S3 Science: Scientific Investigation And Fair Tests (Paper 3 (challenge))

S3 Science: Scientific Investigation and Fair Tests (Paper 3 (challenge))

2026-11-14

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Tutor Prep Guide · the steps of a scientific investigation, hypotheses and testable predictions, independent and dependent variables, controlled variables, fair tests, control groups, repeated measurements and the mean, range, percentage error, accuracy and precision

S3 Science: Scientific Investigation and Fair Tests (Paper 3 (challenge))

This paper practises percentage error, range, choosing controlled variables, relative uncertainty from the smallest division, mean speed from timing data, finding the change per unit and extrapolating, and telling correlation from causation.

Direct answers　Percentage error is error over accepted value times one hundred; the range is largest minus smallest; correlation is not causation; smaller readings carry larger relative uncertainty; extrapolation needs a stated assumption; a rate per unit is found by dividing differences between two data points.

01　Paper details (check answers afterwards)

Item	Detail
Questions	10
Suggested time	20
Difficulty mix	Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1
Chapter	Chapter: S3 Science: Scientific Investigation and Fair Tests
Level	S3

02　Questions (10 items)

FoundationGroup A averages 12.0 cm and group B averages 12.4 cm. By what percentage is group B taller?
FoundationFive readings are 0.42, 0.45, 0.41, 0.44 and 0.48. What is the range?
FoundationWhen comparing the water holding capacity of three soils, what other variables must be controlled besides the soil type?
IntermediateA reading is 9.60 while the accepted value is 9.81. What is the percentage error?
IntermediateA spring stretches 0.6 cm per newton. What stretch is expected under 7.5 N?
IntermediateA balance with a resolution of 0.01 g reads 2.50 g. What is the relative uncertainty from the smallest division?
ChallengeA ruler has 1 mm divisions and the reading uncertainty is taken as half a division, 0.5 mm. What is the relative uncertainty of a 42 mm measurement?
ChallengeA ball rolls 100 m and is timed three times as 19.8, 20.2 and 20.0 seconds. What are the mean time and the mean speed?
ChallengePlants given 2, 4 and 6 hours of light grow 3.0, 4.0 and 5.0 cm. How much growth does each extra hour give, and what is predicted for 8 hours?
Error redoIce cream sales and drowning cases both rise in the same months, so a student concludes that eating ice cream causes drowning. What is wrong?

03　Answers and one-line notes

#	Answer	One-line note
1	3.3 percent	The difference of 0.4 divided by the 12.0 of group A and multiplied by one hundred gives 3.3.
2	0.07	Subtract the smallest reading 0.41 from the largest 0.48.
3	The volume of water, the sunlight, the temperature and the size of the pot	Everything that affects evaporation or absorption has to be identical.
4	2.1 percent	The error of 0.21 divided by the accepted 9.81 and multiplied by one hundred.
5	4.5 cm	Multiply 0.6 by 7.5 to get 4.5 centimetres.
6	0.4 percent	Divide 0.01 by 2.50 and multiply by one hundred; smaller readings carry larger relative uncertainty.
7	1.2 percent	Divide 0.5 by 42 and multiply by one hundred to get 1.19, which rounds to 1.2.
8	The mean time is 20.0 seconds and the mean speed is 5.0 m/s	The three times add to 60.0 and divide by three to give 20.0, then divide 100 by 20.0.
9	0.5 cm per hour, so 6.0 cm for 8 hours	Subtract 3.0 from 5.0 and divide by the 4 hour difference to get 0.5, then add 0.5 for each hour up to 8.
10	Correlation is treated as causation; the shared factor is the air temperature	Two quantities changing together does not mean one causes the other.

04　What to do after marking

After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
Repeat the same item two days later; move to the next paper only when both attempts are correct.
Parents only need the answer and note columns; there is no need to explain every item.

For any investigation ask three questions: what is changed (independent variable), what is measured (dependent variable), and what must stay the same (controlled variables); two changes at once means it is not a fair test.Tutor Registration →

Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.