Science: Two Subjects from Physics, Chemistry, and Biology
What the domain tests
The Science section is a 0–200, 80-minute paper. You choose two of physics, chemistry, and biology; each chosen subject contributes questions, and the paper is in Japanese. The syllabus follows Japanese high school science. Physics covers mechanics, waves, electricity and magnetism, thermodynamics, and atoms. Chemistry covers atomic structure, bonding, states, reactions, inorganic and organic chemistry. Biology covers cells, genetics, reproduction, homeostasis, ecology, and evolution. Calculations and graph reading matter as much as definitions.
Core rules
- Physics: define the system, draw a force diagram, resolve vectors, and check units. For circuits, reduce series and parallel groups before using Ohm’s law.
- Chemistry: convert mass to moles first, use the limiting reagent, and balance charges in ionic equations.
- Biology: distinguish structure from function and cause from correlation; in genetics, write genotypes before calculating ratios.
Worked example
24.0 g of carbon (molar mass 12.0 g/mol) burns completely. What volume of CO2 forms at standard conditions? Moles of C = 24.0 / 12.0 = 2.00 mol. C + O2 → CO2 is 1:1, so 2.00 mol CO2 forms. At 22.4 L/mol, volume = 2.00 × 22.4 = 44.8 L. Reasoning: the mole ratio is the bridge; using 24.0 L or 22.4 L directly would be a unit error.
Traps
- Spending time on all three sciences instead of the two you registered for.
- Mixing mass, moles, and concentration in chemistry.
- Using g = 9.8 or 10 inconsistently with the paper’s instruction in physics.
- Confusing meiosis with mitosis, or genotype with phenotype, in biology.