How IGCSE Co-Ordinated Sciences (0654) is really marked
0654 is examined across 18 paper variants covering Papers 1, 2, 3, 4, 5 and 6, each set in three versions (e.g. 11/12/13, 31/32/33). Papers 1 and 2 (multiple choice, 160 questions each) and Papers 5 and 6 (practical-style, 131 to 160 questions) are marked almost entirely point-by-point: 3,335 of the questions in our bank use this style against 3,524 total, so nearly every mark is awarded for a specific creditable response rather than a general impression of quality.
Papers 3 and 4 (the longer structured papers, running to several hundred questions each at 480 marks a paper) carry the calculation load: 189 questions across the whole syllabus use the calculation style, meaning working is marked as well as the final value. That is a small share of the paper overall, so most marks in 0654 still come from stating or identifying the right fact, term or observation rather than from arithmetic.
Because the syllabus spans Biology, Chemistry and Physics inside single papers, marks are lost as often to mixing up a term from one science with a similar-sounding one from another as to getting a calculation wrong. Precise vocabulary and the correct scientific context matter as much as knowing the underlying idea.
Where candidates actually lose marks
- In moment/turning-effect calculations, some candidates divide force by distance instead of multiplying the two together. (try the question)
- In organic chemistry identification questions, candidates confuse carbon monoxide, methane and ethane with the correct answer, picking a similar-sounding gas or hydrocarbon instead. (try the question)
- Few candidates state the general rule that non-metals form acidic oxides and metals form basic oxides, even when they can describe individual reactions. (try the question)
- Many candidates struggle to describe both the reaction of lithium with water and the trend in reactivity down the group in the same answer. (try the question)
- When explaining expansion gaps on a railway line, many candidates suggest they are designed to slow trains down rather than to allow for thermal expansion. (try the question)
- Alveoli and bronchioles are frequently confused with each other in gas exchange questions. (try the question)
- Many candidates know the relevant factor affecting a process but fail to state whether it causes an increase or a decrease, losing the mark for direction. (try the question)
- In density calculations, some candidates multiply weight by mass instead of dividing weight by mass. (try the question)
- In pulse-rate percentage change questions, many candidates misread the resting pulse value given and cannot complete the percentage increase calculation correctly. (try the question)
- Some candidates confuse large particle size with large surface area, choosing the wrong experiment as having the greatest surface area. (try the question)
Command words in IGCSE Sciences - Co-Ordinated
| Command word | Times in our bank | What it demands |
|---|---|---|
| Identify | 1123 | Give a specific named answer from a diagram, table or description; a general description of the item is not enough. |
| State | 675 | Give a fact concisely, with no explanation needed; extra detail beyond the fact itself does not earn extra marks. |
| Calculate | 326 | Show working and give a numerical answer with the correct unit; a bare correct number can lose the marks reserved for method. |
| Complete | 212 | Fill in a missing entry in a table, diagram or equation so that it is scientifically correct and consistent with the rest of the item. |
| Suggest | 204 | Apply scientific knowledge to a new or unfamiliar situation; there may be more than one acceptable answer, but it must be scientifically sound. |
| Describe | 201 | Give a detailed account of what is observed or what happens, in the correct order, without needing to explain why. |
| Explain | 198 | Give reasons or a mechanism for an observation; a correct description alone, without the underlying reason, will not gain full credit. |
| Record | 164 | Write down a measured or observed value accurately, to the precision the apparatus allows, in the correct place in a table. |
How to revise with past papers
Because most marks in 0654 are point-marked, past-paper practice pays off most when you check your wording against the mark scheme phrase by phrase rather than just checking whether you got the 'gist' right. A description that is scientifically true but expressed too vaguely, or that names the wrong but similar-sounding term, scores zero even though the underlying idea is correct.
Work through past papers by science strand (Biology, Chemistry, Physics) rather than only by paper number, since the syllabus mixes all three inside single papers. This makes it easier to notice where you are muddling vocabulary across the three sciences, which is a common and avoidable way to lose marks.
For the calculation-heavy sections of Papers 3 and 4, practise showing every step of working, not just the final answer, so that method marks are secure even on questions where you make an arithmetic slip. Reading the command word before answering, and checking whether a question wants a number, a description or a named term, avoids the direction and vocabulary errors that are easy to repeat.
Practise real 0654 questions with AI marking →FAQs
Is 0654 mostly a memorising subject or a working-out subject?
Mostly memorising and precise recall: 3,335 of the questions in our bank are marked point-by-point against 189 calculation questions, so most marks come from stating the correct fact or term rather than from arithmetic.
Do I need to show working for calculation questions in 0654?
Yes. Calculation questions in Papers 3 and 4 award marks for method as well as the final value, so showing each step protects marks even if your final answer is slightly wrong.
Which command word appears most often in 0654?
Identify, which appears 1,123 times in our bank, making it the single most frequent instruction across the syllabus.
Why do I keep losing marks on questions I understand?
This is generic exam advice: understanding a concept and answering the exact question asked are different skills. Read the command word carefully, use the specific scientific term expected, and check whether the question wants direction (increase/decrease), a named answer, or a described process.