Fukushima Entrance Science common mistakes
Fukushima Entrance Science · Understand the traps and how to avoid them.
When a problem gives an object launched at an angle, the candidate plugs the full launch speed into the vertical-motion equation instead of first splitting it into v·sinθ and v·cosθ, so the computed time of flight and maximum height come out wrong.
Projectile motion is taught as one formula set, and candidates memorize 'use v in the height equation' without tracking that the vertical component is what gravity acts on. Under time pressure they skip the decomposition step because it feels like extra work.
What to do instead
Before touching any equation, draw the velocity vector and write vx = v·cosθ, vy = v·sinθ as a mandatory first line. Then solve the vertical motion with vy only and the horizontal motion with vx only. Practice three launch-angle problems where θ = 0, 45, and 60 degrees and check that the θ = 0 case reduces to straight vertical throw.
The candidate treats action–reaction pairs as if they cancel, concluding that a horse cannot pull a cart or that a book on a table has zero net force from the table, because it pairs the two forces on the same object.
Newton's third law pairs are visually identical in magnitude and opposite in direction, so they look like balanced forces. Candidates forget that a force pair always acts on two different bodies, while equilibrium requires multiple forces on one body.
What to do instead
For every force, label the object exerting it and the object receiving it, e.g. 'Earth pulls book' and 'book pulls Earth'. Only forces whose receiver is the same object may be summed. Do a quick check: if two forces in your diagram share the same receiver and are equal and opposite, they are not a third-law pair.
When asked about a gas or a mixture at equilibrium, the candidate writes the equilibrium constant expression using the initial concentrations or adds/subtracts stoichiometric amounts in the wrong direction, rather than using the balanced equation and an ICE table with changes in the correct sign.
Le Chatelier-type qualitative questions train a reflex of 'shift right, shift left' without quantitative bookkeeping. Candidates also confuse the coefficient in the balanced equation with the exponent in K.
What to do instead
Always write the balanced equation first, then build an ICE table with columns for initial, change, and equilibrium, and put the stoichiometric coefficient as the multiplier on the change row. Write K with products over reactants and raise each concentration to its coefficient. Verify by substituting equilibrium values back into K.
The candidate identifies an oxidation–reduction reaction but assigns oxidation numbers by counting total atoms of an element rather than per atom, or forgets that oxygen is usually −2 and hydrogen +1, so the oxidizing and reducing agents are swapped.
Oxidation number rules are learned as a list and applied inconsistently, especially in polyatomic ions and peroxides. Total-atom counting feels natural because the formula shows subscripts.
What to do instead
Assign oxidation numbers atom by atom, starting from the standard rules (O = −2 except peroxides and OF2, H = +1 except hydrides, sum equals the ion charge), then compute the change per atom. The species whose atom's number increases is oxidized and is the reducing agent; the one that decreases is reduced and is the oxidizing agent. Practice on at least five polyatomic-ion cases.
When explaining why an enzyme-catalysed reaction slows at high temperature, the candidate says the enzyme 'runs out of substrate' or 'the reaction reaches equilibrium', instead of stating that the enzyme protein denatures and loses its active-site shape.
Temperature effects on rate are taught alongside collision theory, so candidates apply the 'more collisions, faster rate' logic in both directions and miss the biological specificity of protein structure. The phrase 'optimum temperature' is memorized without its mechanism.
What to do instead
Learn the two-regime curve explicitly: below the optimum, rate rises with temperature because molecular collisions increase; above the optimum, rate falls sharply because hydrogen bonds and other interactions holding the tertiary structure break, the active site changes shape, and substrate no longer binds. State the denaturation mechanism by name in every answer about high-temperature enzyme inhibition.
The candidate describes diffusion of water across a membrane as 'water moves from high solute concentration to low solute concentration' rather than from high water potential (low solute concentration) to low water potential (high solute concentration).
Osmosis is often summarized as 'water follows salt', which inverts the direction if the candidate then reasons about solute rather than water. The term 'concentration gradient' is applied to the wrong substance.
What to do instead
Rewrite the rule as: water moves from the region of higher water potential (more free water, less solute) to the region of lower water potential (less free water, more solute). Draw an arrow labeled 'water' on a diagram of two solutions separated by a membrane and confirm the arrow points toward the more concentrated side. Test yourself with a plant cell in a hypertonic solution and predict plasmolysis.
The candidate explains the seasons by saying Earth is closer to the Sun in summer, or explains day and night length by the distance from the Sun, instead of citing the 23.5° axial tilt and the changing angle of incidence and daylight duration.
The orbit is elliptical and perihelion is a memorable fact, so distance becomes the default cause. The tilt is known as a number but not connected to insolation and day length.
What to do instead
Memorize the decisive test: the Northern and Southern Hemispheres have opposite seasons at the same time, which distance cannot explain because both are equidistant from the Sun. Attribute seasons to axial tilt changing the solar elevation angle and the number of daylight hours. Sketch the solstices and equinoxes with the tilt fixed in the same direction in space.
The candidate reads a phase diagram or a heating curve and states that boiling occurs gradually as temperature rises through the liquid region, or that the melting point changes with the amount of substance, instead of recognizing that phase changes occur at constant temperature with latent heat absorbed.
Everyday experience of slow evaporation and gradual heating blends with the textbook model. The flat plateaus on a heating curve are drawn but not interpreted as constant-temperature transitions.
What to do instead
On a heating curve, label each plateau with the phase change and the latent heat absorbed at constant temperature, and label each rising segment with the specific heat of a single phase. State that melting and boiling points are intensive properties independent of sample size. Check any answer against the plateau: if temperature is changing, no phase change is occurring at that moment.
The candidate computes speed as distance divided by time but then treats velocity, acceleration, and speed as interchangeable in a graph question, reading the slope of a distance–time graph as acceleration or the area under a velocity–time graph as distance without checking units.
The words are used loosely in everyday language, and graph interpretation is often taught as a set of tricks rather than as a consistent slope/area framework. Unit analysis is skipped under exam pressure.
What to do instead
Build a fixed table: on a distance–time graph the slope is velocity; on a velocity–time graph the slope is acceleration and the area is displacement. Always attach units to the slope and area you compute and confirm they match the quantity asked for (m/s for slope of distance–time, m for area under velocity–time). Redo one graph of each type until the unit check is automatic.
In a genetics problem, the candidate calculates phenotype ratios from a dihybrid cross without confirming independent assortment, or confuses genotype ratio with phenotype ratio and reports 9:3:3:1 as the genotype ratio.
The 9:3:3:1 ratio is memorized as a single fact and applied to any two-trait cross, including linked genes. Genotype and phenotype are both ratios of the same cross, so the labels blur.
What to do instead
State the assumptions before computing: the genes are on different chromosomes or far apart, and alleles assort independently. Then write the Punnett square or the product rule explicitly, and label the result as phenotype ratio or genotype ratio. For linked genes, work the gamete frequencies from recombination rather than forcing 9:3:3:1. Verify by counting the distinct genotypes in the square.