Chiba Entrance Science common mistakes
Chiba Entrance Science · Understand the traps and how to avoid them.
On multi-part calculation problems, carrying an unrounded intermediate value into the final answer but reporting it with too many significant figures (e.g. writing 1.7320508 for a length given data to 2 s.f.).
Candidates focus on getting the arithmetic right and forget the exam marks the final value for significant figures and units; calculators display many digits and the temptation is to copy them all.
What to do instead
Before writing the final answer, decide the limiting significant figures from the given data, round only at the end, and write the unit explicitly. Practise by covering the calculator display after the third digit for a week of past-paper drills.
In mechanics, substituting a value into a formula without first drawing a free-body diagram, so a force (normal reaction, tension, friction) is omitted or given the wrong direction.
Under time pressure candidates pattern-match a formula to the words in the question; the formula is remembered but the physical situation it applies to is not reconstructed.
What to do instead
Make a labelled free-body diagram mandatory for every force question, however simple, and write the equation of motion along a chosen axis before substituting numbers. Mark direction with arrows and a sign convention.
Treating an equilibrium problem as complete once the mole calculation is done, without checking whether the reaction actually goes to completion or whether a limiting reagent remains.
School practice often uses reactions that go to completion; candidates transfer that habit to equilibrium and weak-acid questions where the extent of reaction is the whole point.
What to do instead
Before calculating, ask 'does this go to completion, reach equilibrium, or is one reagent limiting?' and write an ICE (initial-change-equilibrium) table whenever the answer depends on extent. Check that the answer is physically sensible (concentrations positive, pH in range).
Describing a biological process as a list of named stages without linking structure to function, so answers to 'explain why' questions earn no marks even though the terminology is correct.
Revision is often done by memorising stage names and definitions; exam questions in this subject frequently ask for a causal explanation, and a list of terms does not answer 'why'.
What to do instead
For each process, practise writing one sentence of the form 'structure X allows function Y because Z'. Self-test by covering the name and explaining the mechanism from the diagram, then compare with the mark scheme's causal wording.
Confusing the cause of seasons, tides and phases of the Moon, attributing them to distance from the Sun or to the Earth's rotation rather than to axial tilt, gravitational gradients and orbital geometry.
These are everyday phenomena with intuitive but wrong explanations, and diagrams in textbooks compress the geometry so the key angle or alignment is not internalised.
What to do instead
Build a scale sketch for each phenomenon showing the relevant angle or alignment, and state the one geometric fact that drives it (23.5° tilt; near/far side of Earth relative to Moon and Sun; Earth-Moon-Sun angle). Test yourself by predicting a season or tide for a stated date and hemisphere.
Answering English reading comprehension questions from general knowledge or from a single matching word, without locating and quoting the sentence in the passage that supports the choice.
The passage is long and time is short, so candidates skim for a keyword and choose the option containing it; distractors are deliberately written to share vocabulary with the passage.
What to do instead
For every answer, underline the supporting sentence and note its line number before selecting an option. If no single sentence supports the choice, treat the option as wrong. Time yourself to keep this habit under exam conditions.
In English writing, producing a grammatically correct sentence but with the wrong register or an unnatural collocation (e.g. 'I am looking forward to hear from you'), and not proofreading for subject-verb agreement in long sentences.
Candidates translate from their first language and check grammar at the clause level, so errors that span clauses or depend on idiom survive.
What to do instead
Keep a personal error log of recurring collocation and agreement mistakes, and do a final two-minute read of the whole text checking only verb agreement and prepositions. Learn fixed phrases as whole chunks rather than word by word.
Showing no working for a numerical answer, then losing all method marks when a single arithmetic slip makes the final value wrong.
Candidates believe the answer is what is marked and want to save time; they also fear that messy working will be penalised.
What to do instead
Write the formula, then the substitution, then the answer on separate lines for every calculation. Method marks are awarded for the first two lines even when the arithmetic fails, so this costs seconds and protects marks.
Misreading the question's command word, giving a description where an explanation is required, or a comparison where only one item was asked for.
Candidates read for topic rather than for the instruction, and the command words (describe, explain, compare, evaluate, state) look similar under time pressure.
What to do instead
Circle the command word and the number of items requested before starting to write, then check the finished answer against both. Practise by rewriting past questions as one-line instruction summaries before answering them.
Running out of time because effort is distributed evenly across questions, leaving long high-mark questions attempted in the last minutes.
Candidates work front to back and are reluctant to leave a question unfinished, so a single hard early question consumes time that later, easier marks needed.
What to do instead
Do a two-minute scan, note the mark value of each question, and allocate minutes roughly proportional to marks. If a question stalls for more than its allocated time, write the method so far, mark it, and move on; return at the end.