Did you know that two students can both say they are studying G3 Combined Science and still be preparing for different theory papers? One might take Physics and Chemistry; another Physics and Biology; a third Chemistry and Biology. The new 2027 Singapore-Cambridge Secondary Education Certificate retains these three combinations and uses separate codes so that the actual registration is clear. For Bukit Timah families, this guide explains exactly how the papers fit together and why the practical examination cannot be confused with the practicals for pure Physics, Chemistry or Biology.
The quick answer: SEAB lists K326 Science (Physics, Chemistry), K327 Science (Physics, Biology) and K328 Science (Chemistry, Biology) for 2027. Each combination uses Paper 1: 40 compulsory MCQs, one hour, 20%; two 65-mark subject-specific theory papers of 1 hour 15 minutes and 32.5% each; and Paper 5: a 1-hour-30-minute practical, 30 marks, 15%. Students enter Paper 1, Paper 5 and exactly the two relevant theory papers from Physics Paper 2, Chemistry Paper 3 and Biology Paper 4. The practical paper can assess both sciences in the student’s combination and may ask for proposed improvements to an investigation.
Updated 25 October 2026. Featured image depicts general classroom revision, not an examination laboratory or practical specimen. All scientific examples are fictional unless a specific official source is named.
Jump to: 1. Why the combination name matters more than the word ‘Science’ · 2. The 2027 assessment adds up to 100% in a particular way · 3. How K326 Physics and Chemistry works · 4. How K327 Physics and Biology works · 5. How K328 Chemistry and Biology works · 6. The 40-question MCQ paper covers two sciences · 7. What each 65-mark theory paper contributes · 8. Why the combined Science practical is Paper 5 · 9. The 10–20% improvement task inside practical assessment · 10. Why observation and inference should be separated · 11. Units, graphs and basic numeracy span the science pair · 12. Physics within the combined syllabus: the important habits · 13. Chemistry within combined Science: particles and evidence · 14. Biology within combined Science: systems and functions · 15. Choosing between combined and pure Science is not a prestige test · 16. Using science diagrams without memorising shapes blindly · 17. Practical reliability: a neat table is not enough · 18. Common revision mistakes across K326, K327 and K328 · 19. A two-subject study calendar for the remaining months of 2026 and 2027 · 20. What parents should ask about 2028 pathways · Related 2027 guides
1. Why the combination name matters more than the word ‘Science’
Under Full Subject-Based Banding, the common 2027 SEC certificate identifies subjects at G1, G2 and G3 levels. For G3 combined Science, the subject title also identifies the two scientific disciplines examined. K326 represents Physics and Chemistry, K327 represents Physics and Biology, and K328 represents Chemistry and Biology. The earlier codes 5086, 5087 and 5088 appear for reference in SEAB’s directory.
A pupil should not download an arbitrary ‘SEC Combined Science’ booklet without checking the code. A Biology explanation is not a substitute for an electricity question, even though both may appear under the umbrella of Science. The two-subject combination determines which concepts and practical skills the student is responsible for.
The school’s actual offering and the student’s approved subject entry determine what should be studied. A Bukit Timah address does not imply that every nearby school offers all three combinations. Ask the teacher to confirm the code and theory papers before arranging revision.
- K326 — Physics and Chemistry, formerly 5086.
- K327 — Physics and Biology, formerly 5087.
- K328 — Chemistry and Biology, formerly 5088.
- These are three distinct registered subject combinations, not elective questions within one paper.
2. The 2027 assessment adds up to 100% in a particular way
Paper 1 contributes 20% of the combined subject. Each of the two relevant subject-specific theory papers contributes 32.5%, producing 65% from those theory papers together. Paper 5 practical contributes the remaining 15%. The resulting 20 + 32.5 + 32.5 + 15 equals 100%.
The raw marks are not identical across components. Paper 1 is worth 40 marks, each theory paper 65 marks, and practical 30 marks. A parent who adds all the raw marks and treats them as equally weighted will misinterpret performance. Schools assess according to the published scheme and subject entry.
Balanced preparation is therefore essential. The compulsory one-hour MCQ paper matters, each separate science theory paper matters considerably, and the practical remains a distinct assessed skill. A pupil cannot neglect an entire discipline and expect the other theory paper to compensate automatically.
