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O Level Combined Science Scientific Inquiry Quiz
Free O Level Combined Sci Scientific Inquiry quiz, HY3 Exam version, with questions, answers, and O Level-style practice for Singapore students.
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O-Level Combined Science Quiz - Scientific Inquiry (Answer Key)
Total Marks: 40
Topic: Scientific Inquiry
Section A (1–5, 1 mark each)
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Answer: To keep all other conditions the same so that any change in the outcome is due only to the independent variable.
Teaching note: A control variable is held constant; this isolates the effect of the factor being tested. -
Answer: Science is evidence-based / model-building / open to change / reliable. (Any one NOS point)
Teaching note: NOS states scientific knowledge comes from evidence and can be revised. -
Answer: (B) The solution turned blue
Teaching note: Qualitative = described without numbers; others are quantitative measurements. -
Answer: e.g. pollution from factories / radiation from nuclear plants / pesticide harm to wildlife.
Teaching note: STSE looks at risks of science in society. -
Answer: Hypothesis
Teaching note: A hypothesis is a testable starting explanation.
Section B (6–10, 2 marks each)
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Average time: (4.1 + 4.3 + 4.2) / 3 = 12.6 / 3 = 4.2 s [1]
Reason: Repeating reduces effect of random error and gives more reliable mean. [1]
Working: sum ÷ count. -
Answer: Changing only one independent variable means any observed effect can be linked to that variable; if many change, cause is unclear. [2]
Teaching note: Fair test = only one factor varied. -
Independent: length of pendulum [1]
Dependent: period / time for one swing [1] -
Two values: e.g. integrity, objectivity, curiosity, open-mindedness (any two) [2]
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Liquid: A [1]
Reason: Line A has steeper slope, so temperature rises more per second. [1]
From placeholder: A reaches 60 °C at 120 s, B only 45 °C.
Section C (11–20, 3–4 marks each)
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(a) Hypothesis: Increasing ramp height increases speed at bottom. [1]
(b) Control: same car, same surface, same distance. [1]
(c) Record: Measure time at bottom for each height, repeat 3 times, tabulate height vs speed. [2] -
Benefit: higher food production. [1]
Risk: bee population decline. [1]
Reduction: use pesticide only at night / selective spray. [1] -
(a) Blue [1]
(b) Bar chart drawn with 3 bars per values. [1]
(c) Reason: Plants reflect green, less absorbed for photosynthesis. [2] -
Accuracy = closeness to true value. Precision = closeness of repeated values. Example: hits near bullseye = accurate; tight cluster elsewhere = precise. [3]
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Answer: NOS says knowledge is reliable but open to change; "proves all" is too absolute, should be "supports". [2]
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Independent: water temperature [1]
Dependent: time to dissolve [1]
Control: mass of sugar, volume of water [1]
Method: Heat water to set temps, add same sugar, stir same way, time until clear. [1] -
(a) Shows if current flows (lights if conductive). [1]
(b) Bulb does not light. [1]
(c) Avoid water on battery / disconnect after test. [1] -
(a) Mean = (22+24+21)/3 = 67/3 = 22.3 breaths/min [2]
(b) Exercise increases breathing rate. [1] -
Answer: Models simplify reality, e.g. particle model of matter explains states. Evidence supports models, revised when new data appears. [3]
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Evaluation: Only one trial, reaction time error, not reliable. [2]
Improvement: Repeat many times, use light gate, average. [2]