Quick answer: In the Singapore-Cambridge 2027 SEC, G2 Combined Science is available as three two-discipline subjects: K223 Science (Physics, Chemistry), K224 Science (Physics, Biology) and K225 Science (Chemistry, Biology). Each candidate takes the multiple-choice and structured paper for each of their two Sciences, giving four papers in two sessions, each session lasting 1 hour 15 minutes. The subject’s total assessment splits into 40% multiple-choice and 60% structured questions. There is no separate G2 practical examination paper in this 2027 scheme, although scientific investigation skills are assessed through theory questions and taught through practical learning.
For a Secondary 2 family: G2 Combined Science is a future upper-secondary option, not a compulsory national Secondary 2 exam. The student’s school determines its current Lower Secondary Science assessments and available Secondary 3 subject combinations. A child in Secondary 2 during 2026 would ordinarily reach Secondary 4 in 2028; the 2027 codes and assessment formats are planning references pending the applicable 2028 SEAB documents.
The third-paragraph checklist: what to do next
1. Confirm the child’s actual G1/G2/G3 Science and Mathematics levels, not only the Posting Group. 2. Ask which of K223, K224 and K225 corresponds to the school’s planned upper-secondary offering and actual student eligibility. 3. Read the current Secondary 2 syllabus topics, school assessment rubrics and teacher feedback before using an upper-secondary revision book. 4. Match every Science combination to two different paper pairs; do not buy Biology revision for a Physics/Chemistry-only route. 5. Train both multiple-choice precision and structured explanations—the exam rewards different abilities. 6. Build investigation skills even though there is no standalone G2 practical national paper. 7. Plan for the correct future 2028 examination cohort, and verify any school subject-level change and bridging rules.
Official sources: SEAB’s 2027 G2 K223/K224/K225 syllabus, 2027 G2 syllabus list and MOE’s Full SBB explanation.
Which combination should the student understand?
| 2027 SEC G2 combination | Code | Included disciplines | Papers | |—|—|—|—| | Science (Physics, Chemistry) | K223 | Physics and Chemistry | 1, 2, 3, 4 | | Science (Physics, Biology) | K224 | Physics and Biology | 1, 2, 5, 6 | | Science (Chemistry, Biology) | K225 | Chemistry and Biology | 3, 4, 5, 6 |
The code determines the national subject entry. A school may offer one combination and not another, depending on its curriculum and timetable.
Do not choose based solely on what a friend offers. Compare the child’s interest, demonstrated skills, subject requirements and the school’s actual subject-option booklet.
Why is G2 Science called Combined Science?
Combined Science is one examinable subject combining two scientific disciplines, not a statement that the student has enrolled in two separate Pure Science subjects.
The term “Combined Science” describes the structure of the course. It does not mean laboratory science is omitted or that the subject is unimportant. Students still need scientific concepts, accurate explanation, numerical reasoning, experimental understanding and the ability to respond to unfamiliar information.
At G2, the assessment combines a multiple-choice and structured paper for each selected discipline. This structure differs from standalone G3 Physics K323, Chemistry K324 or Biology K325, which each have their own larger syllabuses and practical examination.
Exact 2027 G2 Science paper scheme
The official G2 syllabus uses six possible paper numbers, but a candidate takes only four, determined by the chosen subject combination.
| Paper | Discipline and format | Marks | Final-weight contribution |
|---|---|---|---|
| 1 | Physics multiple-choice | 20 | 20% |
| 2 | Physics structured | 30 | 30% |
| 3 | Chemistry multiple-choice | 20 | 20% |
| 4 | Chemistry structured | 30 | 30% |
| 5 | Biology multiple-choice | 20 | 20% |
| 6 | Biology structured | 30 | 30% |
The multiple-choice and structured components for each discipline are held in a combined 1-hour-15-minute session. The official syllabus advises candidates not to spend more than 30 minutes on each 20-mark multiple-choice part.
Therefore, a G2 candidate’s two included disciplines each contribute 50% overall: 20% multiple-choice plus 30% structured.
Example: K225 candidate
A student taking K225 Chemistry/Biology sits Chemistry Papers 3 and 4, and Biology Papers 5 and 6. They do not sit Physics Papers 1 and 2.
One consequence is practical: buying a collection of “six G2 Science papers” without knowing the subject code may waste time and focus.
Does G2 Combined Science have a practical national paper?
No separate practical paper is listed in the 2027 G2 K223/K224/K225 scheme. However, the syllabus retains experimental-skills objectives and includes questions on investigations, observations, safety, data and methods within the theory assessment.
The official assessment objectives allocate approximately 10% of theory marks to experimental skills and investigations. This is not a separate 10%-weighted practical paper.
