Scientific questions and observations

The observation leads to a testable question about temperature and evaporation. Identify variables from observations.

Clear variables show what will be changed and measured. Identify independent and dependent variables.

Drooping leaves can be directly observed while the other statements are inferences. Separate observation from inference.

Careful observation and existing knowledge help form scientific questions. Remember the sources of question formation.

The word best is vague so a measurable outcome such as growth should be specified. Convert vague terms into operational terms.

This question clearly identifies duration as the independent variable and height as the dependent variable. Look for clear time and measurement.

The word warm is subjective while temperature measurement provides objective information. Choose the proper instrument.

A standardised method and clear criteria reduce observer differences. Identify methods for objective observation.

Condensation is an explanation of the cause while the others are directly observed or measured facts. Treat causal interpretations as inferences.

Time and measurement are both needed to determine a rate of change. Identify time in rate-based questions.

Soil type can be changed and plant height can be measured. Identify the changed factor and measured outcome.

Keeping conditions identical enables a clear comparison of the main variable's effect. Recognise the idea of a fair test.

The direct answer is B: record the time taken for the candle to go out. The word “quickly” is vague because different people may understand it differently. A precise observation uses something that can be measured and checked by another person. Step by step: start the timer when the candle is lit or when the stated event begins; stop it when the flame goes out; record the value, such as seconds or minutes, and keep the conditions clear. Option B is correct because time changes an unclear description into quantitative evidence. Option A is wrong because favourite colour does not tell when the candle went out. Option C is wrong because the student's feeling is subjective and cannot measure the event. Option D is wrong because room beauty is unrelated to the candle's extinction time. Memory cue: replace words such as quickly, brightly, or large with a number or a clear measurement.

A clear method and recorded conditions allow others to repeat the observation. Identify reproducible recording.

Selecting only one special example may hide the true pattern of the group. Record all relevant observations.

Bird presence and frequency can be directly observed and recorded. Identify measurable observational questions.

A broad question should be narrowed using specific variables time and conditions. Choose clear and focused questions.

The word good is vague while germination percentage is measurable. Replace value terms with scientific measurements.

A stopwatch is used to measure a time interval, not mass. Mass is generally measured using a balance or an electronic balance. A thermometer for temperature and a stopwatch for time are correct pairs. Exam tip: revise physical quantities along with their standard measuring instruments.

Instruments can provide finer or more accurate information than the senses. Understand the role of instruments.

One day's observation may not represent the entire month. Look for adequate duration and sampling.

Location may affect conditions such as temperature light or environment. Record contextual details.

Standard lighting makes colour comparison more objective. Remember to control observation conditions.

Growth changes over time so the duration should be clear. Look for time in questions about change.

The direct answer is B: examine the cause and effect of the missing data. A conclusion should be based on trustworthy evidence. If values are absent, we must first ask why they are missing: perhaps an observation was not made, an instrument failed, or a record was lost. We should also consider whether the missing values could change the pattern or trend. Option A is wrong because inserting desired numbers is fabrication and introduces bias. Option B is correct because checking the reason and possible effect protects the reliability of the conclusion. Option C is too extreme: the whole table need not be discarded; useful recorded data may still remain. Option D is wrong because selecting the largest value ignores the rest of the evidence and cannot replace missing observations. A careful investigator marks missing values clearly, investigates them, and avoids pretending that unknown data are known. Exam cue: never fill a gap with a convenient value unless a justified method is explicitly provided.