eduKateSG · SEC SCIENCE PATHWAYS · G1 / G2 / G3 · 2027 · PHASE 4
Under Full Subject-Based Banding, “What Science Does My Child Take?” Is No Longer the Same Question as “Which Stream Is My Child In?”
From 2027, graduating students sit the Singapore-Cambridge Secondary Education Certificate at their respective subject levels—G1, G2 or G3. Under Full Subject-Based Banding, those are subject levels, not old-style stream identities. A student’s Science route should therefore be understood as a specific subject choice with a specific syllabus, assessment structure and learning load.
For Science, the map is especially important because the three levels are structurally different. G1 has one integrated Science subject, K123. G2 offers three combined Science pairs, K223–K225. G3 offers both combined Science, K326–K328, and pure Physics, Chemistry or Biology, K323–K325.
This page is the route map. Its job is not to rank children. Its job is to make the differences visible enough that families, students and tutors can prepare for the Science the student is actually taking.
What This Page Owns
This page owns the SEC Science routing job: G1 vs G2 vs G3, combined vs pure, 2027 K-codes, major assessment differences, learning implications and the questions families should ask before choosing or preparing a route.
The level pages own instruction within each route: SEC G1 Science, SEC G2 Science and SEC G3 Science.
First Principle: G1, G2 and G3 Are Subject Levels
MOE describes G1, G2 and G3 as subject levels under Full Subject-Based Banding. They are mapped broadly from the former N(T), N(A) and Express standards respectively, but the point of the new system is greater subject-level flexibility rather than preserving old stream labels under new names.
From 2027, the SEC replaces the former N- and O-Level certificates. Graduating students sit subjects at the levels they offer. MOE also states that students can adjust subject levels at appropriate junctures depending on their abilities, strengths, interests and learning needs.
Official references: MOE Full SBB / SEC announcement and the SEAB SEC syllabus directory.
This matters psychologically. “G2 Science” should not become a permanent identity statement about a child. It is the Science level and route being studied at a particular stage.
The 2027 SEC Science Map at a Glance
| Level | Science routes | Main architecture |
|---|---|---|
| G1 | K123 Science | Integrated Science; e-Exam + written paper |
| G2 | K223 Physics–Chemistry; K224 Physics–Biology; K225 Chemistry–Biology | Combined Science; two disciplines, each with MCQ + structured paper |
| G3 Combined | K326 Physics–Chemistry; K327 Physics–Biology; K328 Chemistry–Biology | Combined Science; mixed MCQ + two discipline papers + common practical |
| G3 Pure | K323 Physics; K324 Chemistry; K325 Biology | One discipline at greater syllabus and practical resolution |
G1 Science: Integrated and Applied
K123 keeps Science integrated. The 2027 assessment uses two compulsory papers worth 50% each.
- Paper 1: 1 h 15 min e-Examination, 50 marks.
- Paper 2: 1 h written short-answer and structured paper, 50 marks.
The e-Exam can include MCQ, selected-response formats and interactive/video/animation stimuli. Paper 2 contains a substantial data-response question. Experimental skills can be assessed through the written/e-Exam questions even without a separate practical paper.
The learning implication is clear: G1 students benefit from Science that stays close to observable situations while still training models, data, graphing, apparatus reasoning and concise explanation.
Detailed route: SEC G1 Science Tuition Singapore.
G2 Science: Two Disciplines, Equal Weight
G2 Science is always a combined pair in the published 2027 list. The student takes two of Physics, Chemistry and Biology.
Each chosen discipline contributes 50%:
- 20% discipline MCQ;
- 30% discipline structured paper.
This makes G2 unusually transparent. If one discipline is weak, the combined result may hide it temporarily but cannot eliminate its weight.
The learning implication is to keep two separate scientific models and two separate error ledgers while sharing one retrieval, graph and experimental-reasoning system.
Detailed route: SEC G2 Science Tuition Singapore.
G3 Combined Science: Two Disciplines Plus a Common Practical
G3 combined Science keeps the two-discipline idea but increases resolution and changes the assessment architecture.
- Paper 1: mixed MCQ across the two chosen disciplines, 20%.
- Two discipline papers: 65 marks each, 32.5% each.
- Paper 5 Practical: 1 h 30 min, 30 marks, 15%.
The practical paper makes evidence handling a visible part of the final assessment. The student therefore needs not only theory but measurement, graphing, observation, method evaluation, error analysis and safety reasoning.
The learning implication is higher generated-response and practical demand while retaining the need to switch cleanly between two disciplines.
G3 Pure Science: One Discipline at Greater Resolution
The pure routes—K323 Physics, K324 Chemistry and K325 Biology—go deeper into one discipline and use their own assessment schemes.
The learning implication is not merely “more chapters”. It is more resolution:
- Physics uses more quantitative relationships, models and measurement;
- Chemistry uses more symbolic, particulate, quantitative and practical reasoning;
- Biology uses more detailed structures, mechanisms, systems, data and practical interpretation.
Pure Science is therefore most useful when the student can sustain the additional detail while preserving the model underneath it.
Detailed overview: SEC G3 Science Tuition Singapore. Chemistry-specific route: SEC G3 Chemistry.
The Levels Differ in More Than Difficulty
| Dimension | G1 | G2 | G3 |
|---|---|---|---|
| Subject structure | Integrated Science | Two-discipline combined Science | Combined or pure |
| Digital assessment | Dedicated e-Exam Paper 1 | Not the defining architecture | Not the defining architecture |
| Generated response | Short/structured + data-response | Discipline structured papers | Higher-resolution structured/free response |
| Practical assessment | Experimental skills through theory/e-Exam | Experimental reasoning through theory | Combined route includes common practical; pure routes have discipline-specific schemes |
| Disciplinary separation | Low | Medium: two explicit disciplines | High: two deeper disciplines or one pure discipline |
| Representation load | Applied/data/digital | Discipline-specific MCQ + structured | Higher quantitative, symbolic, mechanism and practical resolution |
“Harder” is too crude a description. The operating demands are different.
