Scientific and Technical Aptitude
The syllabus in practice
Items stay at school-leaving level and reward clean physical reasoning rather than recall of formulae: units and dimensions, force and motion, levers, pulleys and simple machines, pressure, density and buoyancy, heat and temperature, electricity (Ohm's law, series and parallel), energy and power, basic sound and light, and elementary chemistry - atomic structure, acids and bases, common reaction types, and materials.
Concepts to master
- Newton's laws: no net force means no acceleration, not necessarily no motion.
- Mass versus weight: mass in kilograms is constant; weight in newtons depends on gravity.
- Ohm's law: V = IR. In series, current is common and resistances add; in parallel, voltage is common and 1/R adds.
- Moments: a lever balances when load x load arm = effort x effort arm, measured from the fulcrum.
- Density and buoyancy: an object floats when its density is less than the fluid's, and displaces its own weight of fluid.
Traps that appear
- Mixing grams and kilograms, or centimetres and metres, mid-calculation.
- Applying the parallel rule to a series circuit.
- Confusing speed with acceleration in a motion graph.
- Measuring a lever arm from the wrong end.
- Ignoring the assumption of frictionless motion stated in the stem.
Worked example
A load of 400 N sits 1 m from the fulcrum of a lever; the effort is applied 4 m from the fulcrum. Balance requires 400 x 1 = E x 4, so E = 100 N. The mechanical advantage is 4, meaning the lever multiplies force but the effort must travel four times as far - energy is conserved. Rule of thumb: always sketch the lever, mark the fulcrum, measure both arms from it, and sanity-check the answer by asking whether a machine should ever reduce the total energy needed.