- Paper 1: 40 marks, one hour, 20%.
- Two theory papers: each 65 marks, 1h15m, 32.5%.
- Paper 5: 30 marks, 1h30m, 15%.
- One combined SEC subject grade follows the relevant component weightings.
3. How K326 Physics and Chemistry works
For K326, the shared Paper 1 draws on Physics and Chemistry content. Candidates sit Physics Paper 2, Chemistry Paper 3 and the Paper 5 practical involving the prescribed Physics/Chemistry scope. There is no Biology theory paper within this registration. This sounds obvious, but it is a surprisingly useful check when searching for resources online.
The Physics portion may involve mechanics, thermal effects, waves or electricity within the combined syllabus. The Chemistry portion may involve particles, chemical reactions, bonding and other listed outcomes. A student should build accurate concepts in each discipline, then practise how questions ask them to apply those ideas to new examples.
The official K326 PDF contains the combined syllabus and a specific assessment table. It should be the primary study reference for the candidate, supplemented by the school’s course plan rather than replaced with a pure Chemistry or pure Physics paper that has a different structure.
4. How K327 Physics and Biology works
For K327, Paper 1 draws on Physics and Biology; the student sits Physics Paper 2 and Biology Paper 4, plus the compulsory Paper 5 practical within the relevant subjects. Chemistry Paper 3 is not one of the required theory examinations for K327.
Physics encourages thinking about measurements, forces, energy and physical systems. Biology asks how structures and processes work in living things, from cells to whole organisms. Both rely on sound evidence, yet the language, diagrams and typical explanations differ. A student who memorises Physics equations will still need biological causal reasoning.
An effective weekly plan might alternate concept work from the two subjects while preserving short review sessions for each. It should not be described as half of a pure Physics qualification plus half of a pure Biology qualification; it is the distinct combined subject governed by K327.
5. How K328 Chemistry and Biology works
K328 includes Chemistry and Biology. Its theory papers are Chemistry Paper 3 and Biology Paper 4, alongside a Paper 1 based on both and the Paper 5 practical. A student in this combination should not expect Physics Paper 2 to appear merely because the word ‘Science’ appears on the cover.
The combination offers many useful connections. Chemical structures and reactions help explain biological molecules, enzymes and food processes; biological questions about cells and organisms often require careful understanding of substances and energy. The examined outcomes remain those specified for the combined curriculum.
For revision, ask the pupil to distinguish chemical explanation from biological explanation. A correct answer about a cell’s function does not automatically explain the molecular mechanism behind every process. The teacher should show how much detail the K328 syllabus requires.
6. The 40-question MCQ paper covers two sciences
Paper 1 has 40 compulsory multiple-choice questions in one hour. SEAB states that coverage is approximately equal between the two appropriate science sections, and that the paper is set at the same time for all three combined Science syllabuses. The actual questions a candidate receives depend on the registered pairing.
The time constraint rewards understanding and careful interpretation, not guessing at the first familiar term. Students should read diagrams and units, decide which principle applies and eliminate responses that violate the information supplied. A correct guess can conceal a misconception that later appears in a structured paper.
An error log can record why an option was wrong. Was the problem a mistaken physical unit, a wrong chemical formula, or confusion over a biological structure? Sorting by discipline and cause helps a student make the next study session relevant.
7. What each 65-mark theory paper contributes
Physics Paper 2, Chemistry Paper 3 and Biology Paper 4 each last one hour fifteen minutes and are worth 65 raw marks when taken as part of the relevant combination. Each contributes 32.5% of the overall result. Students take two of these subject-specific papers according to the code, not all three.
Structured questions may ask for a short definition, calculations, explanations, interpretations of unfamiliar data or longer reasoning. The official syllabus emphasises using known scientific principles logically in novel situations. It does not require the pupil to have encountered every story or device that appears in an examination context.
Practice should combine concise factual recall with data interpretation and evidence-based explanation. Spending every session memorising a model paragraph can leave students unable to work with a fresh graph. Conversely, knowing how to read graphs without learning the scientific concepts can also weaken results.
