Three marks available, five lines of correct physics written, one mark awarded. Nothing in the answer was actually wrong, which is what makes that kind of script so deflating to get back.
At A Level the concepts themselves are manageable. School notes and the textbook cover them properly, and a student who has kept up can usually talk you through the physics of a question in conversation without stumbling. The gap opens when that understanding has to reach paper in a form a marker is allowed to credit. Closing it is the whole of the Decode stage in our Establish-Decode-Score methodology, and it takes up a large share of H2 physics tuition at Candela in the months before the papers.
The instructions that ask you to explain
The syllabus sorts its command words by what they test. Recall and understanding are examined by questions opening with define, state, describe, or explain, while application to an unfamiliar situation is examined by predict, suggest, deduce, calculate, or determine.
In the structured papers, four of those verbs are asking for prose. “Explain” is the core of it. “State and explain” behaves the same way, with the conclusion put first and the reasoning after. “Describe” wants the main points set out in words, usually a sequence or an observation. “Suggest” turns up where the context is unfamiliar or where more than one answer can be credited, which still leaves you writing an explanation, only one you build from principles rather than pull from memory.
“State” on its own is the one students rarely fumble, since it usually asks for a definition or a value, and the same instruction has been used on them since the O-Level years. Papers 2 and 3 carry 30 per cent and 35 per cent of the grade, so around two thirds of an H2 Physics result rests on written answers, and explanation questions make up the bulk of what those two papers ask for.
Four patterns an explanation can take
Explanation questions look endlessly varied when you meet them one at a time, and yet they fall into a small number of patterns. Reading through more than a thousand papers, local and overseas, produced four categories, refined over more than ten years of teaching since.
The categorisation is our own. School notes group questions by topic and the published guidebooks group them by command word, but we have yet to come across another centre or resource that sorts explanation questions by the structure the answer itself has to take. Every explanation question in H2 Physics belongs to one of them, or to a combination of them.
1. Factual
A single principle carries the answer. Name it, then apply it to the situation in front of you. Asked why the gravitational force does no work on a satellite in a circular orbit, the answer names the perpendicularity of that force to the velocity at every point, then applies it through W = Fs cos θ. The commonest way to lose these marks is describing the situation again in fresh words instead of naming the physics that governs it.
2. Comparison
Two situations are set against each other, and both have to appear in the answer, described in the same terms, with the comparison made in so many words. A student who explains one side thoroughly and leaves the other to be inferred has written half an answer, however good that half is. Questions asking why the amplitude at resonance is larger for light damping than for heavy damping sit in this category, and so does most of what gets asked about two circuits, two orbits, or two waves.
3. Story
A chain of events, each link causing the next, told in order. A magnet falling through a coil is the standard example: the flux linkage changes, an e.m.f. is induced, a current flows, Lenz’s law sets its direction, and the resulting force opposes the motion. Mark schemes for these tend to award a mark per link, so an answer that leaps from the first link to the last collects a mark for each and nothing between.
4. Formula
The relationship does the arguing. Quote the equation, say which quantity is being held constant, and read off what follows for the rest. Parallel plates pulled further apart with the charge fixed: C = εA/d falls as d rises, and with Q constant, V = Q/C must rise. Leave the equation off the page and the same reasoning reads as assertion.
Most questions announce which pattern they want. Comparative wording points to a comparison, a sequence of events points to a story, two quantities in a defined relationship point to a formula, and a plain “explain why” with one governing principle points to the factual pattern. Plenty of questions want more than one at a time, and a comparison argued through a formula is especially common in electricity and fields.
Why memorised answers come apart
Model answers learned by heart hold up only while the wording holds. Shift the context, swap the quantity being varied, or set the same physics in an unfamiliar apparatus, and a memorised paragraph either does not fit or fits badly enough for the marker to notice. Working from a category and its structure generates an answer for the question actually asked. Students tend to find the habit spreads beyond physics too, since organising a written argument is a transferable skill long before it is a scoring one.
Practising this before November
Explanation technique responds well to short, deliberate drills, and it needs no full papers. Fifteen minutes does the job. Pull ten explanation questions from different topics, and before writing anything, label each one factual, comparison, story, or formula. Then write to the structure that category calls for and check yourself against the marks on offer.
Label the category before writing a word.
For factual, name the principle in your opening clause.
For comparison, write both sides in the same terms.
For story, put one link in each clause, in time order.
For formula, quote the equation before drawing anything from it.
Count your distinct points against the mark allocation, then check the physics.
Gradient and area questions are where the formula and story categories cluster most tightly, so this drill pairs well with reading graphs correctly in H2 Physics.
Closing the gap between knowing and scoring
None of this replaces understanding the physics. It makes sure the understanding you already have lands where a marker can credit it, which is the whole job of the Score stage in our Establish-Decode-Score methodology.
Candela Learners Cove runs as a tuition centre supporting what students are taught in school, so a good deal of our time goes on that final gap between knowing a topic and presenting it. The four categories are not something a student will pick up elsewhere, and they are taught here from the first term onwards. If your child is getting the concepts but not the marks, come and talk to us about where those marks are going, and we will go through their working with them line by line.