Practical skills - Instruments and equipment — OCR A-Level Biology
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Practical skills - Instruments and equipment explained
This practical-skills statement asks you to select and use instruments, equipment and techniques that match the biology being investigated across the whole H420 specification.
Read the full explanation
It is not a list to memorise in isolation: for each context you decide what to measure, choose apparatus with suitable range, resolution and precision, and use a technique that controls the relevant variables. For example, measuring the rate of an enzyme-controlled reaction might use a colorimeter, a water bath and a stopwatch; observing cells might use a light microscope with a calibrated eyepiece graticule. You should practise choosing equipment, justifying the choice, using it safely and recording readings with appropriate units and uncertainty. Assessment is through the practical endorsement and practical-based questions, not a fixed mark scheme.
Your focus
- Select appropriate instruments and equipment for a given biological investigation and justify the choice.
- Carry out practical techniques safely and accurately, controlling relevant variables.
- Record and present measurements with correct units, precision and uncertainty.
Practical skills - Instruments and equipment exam tips
Examiner Tips
- 💡For each practical context, write a short justification linking the apparatus to the quantity measured, its range and its resolution.
- 💡Practise recording readings with correct units, significant figures and an estimate of uncertainty.
- 💡When answering practical questions, describe the technique step by step and name the equipment used at each stage.
Common Mistakes
- Treating the statement as a fixed list of named instruments to memorise. Correction: learn to justify apparatus choice by range, resolution, precision and the variable being measured in each context.
- Choosing equipment without considering resolution or uncertainty. Correction: state why a particular balance, thermometer, pipette or meter gives readings precise enough for the investigation.
- Using a technique without controlling relevant variables. Correction: identify the independent, dependent and controlled variables and show how the equipment and method keep controls constant.