Science: Processes, Formulas, and Units
Science
The Science portion samples general biology, chemistry, physics, and earth science. Expect definitions, simple calculations, process ordering, and interpretation of basic diagrams described in words.
Core rules
- Cell: nucleus stores genetic material; mitochondria release energy; ribosomes build proteins; chloroplasts carry out photosynthesis in plants.
- Photosynthesis uses carbon dioxide and water plus light to make glucose and oxygen; respiration reverses the overall equation, using oxygen and glucose to release energy.
- Newton's laws: inertia; F = ma; action–reaction pairs act on different bodies.
- Speed = distance ÷ time; density = mass ÷ volume; force is measured in newtons, energy in joules.
- pH below 7 is acidic, 7 neutral, above 7 basic; each whole step is a tenfold change in hydrogen-ion concentration.
- Water cycle order: evaporation, condensation, precipitation, collection/runoff.
Worked example
A vehicle travels 150 km in 3 hours. Average speed = 150 ÷ 3 = 50 km/h. If the question asks for m/s, convert: 50 × 1000 ÷ 3600 ≈ 13.9 m/s.
Traps
- Confusing mass (amount of matter, kg) with weight (force, N).
- Saying plants only photosynthesize; they also respire.
- Using the wrong unit or forgetting to convert hours to seconds.
- Treating pH 5 as 'twice as acidic' as pH 6; it is ten times more acidic.