Gunma Entrance Science common mistakes
Gunma Entrance Science · Understand the traps and how to avoid them.
When a problem gives a distance–time graph or a speed–time graph, the candidate reads the height of the curve as the speed in both cases, so on a distance–time graph they report a steep straight segment as 'constant acceleration' rather than 'constant speed'.
The two graph types look almost identical, and the vertical axis is labelled only with a quantity name and a unit that is easy to skim. Candidates memorise 'gradient = speed' without attaching it to the axis labels, so the rule collapses when the axes change.
What to do instead
Before reading any value, write the vertical axis unit and the horizontal axis unit at the top of the working. Then apply a fixed rule: distance–time gradient = speed, speed–time gradient = acceleration, speed–time area = distance travelled. Practise by taking one journey and drawing both graphs from it, checking that the flat part of the distance–time graph corresponds to the zero-height part of the speed–time graph.
The candidate adds forces as plain numbers even when they act in different directions, for example treating a 5 N force to the right and a 3 N force to the left as a total of 8 N, or writing 'the forces balance' when only their magnitudes are equal but their directions are not opposite along the same line.
Force is introduced through everyday pushing and pulling, where the number feels like the whole story. Arrows are drawn in class but the numerical work is often done without them, so the vector nature of force is never practised under exam pressure.
What to do instead
Make a free-body diagram mandatory before any calculation: one arrow per force, labelled with magnitude, all starting from the object. Then state the sign convention in writing (right positive) and sum with signs. For balance questions, require three checks: equal magnitude, opposite direction, same line of action.
On a circuit question the candidate calculates current with the total voltage across every resistor in a series circuit, or assumes current is used up as it passes through each component, so the current after the second bulb is reported as smaller than before it.
Everyday language about 'using up' energy encourages the idea that current is consumed. Series and parallel rules are also learned as formulas without the underlying conservation of charge, so candidates cannot tell which quantity is shared and which is divided.
What to do instead
Anchor both circuits in conservation statements: charge is not consumed, so current is the same at every point in a series loop; the total voltage is shared among series components in proportion to resistance. Draw the same two-resistor circuit in series and in parallel side by side and tabulate which quantity is equal and which adds, then compute both with numbers.
The candidate describes an energy transfer as 'the energy is lost' or 'the force gives the object energy' without naming the store and the pathway, and on a falling-object question claims kinetic energy appears from nowhere rather than from a decrease in gravitational potential energy.
Energy is taught with slogans such as 'energy cannot be created or destroyed' but the bookkeeping of stores is rarely drilled, so the candidate can state the principle yet cannot apply it to a specific change.
What to do instead
Use a two-column account for every energy question: stores before, stores after, and the pathway (heating, mechanical work, electrical, radiation) between them. Insist that the total of the store columns is equal. For a falling ball, write gravitational store decreasing by mgh and kinetic store increasing by ½mv², then equate them.
Given a table of melting points and a substance's behaviour, the candidate classifies a substance as a mixture or a pure substance by appearance alone, or labels a change as chemical because bubbles or a colour change appeared, without checking whether a new substance was formed and whether the change is reversible.
Signs of reaction are taught as a checklist (gas, colour, precipitate, heat) and candidates apply the list mechanically, forgetting that boiling also produces bubbles and that dissolving can change colour.
What to do instead
For each observation, ask two questions in writing: is a new substance formed, and can the original be recovered by a physical method such as filtration, evaporation, or distillation? Treat gas evolution as chemical only when the gas is identified (for example a burning splint test) and treat melting, boiling, and dissolving as physical.
The candidate writes a word or symbol equation with the correct reactants and products but does not balance it, or balances it by changing a subscript inside a formula (turning H2O into H2O2) instead of placing a coefficient in front.
Balancing is often done by inspection and guesswork, and candidates do not consistently count atoms on both sides. The notation rule that subscripts belong to the formula and coefficients belong to the reaction is easily confused.
What to do instead
Adopt a fixed procedure: list each element in a column, count atoms left and right, adjust only the large numbers in front, and recount after every change. Finish by checking that no subscript was altered and that the total charge is equal if ions are involved. Do five equations this way before the exam so the procedure is automatic.
