Akita Entrance Science common mistakes
Akita Entrance Science · Understand the traps and how to avoid them.
When a problem gives a velocity–time graph, the candidate reads the vertical coordinate as the distance travelled instead of calculating the area under the line.
Everyday language ('how fast', 'how far') blurs the distinction, and the axes look like a position graph. The candidate has memorised 'v–t graph' without attaching the meaning of gradient (acceleration) and area (displacement).
What to do instead
Before answering any kinematics graph question, write two labels on the graph: 'slope = acceleration' and 'area = displacement'. Then compute the area by splitting the region into triangles and rectangles and state the units (m) explicitly. Practise with a graph whose line crosses the time axis so that area below the axis must be subtracted.
The candidate adds or subtracts forces that act on different objects, or omits a force from the free-body diagram, when applying Newton's second law to a connected-body or pulley problem.
The candidate draws one diagram containing both bodies and treats the tension as an external force on the system, or forgets that friction and normal force act on each body separately. This produces equations that are dimensionally plausible but physically inconsistent.
What to do instead
Draw a separate free-body diagram for each body, with exactly one arrow per force and a label naming the object exerting it. Write ΣF = ma for each body separately, then eliminate the internal force (tension or contact force) by adding the equations. Check that every force in the diagram has a Newton's-third-law partner on another object.
The candidate treats 'moles' as a mass unit, for example calculating the number of moles by dividing the given mass by the molar mass but then using that number directly as grams in a later step, or writing '1 mol = 18 g' for all substances.
The mole is introduced alongside mass and volume, and the candidate memorises 'n = m/M' as a formula without internalising that n counts particles while m measures inertia. The confusion is reinforced by laboratory language such as 'we used 2 moles of water'.
What to do instead
Write the unit for every quantity in every line of working: n in mol, m in g, M in g/mol. Before substituting, say aloud 'I have grams, I need moles, so I divide by g/mol and the grams cancel.' Practise converting the same sample among mass, moles and number of particles in both directions until the unit cancellation is automatic.
When asked to balance a chemical equation, the candidate changes a subscript inside a formula (for example turning H2O into H2O2) rather than placing a coefficient in front of the formula.
The candidate focuses on making the atom counts equal and treats the symbols as arithmetic tokens, forgetting that a subscript defines the identity of the substance. This is a conceptual error about what a chemical formula represents, not a slip.
What to do instead
State the rule before starting: 'Only coefficients may change; subscripts are part of the substance's name.' Balance by inspection in the order metals, non-metals, hydrogen, oxygen, and verify by recounting each element on both sides. For ionic equations, check both atoms and charge. If a subscript seems to need changing, the formula is probably wrong and should be re-derived from the names and charges.
The candidate describes diffusion as 'particles wanting to spread out' or as being pushed by a pressure gradient, instead of explaining it as net movement from higher to lower concentration due to random molecular motion.
Textbook diagrams show arrows from high to low concentration, which invites a teleological or force-based reading. The candidate has not connected the statistical nature of diffusion to the random motion of individual particles.
What to do instead
Write the definition in mechanistic terms: 'Each particle moves randomly; because there are more particles in the high-concentration region, more cross to the low-concentration side per unit time, giving a net flow until concentrations are equal.' Then apply it to a specific case such as gas exchange in alveoli, naming the concentration gradient and the random motion explicitly.
The candidate confuses genotype and phenotype when predicting the results of a monohybrid cross, for example writing '3:1' as the genotype ratio or labelling a heterozygous individual as showing the recessive trait.
The two ratios (1:2:1 for genotypes, 3:1 for phenotypes) are memorised as isolated numbers without linking them to what is being counted. The candidate also forgets that a dominant allele masks the recessive one in the heterozygote.
What to do instead
For every cross, draw a Punnett square and label each box with both the genotype (e.g. Aa) and the phenotype (e.g. dominant). Then count genotypes and phenotypes in separate rows and write both ratios with their labels. Repeat with a test cross (Aa × aa) so that the 1:1 outcome is also familiar.
The candidate explains the seasons by saying Earth is closer to the Sun in summer, or explains day and night by saying Earth orbits the Sun.
The candidate conflates the annual orbit with the daily rotation, and the elliptical orbit is visually exaggerated in diagrams. The correct cause, the tilt of Earth's axis, is less intuitive than distance.
What to do instead
Write two separate sentences: 'Day and night are caused by Earth's rotation on its axis once per day' and 'Seasons are caused by the 23.5° tilt of the axis, which changes the angle of incidence of sunlight and the length of daylight, not by distance from the Sun.' Then test the claim against a counterexample: Earth is closest to the Sun in early January, which is winter in the Northern Hemisphere.
The candidate reads a weather map or a topographic map without using the key, for example treating isobars as lines of equal temperature or interpreting closely spaced contour lines as a flat area.
The candidate looks only at the shape of the lines and not at the labels, and has not practised translating line spacing into a physical quantity. Map reading is treated as a memory task rather than a spatial-reasoning task.
What to do instead
Before answering, locate the legend and the units, and state in words what one line represents. For isobars, note that close spacing means a steep pressure gradient and stronger wind; for contours, close spacing means a steep slope. Practise by sketching a profile along a straight line across the map and checking that the steep parts match the closely spaced lines.
The candidate states a conclusion that the data do not support, such as 'the plant grows faster in light' after measuring only one plant in each condition, or reports a difference as real without considering whether it exceeds measurement uncertainty.
The candidate treats any numerical difference as evidence and has not been taught to ask about sample size, controls and uncertainty. School experiments often produce a single dramatic result, reinforcing this habit.
What to do instead
Before writing a conclusion, answer three questions in writing: How many independent measurements were there? What was held constant? How large is the difference compared with the uncertainty of the measuring instrument? Then phrase the conclusion with its scope, for example 'for these two plants under these conditions, the illuminated plant was taller; a larger sample is needed before generalising.'
The candidate designs an experiment with no control group, or changes two variables at once, and then cannot attribute the result to the intended cause.
The candidate focuses on the interesting condition and treats the control as an optional extra. The language of 'fair test' is known as a slogan but not applied when writing a procedure.
What to do instead
Write the design as a table with three rows: independent variable (what is changed), dependent variable (what is measured, with instrument and unit), and controlled variables (at least three, each with how it is kept constant). Then add a control group and state explicitly what it is compared against. Check the design by asking 'if the result changes, what else could have caused it?' and eliminate each alternative.