AQA GCSE Biology · Topic 21
Scientific method and science in society, designing investigations, handling data, units and uncertainty.
201 questions 5 subtopics
Every subtopic below has its own questions, mark schemes and notes once you start.
How scientific ideas are built, checked and replaced, and what happens when those ideas meet the rest of the world: money, ethics, the media and people's very uneven sense of risk.
Everything that has to be decided before any data is collected, and the critical look back at the method afterwards.
Getting measurements that are worth having, spotting the ones that are not, and turning a column of numbers into something meaningful.
Choosing the right chart, reading a rate off a graph, and writing a conclusion that says exactly what the data shows and nothing more.
The arithmetic that biology marks quietly depend on: units and prefixes, converting between them, standard form, rearranging a formula, and putting a number on how sure you are.
Key definitions, in exam-ready wording.
The mistakes that come up again and again in this topic.
Never write that data proves a hypothesis. Data supports or disproves.
Peer review does not make findings correct, only free of obvious error.
Hazard and risk are different words with different meanings; do not swap them.
Social issues affect people as a group; personal issues affect the individual concerned.
Suggesting an improvement without saying why it would help usually loses the second mark.
A control variable and a control experiment are different things.
Repeating your own experiment shows repeatability, not reproducibility.
Precise does not mean accurate. A zero error gives precise readings that are all wrong.
Taking more repeats does nothing about a systematic error.
Put the results in numerical order before picking the median.
Check every value for significant figures, not just the first one.
Joining points dot to dot instead of drawing a line of best fit is the most commonly penalised graph error.
A conclusion that names a species or condition that was never tested goes beyond the data.
Correlation is not cause; say so explicitly when a question invites the assumption.
Give the unit of a rate as the y unit over the x unit.
Uncertainty is half the range, not the whole range.
Minutes to seconds is × 60, not × 1000.
Both lengths must be in the same unit before calculating a magnification.
In standard form, A must be less than 10, so 62 × 10⁻⁵ is not standard form.
201 questions on Working scientifically, marked against the scheme. Anything you get stuck on will be scheduled to come back sooner.