Students should still take school laboratory activities seriously. These experiences provide the observations and reasoning needed for source-based and investigation questions.
A good classroom investigation question
“What measurements and controls would allow us to compare two simple materials fairly?” The learner needs to identify the independent variable, measured outcome and what must remain consistent.
This is a safer and more useful skill than memorising a list of laboratory tools without knowing their purpose.
What is in the G2 Science syllabus?
The 2027 official G2 document contains separate sections for Physics, Chemistry and Biology, each with disciplinary ideas, topic content, quantities and practical guidelines.
The same guiding approach appears across the subject: Science is evidence-based, uses explanatory models, and connects knowledge to society and the environment. Students must learn both scientific terms and how to apply them to unfamiliar contexts.
Physics
Work often involves forces, energy, electricity, thermal effects, motion and related models appropriate to the level. A Physics question may require a calculation, diagram interpretation or explanation of a physical process.
Chemistry
Chemical questions may involve particle ideas, formulas, reactions, materials, periodic patterns, acids and observations. The student must understand the substance and conditions rather than simply copy an equation.
Biology
Biology includes understanding cells, life processes, transport, organisms, human systems and environments appropriate to the syllabus. Students need to connect structure with function and use biological evidence to justify conclusions.
The exact assessed content must be checked in the 2027 official G2 syllabus PDF. This broad paragraph is not intended as an exhaustive or school-specific chapter order.
Which two Sciences should a student consider?
A student may be interested in Physics because they enjoy forces, electricity and quantitative models. Another may prefer Biology because they like life processes and ecosystems. Chemistry can appeal to students interested in materials, particle reasoning and chemical changes.
But liking a subject’s videos or demonstrations is not the same as enjoying the work required for its examinations.
Ask the student: – Can I explain a scientific idea in my own words? – Am I comfortable reading graphs and doing calculations? – Do I enjoy scientific diagrams, experiments and careful reasoning? – Which mistakes appear repeatedly in my school scripts? – Which pair is actually available under the school’s options? – Will my preferred combination fit my other subjects and interests?
A better decision is evidence-based and individual rather than a popularity ranking.
Physics foundation 1: units and speed
For a simplified movement question, average speed equals distance divided by elapsed time.
Original worked example
A student cycles 150 m in 25 s.
Average speed = 150 ÷ 25 = 6 m/s.
The result does not prove that the cyclist maintained exactly 6 m/s at every moment. A strong Physics answer distinguishes an average over an interval from an instantaneous value.
Why students lose marks
They divide by the wrong number, omit units, use minutes instead of seconds without conversion, or interpret a graph’s gradient without checking what is on each axis.
Correction: write the quantity name and unit beside each given value before selecting a formula.
Physics foundation 2: forces and balanced motion
A learner should identify which object is being considered and which forces act on it.
Consider an idealised box resting on a floor. Its weight acts downwards while a support force acts upwards. When balanced, the net vertical force is zero.
Do not conclude that gravity has vanished. The support force balances the downward weight.
A useful follow-up asks what could cause the object to accelerate horizontally. It encourages students to consider the net force in a specified direction, not just use the phrase “forces cause movement”.
Physics foundation 3: current, voltage and resistance
An elementary relationship for an ohmic resistor under the appropriate conditions is V = IR.
Original numerical example
With V = 9 V across a hypothetical 3 Ω resistor, I = 9 ÷ 3 = 3 A.
Students should first check whether the circuit assumptions make this relationship applicable. In a series or parallel circuit, selecting the wrong voltage or resistance leads to a correct formula but wrong answer.
Classroom circuit experiments must use school-approved low-voltage arrangements and appropriate supervision. Students should never test the relationship by improvising with household mains electricity.
Chemistry foundation 1: distinguish elements, compounds and mixtures
An element contains one chemical element, while a compound has different elements chemically combined in a defined composition. A mixture involves different substances without all of them forming one new compound.
Original example
Pure water is a compound. Air is a mixture of gases. A salt solution contains dissolved salt and water.
This distinction helps a student choose whether the task calls for physical separation, particle reasoning or explanation of a chemical reaction.
A weak answer says that every dissolved substance becomes a new compound. That is not a generally valid conclusion.
Chemistry foundation 2: formulas and conservation
The formula CO₂ means one carbon and two oxygen atoms per molecule.
The expression 3CO₂ represents three carbon dioxide molecules, containing three carbon atoms and six oxygen atoms in total.
A student should differentiate a coefficient from a subscript. When balancing reactions, adjust coefficients according to conservation; do not change the chemical identity of a compound merely to make an equation appear balanced.
