Scientific questions and observations

The percentage of germinated seeds is the measured outcome and therefore the dependent variable. In exams identify the value recorded as the result.

Light duration is the changed variable and weekly height increase is the measured variable. In exams choose questions with a clear cause and outcome.

Repeated values close to one another indicate high precision. In exams connect precision with closeness of repeated values.

Changing both fertiliser and water makes the true cause of the result unclear. In exams keep only one independent variable in a fair test.

Attributing weakness to mineral deficiency is an interpretation of evidence and therefore a conclusion. In exams separate observed facts from explanations.

Keeping the initial amount of water the same allows a valid comparison of surface area. In exams control other influencing factors.

Blue is a qualitative description while thirty millilitres is a quantitative measurement. In exams identify both description and number.

Selecting only favourable data is confirmation bias. In exams choose objective recording of all results.

Using more seeds reduces the effect of individual variation and makes the sample more representative. In exams identify the problem of a small sample.

Temperature is read more reliably after the thermometer reading becomes stable. In exams allow the instrument time to reach equilibrium.

The word best is based on personal opinion and gives no clear measurable outcome. In exams identify subjective questions.

The growth is stated with a number and unit so it is a quantitative observation. In exams treat measured values as quantitative even when approximate.

A consistent deviation in one direction indicates systematic error. In exams connect regular bias with the instrument or method.

A measured pH value is independent of personal opinion and is therefore more objective. In exams choose data obtained with standard instruments.

The number of oxygen bubbles in a fixed time is a measurable indicator of rate. In exams identify suitable indicators for indirect measurement.

The values are precise because they are close together but inaccurate because they are far from the accepted value. In exams distinguish accuracy from precision.

The effect of fertiliser should be compared with a normal group receiving no fertiliser. In exams identify the baseline group for a treatment.

A very short period does not provide enough evidence about long-term growth. In exams match the scope of the conclusion with the duration of data.

The third question presents a measurable cause and effect related to the observation. In exams form testable questions from facts.

Using the same ball allows a fair comparison of the effect of drop height. In exams keep influencing factors other than the tested one constant.

Smoke is directly observed evidence while the presence of fire is a possible interpretation. In exams separate direct evidence from explanation.

A tilted cylinder makes it difficult to read the liquid volume correctly. In exams remember the importance of correct instrument positioning.

An automatic sensor reduces dependence on human reaction time. In exams consider automated measurement more objective.

Growth requires the difference between final and initial height. In exams record a starting value when measuring change.

Two events changing together does not prove that one causes the other. In exams distinguish correlation from causation.