How Should a Family Think About the Right Science Level?
The school determines subject offerings and applies the relevant eligibility/progression rules. Tuition does not decide a student’s official subject level. But families can understand readiness more intelligently than by using one Science mark.
1. Conceptual readiness
Can the student explain the scientific relationship, or only recognise familiar questions?
2. Representation readiness
Can the same concept survive as prose, graph, diagram, equation, table or experimental setup?
3. Quantitative readiness
For routes with more Physics/Chemistry calculation, can the student handle ratios, algebra, units and multi-step working without losing the Science?
4. Practical readiness
Can the student identify variables, measure carefully, graph correctly and evaluate evidence?
5. Language readiness
Can the student distinguish describe, explain, compare, predict, suggest and evaluate tasks?
6. Workload readiness
Can the student sustain this Science resolution alongside their other subjects without every week becoming recovery?
Do Not Choose a Science Route Only for Prestige
Pure Science can be an excellent route for a student who benefits from the depth and may need it for later study. It can also become counterproductive if the extra resolution consumes so much cognitive and time budget that the learner loses coherence across the rest of the curriculum.
Likewise, G2 should not be described as “giving up” on Science. A well-mastered G2 route can produce stronger scientific competence than a poorly understood G3 route.
And G1 should not be treated as Science without reasoning. K123 explicitly assesses knowledge, handling/applying information, data and experimental skills.
The useful route is the one in which the student can build stable Science and keep future options appropriate to their goals.
What Stays the Same Across G1, G2 and G3
The syllabus resolution changes. Several scientific backbeats do not.
- observe before over-explaining;
- distinguish evidence from inference;
- identify what changes and what is measured;
- read units and axes before interpreting data;
- use models for a purpose;
- trace cause to effect;
- keep disciplinary vocabulary precise;
- change an explanation when evidence contradicts it;
- apply a known relationship in an unfamiliar context;
- treat safety and method quality as part of Science.
These are the common wires. Tuition should preserve them when a student changes level or discipline.
The Pathway Error Map
| Mistake | Why it causes trouble | Better frame |
|---|---|---|
| “G3 is always better” | Ignores readiness, workload and goal | Choose appropriate resolution with future pathway in view |
| “G2 is just easier G3” | Assessment and discipline architecture differ | Prepare directly for K223/K224/K225 |
| “G1 has no real experiments” | Experimental skills can be assessed through papers | Train apparatus/data/evidence explicitly |
| “Combined Science is one blurred subject” | Discipline reasoning becomes contaminated | Maintain separate Physics/Chemistry/Biology models |
| “Pure Science = more notes” | Detail grows without mechanism | Higher resolution must remain organised |
| “One overall mark tells us the route” | Hides component and skill differences | Map concept, quantitative, practical, language and workload readiness |
If a Student Changes Science Level, Preserve the Knowledge That Still Transfers
Subject-level flexibility is valuable only if a change does not trigger unnecessary relearning.
When moving between levels, we identify three layers:
- shared concepts that remain valid;
- resolution delta—new depth, mathematics, vocabulary or practical demand;
- assessment delta—different paper types, timings or response modes.
The student should not discard the old model if it is still correct. They should refine it where the new route requires more detail.
This is especially important from lower secondary into upper secondary, and when a school changes a student’s subject level at an appropriate juncture.
The Four Questions to Ask Before Planning SEC Science Tuition
- What exact SEC code is the student taking? K123, K223–K225, K326–K328 or K323–K325?
- What are the current weak nodes? Content, retrieval, representation, quantitative work, practical reasoning, language or timing?
- What does the actual assessment require? e-Exam, discipline MCQ/structured, mixed MCQ, free response, practical?
- What future pathway matters? What level of Science competence is useful for the student’s next educational step?
Those four questions produce a much better plan than asking only, “How many worksheets per week?”
Frequently Asked Questions
When does the SEC begin?
The Singapore-Cambridge Secondary Education Certificate begins for graduating students from 2027, replacing the former N- and O-Level certificates.
Does every student take all subjects at the same G level?
Full Subject-Based Banding is designed around subject levels. Students can offer subjects at levels suited to their learning, subject to the school’s and MOE’s applicable arrangements.
Is there pure Science at G2?
SEAB’s published 2027 G2 Science entries are the three combined pairs K223, K224 and K225. Pure Physics, Chemistry and Biology are listed at G3 as K323, K324 and K325.
Does G3 combined Science have practical?
Yes. K326–K328 include a common Paper 5 Practical Test worth 15%.
Does G1 have practical skills?
Yes. K123 can assess experimental skills and investigations through its e-Exam and written paper even though it does not list a separate practical examination.
Can students change subject levels?
MOE states that students have flexibility to adjust subject levels at appropriate junctures. The exact school decision follows the applicable criteria and arrangements.
Which Science route is best?
There is no universal best route. The useful route matches the student’s readiness, school offering, learning load and future pathway while allowing the Science itself to become stable.
SEC Science Route Directory
How SEC Science Pathways Work
The new certificate puts different subject levels on one common national framework. That makes comparison easier only if we preserve what the levels actually mean.
G1 is integrated and applied. G2 carries two disciplines at a moderate combined resolution. G3 can carry two disciplines at greater combined resolution or one pure discipline in greater depth. Across all three, evidence, models, data and explanation remain Science.
Do not turn G1, G2 and G3 into labels for children. Use them as coordinates for the Science that needs to be taught.