These concepts are important for accurate Chemistry even before more demanding mole calculations.
Chemistry foundation 3: observation versus inference
Suppose a teacher-supervised experiment produces a visible change in colour or a precipitate.
Observation: describe the actual colour or appearance.
Inference: explain what the change may suggest, given known reagents and relevant scientific tests.
Limitation: without complete conditions or further evidence, one observation might not identify a substance uniquely.
This habit can prevent overclaiming in qualitative-analysis questions. It also teaches scientific integrity: do not invent a result you did not observe.
Biology foundation 1: cells and their roles
Biology uses the relationship between structure and function. Cells differ because they carry out different tasks.
A root hair cell has features suited to absorbing materials from the surrounding soil solution. A red blood cell has features that assist gas transport.
A useful answer should explain how a particular structural feature supports the function, not simply state that the cell is “special”.
Test the learner’s reasoning
Ask, “Which feature matters, and what would be different if it were not present?” This pushes the explanation beyond a memorised label while staying within the student’s actual taught content.
Biology foundation 2: diffusion and osmosis
Diffusion concerns net particle movement down a concentration gradient. Osmosis refers to net water movement across an appropriately partially permeable membrane under a water-potential difference.
Students often use the terms interchangeably. Correct them by identifying the moving substance, membrane and relevant gradient.
Original numerical illustration
A plant tissue sample has mass 5.0 g before immersion and 5.5 g afterwards.
Percentage change in mass = (5.5 − 5.0) ÷ 5.0 × 100% = 10%.
The observed measurement indicates a mass increase. Its biological interpretation requires understanding the setup and conditions. The calculation alone does not prove that a particular membrane mechanism caused the result.
Biology foundation 3: food webs and ecosystems
In a food web, students should interpret the direction of energy transfer using the diagram’s convention. Arrows are not decorative.
If one organism becomes less abundant, other populations may be affected, but real ecosystems contain multiple interactions. A simple chain does not establish a guaranteed numerical result.
An accurate answer states the suggested effect and explains the pathway, then recognises where the evidence is incomplete.
Structured answers: the habit that matters most
The 2027 G2 exam allocates 60% of marks to structured questions. A student who performs reasonably in multiple-choice practice but cannot explain a mechanism may face a substantial problem.
Use point → scientific explanation → relevant evidence or detail → conclusion.
Original worked comparison
Question: Explain why a metal cooking spoon can become hot after one end is left in hot liquid.
Weak: “Because the spoon is metal and metals are hot.”
Stronger: “Thermal energy transfers along the spoon from the heated part toward the cooler part by conduction; metals can conduct energy effectively through relevant particle and electron interactions.”
The stronger explanation links the situation to a process. The teacher should adjust the particle-level explanation to the exact G2 content being assessed.
Multiple-choice: avoid answering too early
G2 multiple-choice requires recognising not only the right concept but also the limits of distractors.
Before choosing, read the entire question, identify conditions, use units and test whether an option contradicts a basic principle. Two answers may sound plausible until a small phrase changes the context.
A useful method
1. Underline the quantity or relationship asked. 2. Predict the answer in words. 3. Evaluate every offered option. 4. Check units or diagram labels. 5. Choose and move on; return if time permits.
Students should not spend the whole session on one difficult multiple-choice item and leave structured questions unanswered.
The two 1h15 sessions: practical exam time management
For 2027 G2 Combined Science, each of the two chosen disciplines has a 20-mark multiple-choice paper and a 30-mark structured paper taken together in a 75-minute session.
SEAB advises candidates not to spend more than 30 minutes on the multiple-choice part. That leaves approximately 45 minutes for the structured component.
A student can simulate the format with appropriate school-approved questions, but should avoid memorising a fixed number of seconds per mark. Actual problem difficulty varies. The key is to protect time for every compulsory section.
A G2 structured-paper distinction students miss
Each 30-mark structured paper includes: – Section A: 22 marks, compulsory structured questions, with the final question worth 8 marks. – Section B: 8 marks, offering two structured questions, of which the candidate answers one.
A student should not attempt both alternatives in Section B if the exam instruction requires selecting only one.
The 2027 Physics, Chemistry and Biology structured papers share this broad format, but they test the separate discipline content.
Should a student prioritise the discipline they score higher in?
One discipline may feel easier, but each contributes 50% to the combined subject. Ignoring the weaker half is a risky long-term strategy.
A more useful approach is to identify exactly what is weak. Perhaps Physics numerical work is unstable because of algebra, while Biology comprehension is strong. In that case, repairing the Mathematics foundation may give a large improvement.
The goal is balanced competence. A strong half can support confidence, but the weaker half still needs regular deliberate practice.
