Exploring the Investigative World of Science — Class 8 MCQs with Answers

Exploring the Investigative World of Science — important questions & MCQs with answers (Class 8 Science)

6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.

0 of 6 answered

1. Q1 of 6Easy

   A scientific investigation usually begins with:

   Amemorising factsBexpensive equipmentCcuriosity and careful observationDguessing randomly
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   Answer: curiosity and careful observation

   Explanation: Science starts with curiosity and careful observation of the world, not with memorised facts or costly equipment — noticing something surprising is what sparks the first question.

2. Q2 of 6Easy

   A good scientific investigation starts by asking a:

   AconclusionBfinal answerCquestionDstory
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   Answer: question

   Explanation: Investigations start from a question, not a ready-made conclusion or story — the question is what tells you what to observe and test next.

3. Q3 of 6Medium

   In the puri experiment, dropping the dough vertically or at an angle tests the effect of:

   Athe flour typeBthe oil temperatureCthe way of droppingDthe thickness
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   Answer: the way of dropping

   Explanation: Dropping the dough vertically or at an angle isolates the effect of the dropping method itself, since every other factor stays the same in that comparison.

4. Q4 of 6Medium

   A scientific conclusion should be based on:

   Athe observations and data collectedBpersonal likesCa coin tossDthe teacher's mood
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   Answer: the observations and data collected

   Explanation: A scientific conclusion must follow from the observations and data actually collected during the experiment, not from personal preference or chance.

5. Q5 of 6Hard

   If your results are different each time you repeat, you should:

   Arepeat more and look for a patternBpick the answer you likeCstop investigatingDchange the question secretly
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   Answer: repeat more and look for a pattern

   Explanation: Different results each time call for more repeats and a search for a pattern in the data, rather than picking whichever answer you prefer.

6. Q6 of 6Hard

   The factor a scientist deliberately changes is the:

   Adependent variableBcontrolCobservationDindependent variable
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   Answer: independent variable

   Explanation: The factor a scientist deliberately changes is the independent variable — it is set on purpose, distinct from the dependent variable, which is measured as the outcome.

Exploring the Investigative World of Science notes: key concepts (Class 8 Science)

This opening chapter is about how science actually works — systematic investigation. Science starts with curiosity and careful observation, turning everyday wonders (like why a puri puffs up) into focused, testable questions. You learn to plan an experiment by deciding what to change and what to observe, to run a fair test by changing only one thing at a time, to record both qualitative (yes/no) and quantitative (measured) observations, and to draw conclusions from the evidence — while remembering that science is always evolving as new questions arise.

Systematic investigation

A careful, step-by-step way of answering a question: observe, ask a testable question, experiment, record, and explain — the heart of how science works.

Careful observation

Using the senses to notice details of what actually happens; good observation is the solid ground on which investigation is built.

Scientific question

A focused, testable question such as 'what happens to a puri if the oil is hotter?' that can be explored by observation or experiment.

Hypothesis

A possible explanation put forward to be tested by an experiment; if the evidence disagrees, the hypothesis is revised or rejected.

Variables you control

The factors you can change in an experiment, such as the dough thickness, flour type or oil temperature; the deliberately changed one is the independent variable.

Variables you observe

The outcomes you watch or measure, such as whether a puri puffs or how many seconds it takes; the measured outcome is the dependent variable.

Fair (controlled) test

An experiment in which only one factor is changed at a time while all others are kept the same, so any effect can be traced to that single change.

Qualitative vs quantitative

Qualitative observations describe without numbers (the oil smoked), while quantitative observations are measured numbers (it took 8 seconds).

Recording data

Keeping careful notes of everything observed, even surprises, so results can be compared, patterns spotted and conclusions justified.

Drawing conclusions

Explaining the results from the evidence collected, not from personal likes; a conclusion follows from the data.

Science is evolving

Each answer opens new questions and ideas change as evidence grows, so even a simple puffing puri is not yet fully understood.