How to Answer 'Describe' Questions in IGCSE Physics

Use this guide to write ‘describe’ answers that score full marks in Cambridge IGCSE Physics 0625.

What ‘describe’ means

‘Describe’ asks you to state what happens. You need to say WHAT occurs, in WHAT order, and with WHAT result. You do not need to explain WHY.

The describe structure

For a process or event:

1. State the starting condition.
2. State what changes.
3. State the final condition or result.

For a pattern in data:

1. State the overall trend.
2. State any specific values or turning points.
3. State any exceptions.

Worked example 1: Describe what happens (3 marks)

Question: Describe what happens to the length of a spring as the load on it is increased from zero.

Strong answer: “As the load increases from zero, the spring extends. The extension is proportional to the load (the spring stretches by equal amounts for equal increases in load). Beyond a certain load (the limit of proportionality), the extension increases more rapidly for each additional unit of load.”

Worked example 2: Describe the pattern (2 marks)

Question: Describe the pattern shown in the graph of current against voltage for a filament lamp.

Strong answer: “As the voltage increases, the current increases. However, the graph curves, showing that the current increases at a decreasing rate as the voltage increases.”

Worked example 3: Describe an observation (2 marks)

Question: Describe what is observed when iron filings are sprinkled around a bar magnet.

Strong answer: “The iron filings form a pattern of curved lines that run from one pole of the magnet to the other. The lines are closest together near the poles, where the field is strongest.”

Common mistakes

• Giving a reason when only a description is needed (wastes time, though it is not penalised).
• Being too vague: “it goes up” instead of “the temperature increases.”
• Missing a stage in a sequence: describing the start and end but not the middle.
• Not using physics vocabulary: “the stuff spreads out” instead of “the particles diffuse.”

Tip

Read the question carefully. If it says “describe AND explain”, you need both what happens and why. If it says only “describe”, focus on a clear, precise account of what happens.