How to Revise for Science Exams: A KS3 Guide

Science revision works best when you test yourself actively rather than re-reading notes. At KS3 you study biology, chemistry, and physics as one combined subject, covering three distinct styles of thinking. The good news is that one core set of strategies — retrieval practice, diagrams, and definitions — works well across all three.

Why science revision is different from other subjects

Science demands both understanding and recall. You need to remember key definitions and facts, but also understand how concepts connect — why cells need mitochondria, why metals conduct electricity, why a larger mass needs more force to accelerate. Simply memorising without understanding means you will struggle when an exam question asks you to apply a concept in a new context.

The Education Endowment Foundation's guidance on secondary science highlights two key evidence-based approaches: retrieval practice (testing yourself from memory rather than reading) and building conceptual understanding through explanation, not just repetition. Both should be in your science revision toolkit.

Step 1 — Organise your topics before you start

Before any active revision, map out what you need to know. At KS3 (and into GCSE), science is typically split as follows:

Topic area | Example KS3 topics
Biology | Cells, organ systems, reproduction, ecosystems, genetics
Chemistry | Particles, elements and compounds, acids and alkalis, the periodic table
Physics | Forces, energy, waves, electricity, space

Use your teacher's specification or scheme of work to check which topics your exam covers. Mark each one as: secure, developing, or weak. Spend the most revision time on developing and weak topics.

Step 2 — Use retrieval practice, not passive re-reading

The single most effective change you can make to your science revision is to stop re-reading your notes and start testing yourself instead. Here is how:

Read a section of notes — one topic, not a whole chapter.

Close your notes and write — from memory — everything you can recall about that topic. This is called a brain dump.

Compare to your notes — what did you miss? Underline it.

Wait a day — revisit the underlined content and test yourself again.

Repeat until you can recall the topic fully from memory.

This cycle — read, close, recall, check, repeat — is supported by decades of evidence on how memory works. It feels harder than re-reading, and that difficulty is precisely why it works.

Step 3 — Draw diagrams from memory

Science is a visual subject. At KS3 and GCSE, you will need to draw and label diagrams under exam conditions: plant and animal cells, the digestive system, the water cycle, circuit diagrams, force diagrams.

Do not just look at diagrams in your textbook. Cover the page and redraw them from memory. Then check for accuracy. The act of reconstructing a diagram forces your brain to encode the structure far more deeply than passive looking.

BBC Bitesize provides free labelled diagrams and interactive quizzes for KS3 biology, chemistry, and physics — useful for checking your recall attempts.

Step 4 — Learn key definitions precisely

In science exams, many marks are lost because students describe a concept rather than define it accurately. Learn the exact definitions your exam board expects. For example:

Speed = distance ÷ time (not "how fast something moves")

Photosynthesis = the process by which plants use light energy to convert carbon dioxide and water into glucose and oxygen

Atom = the smallest part of an element that still has the properties of that element

Test yourself by covering the definition and saying it aloud or writing it from memory. Getting the keywords exactly right often means the difference between one mark and zero.

Step 5 — Practise calculation questions separately

Physics and chemistry both include calculation questions — speed, pressure, energy, concentrations. These need separate practice from recall revision because they require applying a formula, substituting values, and showing clear working.

For each type of calculation you need to know:

Write out the formula.

Identify the values given in the question.

Substitute and calculate.

Write units in your answer (marks are often lost for missing units).

Practice at least five calculation questions per topic. Start with straightforward examples, then tackle past-paper-style questions.

How to split your revision time across three sciences

A common mistake is spending all your revision time on the science you find most interesting. A more strategic approach:

Week before exam | Focus
3+ weeks out | Identify weak topics in all three sciences
2 weeks out | Active recall and diagram practice on weak topics
1 week out | Past-paper questions, definitions, and calculations
2–3 days out | Quick recall of key definitions and formulae — no new topics

Frequently asked questions

How do I revise science if I find it boring?

Start with the topics you find most interesting to build momentum, then move to harder or less engaging areas. Science becomes more interesting when you understand the "why" behind it — try explaining a concept to a friend or family member rather than just reading it. Teaching something to someone else is one of the most effective revision techniques because it immediately shows you where your understanding has gaps.

Do I need to memorise all the formulae for KS3 science?

At KS3, you typically need to know common formulae like speed = distance ÷ time, or power = work done ÷ time. Your teacher will confirm which are given on a formula sheet in the exam and which you must memorise. Even when a formula is provided, you still need to practise using it correctly — knowing where a formula is written does not mean you can apply it under pressure.

How long before a science exam should I start revising?

Ideally three to four weeks before a KS3 assessment, and six to eight weeks before GCSE science papers. Starting early allows you to space out your revision sessions, which is far more effective than cramming the night before. Short, regular sessions of 30 to 40 minutes — with breaks — are more productive than one exhausting marathon session.

What should I do if I do not understand a topic in science?

Do not skip it and hope it will not come up. Ask your teacher to explain it again, look for a clear explanation on BBC Bitesize, or ask a tutor to work through it with you. Understanding a concept even partially before the exam is much better than leaving it blank. The DfE's science curriculum is built on concepts that build on one another, so a gap in understanding tends to compound over time.

For a science tutor that checks understanding, not just recall, and adapts to your child's pace, visit aitutors.me.