CBSE Important Questions Class 8 Science Chapter 1 – Exploring the Investigative World of Science

Class 8 Science Chapter 1 Exploring the Investigative World of Science is the first chapter of the new NCERT Curiosity textbook. It explains how science works: how curiosity leads to a question, how careful observation gives us information, how we test an idea by changing only one factor at a time, and how we draw a conclusion from the evidence we collect. Students also learn that science is not limited to a laboratory; it can be done anywhere in daily life.

These CBSE important questions for Class 8 Science Chapter 1 cover the first step of a scientific investigation, why only one factor should be changed at a time, framing an investigation plan for why ice floats on water, turning the bending of plants towards light into an experiment, the role of curiosity, and the difference between observation and investigation. Every question has a clear step-by-step answer in simple English, so students can practise on their own, parents can check the answers, and teachers can use them for class tests.

Q1. Which of the following represents the correct first step of scientific investigation?
(a) Drawing conclusions
(b) Careful observation
(c) Writing reports
(d) Conducting experiments

Answer: (b) Careful observation
Every scientific investigation begins when we notice something carefully. Observation gives us the information from which a question grows. Only after that do we design experiments, and conclusions and reports come at the very end.

Q2. While making observations in science, why should only one factor be changed at a time during an experiment?
(a) To reduce the effort of recording observations
(b) To easily find out which factor caused the change in results
(c) To ensure the experiment finishes quickly
(d) To make the experiment look more systematic

Answer: (b) To easily find out which factor caused the change in results
If we change several things together, we cannot tell which one caused the change we see. Keeping all other factors the same and changing only one makes the test fair and the result reliable.

Q3. Can an investigation be done outside a laboratory? Give two examples.

Answer: Yes, an investigation can be done outside a laboratory, because science is present in daily life.
• Studying how clothes dry faster in sunlight than in shade shows evaporation.
• Observing how shadows change length during the day shows the movement of the Sun.
These examples prove that investigations can be carried out in our surroundings through observation, questioning and reasoning, not just inside a laboratory.

Q4. Why is it necessary to test only one factor at a time while investigating a problem?

Answer: It is necessary so that the cause-and-effect relationship can be clearly identified. If many factors are changed together, it becomes impossible to know which one influenced the result. Controlling all the other variables makes the experiment fair and reliable. This gives accurate data, avoids confusion and allows us to draw valid scientific conclusions.

Q5. Imagine you are asked: Why does ice float on water? Frame an investigation plan using observation, questioning and testing.

Answer: Observation: Notice that solid ice stays on top of liquid water.
Question: Does ice have a different density from water?
Test: Take equal volumes of ice and liquid water and measure their masses.
Result: Ice is lighter for the same volume, which means its density is lower.
Conclusion: Ice floats because a substance with lower density stays above a denser liquid.

Q6. A student observes that plants near a window bend towards sunlight. Suggest how this observation can be turned into a scientific investigation.

Answer: The student can first frame a question: 'Do plants always grow towards light?'
Then set up an experiment by keeping some plants near a window, some in the centre of the room and some under artificial light.
By recording the direction of growth over several days, the student collects evidence.
Analysing the results leads to the conclusion that plants bend towards light, a response called phototropism. In this way a simple observation becomes a systematic investigation.

Q7. Why is curiosity considered the first step of a scientific investigation?

Answer: Curiosity leads us to ask questions about the world around us. Without curiosity we would not feel the need to explore or look for explanations. It pushes scientists to observe carefully, design experiments and search for answers. Curiosity turns an ordinary everyday event into a problem worth investigating, so it is the driving force behind all scientific discovery.

Q8. Define the term investigation in science. How is it different from mere observation?

Answer: In science, an investigation is a systematic process of asking questions, collecting evidence, experimenting and drawing conclusions in order to understand something.
Observation is only the act of noticing or recording what happens, using our senses.
The difference is that investigation goes beyond observation: it also includes analysing, testing and explaining why something happens. Observation gives the raw information; investigation uses that information to build scientific understanding.

Q9. Which of the following is NOT a step of the scientific method?
(a) Making an observation
(b) Forming a hypothesis
(c) Accepting a result without testing it
(d) Drawing a conclusion from the data

Answer: (c) Accepting a result without testing it
Science never accepts an idea just because someone says so. Every idea has to be tested with evidence. Observing, forming a hypothesis, experimenting and concluding from the data are all genuine steps of the scientific method.

Q10. Which skill is MOST important for a scientific investigator?
(a) Memorising facts
(b) Careful observation and curiosity
(c) Copying experiments exactly
(d) Waiting for answers to come automatically

Answer: (b) Careful observation and curiosity
Memorising facts does not create new knowledge, and simply copying an experiment teaches nothing new. Observation and curiosity are what drive investigation, discovery and invention, so they are the real heart of science.

Q11. Do you agree that science can be done even outside the laboratory? Give three daily-life examples.

Answer: Yes. Science is about observing, questioning and finding explanations in everyday life.
• Watching clothes dry in the Sun shows evaporation.
• Noticing iron rusting in the rain shows a chemical change.
• Observing a ball rolling and slowly stopping shows force and friction.
These examples prove that science is not restricted to laboratories; it is present all around us.

Q12. Why is it important to change only one factor at a time while doing an experiment?

Answer: It is important so that we can clearly see the effect of that one factor on the result. If many factors are changed together, it becomes confusing to say which one actually caused the change. Controlling the other variables keeps the experiment fair, reliable and accurate, which helps in drawing valid conclusions and avoids misleading results.

Related Study Material on Extramarks

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