Explain vs describe is one of the most searched IGCSE topics because mixing them up costs marks. Examiners use command words to tell you what type of answer they want. Getting them right is essential for every subject.

Describe – What It Means

• Describe: Give an account of what happens or what something is. Focus on facts, steps, or features.
• Example: “Describe the process of photosynthesis” → State the steps (light absorbed, water split, CO₂ fixed, glucose formed, etc.) and where they happen. You are not required to give causes or reasons in depth.

Use order (first, then, finally) and precise terms (chlorophyll, stomata, etc.).

Explain – What It Means

• Explain: Give reasons or cause–effect links. Say why something happens or how it works.
• Example: “Explain why enzymes are affected by pH” → Link high or low pH to denaturation, active site shape, and substrate binding. You need because and so logic.

One mark often for a correct reason or mechanism; listing facts without “why” may not get full marks. In science, “explain” often means describe the mechanism (e.g. how enzymes work) or the cause–effect (e.g. why temperature affects rate). In humanities, “explain” might mean give reasons or consequences (e.g. why a policy was introduced, or why an event had a certain effect).

Describe vs Explain: Side-by-Side Examples

Question	Describe answer	Explain answer
Photosynthesis	“Light is absorbed by chlorophyll; water is split; CO₂ is fixed; glucose is formed.” (steps only)	“Light energy is absorbed by chlorophyll and converted to chemical energy, so that water can be split and CO₂ can be fixed into glucose.” (steps + why/how)
Enzyme and pH	“At high pH the rate decreases.” (what happens)	“At high pH the enzyme denatures, so the active site changes shape and the substrate can no longer bind, so the rate decreases.” (why it happens)

Practise with past papers and mark schemes to see the exact level of detail required for “describe” and “explain” in your subject.

Other Command Words That Affect Your Answer

• State or name – Short, factual answer; often one word or phrase.
• Suggest – Give a plausible reason or idea that fits the context; you don’t have to prove it.
• Compare – Similarities and differences between two or more things.
• Evaluate – Weigh up arguments or factors and give a judgement with reasons.
• Outline – Main points only; less detail than “describe”.

Always read the command word first and shape your answer to match it.

How to Use This in Exams

• Read the command word first. If it says “describe”, give what/how; if “explain”, add why/cause–effect.
• Match length to marks – e.g. 2 marks often = 2 distinct points (or 1 developed point for “explain”).
• Practise with past papers and mark schemes so you see exactly how “describe” and “explain” are marked.

Common Mistakes With Describe and Explain

• Explaining when asked to describe – You waste time and may not get extra marks; the mark scheme may only credit the “what” for a describe question.
• Describing when asked to explain – You miss the “why” or “how” and lose marks. Add “because”, “so that”, “this means that”, or a clear mechanism.
• Vague language – Use precise terms (e.g. “denatured”, “active site”) rather than “stops working” or “gets damaged”.
• Wrong length – Match the number of points to the marks (e.g. 2 marks often = 2 distinct points for describe, or 1 cause–effect chain for explain).

Tutopiya’s tutors can help you apply command words correctly in every subject and show you how describe and explain are marked in your syllabus.

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