S3 Science: Scientific Investigation And Fair Tests (Paper 2 (intermediate))

S3 Science: Scientific Investigation and Fair Tests (Paper 2 (intermediate))

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 2 (intermediate))

This paper practises testable hypotheses, calculating a mean, the role of a control group, telling precision from accuracy, spotting systematic error, significant figures, and finding a slope and predicting from proportional data.

Direct answers　A hypothesis must be measurable; the mean is the total divided by the count; a control group gives a baseline; precision is how close readings are; a systematic error always shifts the same way; significant figures start at the first non zero digit.

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)

FoundationWhich of these is a testable hypothesis?
FoundationFive readings are 4.2, 4.4, 4.3, 4.1 and 4.5. What is the mean?
FoundationWhat is the purpose of a control group in an experiment?
IntermediateFour thermometers read 10.4, 10.5, 10.4 and 10.5 degrees for water whose true temperature is 10.0 degrees. How would you describe these readings?
IntermediateA balance is used without being zeroed first. What kind of error is this?
IntermediateTwenty beans have a total mass of 36.0 g. What is the average mass of one bean?
ChallengeA rod is measured as 4.8 cm while the accepted length is 5.0 cm. What is the percentage error?
ChallengeThe data pairs (1, 3.0), (2, 6.0), (3, 9.0) and (4, 12.0) are proportional. What is the slope and what is y when x is 5?
ChallengeWhat is 1234 rounded to three significant figures?
Error redoA student draws a conclusion after a single measurement. What is the best improvement?

03　Answers and one-line notes

#	Answer	One-line note
1	Plants given two extra hours of light each day will grow taller	A claim about looking nicer cannot be measured; only a prediction that can be measured is testable.
2	4.3	The five values add up to 21.5 and dividing by five gives 4.3.
3	It gives a baseline for comparison and shows the change comes from the variable tested	Without a control group you cannot tell whether a change comes from the treatment or from other factors.
4	Precise but not accurate	The readings are very close to each other yet all are away from the true value.
5	A systematic error	Every reading is shifted the same way, which is systematic; scatter caused by rounding readings is random error.
6	1.8 g	Divide 36.0 by 20 to get 1.8 grams.
7	4.0 percent	The error of 0.2 divided by the accepted value 5.0 and multiplied by one hundred.
8	The slope is 3.0 and y is 15.0 when x is 5	Dividing y by x always gives 3.0, so multiply 3.0 by 5.
9	1230	The digit 4 after the third significant figure is dropped and a zero keeps the place value.
10	Repeat the measurement at least three times and take the mean	A single result may be shifted by random error, so repeated readings averaged together are far more reliable.

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.