Practical guide · Updated
Keep raw observations separate from processed results
A practical record should make it possible to follow the path from observation to conclusion. Replacing the original measurements with tidied averages removes part of that evidence trail.
A practical example
Use a fictional set of repeat measurements to create one raw-data table and a separate processing section. Label units, show one calculation and explain any rounding. If a value is questioned, retain it with an explanatory note rather than silently overwriting it.
Connect the processed result to the biological question and the method’s limitations. Follow the school’s practical procedures and exam-board requirements for formal records; this checklist supports discussion and revision, not certification of practical competence or instructions to repeat laboratory work unsupervised.
Explain what a repeat measurement can and cannot fix
Using a fictional dataset, compare repeated readings from the same setup and calculate the mean where appropriate. Discuss whether the spread suggests random variation, then consider a systematic offset affecting every reading.
More repeats do not automatically remove that offset. Name the specific limitation and the adjustment that addresses it, following school procedures for any real practical work. Keep this as a data-review exercise rather than instructions to perform unsupervised experiments or evidence that a formal practical requirement has been completed.
Start with your exam board
AQA, OCR and Pearson Edexcel organise and name their practical activities differently. The transferable apparatus and practical skills are common, but the required or core practical list must be checked against your own current specification.
Exam board: __________________ Specification: __________________ Review date: __________________
September quick start: record the first practical properly
Use the first Year 12 or Year 13 practical of the new term to set up a repeatable record. Do not wait until revision season to reconstruct why an apparatus choice or control variable mattered.
Core practical skills
Tick a skill only when you can apply it without copying a model answer.
Apparatus and technique tracker
AQA required practical themes
This section follows the twelve practical activities in the current AQA A-Level Biology 7402 specification. OCR and Pearson Edexcel students should use the skills sections above and replace this table with the named activities from their own specification.
| Practical theme | Method secure | Data and graph secure | Evaluation secure |
|---|---|---|---|
| 1. Effect of a variable on an enzyme-controlled reaction. | □ | □ | □ |
| 2. Root-tip squash, microscopy, stages of mitosis and mitotic index. | □ | □ | □ |
| 3. Dilution series and calibration curve to find plant tissue water potential. | □ | □ | □ |
| 4. Effect of a variable on cell-surface membrane permeability. | □ | □ | □ |
| 5. Dissection of a gas-exchange or mass-transport system or organ. | □ | □ | □ |
| 6. Aseptic investigation of antimicrobial substances and microbial growth. | □ | □ | □ |
| 7. Chromatography of pigments isolated from plant leaves. | □ | □ | □ |
| 8. Effect of a factor on dehydrogenase activity in chloroplast extracts. | □ | □ | □ |
| 9. Effect of a variable on respiration in single-celled organisms. | □ | □ | □ |
| 10. Effect of an environmental variable on animal movement. | □ | □ | □ |
| 11. Glucose dilution series and colorimetry to identify an unknown concentration. | □ | □ | □ |
| 12. Effect of an environmental factor on the distribution of a species. | □ | □ | □ |
One-page revision frame for any practical
Practical: __________________________________________________________________________________
Biological principle being tested:
Independent, dependent and control variables:
Essential apparatus and why it is suitable:
Method in six precise steps:
Expected graph or result pattern:
Most important limitation and a linked improvement: