NSO Class 6 Olympiad MCQs: The Wonderful World of Science (Chapter 1) with Answers & Explanations
Practice 25 NSO Class 6 Olympiad-level MCQs on Chapter 1, ‘The Wonderful World of Science,’ covering the scientific method, curiosity, observation and hypothesis-testing, complete with answers and detailed explanations.
Q1. According to the chapter, science is best defined as:
(a) A subject that only trained scientists can study inside laboratories
(b) A way of thinking, observing and doing things to understand the world and uncover the secrets of the universe
(c) A collection of facts that must be memorised for examinations
(d) A set of experiments that can only be performed with expensive equipment
Answer: (b) A way of thinking, observing and doing things to understand the world and uncover the secrets of the universe
Explanation: The chapter directly defines science as ‘a way of thinking, observing and doing things to understand the world we live in and to uncover the secrets of the universe.’
Q2. Which quality does the chapter call the most important thing needed to do science well, and from which the textbook’s title is derived?
(a) Intelligence
(b) Curiosity
(c) Patience
(d) Memory
Answer: (b) Curiosity
Explanation: The text states, ‘the most important thing is to have Curiosity, which is where the title of this book comes from.’
Q3. Arrange the following in the correct order of the scientific method described in the chapter: (i) Guess a possible answer (ii) Observe something interesting or not understood (iii) Test the guess through experiments/observations (iv) Analyse the results to see if the question is answered (v) Think of a question about it
(a) ii, v, i, iii, iv
(b) ii, i, v, iii, iv
(c) v, ii, i, iv, iii
(d) i, ii, iii, iv, v
Answer: (a) ii, v, i, iii, iv
Explanation: The correct sequence given in the chapter is: observe -> wonder/question -> guess an answer -> test the guess -> analyse the results, i.e., ii, v, i, iii, iv.
Q4. In the ‘pen stops writing’ example, the guess ‘the ink has finished’ represents which step of the scientific method?
(a) Observation
(b) Question
(c) Hypothesis (a guess)
(d) Analysis of results
Answer: (c) Hypothesis (a guess)
Explanation: Guessing that the ink finished is the ‘guess a possible answer’ step, i.e., forming a hypothesis, which is then tested by opening the pen.
Q5. Opening the pen and checking the ink refill, in the same example, represents which step?
(a) Observation
(b) Testing the guess
(c) Asking a question
(d) Stating the final rule of science
Answer: (b) Testing the guess
Explanation: Checking the refill is how the guess is tested — the ‘test this guess through experiments or more observations’ step.
Q6. If your first guess about why the pen stopped writing turns out to be wrong (the ink was not finished), what does the chapter say you should do next?
(a) Stop trying to find a reason
(b) Assume the pen is permanently broken without checking further
(c) Make another guess and test it, for example that the ink has dried up
(d) Buy a new pen without any further investigation
Answer: (c) Make another guess and test it, for example that the ink has dried up
Explanation: The chapter shows that when a guess is wrong, you form a new guess (‘perhaps the ink might have dried up’) and test that one, repeating the cycle.
Q7. Which of the following is NOT described in the chapter as an example of someone using the scientific method in daily life?
(a) A cook wondering whether too much water caused the dal to spill from the cooker
(b) A bicycle repair person trying to find out where air is leaking from a flat tyre
(c) An electrician checking whether the bulb or the switch is faulty
(d) A person who reaches a conclusion without observing or testing anything at all
Answer: (d) A person who reaches a conclusion without observing or testing anything at all
Explanation: The cook, the bicycle repairer and the electrician are all given as examples of people who observe, question, guess and test — unlike option (d), which skips the scientific method entirely.
Q8. The chapter compares science to a ‘giant and unending jigsaw puzzle.’ What does this comparison mainly emphasise?
(a) Science has a fixed number of facts that will eventually run out
(b) Every new discovery adds a piece of knowledge, but also raises further questions, so there is no limit to what can be discovered
(c) Science is a game with a fixed set of rules and a declared winner
(d) Puzzles and scientific discovery have nothing in common
Answer: (b) Every new discovery adds a piece of knowledge, but also raises further questions, so there is no limit to what can be discovered
Explanation: The text says every discovery ‘adds another piece to that puzzle’ and ‘there is no limit to what we can discover, since every new piece of knowledge leads to more questions.’
