The Wonderful World of Science Part 3: MCQs (Q51–Q75)
Part 3 — Questions 51–75
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Which of these statements about models is FALSE?
A. Models simplify reality.
B. Models can be physical, mathematical or conceptual.
C. Models always perfectly represent nature. ← Correct answer: C
D. Models help explain phenomena.
Explanations:
A/B/D) True statements.
C) False — models are approximations and have limitations. -
The unit for measuring volume of a liquid in the lab is usually:
A. Metre.
B. Millilitre (mL) or litre (L). ← Correct answer: B
C. Gram.
D. Kelvin.
Explanations:
A) Length unit — incorrect.
B) Correct — volume measured in mL or L.
C) Mass unit — incorrect.
D) Temperature unit — incorrect. -
Which practice avoids experimental bias?
A. Ignoring data that disagree.
B. Recording all results and following fixed procedures. ← Correct answer: B
C. Only publishing positive data.
D. Changing hypothesis to fit data without testing.
Explanations:
A/C/D) Biased or unethical.
B) Correct — transparency and consistent methods reduce bias. -
In a report, the conclusion should:
A. Repeat raw data only.
B. Summarize findings and state whether the hypothesis is supported. ← Correct answer: B
C. Be entirely emotional.
D. Contain no connection to results.
Explanations:
A/C/D) Incorrect.
B) Correct — conclusion links data to hypothesis. -
Which is an example of applying science to solve a problem?
A. Writing poems about stars.
B. Designing a water filter to purify drinking water. ← Correct answer: B
C. Complaining about rain.
D. Ignoring pollution.
Explanations:
A/C/D) Not problem-solving using science.
B) Correct — engineering solutions come from scientific understanding. -
A thermometer should be read at eye level to:
A. Improve the thermometer.
B. Avoid parallax error and read correct value. ← Correct answer: B
C. Make it heavier.
D. Prevent it from breaking.
Explanations:
A/C/D) Incorrect.
B) Correct — reading from above/below can mislead the reading. -
Which of the following is true for peer discussion in science class?
A. It prevents learning.
B. It helps students refine ideas and spot errors. ← Correct answer: B
C. It’s always harmful.
D. It replaces experiments.
Explanations:
A/C/D) Incorrect.
B) Correct — discussion fosters critical thinking. -
The role of a control group in investigations is to:
A. Cause confusion.
B. Provide a baseline to compare the effect of the variable. ← Correct answer: B
C. Make the experiment longer.
D. Change random parameters.
Explanations:
A/C/D) Incorrect.
B) Correct — control is crucial for comparison. -
Which action is safe when heating a liquid in the lab?
A. Look directly over the vessel.
B. Heat gently and use appropriate safety equipment (tongs, goggles). ← Correct answer: B
C. Point it at friends.
D. Leave it unattended.
Explanations:
A/C/D) Unsafe.
B) Correct — safety protocols minimize accidents. -
Which is NOT a step of the scientific method?
A. Observation.
B. Hypothesis.
C. Fortune telling. ← Correct answer: C
D. Experimentation.
Explanations:
A/B/D) Real steps.
C) Incorrect — fortune telling is not scientific. -
Scientific knowledge changes because:
A. Scientists always disagree for no reason.
B. New evidence and better experiments refine understanding. ← Correct answer: B
C. Books magically update.
D. Science dislikes old facts.
Explanations:
A/C/D) Incorrect.
B) Correct — science is self-correcting and evolves with evidence. -
An accurate measuring instrument gives values:
A. Far from true value.
B. Close to the true or accepted value. ← Correct answer: B
C. With no units.
D. Randomly different each time.
Explanations:
A/C/D) Incorrect.
B) Correct — accuracy = closeness to true value. -
Which of the following is a reason to wash hands after doing experiments?
A. To waste water.
B. To remove chemicals, microbes and prevent contamination. ← Correct answer: B
C. Because soap cleans instruments.
D. It’s an optional luxury.
Explanations:
A/C/D) Incorrect.
B) Correct — hygiene and safety. -
When making a chart of results, labels must show:
A. Only funny drawings.
B. Variable names and units. ← Correct answer: B
C. The experimenter’s favorite color.
D. Nothing.
Explanations:
A/C/D) Incorrect.
B) Correct — labels help interpret data. -
Which is an example of a fair test in plant growth experiments?
A. Using different amounts of soil for each plant.
B. Keeping soil, temperature and water same except light amount. ← Correct answer: B
C. Changing soil and light together.
D. Not measuring growth at all.
Explanations:
A/C/D) Incorrect.
B) Correct — only independent variable differs. -
The device used to measure small amounts of liquid precisely is:
A. Beaker.
B. Pipette or burette (in lab), or graduated cylinder for larger volumes. ← Correct answer: B
C. Ruler.
D. Thermometer.
Explanations:
A) Beaker is approximate.
B) Correct — pipettes/burettes give accurate small volumes.
C/D) Incorrect. -
Science class experiments should be recorded:
A. Only if they succeed.
B. Always, including failures and observations. ← Correct answer: B
C. Never.
D. In secret.
Explanations:
A/C/D) Incorrect.
B) Correct — full records help understanding and replication. -
The purpose of a conclusion in an experiment is to:
A. Hide results that disagree.
B. Summarize what was learned and whether the hypothesis was supported. ← Correct answer: B
C. Be as long as possible for impressing others.
D. Ignore data.
Explanations:
A/C/D) Incorrect.
B) Correct — conclusions report inference from data. -
Which of these best describes ‘theory’ in science?
A. A casual opinion.
B. A well-tested explanation that unifies many observations. ← Correct answer: B
C. A guess that cannot be tested.
D. Always unchangeable.
Explanations:
A/C/D) Incorrect.
B) Correct — theories explain why phenomena occur and are supported by evidence. -
Which instrument measures time accurately during an experiment?
A. Balance.
B. Stopwatch or clock. ← Correct answer: B
C. Ruler.
D. Thermometer.
Explanations:
A/C/D) Incorrect.
B) Correct — stopwatch measures elapsed time precisely. -
Which is an example of direct observation?
A. Using a model without looking.
B. Watching the colour change of a solution as you add reagent. ← Correct answer: B
C. Reading someone else’s description only.
D. Making up data.
Explanations:
A/C/D) Indirect or improper.
B) Correct — direct sensory observation. -
How does science help predict natural events?
A. By ignoring past data.
B. By analyzing patterns and using models to forecast outcomes (e.g., weather). ← Correct answer: B
C. By random guessing.
D. By astrology.
Explanations:
A/C/D) Incorrect.
B) Correct — patterns and models enable predictions. -
In a graph, the independent variable is usually plotted on the:
A. Z-axis.
B. X-axis (horizontal). ← Correct answer: B
C. Y-axis.
D. Ceiling.
Explanations:
A/C/D) Incorrect.
B) Correct — convention: independent on x-axis, dependent on y-axis. -
Which method helps to reduce the effect of random errors?
A. Doing one measurement only.
B. Taking multiple measurements and averaging. ← Correct answer: B
C. Ignoring measures.
D. Changing instruments midway.
Explanations:
A/C/D) Incorrect.
B) Correct — averaging smooths out random variation. -
Which phrase best describes scientific knowledge?
A. Fixed and never changing.
B. Evolving and improved as new evidence appears. ← Correct answer: B
C. Always wrong.
D. Based on astrology.
Explanations:
A/C/D) Incorrect.
B) Correct — science updates with new evidence.