What Makes a Good Science Answer in an Exam?

Many students know their science well enough to pass — but not well enough to achieve the grades they want. The difference often comes down not to knowledge, but to how that knowledge is communicated in exam answers.

Understanding what examiners are looking for is a skill that can be learned and practised. Here is what separates a good science answer from an average one.

Understand the command words

Every exam question begins with a command word that tells you exactly what the examiner expects. Ignoring this word — or misunderstanding it — is one of the most common reasons students lose marks.

Here are the key command words in GCSE science and what they require:

• State — Give a brief, factual answer. No explanation needed.
• Describe — Say what happens, step by step. No explanation of why.
• Explain — Say what happens AND why. This requires linking cause to effect.
• Evaluate — Weigh up the evidence or arguments and reach a conclusion.
• Compare — Identify similarities AND differences between two things.
• Suggest — Use your knowledge to propose an answer, even if the exact topic was not in your revision. This tests your ability to apply understanding to new situations.
• Calculate — Show your working and give a numerical answer with correct units.

A student who "describes" when asked to "explain" will lose marks, even if their science is correct. Read the command word carefully before you begin writing.

Use scientific language precisely

Examiners mark according to specific mark schemes, and those mark schemes use precise scientific terminology. Using everyday language instead of scientific terms will cost you marks.

For example:

Everyday language	Scientific language
"The plant makes food"	"The plant produces glucose by photosynthesis"
"The particles move faster"	"The kinetic energy of the particles increases"
"The body fights the disease"	"White blood cells produce antibodies"

You do not need to use complicated words for the sake of it. But where a specific scientific term exists, use it. Practise incorporating these terms into your written answers until they come naturally.

Structure longer answers clearly

For 4- and 6-mark questions, structure matters as much as content. A well-organised answer that covers the key points in a logical order will always score higher than a rambling paragraph that contains the same information.

A useful structure for extended answers:

1. Opening statement — Directly address the question
2. Key points — Present your scientific reasoning, one point per sentence
3. Linking — Connect cause and effect using words like "because," "therefore," "this means that"
4. Conclusion — For evaluate questions, state your judgement

Example question: "Explain why the rate of photosynthesis increases as light intensity increases, up to a certain point." (4 marks)

Weak answer: "More light means more photosynthesis. But at some point it stops increasing because something else limits it."

Strong answer: "As light intensity increases, more light energy is available for the light-dependent reactions of photosynthesis, so glucose is produced at a faster rate. However, at high light intensities, another factor such as carbon dioxide concentration or temperature becomes the limiting factor, so the rate plateaus despite further increases in light."

The strong answer uses scientific terminology, explains the mechanism, and addresses both parts of the question.

Show your working in calculations

For calculation questions, the final answer is not the only thing that earns marks. Most calculation questions award marks for:

1. Writing the correct formula
2. Substituting the values correctly
3. Performing the calculation accurately
4. Giving the answer with the correct unit

Even if your final answer is wrong, you can still earn marks for correct working. Conversely, a correct answer with no working may receive fewer marks than expected.

Always include units. Forgetting to write "J" for energy, "m/s" for speed, or "mol/dm³" for concentration is an easy mark to lose.

Answer the question that was asked

This sounds obvious, but it is remarkably common for students to write about a related topic instead of answering the specific question. This usually happens when a student recognises a topic and writes everything they know about it, rather than focusing on what was asked.

Before you write, ask yourself: "What exactly is this question asking me to do?" If the question asks about the function of the mitochondria, do not write about the nucleus or the cell membrane. Stay focused.

Use data when it is provided

If a question includes a table, graph, or diagram, the examiner expects you to refer to it in your answer. Ignoring provided data is a missed opportunity for marks.

When using data:

• Quote specific values — "The rate increased from 12 cm³/min to 28 cm³/min" is better than "The rate increased."
• Identify trends — "As temperature increased from 20 to 40 degrees, the rate of reaction increased steadily."
• Use data to support your explanation — "This suggests that enzyme activity was highest at 37 degrees, which is consistent with it being the optimum temperature."

Check your answers

If you finish an exam early, use the remaining time to review your answers. In particular:

• Have you answered every question?
• Have you given the right number of points for each question? (A 3-mark question generally needs three distinct points.)
• Have you included units in your calculations?
• Have you used the correct command word response?
• Is your handwriting legible?

These final checks can rescue marks that would otherwise be lost to careless errors.

Practise with mark schemes

One of the most effective ways to improve your exam technique is to practise past papers and then mark your own answers using the official mark scheme. This shows you exactly where you gain and lose marks, and it helps you understand what examiners are looking for.

Pay attention to the wording of mark scheme answers. Notice which scientific terms appear. Notice how points are structured. Then incorporate those patterns into your own writing.

Final thoughts

A good science answer demonstrates three things: accurate knowledge, precise language, and clear communication. Many students have the knowledge but lose marks through imprecise language or poorly structured answers.

The good news is that exam technique is a skill, not a talent. With practice and attention to these principles, any student can improve the quality of their answers — and their grades.