Subject-level decisions: G2 versus G3
A G2 student may potentially offer individual subjects at a more demanding level under applicable Full SBB school criteria. A higher raw mark is not automatically a guarantee that the student will receive G3 Combined Science.
Parents should ask the school: – Which levels and combinations are available? – What evidence of readiness is considered? – When is the review conducted? – Which bridging work is needed? – How will the choice affect other subjects and timetable? – What happens if the course becomes unsuitable?
A good subject decision considers interest, sustainable workload, current performance and long-term possibilities without promising one particular future pathway.
An eight-week G2 Science repair schedule
### Week 1: diagnose both disciplines Choose two marked questions from each. Identify calculation, misconception, vocabulary, source interpretation or working-presentation errors.
Week 2: repair units and graphs
Use short tasks on measurement, scales, unit conversion and simple gradients.
Week 3: strengthen Chemistry’s particle model
Explain elements, compounds, mixtures and simple equations in accurate language.
Week 4: strengthen Biology’s structure and function
Explain cells, transport or ecosystems from the student’s actual syllabus.
Week 5: practise Physics explanations
Use forces, energy and elementary circuit contexts, focusing on complete reasoning.
Week 6: train scientific data
Interpret a novel table and distinguish observations, inferences and limitations.
Week 7: simulate a single 75-minute paper pair
Use an appropriate paper at the student’s level. Protect time for both multiple-choice and structured tasks.
Week 8: reattempt earlier mistakes
Redo the Week 1 tasks independently and explain each correction. Set the next goal based on evidence.
This is an eduKate teaching suggestion rather than a mandated national Secondary 2 study plan.
How parents can support without teaching three Sciences
Ask one question: “Which evidence supports that answer?” Another useful question is: “What does this unit or diagram label mean?”
Parents can help the student keep a folder separating the two chosen disciplines and a short error log. They do not need to replicate all classroom demonstrations at home.
For hands-on topics, use school-provided safe activities or established educational resources. Unsupervised chemical mixing, hazardous electrical work or biological culturing are not appropriate preparation methods.
Common mistakes to avoid
– Confusing K223, K224 and K225: each has a specific pair of disciplines. – Preparing all six papers as if one student takes them all: only four apply to the selected combination. – Claiming G2 has a standalone 2027 practical paper: experiment skills are included within theory assessment, not a separate national practical paper. – Ignoring one discipline because the other has a stronger grade: each contributes half. – Treating MCQ marks as the majority: the combined structured component contributes 60%. – Copying an observation as if it proves a cause: distinguish evidence from mechanism. – Misreading the 75-minute format: it applies to each discipline’s paper pair, not to the whole four-paper combined subject. – Applying the 2027 timetable to 2028 without checking: use the correct graduating year.
Frequently asked questions
### Is G2 Combined Science the same as Pure Biology? No. Standalone G3 Biology K325 is a different subject and exam structure.
Which G2 code includes Physics and Chemistry?
K223.
Which G2 code includes Physics and Biology?
K224.
Which G2 code includes Chemistry and Biology?
K225.
Does the 2027 G2 paper include national practical?
There is no separately timetabled national practical paper in this syllabus, but questions may assess experimental skills.
How many papers does one student sit?
Four, with a multiple-choice and structured paper for each chosen Science.
How long is each discipline’s test session?
1 hour 15 minutes for its paired multiple-choice and structured papers.
Are G2 MCQ and structured weights equal?
No. Each discipline contributes 20% MCQ and 30% structured, a total of 40% MCQ, 60% structured across the combination.
Can a student move from G2 Science to G3 Science?
Subject-level progression is possible only under applicable criteria and school decisions. Check readiness and bridging needs.
Should a 2026 Secondary 2 learner use the K223 paper as their school test?
No. Current Secondary 2 assessments are school-based; K223 is a 2027 graduating-year national reference.
Official sources and next reading
– SEAB 2027 G2 Science K223/K224/K225 official syllabus. – SEAB’s 2027 G2 subject list. – G3 Combined Science K326/K327/K328 guide. – G1 Science K123 guide. – Pure Biology K325, Pure Physics K323 and Pure Chemistry K324. – Secondary 2 G1 G2 G3 Science foundation guide. – Secondary 2 Mathematics. – eduKate’s immutable reference on targeted foundations.
Reviewed 13 November 2026. Codes, paper combinations, durations and mark weights are grounded in SEAB’s 2027 G2 Science syllabus. All calculations and classroom examples in this article are original illustrative exercises, not actual school or SEC papers. The student’s school determines their present learning, and the relevant 2028 syllabus should be checked when released.