The Wonderful World of Science Part 4: MCQs (Q76–Q100)

Part 4 — Questions 76–100

76. Why should observations be recorded soon after they are made?
    A. To forget them quickly.
    B. To avoid forgetting details and to preserve accuracy. ← Correct answer: B
    C. So they can be changed later.
    D. So nobody can read them.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — prompt recording minimizes memory errors.

77. Which is a primary source for scientific information?
    A. A popular magazine summarizing research.
    B. An original research article or lab notebook. ← Correct answer: B
    C. A movie about science.
    D. A fictional story.
    Explanations:
    A/C/D) Secondary or non-scientific sources.
    B) Correct — primary sources are original data/reports.

78. Which of the following would be considered scientific evidence?
    A. Personal belief.
    B. Measured and observed data collected systematically. ← Correct answer: B
    C. Rumours.
    D. Myth.
    Explanations:
    A/C/D) Subjective or anecdotal.
    B) Correct — empirical evidence is required.

79. A laboratory logbook should contain:
    A. Only conclusions.
    B. Procedures, raw data, observations, date and signature. ← Correct answer: B
    C. Only drawings.
    D. Nothing.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — full documentation supports reproducibility.

80. Which of the following best describes ‘investigation by comparison’?
    A. Only using numbers.
    B. Comparing outcomes between different conditions (e.g., sunlight vs shade). ← Correct answer: B
    C. Ignoring differences.
    D. Making the experiment secret.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — comparisons help identify effects of variables.

81. Which science tool would you choose to separate sand from water?
    A. Balance.
    B. Filter paper and funnel (filtration). ← Correct answer: B
    C. Thermometer.
    D. Microscope.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — filtration separates solid particles from liquids.

82. A good scientific report includes:
    A. Only pictures.
    B. Title, objective, materials, method, results, conclusion. ← Correct answer: B
    C. Random text.
    D. Secret codes.
    Explanations:
    A/C/D) Incomplete or irrelevant.
    B) Correct — standard structure for clarity.

83. Which is an example of indirect observation?
    A. Counting leaves by looking at a plant.
    B. Inferring presence of gas by seeing bubble formation. ← Correct answer: B
    C. Smelling a fragrance directly.
    D. Hearing a bell.
    Explanations:
    A/C/D) Direct senses.
    B) Correct — bubble formation is observed; gas presence inferred.

84. When designing an experiment, why keep several trials?
    A. To increase random errors.
    B. To check consistency and improve accuracy of results. ← Correct answer: B
    C. So it takes more time.
    D. To confuse others.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — multiple trials yield reliable averages.

85. Which action is correct when observing a live animal in class?
    A. Handle it roughly.
    B. Observe without causing stress; follow ethical guidelines. ← Correct answer: B
    C. Force it to perform tricks.
    D. Feed any chemical to it.
    Explanations:
    A/C/D) Cruel or dangerous.
    B) Correct — welfare and ethics are important.

86. Which instrument would measure mass of a small object most accurately?
    A. Meter scale.
    B. Analytical balance (lab balance). ← Correct answer: B
    C. Thermometer.
    D. Stopwatch.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — analytical balances offer precise mass readings.

87. Which is the best way to present data for comparing growth over time?
    A. A story.
    B. A line graph showing time on x-axis and growth on y-axis. ← Correct answer: B
    C. A poem.
    D. A single number.
    Explanations:
    A/C/D) Not effective for trends.
    B) Correct — line graphs show changes over time clearly.

88. If a result contradicts your hypothesis, you should:
    A. Hide it.
    B. Re-evaluate, repeat experiments and accept or revise the hypothesis. ← Correct answer: B
    C. Burn the lab notebook.
    D. Ignore science.
    Explanations:
    A/C/D) Unethical.
    B) Correct — science advances by testing and revising ideas.

89. A safety symbol showing goggles indicates:
    A. Wear gloves.
    B. Wear eye protection (goggles). ← Correct answer: B
    C. Use a fire extinguisher.
    D. No food allowed.
    Explanations:
    A/C/D) Different symbols.
    B) Correct — goggles protect eyes from splashes/particles.

90. Which is true about collaboration in science?
    A. Always harms progress.
    B. Helps combine expertise and improves research quality. ← Correct answer: B
    C. Only done by rivals.
    D. Not allowed.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — teamwork speeds innovation and verification.

91. A digital thermometer reads 37.0 °C. This is an example of:
    A. Qualitative observation.
    B. Quantitative observation. ← Correct answer: B
    C. An inference.
    D. A story.
    Explanations:
    A) Qualitative = descriptive (no numbers).
    B) Correct — numeric temperature is quantitative.
    C) Inference is interpretation, not the raw reading.
    D) Irrelevant.

92. Which of these best shows cause and effect in an experiment?
    A. Random storytelling.
    B. Manipulate only one factor and observe resulting changes in measured outcome. ← Correct answer: B
    C. Changing everything at once.
    D. Ignoring outcomes.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — controlled manipulation demonstrates causality.

93. Why is it important to use correct units (e.g., m, g, s)?
    A. Units are optional.
    B. They give meaning to numbers and allow comparisons. ← Correct answer: B
    C. Units confuse readers.
    D. Units are only for teachers.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — numbers without units are ambiguous.

94. Which action demonstrates honesty in scientific work?
    A. Faking graphs.
    B. Reporting all data, even unexpected ones. ← Correct answer: B
    C. Copying another’s results as your own.
    D. Destroying inconvenient data.
    Explanations:
    A/C/D) Unethical.
    B) Correct — honesty builds trust and validity.

95. The magnification power of a microscope tells you:
    A. The actual size of an object.
    B. How many times larger the image appears compared to the object. ← Correct answer: B
    C. The weight of the object.
    D. The color of the object.
    Explanations:
    A) Magnification changes apparent size, not actual size.
    B) Correct — e.g., 40× means image looks 40 times larger.
    C/D) Incorrect.

96. Which graph type is useful for showing parts of a whole (like percentages)?
    A. Line graph.
    B. Pie chart (circle graph). ← Correct answer: B
    C. Scatter plot only.
    D. Histogram always.
    Explanations:
    A/C/D) Less suitable for part-of-whole percentages.
    B) Correct — pie charts visualize percentage distribution.

97. Which is the correct sequence for conducting a simple experiment?
    A. Publish → test → ask question.
    B. Ask question → form hypothesis → experiment → record data → draw conclusion. ← Correct answer: B
    C. Draw conclusion → ask question.
    D. Ignore data entirely.
    Explanations:
    A/C/D) Illogical order.
    B) Correct — standard scientific workflow.

98. If a scale gives readings that gradually decrease though the same weight is placed, the scale is:
    A. Accurate.
    B. Unreliable (needs calibration or repair). ← Correct answer: B
    C. Perfect.
    D. Measuring temperature.
    Explanations:
    A/C/D) Incorrect.
    B) Correct — drift indicates instrument fault.

99. Why should you wear closed shoes in the science lab?
    A. For fashion only.
    B. To protect feet from spills, broken glass and heavy objects. ← Correct answer: B
    C. To make noise.
    D. To confuse others.
    Explanations:
    A/C/D) Silly reasons.
    B) Correct — safety standard in labs.

100. The term ‘empirical’ in science refers to knowledge based on:
     A. Pure imagination.
     B. Observation or experiment (evidence). ← Correct answer: B
     C. Ancient myths.
     D. Opinions only.
     Explanations:
     A/C/D) Incorrect.
     B) Correct — empirical evidence grounds scientific claims.

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