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9 exam-style questions with model answers, plus 12 quick multi-choice questions — every question on the site for this standard, grouped by the 3 pages of notes they come from.
Write a full answer before you reveal the model one — that comparison is where the marks come from. Every block links back to the notes that teach it.
For an investigation into the effect of light intensity on the rate of photosynthesis in pondweed, write a suitable hypothesis and identify the independent, dependent and three controlled variables.
Explain why controlling the temperature and the carbon dioxide concentration is essential to the validity of a photosynthesis investigation.
Justify your choice of range and number of repeats for an investigation into the effect of temperature on enzyme activity, and evaluate the limitations that remain in your design.
Explain the difference between validity and reliability, and state one way to improve each.
A student sampling plants on a hillside places all their quadrats near the track because the rest of the slope is steep. Explain why this is a problem and how it should be corrected.
A student's repeat readings are very close together at every value, so they conclude their investigation was accurate. Evaluate this reasoning.
A student's three repeats at 30 °C are 18, 20 and 19 mm. Calculate the mean, and state two features every results table must have.
Explain why a conclusion must be based on processed data rather than on individual raw readings.
A student's results do not support their hypothesis. Discuss how they should handle this in their report, and explain why a result that contradicts a prediction is not a failed investigation.