Natural Sciences: Physics, Chemistry, Biology
What you must understand
Physics: motion and Newton's laws, work, energy and power, electricity and simple circuits, waves and light. Chemistry: atomic structure, the periodic table, chemical bonding, balancing equations, acids and bases, and the mole concept. Biology: cell structure, transport in plants and animals, respiration and photosynthesis, genetics, and basic ecology.
Traps that appear in questions
- Units: speed in m/s, force in newtons, energy in joules; converting km/h to m/s requires dividing by 3.6.
- Unbalanced equations: atom counts must match on both sides before you use a ratio.
- Confusing similar processes: photosynthesis versus respiration, diffusion versus osmosis.
- Circuit questions that mix series and parallel rules; resistance adds in series, and voltage is shared in series.
Worked example
A car travels 72 km/h. Convert to m/s: 72 ÷ 3.6 = 20 m/s. In 5 s it covers 20 × 5 = 100 m. Write the unit at every step; most lost marks come from unit slips, not from misunderstanding.
Rule of thumb
For any numerical problem, list knowns with units, state the formula, substitute, then check that the unit of the answer matches what was asked.