Edexcel IGCSE Science Double Award 4SD0: Frequent mistakes

Pearson Edexcel Principal Examiner Feedback for Science Double Award identifies recurring errors across the Biology, Chemistry and Physics components. These patterns appear in Papers 1B, 1C, 1P and 2B, 2C, 2P.

General science errors

Hidden edges and 3D shapes

Foundation tier candidates struggle with hidden edges when counting edges on 3D shape diagrams. Missing edges that are not visible.

Fix: Count all edges—visible and hidden. Use correct terminology (vertices, edges, faces).

Mathematical terminology

Unfamiliar with terms like “terminating decimal”. Confusion between multiples and factors.

Fix: Terminating decimal = ends (e.g. 0.5). Multiples = times table; factors = divide exactly.

Precision in language

Lacking precision in scientific language. Failing to make clear comparisons when required. Vague wording instead of syllabus terms.

Fix: Use correct scientific terms. Compare explicitly. “X is greater than Y because…”

Reading scales and graphs

Difficulty reading scales on graphs. Wrong values; incorrect units; poor interpretation of trends.

Fix: Check scale. Units on axes. Describe trends with reference to data.

Standard form and symbols

Errors with standard form calculations. Using invalid symbols or wrong notation.

Fix: a × 10ⁿ, 1 ≤ a < 10. Correct symbols (Ω, V, A, etc.). Minus sign in negative powers.

Biology component

• Command word confusion: Describe vs. explain (see Edexcel Biology 4BI1)
• Energy in food chains: Incorrect use of “lost” vs. “transferred”
• Specificity: Vague answers; use precise terminology

Chemistry component

• Mole calculations: Limiting reagent; correct ratios (see Edexcel Chemistry 4CH1)
• Burette readings: Trailing zeros; correct format
• Terminology: Bonds between atoms, not molecules

Physics component

• Show working: All calculation steps
• Units: Include in final answers
• Applying concepts: Suggest questions require application to scenario

Exam technique

• Show all working—method marks available
• Use the resource—diagrams, tables, graphs
• Answer the question—match focus and command word
• Check accuracy—significant figures, units

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Based on Pearson Edexcel IGCSE Science Double Award Principal Examiner Feedback (2021–2023).