When asked to identify an ion from a test result, the candidate confuses the flame colour or precipitate with the wrong ion, for example reporting a white precipitate with sodium hydroxide as proof of chloride, or treating a flame test as a test for the metal's reactivity rather than its identity.
Ion tests are a list of colour–ion pairs learned by rote, and the reagent used matters as much as the observation. Candidates memorise the colour but not which reagent produces it, so silver nitrate and sodium hydroxide results get swapped.
What to do instead
Build a two-way table with reagent as the row and observation as the column, and fill it from memory weekly. For each entry state the ionic equation, for example Ag⁺ + Cl⁻ → AgCl, so the reagent is tied to the ion. In the exam, name the reagent first, then the observation, then the ion.
The candidate explains a food chain or population change by saying the predator 'needs' to eat the prey or that the prey 'tries' to avoid being eaten, attributing purpose or intention to organisms instead of describing selection and the flow of energy and matter.
Everyday and documentary language is full of purpose-driven phrasing, and candidates transfer it into answers. The mechanism of variation plus differential survival is understood in principle but not used as the explanatory tool.
What to do instead
Ban intentional verbs in written answers and replace them with consequence statements: individuals vary, those with the advantageous feature leave more offspring, so the feature becomes more common. For population questions, always trace the chain one link at a time and state the direction of energy flow from producer to consumer.
On a genetics question the candidate treats a dominant allele as 'the stronger gene' and concludes that a dominant characteristic must be the more common one in the population, or writes that a recessive allele is absent in a heterozygous individual.
The words dominant and recessive carry everyday meanings of strength and frequency, and the distinction between genotype and phenotype is stated in textbooks but rarely tested against counterexamples in class.
What to do instead
Define dominance operationally: in a heterozygote the dominant allele's phenotype is expressed, but both alleles are present and are passed on with equal probability. Work one counterexample, such as a rare dominant condition or a common recessive one, and draw the Punnett square with alleles written as symbols so the presence of the recessive allele is visible.
The candidate reads a rock cycle or geological cross-section as a sequence of events in the order the layers are drawn top to bottom, ignoring that a cut across layers, an intrusion, or a fold must postdate the features it cross-cuts, and confusing weathering with erosion.
Diagrams are read like a story from top to bottom, and the principle of cross-cutting relationships is a reasoning rule rather than a fact to recall, so it is not applied unless specifically practised.
What to do instead
Apply three ordering rules explicitly in writing: undisturbed sediment is deposited oldest at the bottom; any feature that cuts another is younger than it; folding or faulting happened after the layers formed. Distinguish weathering (breakdown in place) from erosion (transport away) by asking whether material moved.
The candidate explains seasons by saying Earth is closer to the Sun in summer, or explains day and night by saying Earth moves around the Sun, rather than by Earth's rotation on its axis and the tilt of that axis relative to the orbital plane.
The two motions, rotation and revolution, are taught together and their effects get attached to the wrong motion. Distance-based explanations are also intuitive and reinforced by diagrams that exaggerate the ellipse.
What to do instead
Separate the motions into a table: rotation gives day and night and the apparent daily motion of the Sun; revolution plus axial tilt gives the seasons and changing day length. Add the disproof that both hemispheres have opposite seasons at the same distance, and sketch the tilted axis with the Sun to confirm the reasoning.
The candidate records a measurement to more decimal places than the instrument allows, or averages readings without noticing that one value is far from the rest, and reports a conclusion that the data do not support.
Candidates believe more digits signal a better answer and have not been taught that precision is set by the smallest scale division. Outliers are kept because deleting data feels dishonest, and the conclusion is written from expectation rather than from the numbers.
What to do instead
State the instrument and its smallest division before recording, and give the reading to that precision plus one estimated digit. For repeated readings, calculate the mean, flag any value differing by more than the spread of the others, and either repeat the measurement or report the anomaly explicitly. Write the conclusion as a sentence that names the variables and the direction of the trend shown.