Core Practicals Overview — Biology

Around 15% of the total marks across all six Edexcel GCSE Combined Science papers (1SC0) assess your knowledge of practical procedures. You do not sit a separate practical exam, but questions about core practicals appear on the written papers. This lesson covers the key Biology core practicals you must know.

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What Examiners Test

For every core practical, you may be asked about:

• The method and apparatus used.
• Variables: independent (IV), dependent (DV), control variables (CVs).
• How to make results reliable (repeats, calculating means).
• How to make the test valid (controlling variables).
• Sources of error and how to reduce them.
• How to process and present results (tables, graphs).
• Conclusions and whether the data supports a hypothesis.
• Safety precautions.

Exam Tip: Learn the structure above as a checklist. For any practical, you should be able to talk about method, variables, reliability, validity, errors, results and safety.

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Core Practical 1: Investigating Osmosis in Potato Chips

Aim

To investigate the effect of concentration of sucrose solution on the mass of potato chips (and therefore osmosis).

Method