8. Why the combined Science practical is Paper 5
Pure G3 Physics, Chemistry and Biology have their own 20%-weighted Paper 3 practical arrangements. Combined G3 Science uses Paper 5, worth 15% of its own subject, and lasting one hour thirty minutes. The two schemes are different; ‘Science practical’ is not a sufficient label for selecting preparation material.
SEAB explains that candidates may be asked to carry out practical exercises appropriate to the two sciences or interpret scientific observations. The experiment environment and apparatus are governed by the examining authority and the school. A family should not assume that a 1h50 pure-Science practice paper accurately simulates the 1h30 combined-Science assessment.
Parents can support the reasoning side of practical work by asking how a result is recorded, what variables matter and why an inference follows. Actual laboratory manipulation and equipment handling belong to trained school supervision.
9. The 10–20% improvement task inside practical assessment
The syllabus notes that one or more Paper 5 questions may ask candidates to suggest a modification or an extension to an investigation without actually performing it. Depending on the context, this element accounts for about 10–20% of the raw marks in the practical test. This is a share of Paper 5 marks, not an extra 10–20% of the entire Science qualification.
The task tests whether students understand the purpose and limitations of an experimental method. A weak response may say ‘repeat the experiment’ without explaining which problem repetition addresses. A stronger response names a specific issue, suggests a relevant modification and explains how it could improve evidence.
The actual practical instructions have safety and resource constraints. At home, pupils should practise evaluating teacher-provided methods or datasets rather than devising unsupervised experiments with chemicals, electrical apparatus or biological samples.
10. Why observation and inference should be separated
An observation records what a student detects: a measured value, colour change, movement or other directly described result. An inference proposes what that observation indicates. This distinction is valuable across all three possible science pairs. Recording the anticipated result instead of what was observed undermines the investigation.
Imagine a fictional results table showing a measured quantity increasing as another variable changes. The observation is the displayed pattern; the explanation may involve a principle from Physics, Chemistry or Biology. The student should identify which science is relevant and whether other uncontrolled variables could also explain the pattern.
Useful practice uses a three-column sheet: observation, proposed explanation and limitation. That trains clear thinking without requiring any real laboratory experiment outside school. Scientific honesty is an assessment skill, not an optional courtesy.
11. Units, graphs and basic numeracy span the science pair
Regardless of pairing, students may need to read measurements, interpret units and present data. Physics often uses rates or gradients, Chemistry uses ratios or concentrations, and Biology may use relative changes and graphical trends. These examples depend on the actual prescribed content and question.
If an invented graph plots mass against time, the gradient’s units reflect mass divided by time. It is not a velocity merely because the graph slopes upwards. If a Biology chart shows population growth, the student must check the sample period and axes before inferring a cause.
Families can practise with small, fictional data tables. Ask which variables are measured, which values are calculated and whether the chart supports the proposed conclusion. Avoid collecting classmates’ private personal or health information to create practice data.
12. Physics within the combined syllabus: the important habits
Physics concerns physical quantities and relationships among forces, motion, energy and other phenomena within the combined Science scope. It often involves mathematical models, but the student must interpret what the symbols and units mean. A correct calculation for the wrong quantity is not an adequate scientific answer.
Take a safe thought experiment: a person moves four metres east and then two metres west. The distance travelled is six metres, but displacement is two metres east. The distinction is conceptual and can be explained without apparatus. It helps a pupil avoid treating every movement question as the same speed equation.
Students should also learn to explain diagrams in words, distinguish a stated condition from an assumption and check whether a calculated value is physically plausible. The appropriate content depth belongs to K326 or K327’s combined Physics section, not automatically the pure Physics syllabus.
13. Chemistry within combined Science: particles and evidence
Chemistry questions may involve the particulate nature of matter, reactions, chemical symbols and relevant properties in the prescribed combined section. The student should distinguish what particles exist, how a symbolic equation represents a change and what observable evidence supports a proposed conclusion.
Balanced equations express conservation of atoms, but they do not tell students how quickly a reaction proceeds or which substances are safe to handle. In a fictional paper exercise, pupils can check whether the number of each element matches on both sides without attempting the reaction.
Experimental Chemistry can involve reagents or unfamiliar equipment. Such work must stay in school laboratories under trained supervision. A parent can help by asking the child to explain what a supplied result indicates and what further information would be needed to distinguish possible chemical interpretations.
