Science: applying physics, chemistry and biology to unfamiliar situations
The NSTSE Science section tests whether you can apply physics, chemistry and biology ideas, not just recite them.
What the section rewards
Questions at your class level ask you to predict, explain or calculate rather than reproduce a definition. Expect motion and force, electricity, light, matter and reactions, living systems and ecology, often wrapped in a data table or diagram you must interpret. The correct option usually follows from one clean principle, so identify the principle before you compute.
Core rules to hold onto
- Units and scale: convert to SI before substituting; 1 km/h = 5/18 m/s.
- Newton's laws: net force causes acceleration, and an action–reaction pair acts on two different bodies.
- Circuits: series elements share current, parallel elements share voltage; use R = V/I.
- Chemical change: mass is conserved, so balance atoms before using mole ratios.
- Living systems: structure follows function - exchange surfaces are thin, moist and well supplied with blood.
Worked example
A car starts from rest and reaches 20 m/s in 5 s with uniform acceleration. How far does it travel? Acceleration a = (20 − 0)/5 = 4 m/s². Then s = ut + ½at² = 0 + ½ × 4 × 25 = 50 m. The same answer comes from the area under the v–t graph: ½ × 5 × 20 = 50 m. Using s = vt = 100 m is wrong because the velocity is not constant.
Traps that cost marks
- Calling the normal force the reaction to the book's weight; it is the reaction to the book pressing on the table.
- Mixing average speed with instantaneous speed.
- Treating every dissolving or colour change as a chemical reaction.
- Ignoring the scale on a graph or the unit stated in an option.