Each has a worked answer and the textbook page it comes from. The chapter is about how science works, so the questions ask you to put the steps of the scientific method in order, tell an observation from a guess, judge whether a test really answers the question, say in advance what a test should show, decide which questions can be tested, and explain why scientific ideas can change. Try each one on paper before you open the answer. The next chapter of the same book is Diversity in the Living World.

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 1, printed pages 1 to 8):

The steps of the scientific method

Question 1. These sentences tell what Meera did, but they are mixed up. Put them in order and name the step of the scientific method each one shows. (a) She waters the plant less for a week, and the new leaves come out green. (b) She notices that the leaves of her tomato plant are turning yellow. (c) She thinks, "Maybe I am giving it too much water." (d) She decides that too much water was the likely cause. (e) She asks herself, "Why are the leaves turning yellow?"

Answer: (b), (e), (c), (a), (d). First she observes something: the yellow leaves (b). This makes her ask a question: why is this happening? (e). She guesses an answer: too much water (c). She tests the guess by watering less (a). Last, she analyses the result: the new leaves are green, so her guess was probably right (d). (The steps of the scientific method, page 6.)

Question 2. Say whether each sentence is an observation or a guess. (a) "The puddle outside the gate was bigger at 9 o'clock than at 3 o'clock." (b) "The sun must have dried the puddle." (c) "The leaves of the plant near the window bend towards the glass."

Answer: (a) observation, (b) guess, (c) observation. An observation is something we notice with our senses or measure, such as the size of the puddle at two times (a) or the way the leaves are bending (c). A guess is a possible explanation that still has to be tested: the sun is one possible reason the puddle shrank, but water could also have soaked into the ground (b). In the scientific method we observe first, and the guess comes after the question. (Observing, questioning and guessing, page 6. Sorting the sentences is our own question.)

Testing a guess

Question 3. Kabir's phone will not charge. He has two guesses: the charger is faulty, or the cable is faulty. He changes the charger and the cable at the same time, and the phone charges. What can he say about his guesses? What should he have done?

Answer: he cannot tell which one was faulty; he should change only one thing at a time. Because he changed both together, the phone could be charging because of the new charger, or because of the new cable, or both. His test does not separate his two guesses. A better plan is to change only the cable first. If the phone charges, the old cable was the problem. If it does not, put the old cable back and change only the charger. Each test then checks just one guess. (Testing a guess, page 5; testing and analysing, page 6. Changing one thing at a time is our own step, not the chapter's.)

Question 4. Ali sees that the money plant near the window has grown longer than the one in a dark corner. He guesses, "It grew more because it gets more light." Before he tests this, what result should he expect if his guess is right? What result would show that his guess is wrong?

Answer: if the guess is right, a cutting kept in the light should grow more than one kept in the dark; if both grow about the same, the guess is wrong. A good test is planned before it is done, with a clear idea of what each result would mean. Ali could take two similar cuttings, keep one near the window and one in the dark corner, and water both the same. If light is the reason, the one near the window should grow more. If both grow about the same, light was not the reason, and he needs a new guess, for example that the corner pot gets less water. Deciding in advance what would count as "right" and "wrong" stops us from reading whatever we hope into the result. (Guess, test and analyse the results, page 6. Saying the expected result before testing is our own step, not the chapter's.)

Question 5. Riya plants one seed in a pot of sand and one in a pot of garden soil. Only the seed in soil sprouts. She says, "Seeds can never grow in sand." Is her conclusion fair? How could she make her test better?

Answer: no; one seed is not enough to be sure. The seed in sand might not have sprouted because that one seed was bad, not because of the sand. To be more confident, she should plant many seeds in each kind of pot, keep everything else the same (the same kind of seed, the same water and the same place), and see what happens to most of them. Even then she could only say how well seeds sprouted in her sand, not that seeds can never grow in sand. (Testing a guess and analysing the results, page 6. Using many seeds and keeping the rest the same is our own step.)

Questions, observations and changing ideas

Question 6. Which of these questions can be answered by doing a test, and which cannot? (a) "Is blue the most beautiful colour?" (b) "Does salty water take longer to freeze than plain water?" (c) "Do bean seeds sprout faster in a warm room or in a cold room?"

Answer: (b) and (c) can be tested; (a) cannot. For (b), put the same amount of salty water and plain water in the freezer and check which turns to ice first. For (c), keep similar bean seeds in a warm room and a cold room and count the days until they sprout. Question (a) asks for an opinion: people can honestly disagree about it, and no experiment can settle it. The scientific method works on questions whose guesses can be checked with experiments or observations. (Testing a guess through experiments or more observations, page 6. Sorting the questions is our own question.)

Question 7. Two students write about the Moon. Asha writes, "The Moon looked beautiful tonight." Ravi writes, "At 7 o'clock the Moon was just above the water tank, it looked orange, and by 9 o'clock it was higher and white." Which note is more useful for a scientist, and why?

Answer: Ravi's note. Asha's note tells us how she felt, which is fine, but it gives no details anyone could check or compare. Ravi recorded what he saw, where and when: the time, the position and the colour, at two different times. Notes like these can be compared with other nights or with friends' notes, and they lead to questions such as "Why does the Moon look orange when it is low in the sky?" The chapter says that learning science starts with observing our surroundings keenly. (Be curious and observe keenly, page 7. Comparing the two notes is our own question.)

Question 8. Gopal says, "Scientists sometimes find out that an old idea was wrong. So we cannot trust science." Using the chapter's picture of science as a jigsaw puzzle, explain what is wrong with his argument.

Answer: finding and fixing a wrong piece is how science gets better, not a reason to distrust it. The chapter compares science to a jigsaw puzzle with no end. Each discovery adds a piece, and sometimes we find that a piece was put in the wrong place and has to be moved. Moving it makes the picture more correct than before. Ideas in science change because people keep testing them against new observations, and an idea that has passed many tests is one we can rely on, while staying ready to improve it. (Science as an unending jigsaw puzzle, page 2. The point about trust is our own.)

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Sources

All opened and read on 2 November 2026. Page numbers are the printed page numbers of the textbook; printed page = PDF page + 0.

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.