14. Biology within combined Science: systems and functions
Biology content concerns structures and processes in living organisms. Students should link the features of cells, tissues or systems to what they do, and explain relevant interactions using suitable biological terms. A labelled diagram may require both identification and a causal explanation.
For example, an appropriate school diagram of a plant root may show structures linked to water or mineral uptake. A strong answer explains how a feature is related to its function rather than merely writing ‘for absorption’. The exact level of required detail is controlled by the combined Biology syllabus.
Questions about living systems can also involve data and uncertainty. A measured association is not necessarily proof of a cause. Students should reason from the information and avoid applying simplified textbook examples to an individual’s medical circumstances.
15. Choosing between combined and pure Science is not a prestige test
Some students take pure Physics, Chemistry or Biology; others take an approved combined Science pair. These are different curricular and examination routes. The appropriate choice can depend on a child’s strengths, learning needs, interests, school offerings and post-secondary goals. It should not be treated as a verdict on intelligence or worth.
Pure K323 Physics, K324 Chemistry and K325 Biology each have their own three-paper schemes with 20% practical weight. The combined codes K326–K328 carry their own four-component scheme and 15% Paper 5 practical. A pupil does not simply take an arbitrary half of the pure paper.
Ask the school what is offered, what the student is eligible for and which options support their intended next steps. A clear explanation of fit is far more useful than a family comparison based on school labels alone.
16. Using science diagrams without memorising shapes blindly
Diagrams are often simplified models. A textbook may use arrows to show direction or omit details to highlight a relationship. Students should interpret what is labelled and what the model is designed to show, not pretend that every sketch is a photographic record.
A good revision activity is to cover the labels on a teacher-approved diagram, identify the relationship, then explain one feature in ordinary words. If the student cannot say why an arrow points a certain way, more copying of the same diagram may not solve the misunderstanding.
The strongest learners can transfer an idea from a familiar diagram to a new one. They notice invariant relationships rather than relying on page layout. This is relevant across physics circuits, chemistry particle models and biological transport sketches.
17. Practical reliability: a neat table is not enough
A carefully ruled table helps readers follow results, but presentation is only one part of an investigation. A student also needs appropriate measurements, clear units and valid interpretation. A result that is repeated consistently may still be affected by an instrument limitation or an uncontrolled factor.
Consider a fictional school dataset with three readings, 4.9, 5.0 and 5.1. The values are close, yet that does not prove they are perfectly accurate without knowing what is being measured and how the instrument works. Precision and accuracy address different questions.
The pupil should be able to identify a limitation that matters to the given experiment and propose a specific, permitted improvement. Generic phrases such as ‘avoid human error’ are often too vague to demonstrate real evaluation.
18. Common revision mistakes across K326, K327 and K328
The first is opening a question paper for the wrong science combination. The second is practising a pure subject’s exam structure and assuming the same practical timing and percentage apply. The third is memorising one science in depth while neglecting the other component that contributes an entire 32.5% theory paper.
A fourth mistake is treating the practical as a minor event because it has 15% weight. A fifth is expecting every question to reproduce an example from a worksheet. The examination explicitly assesses scientific reasoning and application to unfamiliar settings, alongside knowledge.
Correct the habits one at a time: check the code, map the correct papers, keep a two-subject revision log, attend supervised laboratory lessons and practise interpreting information from varied contexts. Parents can reinforce the process without doing the student’s work.
19. A two-subject study calendar for the remaining months of 2026 and 2027
Before the 2027 school year, confirm the pair and subject code. Review which foundations are secure in each discipline and which need help. A family should resist buying three sets of pure-Science practice books when the child is registered for only two combined sections.
In early 2027, alternate short knowledge checks with explanation questions. As the year progresses, add timed Paper 1 practice, each relevant theory paper, and school-supervised Paper 5 skills. Keep an error log with separate columns for the two sciences and one shared column for graphing or investigation problems.
When SEAB issues the actual examination timetable, organise the final revision around confirmed dates. The broad September-to-November written examination period does not give permission to invent Paper 5 dates. Rest, learning feedback and reasonable workloads remain important throughout.
- Confirm K326, K327 or K328 on school documents.
- Identify which two of Papers 2, 3 and 4 apply.
- Know the 20% MCQ + 32.5% + 32.5% theory + 15% practical scheme.
