Use this guide to build compare-and-contrast answers that earn full marks in Cambridge IGCSE Physics 0625.
Why students lose marks on ‘compare’ questions
A frequent mistake is describing item A in full, then describing item B in full, without ever stating the link between them. The examiner needs an explicit comparison statement.
The comparison template
For each point you compare, write one sentence that contains BOTH items:
In [A], [feature X] is [value/behaviour]. In [B], [feature X] is [different value/behaviour].
This forces the link to be visible.
Worked example: Compare series and parallel circuits
Question: Compare the current in a series circuit with the current in a parallel circuit. [2 marks]
Strong answer: “In a series circuit, the current is the same at every point. In a parallel circuit, the current splits at each junction, so the current through each branch is less than the total current from the supply.”
Why it scores: Both circuits are named, the same property (current) is discussed for each, and the difference is stated.
Worked example: Compare conduction and convection
Question: Compare conduction and convection as methods of thermal energy transfer. [4 marks]
Strong answer: “Conduction transfers energy through vibrations of particles that are in fixed positions, mainly in solids. Convection transfers energy through the bulk movement of a fluid (liquid or gas). In conduction, the particles do not change their position; in convection, warmer regions of the fluid rise and cooler regions sink, creating a convection current. Both require a material medium and cannot occur in a vacuum.”
Why it scores: Each point explicitly names both processes, covers the same feature, and includes a similarity.
Key comparisons in the IGCSE Physics syllabus
| Comparison | Common topics |
|---|---|
| Series vs parallel circuits | Current, voltage, resistance |
| Conduction vs convection vs radiation | Medium, mechanism, examples |
| Real vs virtual images | Lens/mirror diagrams, location |
| Transverse vs longitudinal waves | Oscillation direction, examples |
| Core vs Extended content | Syllabus scope, grade range |
| Alpha vs beta vs gamma radiation | Penetration, ionisation, charge |
Technique checklist
- Identify the two (or three) items being compared.
- Choose features that exist in both items.
- Write each comparison point with both items in the same sentence or adjacent sentences.
- If the question is worth 4+ marks, include at least one similarity and one difference.
- Use comparative language: “whereas”, “in contrast”, “similarly”, “both”.
Frequently Asked Questions
Do I need to write about both things in every sentence?
Does 'compare' mean I need differences only?
How many comparison points do I need?
Next useful steps
Need Help Applying This?
A 0625 specialist can work through the student's current paper or question and help identify whether the main difficulty is content, mathematics, practical reasoning or exam technique.