Q9. In the same jigsaw-puzzle idea, what does the chapter mean when it says ‘a piece of this puzzle has been put in the wrong place and needs to be moved’?
(a) Old experiments must always be repeated exactly as before
(b) A new discovery has shown that an earlier scientific idea was incorrect and understanding must be corrected
(c) A textbook printing mistake has occurred
(d) A puzzle piece has been lost forever
Answer: (b) A new discovery has shown that an earlier scientific idea was incorrect and understanding must be corrected
Explanation: This line explains that ‘new discoveries often change our understanding of the world,’ meaning earlier ideas can be corrected as we learn more.
Q10. Which everyday change is used in the chapter to describe water gaining heat energy?
(a) Water freezing into ice
(b) Water boiling and becoming steam
(c) Steam turning directly into ice
(d) Ice turning directly into a solid rock
Answer: (b) Water boiling and becoming steam
Explanation: The chapter states water ‘boils and becomes steam when we heat it,’ which describes water gaining heat energy.
Q11. Which phrase does the chapter use to link being wise with asking questions?
(a) ‘A wise person avoids asking why’
(b) ‘To be a wise person, you must be a whys person’
(c) ‘Why questions slow down science’
(d) ‘Science discourages curiosity’
Answer: (b) ‘To be a wise person, you must be a whys person’
Explanation: The closing thought box in the chapter states, ‘After all, to be a wise person, you must be a whys person!’
Q12. Based on the chapter, how is scientific work generally carried out?
(a) Always completely alone, since teamwork spoils discoveries
(b) Mostly alone, since teamwork is rarely useful in science
(c) Often in large teams, and asking friends for help is encouraged
(d) Only by scientists who are not allowed to collaborate with anyone
Answer: (c) Often in large teams, and asking friends for help is encouraged
Explanation: The chapter says, ‘Science is rarely done alone. Scientists across the world work together, often in large teams… ask your friends to help you out!’
Q13. Whenever you want to apply the scientific method to a problem, what should you do first?
(a) Immediately perform an experiment without observing anything
(b) Observe something you find interesting or do not understand
(c) Write down the final conclusion first
(d) Ask someone else to solve the whole problem for you
Answer: (b) Observe something you find interesting or do not understand
Explanation: The chapter’s first step is always observation: ‘First, we observe something that we find interesting or we do not understand.’
Q14. A farmer notices that plants in one corner of the field are wilting despite regular watering. Following the scientific method, what should the farmer do immediately after making this observation?
(a) Immediately cut down all the wilting plants
(b) Think of a question, such as ‘why are only these plants wilting?’
(c) Ignore the wilting since watering is already being done
(d) Directly conclude the soil has no nutrients, without checking anything
Answer: (b) Think of a question, such as ‘why are only these plants wilting?’
Explanation: After observing something unusual, the next step in the scientific method is to form a question about it, not to jump straight to action or conclusions.
Q15. Continuing the farmer’s example, suppose the farmer guesses ‘the soil in that corner drains water poorly.’ What should be done next?
(a) Accept the guess as true without checking it
(b) Test the guess, for example by examining soil drainage or comparing soil samples
(c) Move on to a completely unrelated question
(d) Reject the guess immediately without any testing
Answer: (b) Test the guess, for example by examining soil drainage or comparing soil samples
Explanation: Every guess in the scientific method must be tested through experiments or further observation before it can be accepted or rejected.
Q16. Which of the following is NOT one of the five steps of the scientific method mentioned in the chapter?
(a) Observing something interesting
(b) Guessing a possible answer
(c) Publishing the results in a famous journal
(d) Analysing results to check if the question is answered
Answer: (c) Publishing the results in a famous journal
Explanation: The chapter lists observing, questioning, guessing, testing and analysing as the five steps; publishing in a journal is never mentioned.
Q17. According to the chapter, why is Earth described as special among planets?