- Attend supervised practical learning; no home laboratory shortcuts.
- Practise scientific explanations with genuine data and defined limitations.
- Read SEAB and school notices for exact candidate dates.
20. What parents should ask about 2028 pathways
Students sitting the first SEC in 2027 are expected to receive results in January 2028, followed by revised post-secondary admission arrangements. Different programmes have their own subject-level and minimum-grade criteria. A combined-Science grade may be relevant to some courses, but no blanket equivalence or guaranteed admission should be asserted.
Ask the school Education and Career Guidance staff which routes apply to the student’s complete subject profile. Consider the child’s interests: a pupil might be motivated by environment, engineering, healthcare or a completely different field. The appropriate route is informed by official eligibility and genuine learning goals.
Readers comparing science study can see our pure Physics K323 guide, our Chemistry K324 guide and our Biology K325 guide. They cover different syllabuses, not substitute practice papers for K326–K328.
Frequently asked questions
What three G3 Combined Science codes exist for 2027?
K326 Physics/Chemistry, K327 Physics/Biology and K328 Chemistry/Biology.
Is K326 the same as K327?
No. K326 pairs Physics with Chemistry; K327 pairs Physics with Biology. Their subject-specific theory entries differ.
What is the shared multiple-choice weighting?
Paper 1 is one hour, 40 marks and 20%.
How many theory papers do students sit?
Two subject-specific 65-mark papers, each 1h15m and 32.5%, based on the registered combination.
Do candidates sit all Physics, Chemistry and Biology theory papers?
No. They take the two relevant papers from Physics Paper 2, Chemistry Paper 3 and Biology Paper 4.
What is the combined practical paper?
Paper 5, worth 30 marks and 15%, lasting 1 hour 30 minutes.
Is Paper 5 identical to pure Science practical Paper 3?
No. Pure G3 Science subjects have different schemes and practical examinations.
Can practical questions ask for improvements rather than executing them?
Yes. The official syllabus allows proposing an improvement or extension, potentially worth 10–20% of Paper 5’s raw marks.
Does the multiple-choice paper give exactly 20 Physics and 20 Chemistry questions?
SEAB says approximately equal coverage for the two relevant sciences; this article does not guarantee an exact fixed split.
Do the marks make two separate SEC grades?
K326, K327 and K328 are each registered subject combinations with assessment components, not automatic separate pure-science certificates.
Can a parent reproduce the practical tasks at home?
No. Actual laboratory work belongs under authorised school supervision and safe equipment arrangements.
Does combined Science automatically satisfy a particular Polytechnic course?
Not automatically. Check the receiving course’s current subject-level and grade prerequisites.
Where are the official syllabuses?
SEAB’s 2027 G3 school-candidate directory links the K326, K327 and K328 syllabus PDFs.
Are exact practical dates fixed by this article?
No. Use the final SEAB timetable and school instructions.
More 2027 SEC education guides at Bukit Timah
Continue the same 2027 SEC series with these complementary subject and level guides. The correct examination code, the school’s confirmed subject entry and SEAB’s current syllabus take priority when choosing material for a particular pupil.
- Education at Bukit Timah | G2 Mathematics K210: Real-World and Section B
- Education at Bukit Timah | G2 Additional Mathematics K232
- Education at Bukit Timah | G1 English Language K100
Official sources and related reading
SEAB 2027 G3 subject directory — lists the three codes and older references.
SEAB 2027 K326 Physics/Chemistry syllabus — the combined scheme and prescribed pairings.
SEAB 2027 K327 Physics/Biology syllabus — the same assessment framework with Physics/Biology content.
SEAB 2027 K328 Chemistry/Biology syllabus — the Chemistry/Biology pairing.
SEAB SEC overview — national 2027 exam framework and candidate instructions.
MOE SchoolFinder — verify a particular school’s actual subject offerings.
eduKateSG 2027 SEC examination calendar — broader timetable and results transition.
Bottom line: G3 Combined Science is a carefully defined two-discipline examination. Knowing whether a child takes K326, K327 or K328 is essential for selecting the right papers, the right practical preparation and an achievable revision plan. Strong science learning remains the same at every pairing: accurate concepts, honest evidence and explanations that make sense.