IGCSE Physics 6-Mark Questions: How to Build Answers That Score Full Marks

Every IGCSE Physics student knows the moment: a full half-page of blank lines, six marks on the right, and a question that starts with "Explain…". The extended-response questions are where physics grades quietly separate — not because the physics is harder, but because six marks demand a structured chain of reasoning, and most students write an unstructured splash of facts. Here's the method that turns them into predictable marks.

What the examiner is actually holding

Behind a 6-mark question is a mark scheme listing creditable points — typically 6–8 of them, of which any six earn full marks. Each point is a physics idea correctly applied to this scenario: a named process, a stated relationship, a linked consequence. Nothing in the scheme says "well-written"; everything says linked and precise. That has three practical consequences:

• Bullet-clear sentences beat paragraphs. The examiner is hunting for points — make them findable. One idea per sentence is a strategy, not a style crime.
• Precise terms are the currency. "Heat moves" earns nothing; "energy is transferred by conduction, because particles in the metal pass on kinetic energy through collisions" earns twice.
• Repetition earns zero. Saying the same idea three ways fills lines and banks one point. Six marks want six different links in the chain.

The 4-step method

1. Name the physics (10 seconds)
   Which topic is this really about — conduction? electromagnetic induction? pressure and volume? Write the key terms in the margin; they're your skeleton and often creditable points themselves.
2. Build the chain before writing
   List the causal steps from start state to end state: e.g. current flows → wire has resistance → energy transferred → temperature rises → resistance increases. Each arrow is a potential mark.
3. Write one link per sentence, connected
   "Because", "so", "which means", "therefore" — the connective words are literally what distinguishes an explanation from a description, and "explain" is the command word these questions almost always use.
4. End by answering the actual question
   Close the loop with a sentence that addresses exactly what was asked — "…which is why the temperature of B rises more slowly than A." Examiners award the comparison/conclusion point only if you state it.

A worked skeleton

"Explain why a metal spoon left in hot soup becomes hot at the handle, but a wooden spoon does not." (6 marks)

Chain, one link per sentence: metal contains free electrons ✓ — particles at the hot end gain kinetic energy ✓ — energy is passed along by collisions between particles, and by free electrons moving through the metal ✓ — this transfer is conduction ✓ — wood has no free electrons, so it transfers energy only by slower particle-to-particle vibration ✓ — therefore the metal handle reaches a higher temperature much faster than the wooden one ✓. Six sentences, six creditable ideas, question answered in the last line — that's the whole genre.

Where these questions come from

Extended-response questions cluster in the heavily-tested areas — our analysis of 6,500+ real Physics 0625 questions maps exactly which topics dominate, and the thermal, electricity and forces chapters that top the list are precisely where the 6-markers live. Pair this technique with the Physics A* guide, and drill it on real past-paper questions with instant marking so you can see which links in your chains the scheme actually credits.

FAQ

The 6-marker isn't an essay — it's a chain inspection. Name the physics, lay out the links, connect every one with a "because", and close by answering the question. Train it on real marked questions until chains come out on autopilot, and the scariest half-page in the paper becomes your most reliable six marks.