Science is the 13+ subject parents feel least able to help with, and the one where the exam is most predictable. Common Entrance science examines biology, chemistry and physics on broadly the same ground as Key Stage 3 — ISEB frames the syllabus around the national curriculum — and the questions reward two things above all: precise recall, and the ability to think like a scientist about an experiment you have never seen. Neither requires a lab at home. Both can be practised at the kitchen table.

One structural note before the substance. CE science has been offered at more than one level, with the three sciences examined together in some settings and as separate papers in others; and senior schools that set their own 13+ exams treat science very differently from one another — some examine it fully, some lightly, a few not at all. As with everything CE, confirm the current paper structure with ISEB or with the target school, and plan around the durable content below rather than around a remembered format.

The shape of each science

Biology: systems, and the connections between scales

The biology content runs through cells and their structures, the major body systems — digestion, respiration and breathing, circulation — reproduction and growth, health, and ecosystems: food chains and webs, interdependence, and how organisms are adapted to where they live.

What distinguishes a strong Year 8 biology answer is movement between scales. The question is about a sprinting athlete; the marks are for connecting breathing rate to gas exchange to respiration in muscle cells. Children who have learned biology as a list of separate facts find these questions hard; children who have learned it as connected systems find them almost restful.

The classic biology misconceptions that surface at 13+ are old friends to any marker: plants get their food from the soil (they make it by photosynthesis; the soil supplies water and minerals), respiration is breathing (breathing is ventilation; respiration happens in cells), and food chains read backwards. Each is worth explicitly hunting down, because each was usually taught correctly and then quietly reassembled wrongly in the child's head.

Chemistry: the particle picture underneath everything

The chemistry content covers the particle model and changes of state, elements, compounds and mixtures, separation techniques, acids and alkalis, and chemical reactions — including the difference between a chemical and a physical change, and word equations for common reactions.

Almost every chemistry mark at this level traces back to one question: does the child have the particle picture, or just the vocabulary? A child who can see particles gaining energy and breaking free explains melting, dissolving, diffusion and evaporation with one mental model; a child who memorised four separate definitions has four chances to muddle them. Likewise word equations: the marks are for knowing that atoms are rearranged, never created or destroyed — reactants on the left, products on the right, and mass accounted for.

The reliable misconceptions: dissolving is disappearing, bubbles always mean boiling, and the hardy perennial of confusing melting (one substance changing state) with dissolving (two substances mixing).

Physics: predictions, and the honesty to test them

The physics content spans forces and motion, energy, electricity and simple circuits, magnetism, sound, light, and Earth and space.

Physics is where intuition fights the syllabus hardest, because everyday experience teaches plausible falsehoods: a moving object must have a force pushing it (it keeps moving unless a force acts), heavier objects fall faster, cold flows into things. The single most effective preparation habit in physics is prediction: make the child commit — out loud, before seeing the answer — to what the circuit, the ball or the shadow will do, and then confront the gap between the guess and the result. A child who has been wrong out loud fifty times in practice, and has enjoyed finding out why, is precisely the child the paper cannot rattle.

Circuits and light reward disciplined diagram conventions — straight-line rays with arrows, correct circuit symbols — which are easy marks for a child drilled in them and silently expensive for one who is not.

The fourth subject hiding inside all three

Every CE-style science paper spends real marks on working scientifically: identifying the independent, dependent and control variables; saying what makes a test fair; spotting the flaw in a described method; reading a results table; drawing or interpreting a graph; and writing a conclusion that claims only what the data shows.

This is the highest-value preparation target in 13+ science, for a simple reason: it is the same machinery in all three sciences, so practising it once pays three times. It is also where imprecision costs most — "the plant with more light grew better" earns less than "as light intensity increased, the height increased", and a conclusion that overreaches the data loses the mark even when the science instinct behind it is right. Any experiment, described on paper, can host this practice; no equipment is required.

How to prepare three sciences without triple the work

  • Retrieval, little and often. Science at this level is knowledge-dense, and knowledge fades on a schedule. Short, spaced recall — a handful of questions a few evenings a week, across all three sciences, from the autumn of Year 8 — comfortably beats a heroic Easter blitz, and flashcards are the natural tool for it.
  • Hunt misconceptions by name. The lists above are short and stable. An evening spent specifically probing "so where does a plant's food come from?" is worth more than an evening re-reading a revision guide that the child will nod along to.
  • Practise the skills questions across sciences. One variables-and-graphs session using a biology experiment, a chemistry one and a physics one teaches the transferability directly.
  • Precision as a habit. Units on every numerical answer, scientific terms where they exist, conclusions no larger than the data. These are marks awarded for discipline rather than brilliance, which makes them the fairest marks on the paper to go and collect.

Since CE science is KS3 science, this is ground our tutors cover: aitutors.me has a tutor for each science — biology taught as connected systems, chemistry built model-first from the particle picture before any equation, physics run predict-first so the child commits to a guess before seeing the result — plus flashcards for the retrieval layer, and Paper Review for bringing back the wrong questions from a mock, where the tutor walks a similar problem and hands the original back. The same disclosure as ever: none of this predicts a result or replaces the school's own preparation, and a parent running spaced recall and out-loud predictions at the kitchen table is doing the substance of it unaided.

FAQ

What does 13+ Common Entrance science cover?

Biology, chemistry and physics on broadly the same ground as Key Stage 3: cells, body systems, reproduction and ecosystems in biology; particles, elements and compounds, reactions and separation techniques in chemistry; forces, energy, electricity, sound, light and space in physics — plus working-scientifically skills such as variables, fair testing and reading data. ISEB frames the syllabus around the national curriculum.

Is CE science one paper or three?

It depends on the level and the setting: CE science has been offered at more than one level, with the three sciences examined together or as separate papers. Schools setting their own 13+ exams vary too — some examine science lightly or not at all. Confirm the current structure with ISEB or the target school before planning revision around a format.

What loses the most marks in 13+ science?

Rarely missing topics — usually imprecision: everyday-language answers where a scientific term was required, muddled variables in experiment questions, misread graphs, forgotten units, and a handful of classic misconceptions such as "plants get food from the soil" or "a moving object must have a force pushing it".

How should a Year 8 child revise three sciences at once?

By skills as much as by content. The working-scientifically questions — variables, method, tables, graphs, conclusions — are the same machinery in all three papers, so practising them once pays three times. For content, short retrieval practice spread across the year beats a late blitz, because science marks at this level are mostly for secure, precise recall and application.