Nature and meaning of science

The dependent variable is the outcome that is measured or observed in an experiment. Here, seed growth is measured as the temperature changes, so seed growth is the dependent variable. Temperature is the independent variable, while factors such as seed type and amount of water should be kept constant. Exam tip: the factor changed is the independent variable; the result measured is the dependent variable.

Temperature is the independent variable because the experimenter deliberately changes it to observe its effect on seed growth. Seed growth or measured length is the dependent variable because it may change in response to temperature. Exam tip: the factor deliberately changed in an experiment is the independent variable.

A scientific prediction is based on a known relationship and testable conditions. Choose an evidence-based statement.

Science treats unusual results as information that needs checking, not as something to hide. An unexpected result may arise from a genuine effect, an error in measurement, an uncontrolled condition, or a problem in the method. The responsible response is to write down exactly what happened, review the procedure and equipment, and repeat the experiment when possible. Repetition helps show whether the result appears again and can be trusted. Data should never be altered simply to fit an expected conclusion.

Option B is correct because recording and repeating the experiment allow the unusual observation to be investigated. Option A would destroy useful evidence, while option C makes an unsupported claim from one result. Option D is scientifically dishonest because changing other data removes the objectivity of the investigation. A repeated, carefully checked result may lead to a new explanation, but it must first be documented and tested rather than ignored or declared certain.

Checking the source of a claim helps us judge how much confidence we should place in it. A source may be based on direct measurements, a recognised investigation, expert review, personal experience, advertising, or an unsupported statement. Knowing its origin helps us ask whether the information was collected carefully, whether the source has relevant knowledge, and whether the claim can be checked against other evidence. A source should not be accepted or rejected merely because it exists; its reliability and supporting evidence must be examined.

For example, a measured result from a transparent study is generally more useful than an anonymous statement with no data, though even a study must be evaluated carefully. Therefore, option A is correct: source checking helps assess reliability. The other choices do not describe scientific evaluation. Making a claim longer, rejecting every source, or avoiding experiments cannot establish whether the evidence is trustworthy.

Scientific literacy includes understanding information on the basis of evidence. Identify daily-life examples.

Collaboration combines different expertise for better investigation and solutions. Understand science as a collective effort.

The governing concept is scientific ethics, which sets standards for honest, responsible, and safe inquiry. Researchers should record and report observations truthfully, avoid fabrication or selective alteration of results, acknowledge sources, protect participants, obtain informed consent when people are involved, and follow safety procedures. These practices make evidence more trustworthy and allow other researchers to examine or repeat the work. Therefore option A is correct because ethics protects both safety and honesty. Changing results, removing consent, or hiding claims undermines the reliability of science and violates responsible research conduct.

In a fair experiment, the independent variable is deliberately changed while other important conditions are kept the same. The result that may respond to this change is measured as the dependent variable. Keeping other factors controlled makes it much easier to decide whether the observed change was caused by the independent variable rather than by temperature, amount, time, or another uncontrolled condition.

Option A is correct because changing only the independent variable helps isolate its effect and identify it accurately. It does not make every result identical; results may still differ because of the tested effect or measurement uncertainty. The dependent variable does not disappear, and measurement remains essential for recording the outcome. This procedure is therefore a foundation of a fair or controlled test.

The direct answer is option A: an incorrect zero setting can cause zero error. Before measuring, an instrument should show zero when no quantity is being measured, or it should be adjusted according to its instructions. If it does not, every reading may be shifted by a fixed amount or otherwise affected. For example, if a balance shows 2 g when empty, a later reading may include that unwanted offset unless it is corrected. The reasoning is: check the instrument at zero; notice any initial reading; correct or record the offset; then measure; interpret results while considering the error. Option A is correct because the fault is specifically called zero error. Option B is wrong because the sample itself does not become larger merely because the instrument is incorrectly set. Option C is wrong because an instrument setting does not automatically change the hypothesis. Option D is wrong because no instrument error can make an experiment repeat automatically. Memory cue: zero first, measure second.

The direct answer is A: whether the sample represents the wider group. A conclusion from a small study can be applied to a larger population only when the people or objects studied reasonably reflect that population. Step by step: define the wider group; identify the sample selected from it; ask whether the sample includes relevant variety and is chosen fairly; consider sample size and possible bias; only then decide whether generalisation is reasonable. For example, asking only one class about the preferences of an entire school may give a biased conclusion if other classes differ. Option A is correct because representativeness is central to valid generalisation. Option B, “whether the author’s name is long,” has no scientific connection to the quality or applicability of evidence. Option C, “the colour of the report,” is merely appearance and cannot show whether the sample is suitable. Option D, “a photograph of the experiment,” may document activity but does not prove that the sample represents the wider group. A large sample can still be biased if it excludes important members, while a carefully selected smaller sample may be informative. Memory cue: before saying “this applies to everyone,” ask “Who was actually studied, and do they represent everyone?”

Scientific scepticism means testing claims through reasoning and evidence. Do not confuse it with negativity.

Results provide obtained information while the conclusion interprets it. Distinguish data from interpretation.

Open-mindedness means revising ideas according to evidence. Link it with a scientific attitude.

Scientific knowledge develops technology and technology advances science. Understand their mutual relationship.

A control group shows the normal condition for comparison with the treatment. Link it with comparison.

Methods conditions and data should be compared when results differ. Treat retesting as the correct step.

A single experience is not broad controlled evidence. Treat systematic studies as more reliable.

The direct answer is A: identifying patterns helps us understand relationships and make predictions. A pattern is a repeated arrangement or trend in observations or data. Scientists compare measurements, notice whether one quantity changes when another changes, and use that relationship to expect what may happen next. For example, if a plant grows more when it receives more light, repeated observations may reveal a pattern; the pattern can help predict growth under similar conditions. Option A is correct because patterns organize evidence and support reasonable predictions, although a prediction must still be tested. Option B is wrong because recognizing patterns does not stop experiments; it often helps scientists design better experiments. Option C is wrong because patterns are found by examining evidence, not by removing it. Option D is wrong because a pattern does not force every result to be identical; real data may vary. The useful exam cue is: patterns connect observations, reveal relationships, and help predict—not guarantee—future results.

Safety goggles protect the eyes from splashes and particles. Identify the correct use of safety equipment.

Citing sources allows information to be checked and credits original work. Link it with ethics.

Scientific verification depends on evidence and testing rather than majority belief. Prioritise evidence.

Similar results in different laboratories demonstrate reproducibility. Identify independent verification.

Science is a method of questioning evidence and reasoning used in many settings. Understand its broad meaning.

Science is both knowledge and a process based on evidence reasoning testing and revision. Remember these key features.