IGCSE Co-ordinated Sciences (0654): How to Revise It Properly

Quick answer: Revise Cambridge IGCSE Co-ordinated Sciences (0654) by rotating biology, chemistry and physics through every single week instead of blocking one science at a time, and put most of your past-paper time into the structured theory paper (Paper 3 for Core, Paper 4 for Extended, 2 hours) because it carries the largest share of your marks. Multiple choice is Paper 1 or 2, 45 minutes.

I am an English and history person, so Co-ordinated Sciences was the IGCSE I was most nervous about. An earlier version of this article also had the paper numbers flat-out wrong — I had written "Paper 3 multiple choice, Paper 4 structured", which is not the exam. Getting that wrong wastes a fortnight of planning, so the structure comes first.

The paper structure, checked properly

0654 is assessed across three papers, not two, and each one comes in a Core version and an Extended version.

• Paper 1 or Paper 2 — multiple choice, 40 questions, 45 minutes. Paper 1 is the Core version; Paper 2 is Extended.
• Paper 3 or Paper 4 — short-answer and structured questions covering all three sciences, 2 hours. Paper 3 is Core; Paper 4 is Extended.
• Paper 5 or Paper 6 — the practical assessment. Paper 5 is a practical test done in a lab; Paper 6 is the written alternative to practical. Your school chooses which one you sit, not you.

Two things follow. First, the 2-hour structured paper is the biggest block of marks you will sit, so a plan built mostly on quick multiple-choice quizzing aims at the smaller target. Second, 0654 is a Double Award: you get two IGCSE grades reported as a pair, so a weak strand is not quietly averaged away the way people assume.

One question on the alternative-to-practical paper assesses planning, and it can be set on any of the three sciences in a given series — so you cannot revise for it by hoping it lands on your best one.

Core or Extended changes what you actually revise

Find out which tier you are entered for this week, because it changes your syllabus. The Core route is capped: the highest pair available is CC. Extended reaches the top grades and carries extra content on top of everything in Core.

Every topic in 0654 has core statements plus supplement statements. Supplement material separates grades on Paper 2 and Paper 4, and it is exactly what generic "IGCSE science summary" notes online leave out. Print the syllabus content list, highlight every supplement statement, and treat that set as your priority list if you are Extended. If you are Core, it is not wasted learning, but it is not where your marks are.

The rotation that fixed my forgetting problem

Do not revise one science for three weeks and then move on. I did that with biology, felt brilliant about it, and by the time I finished physics I could not remember what a magnification calculation looked like. Rotate instead. A week that works:

1. Monday — one biology topic: 40 minutes recalling it from blank paper, 20 minutes on questions.
2. Tuesday — one chemistry topic, same split.
3. Wednesday — one physics topic, same split.
4. Thursday — 20 mixed multiple-choice questions pulled from a past Paper 1 or 2, timed.
5. Friday — one full structured question from Paper 3 or 4, marked strictly against the mark scheme.
6. Weekend — 30 minutes reviewing only what you got wrong that week.

Because each science reappears every few days, you re-test old material constantly instead of letting it decay. The quiz generator will build the mixed-question step from all three sciences at once, and flashcards are worth making only from wording mark schemes actually accept, not from your notes.

A worked example: where the four marks actually sit

Take a typical calculation: a metal block has a mass of 54 g and a volume of 20 cm^3. Calculate its density and give your answer in kg/m^3. Four marks.

1. Write the formula: density = mass / volume.
2. Substitute: 54 / 20 = 2.7 g/cm^3.
3. Convert: 1 g/cm^3 is 1000 kg/m^3, so 2.7 g/cm^3 becomes 2700 kg/m^3.
4. Write the unit next to the answer: 2700 kg/m^3.

Most people who lose marks here get 2.7 and stop, having skimmed past "in kg/m^3". That is two marks gone on a question they understood completely.

Set your working out on separate lines like the four steps above. Markers award method marks, and if your arithmetic slips at step 2 you can still be credited for a correct conversion at step 3 — but error carried forward only works if the marker can see your route. Unless told otherwise, match the significant figures in the data you were given.

Command words decide the mark, not the content

Cambridge questions are precise about what they want, and the command word tells you how many sentences to write.

• State or give — one short fact. No reasoning, no "because". Do not spend three minutes here.
• Describe — say what happens. You do not need the cause.
• Explain — say what happens and why. If your sentence has no "because" or "so", you have written a describe answer.
• Suggest — apply science you know to an unfamiliar situation. The answer is not sitting in the syllabus word for word, and any scientifically sound reasoning can score.
• Compare — both things must appear in the same sentence. "Metal is a good conductor" scores nothing; "metal conducts thermal energy better than wood" scores.
• Calculate or determine — show working, always.

A two-mark example: explain why a metal spoon feels colder than a wooden spoon at the same temperature. Metal is a better thermal conductor, so it transfers thermal energy away from your hand more quickly. Two linked points, one "so", and anything longer is time you needed elsewhere. Count the marks, make that many distinct points. If you want your practice answers checked against that standard, the grading tool will tell you which point you missed, and a timed mock is the only way to find out whether you can actually do 2 hours of it.

Mistakes that cost me marks in mocks

• Leaving the practical paper until the final fortnight. Variables, tables, anomalies and graph-drawing are learnable skills that need weeks, not days.
• Writing "it goes up" instead of naming the variable. Say which quantity increases.
• Prefix errors: kJ read as J, cm^3 read as m^3, mA read as A. Underline every unit in the question before you start.
• Ignoring the data in the stem. If a question hands you a graph or table, the marks usually require you to quote figures from it, with units.
• Revising by re-reading. If you have not written something down from memory, you have not revised.

Test yourself

1. Which paper is the 2-hour structured theory paper for an Extended candidate?
2. A block has a mass of 90 g and a volume of 30 cm^3. What is its density in kg/m^3?
3. A question begins "Suggest why...". What must your answer do that a "state" answer does not?

FAQ

Is Co-ordinated Sciences harder than the three separate sciences?

It covers less depth per science, but all three, so nothing is optional. Separate sciences let you go deep on one subject at a time; 0654 asks you to hold biology, chemistry and physics in your head at once. That is a memory problem more than a difficulty problem, which is why rotation matters.

How many hours a week should I revise for 0654?

Six focused hours split across the three sciences beats twelve unfocused ones — the week above is roughly five hours plus review. What matters more than the total is whether each session ends with you producing answers rather than reading them.

Can I use past papers from the older syllabus?

Yes, for technique, but check the content list first — topics move between syllabus versions and you do not want to panic over something no longer examined. Any question type still appearing in the current specimen papers is fair practice.

What if one science is much weaker than the other two?

Give it the extra session, not the extra week. Keep the other two ticking over at one session each and add a second slot for the weak one. Dropping the strong sciences to fix the weak one is how people end up with three shaky sciences instead of one.

In short: get the paper structure right, find out whether you are Core or Extended, rotate all three sciences through every week, and spend your past-paper time on the 2-hour structured paper where the marks live. The content in 0654 is not the hard part. Remembering three sciences at once, and answering the command word you were actually given, is.