Science
Core concepts
Science questions sample broad, basic ideas rather than deep computation. Biology: cell structures, photosynthesis and respiration, DNA and Mendelian inheritance, ecosystems, and human body systems. Chemistry: atomic structure, the periodic table, ionic versus covalent bonding, balancing equations, moles, and acids and bases. Physics: Newton's three laws, kinematics, work, energy and power, waves, and Ohm's law. Earth science: plate tectonics, the water cycle, weather, and the solar system.
Traps
- Mass is not weight. Mass is in kilograms; weight is a force in newtons (W = mg).
- Speed is a scalar; velocity includes direction.
- Photosynthesis consumes carbon dioxide and releases oxygen; respiration does the reverse.
- A lower pH means more acidic, not less.
- Know which variable the experimenter changes (independent) and which is measured (dependent).
- Mitosis produces identical body cells; meiosis produces sex cells with half the chromosomes.
Worked example
A 2 kg object accelerates at 3 m/s squared. Using F = ma, the net force is 6 N. If the question instead asks for its weight on Earth, use W = mg = 2 x 9.8 = 19.6 N. Writing the units beside each number prevents confusing the two.
Rule of thumb
Whenever a formula is involved, write the formula, substitute with units, and check that the units of the answer match what is asked.