Aichi Entrance Science common mistakes
Aichi Entrance Science · Understand the traps and how to avoid them.
When calculating work or energy, the student uses the full applied force without resolving it into the direction of motion, or forgets to include the angle between force and displacement.
Students memorize W = F × d and apply it mechanically, ignoring that only the component of force along the displacement does work. They also confuse the applied force with the net force.
What to do instead
Always draw a free-body diagram and identify the displacement direction. Compute the component of force along displacement (F cos θ) before multiplying by distance. Practice with cases where the force is at an angle (e.g., pulling a sled with a rope) and where forces oppose motion (friction).
In electric circuits, students treat current as something that is 'used up' by components, so they expect the current after a resistor to be smaller than before it.
Everyday language about 'consuming' electricity leads to a misconception that charge is consumed. Students also confuse current with voltage or energy.
What to do instead
Emphasize conservation of charge in a series circuit: current is the same at all points. Use a water-flow analogy where current is the flow rate (not the water itself) and voltage is the pressure difference. Have students measure current at multiple points in a series circuit to see it is unchanged.
When predicting the image formed by a convex lens or concave mirror, students rely on memorized rules without considering the object distance, often placing the image on the wrong side or misjudging whether it is real or virtual.
The rules for ray diagrams are numerous and similar, and students try to memorize outcomes instead of applying the lens/mirror equation or constructing rays step by step.
What to do instead
Teach a consistent ray-diagram method: draw two or three principal rays from the top of the object. Use the thin-lens equation 1/f = 1/do + 1/di to verify. Practice with a table of object positions (beyond 2f, at 2f, between f and 2f, at f, inside f) and derive the image characteristics each time.
When separating mixtures, students choose a method based on the names of the substances rather than on the physical property difference (e.g., using filtration to separate salt from water, or distillation to separate sand and water).
Students memorize 'salt water → distillation' without understanding why, and they fail to analyze the property differences (particle size, boiling point, solubility) that make a method work.
What to do instead
For each separation problem, first list the components and their relevant physical properties (state, boiling point, solubility, particle size, magnetism). Then match the method to the property difference. Practice with unfamiliar mixtures (e.g., ethanol and water, iron filings and sulfur) to force property-based reasoning.
When writing ionic equations or predicting precipitation, students include spectator ions or fail to balance charges, writing formulas like NaCl2 or CaOH instead of Ca(OH)2.
Students memorize formulas as strings without understanding ionic charge balance, and they are unsure which ions actually react.
What to do instead
Review common ion charges and practice writing formulas by balancing positive and negative charges. For ionic equations, explicitly cross out spectator ions and write the net ionic equation. Use solubility rules to predict precipitates, and check that both atoms and charge are balanced.
In oxidation-reduction reactions, students identify oxidation as 'gain of oxygen' only and cannot recognize electron transfer when oxygen is absent (e.g., Zn + Cu2+ → Zn2+ + Cu).
The curriculum often introduces oxidation with oxygen examples first, and students do not generalize to electron transfer or changes in oxidation number.
What to do instead
Teach oxidation number rules and have students assign oxidation numbers to every atom before and after the reaction. Define oxidation as an increase in oxidation number (loss of electrons) and reduction as a decrease (gain of electrons). Practice with reactions with and without oxygen.
When explaining inheritance, students treat alleles as blending or assume that a dominant allele is always the most common in a population, and they misapply Punnett squares to sex-linked traits.
Everyday ideas about 'mixed' traits and the word 'dominant' (meaning powerful or common) interfere. Sex-linked inheritance requires tracking chromosomes, which students often forget.
What to do instead
Use explicit genotype-to-phenotype mapping with examples where the dominant phenotype is rare. For sex-linked traits, always write the sex chromosomes (XX, XY) and track the allele on the X. Practice pedigree analysis and test-cross problems.
When describing human body systems, students treat organs as isolated and cannot explain how systems interact (e.g., how the circulatory and respiratory systems cooperate to deliver oxygen and remove carbon dioxide).
Textbooks present systems in separate chapters, and students memorize organ functions without integrating them.
What to do instead
Create concept maps linking systems: for example, trace an oxygen molecule from the alveoli to a muscle cell and a carbon dioxide molecule back. Use questions that require explaining a process across at least two systems. Emphasize the roles of diffusion and transport.
In food chains and ecosystems, students draw arrows in the wrong direction (from predator to prey) or assume that energy is recycled like matter, expecting energy to flow back to producers.
The arrow direction is often memorized as 'who eats whom' without clarifying that the arrow shows energy flow. The cycling of matter is confused with the flow of energy.
What to do instead
State explicitly: the arrow points from the organism being eaten to the eater, showing the direction of energy transfer. Contrast energy flow (one-way, lost as heat) with matter cycling (recycled by decomposers). Have students label each arrow with 'energy to' and calculate energy loss across trophic levels.
When interpreting geological cross-sections or rock sequences, students ignore the principles of superposition and cross-cutting relationships, or they confuse the order of events (e.g., saying a fault is older than the layers it cuts).
Students read diagrams literally from top to bottom without applying relative dating principles, and they do not distinguish between formation and later deformation.
What to do instead
Teach and practice the principles: superposition (oldest at bottom in undisturbed sequences), original horizontality, cross-cutting relationships (a feature that cuts another is younger), and inclusions. For each diagram, list events in order and justify each with a principle.