(a) It is the largest planet in the universe
(b) It is the only planet we know of that supports life and has an environment we must protect
(c) It has no water on its surface
(d) It is the planet closest to the Sun
Answer: (b) It is the only planet we know of that supports life and has an environment we must protect
Explanation: The chapter states Earth ‘is the only planet we know that supports life, and it has an environment that we must protect.’
Q18. When a cook wonders, ‘was there too much water?’ after dal spills out of a pressure cooker, this is an example of which step of the scientific method?
(a) Testing a guess
(b) An observation with no question at all
(c) Forming a question based on an observation
(d) Reaching the final conclusion
Answer: (c) Forming a question based on an observation
Explanation: The cook has observed the spilling dal and is now forming a question about its cause, which is the second step of the scientific method.
Q19. Which of the following statements about science, based on the chapter, is FALSE?
(a) Science is just about memorising facts and figures
(b) Science is a step-by-step process for finding answers to questions
(c) Curiosity is essential for learning science well
(d) New discoveries can change our understanding of the world
Answer: (a) Science is just about memorising facts and figures
Explanation: The chapter explicitly states, ‘Science is not just about memorising facts and figures or doing experiments. It is about following a step-by-step process.’
Q20. The chapter mentions that groundbreaking discoveries can come from unexpected places, such as:
(a) Only inside high-tech laboratories
(b) The kitchen and the playground, among other places
(c) Nowhere except outer space
(d) Only from very expensive equipment
Answer: (b) The kitchen and the playground, among other places
Explanation: The chapter says discoveries can come ‘from what is cooking in the kitchen to what is happening on the playground.’
Q21. An electrician first guesses that ‘the bulb is faulty,’ tests this by replacing the bulb, but the light still does not work. What is the most scientifically correct next step?
(a) Conclude that electricity does not exist in that room
(b) Make a new guess, such as a problem with the switch, and test it
(c) Stop investigating since one guess has already been tested
(d) Blame the manufacturer without checking anything further
Answer: (b) Make a new guess, such as a problem with the switch, and test it
Explanation: When a tested guess turns out to be wrong, the scientific method requires forming and testing a new guess, exactly as shown with the electrician example in the chapter.
Q22. Which of the following best explains why the textbook is titled ‘Curiosity’?
(a) Curiosity is unrelated to studying science
(b) Curiosity is described as the essential quality needed to observe, question and explore the world scientifically
(c) Curiosity is useful only for artists, not for scientists
(d) The title was chosen without any particular reason
Answer: (b) Curiosity is described as the essential quality needed to observe, question and explore the world scientifically
Explanation: The chapter states that having curiosity is ‘the most important thing’ for doing science, and this is ‘where the title of this book comes from.’
Q23. A student sees a seed grow into a plant and wonders how this happens. This wondering is an example of which step of the scientific method?
(a) Testing a guess
(b) Forming a question after making an observation
(c) Skipping straight to a final conclusion
(d) An unrelated, random thought
Answer: (b) Forming a question after making an observation
Explanation: The student has observed something (a seed growing) and is now forming a question, which is exactly the second step described in the chapter.
Q24. According to the chapter, what mainly distinguishes science from an ordinary, casual guess?
(a) Science never involves guessing at all
(b) Science follows a systematic process — observing, questioning, guessing, testing and analysing — rather than relying on a guess alone
(c) Science is defined only by the use of costly instruments
(d) There is no real difference between science and casual guessing
Answer: (b) Science follows a systematic process — observing, questioning, guessing, testing and analysing — rather than relying on a guess alone
Explanation: The chapter emphasises that a guess must be tested and its results analysed; guessing alone, without testing, is not the scientific method.
Q25. Which of the following situations best reflects the COMPLETE scientific method, not just a single step of it?
(a) Only observing clouds in the sky and stopping there
(b) Only guessing why ice melts, without ever checking the guess
(c) A student notices ice melts faster in sunlight, questions why, guesses it is due to heat, tests this by placing ice in sun and shade, and compares the results
(d) Reading about ice melting in a book without making any observation of one’s own
Answer: (c) A student notices ice melts faster in sunlight, questions why, guesses it is due to heat, tests this by placing ice in sun and shade, and compares the results
Explanation: Option (c) includes all five steps — observation, question, guess, test and analysis of results — matching the full scientific method described in the chapter.