Scientific Inquiry & Exam Skills
Formulating hypotheses. Identifying variables (changed, measured, kept the same). Designing fair tests. Reading graphs and tables. Writing explanations with evidence. Applies across all Booklet B questions.
Stage 1 of 6 — Overview
What Booklet B actually tests
Booklet B (40 marks) has 10–11 structured questions worth 2–5 marks each. Each question has multiple parts, typically building from simpler recall to harder application and evaluation. The six skills tested are:
Hypothesis — predict what will happen and why
Variables — identify what changes, what is measured, what stays the same
Fair test — explain why a variable must be kept constant
Analysis — describe patterns and trends in data
Conclusion — state what the results show
Evaluation — judge whether a conclusion is valid, suggest improvements
The most important rule: Every mark-earning answer needs a reason, not just a statement. "The plant died" earns 0. "The plant died because without water, photosynthesis cannot occur, so the plant cannot make food and cannot survive" earns marks.
Stage 2 of 6 — Hypothesis
Writing a hypothesis
A hypothesis is a testable prediction — a statement about what you expect to happen and why, based on scientific knowledge. It is written before the experiment.
Template: "If [changed variable] increases/decreases, then [measured variable] will increase/decrease, because [scientific reason]."
Scenario: Testing whether more light increases the rate of photosynthesis in a water plant.
0 marks "The plant will photosynthesize more with more light."
0 marks "More light is better for plants."
Full marks "If the light intensity increases, then the rate of photosynthesis will increase, because plants require light energy to convert carbon dioxide and water into sugar."
Scenario: Testing whether higher temperature increases evaporation rate.
Partial "Higher temperature increases evaporation."
Full marks "If the temperature increases, then the rate of evaporation will increase, because water molecules gain more energy at higher temperatures and escape from the liquid surface more quickly."
A hypothesis must be falsifiable — it must be possible to prove it wrong. "Plants need sunlight" is a fact, not a hypothesis. "The higher the light intensity, the greater the number of bubbles produced per minute" is a hypothesis.
Stage 3 of 6 — Variables
Identifying the three variables
Changed variable
The ONE factor you deliberately change.Also called: independent variable, manipulated variable.
Measured variable
What you observe or measure to see the effect.Also called: dependent variable, responding variable.
Kept-same variables
Everything else held constant to make it a fair test.Also called: controlled variables, unchanged variables.
Experiment: A student tests how the number of batteries affects the brightness of a bulb in a series circuit.
C
Changed: Number of batteries (1, 2, 3 batteries)
M
Measured: Brightness of the bulb (or current in the circuit)
K
Kept same: Same type/brand of batteries, same bulb, same wires, same circuit setup
The golden rule of fair tests: Only ONE variable should change at a time. If two things change at once, you cannot tell which one caused the observed effect — and the test is not fair.
Stage 4 of 6 — Analysis
Describing data — patterns and trends
Analysis questions ask you to describe what the data shows — look for patterns, trends, or relationships between the changed variable and the measured variable. Always refer to the actual data (numbers or observations) in your answer.
Template for a trend: "As [changed variable] increases, [measured variable] increases/decreases/stays the same."
Template with data: "When [X] increased from [value] to [value], [Y] increased/decreased from [value] to [value]."
Template with data: "When [X] increased from [value] to [value], [Y] increased/decreased from [value] to [value]."
Data: A plant in dim light grew 3 cm; in moderate light, 7 cm; in bright light, 12 cm after 4 weeks.
1/2 marks "More light made the plant grow more."
Full marks "As light intensity increased from dim to bright, the plant's growth increased from 3 cm to 12 cm. The greater the light intensity, the faster the plant grew."
Watch for anomalies: If one data point does not fit the trend, flag it — e.g. "All results show an increase except Trial 3, which may be an error." This shows scientific thinking and earns extra credit.
Stage 5 of 6 — Conclusion & Evaluation
Conclusion vs evaluation — know the difference
Conclusion: What do the results show? State the relationship between the variables based on the evidence. Link back to the hypothesis — was it supported or not?
Evaluation: Is the conclusion valid? Was the test fair? How could it be improved?
Evaluation: Is the conclusion valid? Was the test fair? How could it be improved?
Conclusion question: "What conclusion can be drawn from comparing Dish A (hot water, evaporated 40 mL) and Dish B (cold water, evaporated 10 mL)?"
0 marks "Hot water evaporates more."
Full marks "Higher temperature increases the rate of evaporation. Dish A (hot) lost 40 mL compared to only 10 mL for Dish B (cold), showing that water at a higher temperature evaporates faster."
Evaluation question: "A student concludes that sunlight causes seeds to germinate faster. Is this valid? The experiment changed both temperature and sunlight at the same time."
0 marks "No, because sunlight might not matter."
Full marks "No, this is not a valid conclusion. Two variables were changed at once — both temperature and sunlight. It is impossible to tell whether the faster germination was caused by sunlight, higher temperature, or both. To conclude about sunlight, only sunlight should be changed while temperature is kept the same."
Stage 6 of 6 — Mark-earning habits
10 habits that earn marks in every question
Always give a reason. Every explanation needs "because." "The plant died because..." not just "the plant died."
Name the science. Use the correct scientific term — "photosynthesis," "condensation," "frictional force" — not vague phrases like "a reaction" or "it changes."
Link cause to effect. A → B → C. Show the chain: "more light → more photosynthesis → more sugar made → plant grows faster."
Quote the data. In analysis questions, always include the actual numbers: "increased from 5 cm to 12 cm," not "increased a lot."
Match marks to sentences. A 2-mark question needs two distinct points. A 1-mark question needs one precise point.
For fair test questions: State the variable to keep constant AND explain why it must be kept constant (what it would affect if changed).
For "is this valid" questions: Always say yes or no first, then explain. A hedged answer ("it might be valid") earns 0.
For population change questions: State the feeding relationship → direction of change → reason. Three steps, full marks.
For adaptation questions: Feature → function → survival benefit in that habitat. Three steps, full marks.
Never conclude about an untested variable. If light was not changed in the experiment, you cannot say anything about light's effect.