Nature and meaning of science

The direct answer is option B: evidence for the claim. Science accepts a claim only after asking what observations, measurements, experiments, or repeated results support it. The popularity of an idea does not make it true, and the identity of the speaker is not a substitute for evidence. Option A is wrong because many people may believe a claim and still be mistaken. Option B is correct because evidence can be examined, compared, and used to judge whether the claim is supported. Option C is wrong because the claimant’s age does not determine the truth of the statement; a young or old person can provide good or poor evidence. Option D is wrong because language or impressive wording does not prove a claim, although clear language helps communicate the evidence. A scientific claim may remain tentative when evidence is limited, and it may be revised when stronger evidence appears. Memory cue: in science, ask “What is the evidence?” before asking “Who says it?”

The amount of water is the independent variable because it is deliberately changed. Identify the changed factor in exams.

Scientific knowledge may be revised through new evidence and technology. Remember that science is open to revision.

Seeing yellow leaves is a direct observation while the other statements may be interpretations. Choose what is directly observed.

A scientific hypothesis can be tested through observation or experiment. Choose the testable option in exams.

Keeping similar conditions makes the effect of the changed factor clear. Link this with a fair test.

A conclusion is drawn after analysing the obtained results and data. Remember the sequence of steps.

Repeating measurements and taking the average can reduce random variation. Remember the importance of repetition.

The direct answer is option A: curiosity encourages questioning. Curiosity is the desire to know why something happens, how it works, or what will happen under a different condition. It begins scientific inquiry by helping a learner notice an event and turn it into a clear question. The reasoning is: observe something interesting; wonder about its cause or pattern; ask a specific question; suggest a possible explanation; investigate it with evidence. Option A is correct because questions are the starting point of exploration and testing. Option B is wrong because curiosity does not remove evidence; good curiosity seeks evidence. Option C is wrong because curiosity usually motivates experiments rather than stopping them. Option D is wrong because curiosity does not provide every answer in advance; investigation is needed to find answers. Memory cue: curiosity asks “why?” and science tests the answer.

A clear method allows others to understand and repeat the experiment. Link it with reproducibility.

A table organises data into rows and columns, making it quick and clear to compare different values, groups, or measurements. It does not alter the data values or remove the need to conduct an experiment. Exam tip: When data must be arranged for easy comparison, a table is usually the most suitable form of presentation.

A large and appropriate sample may better represent the diversity of a group. Link sample size with representativeness.

Direct answer: Option C is correct. In an experiment, the dependent variable is the outcome that is measured or observed. Usually, the researcher changes one factor, called the independent variable, and observes how the measured outcome responds. For example, if different amounts of light are given to plants, light is the independent variable and plant growth is the dependent variable. Option A is wrong because the independent variable is the factor deliberately changed or selected. Option B is wrong because a controlled variable is a condition kept the same, such as soil type or pot size. Option C is correct because it names the measured result. Option D is wrong because a constant is a value or condition kept unchanged, not the outcome being measured. A simple question helps: “What am I changing?” gives the independent variable; “What am I measuring?” gives the dependent variable. Memory cue: dependent means the result depends on the changed factor.

A scientific law describes a relationship regularly observed in nature. Link laws with patterns.

A scientific theory is an explanation supported by broad evidence and testing. Do not treat it as a mere guess.

A scientific result becomes more trustworthy when it is supported by a method that other people can repeat. Repetition helps show that the result is not merely caused by accidental conditions, an unnoticed mistake, or an unusual single observation. Scientists therefore describe their procedure carefully and compare results from repeated trials, while also considering measurement error and other controls.

Option B is correct because the ability to repeat an experiment allows the finding to be checked independently. If similar results appear under the same conditions, confidence in the conclusion increases. A result obtained only once may be important, but it is not enough by itself for strong reliability. Popularity of a claim and the fame of a scientist are not evidence that the method or result is scientifically sound.

A hypothesis is examined and revised if necessary according to results. Give priority to evidence.

The direct answer is B: record only what is observed or measured. An objective observation is based on facts available to the senses or instruments, not on expectations, guesses, or opinions. Step by step, watch carefully, measure when possible, write the actual value and unit, and avoid changing the record to fit a prediction. B is correct because it separates evidence from interpretation. A is wrong because recording only expected events hides unexpected evidence. C is wrong because a friend's opinion is not the observation itself. D is wrong because guessing a result is a prediction, not an observation. For example, “the liquid is 25 °C” is an observation, while “the liquid is good” is an opinion. Memory cue: write what happened, not what you hoped would happen.

Science examines claims through evidence and testing. Treat testability as the key difference.

The claim should be tested under controlled conditions. Choose experimentation when evaluating scientific claims.

A scientific model is a simplified representation of a complex object, structure, or process. It helps us understand parts, relationships, and changes that may be difficult to observe directly. A model is not an exact copy of every detail of reality, so option C is incorrect. Exam tip: Remember that models are used to explain, represent, and sometimes predict scientific phenomena.

Standard units make measurements uniform and comparable. Link standardisation with clear communication.

An upward trend often shows a positive relationship between variables. Check the axes before drawing conclusions.

Stating limitations honestly acknowledges the true extent of the evidence. Link it with scientific ethics.

Direct answer: Option A is correct. Peer review is a quality-check process in which other knowledgeable scientists examine a study before or around publication. They consider whether the question is clear, the method is suitable, the measurements and analysis are reasonable, and the conclusions are supported by the evidence. Peer review may identify errors, weaknesses, missing explanations, or claims that are too strong. It does not guarantee that a study is perfect, but it improves scientific reliability and encourages careful communication. Option A is correct because it refers to checking the method and conclusion. Option B is wrong because increasing popularity is not the scientific purpose. Option C is wrong because peer reviewers do not remove data simply because it is inconvenient; they examine how data were collected and used. Option D is wrong because review does not exist to stop an experiment; it evaluates the work. Memory cue: peer review means experts check the work, not that they promote the scientist.