Physics and Chemistry are usually the top two scaling subjects in WA after Mathematics Specialist. They are also the two subjects most often presented as "the hard sciences." Picking between them is a decision most students rush. Below is the comparison framework that helps.
Scaling: roughly equal, slight edge to Chemistry
The 2025 TISC scaling report places Chemistry at +8.7 and Physics at +8.4 in scaled mark lift at the median (raw 70 to scaled ~78.7 vs ~78.4). The gap is small enough to be within year-to-year variation.
The honest reading: scaling is not a useful tie-breaker between Physics and Chemistry. Pick on fit, not on which one scales 0.3 marks more.
| Year | Chem lift @70 | Physics lift @70 |
|---|---|---|
| 2023 | ~+8.5 | ~+8.0 |
| 2024 | ~+8.6 | ~+8.2 |
| 2025 | ~+8.7 | ~+8.4 |
Cognitive style: very different
The two subjects favour different ways of thinking. This is the most important consideration.
| Element | Chemistry | Physics |
|---|---|---|
| Maths involved | Algebra, logarithms, percentages, units | Calculus, vectors, trigonometry, energy/momentum equations |
| Memorisation load | Heavy: reactions, mechanisms, organic structures | Light: 4-5 fundamentals + ~30 derived formulas |
| Question style | Predict outcome of reaction, balance equations, calculate yield | Apply F=ma, calculate energy, predict trajectory |
| Lab work | Titrations, identifying organic compounds, spectroscopy | Force, motion, circuits, optical experiments |
| Failure mode | Forgetting one mechanism step, using wrong reagent | Mis-applying conservation, sign errors in vectors |
The simplest fit test: do you prefer questions where you have to remember the right answer, or questions where you have to figure out the right answer?
If "remember the right answer" feels easier, Chemistry is your subject. The exam rewards students who have memorised the syllabus and can apply it.
If "figure out the right answer" feels easier, Physics is your subject. The exam rewards students who can derive an answer from first principles, even if the question type is unfamiliar.
Workload: similar, distributed differently
Both subjects need 4 hours per week of study to score in the 75-85 raw range. The distribution differs:
- Chemistry: Most of the time goes to past paper practice and memorising organic mechanisms. Steady weekly load.
- Physics: Most of the time goes to problem solving and re-deriving. The load spikes when a new topic is introduced (e.g. Special Relativity in Term 3) because the conceptual ground is new.
University and pathway implications
| Pathway | Physics required? | Chemistry required? |
|---|---|---|
| UWA Engineering (Hons) | Recommended (one of three: Spec, Phys, Chem) | Recommended (one of three) |
| UWA Computer Science | No | No |
| Curtin Engineering | Required for some specialisations | Required for chemical engineering |
| UWA Medicine (postgrad) | No | Recommended |
| Curtin MBBS | No | Required |
| Architecture | Useful | No |
| Physics or Astronomy degrees | Required | Recommended |
If you are uncertain about your pathway, take Chemistry. It opens more doors (medicine plus all sciences). If you are confident your future is in engineering, computing or physics, take Physics.
Can you take both?
Yes. The two subjects pair well: they reinforce each other in calculation skills (Physics) and chemical reasoning (Chemistry), and they demand similar weekly time. Many high-achieving STEM students take both Chemistry and Physics alongside Methods/Specialist.
What to actually do this week
- Sit one Year 11 Physics test and one Year 11 Chemistry test (your school's, or a sample). Time yourself for each. Notice which one you finish faster, and which one you enjoy more.
- Talk to your school's Year 12 students about each subject. Their honest one-line answer about study load is more useful than any blog.
- If you are still undecided in Term 4 of Year 10, take both at school until subject confirmation in Term 1 of Year 11. Most schools allow this.
If your family wants help mapping subject choice for STEM pathways, book a free trial at our Bentley or Canning Vale centres. Subject choice for STEM is one of the most common reasons families come to us in Term 3 of Year 10.