Command Words

Every exam question begins with (or contains) a command word that tells you exactly what the examiner expects. Misinterpreting the command word is one of the most common reasons students lose marks. This lesson covers every command word used in the Edexcel GCSE Combined Science specification (1SC0) and explains what each one requires.

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Why Command Words Matter

• The command word determines the depth and style of your answer.
• A 2-mark "describe" question needs a different response from a 2-mark "explain" question.
• Learning command words is a fast way to pick up marks you would otherwise lose.

Exam Tip: Before writing anything, underline or highlight the command word in the question. This forces you to check what is actually being asked.

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The Full Command-Word Table

Command word	What it means	What to do	Typical marks
State	Recall a fact or give a brief answer	Write a short, direct answer — no explanation needed	1
Name / Give / Identify	Recall or select from information provided	One word or short phrase — do not waste time explaining	1
Define	Give the precise meaning of a term	Use the scientific definition — be exact	1–2
Describe	Set out characteristics or features	Say what happens, step by step — do not explain why	2–4
Explain	Give reasons for something	Say what happens and why, using scientific knowledge	2–4
Compare	Identify similarities and/or differences	Write about both things; use comparative words (whereas, however, both)	2–4
Suggest	Apply your knowledge to an unfamiliar situation	The answer may not be in the specification — use logic and scientific principles	1–3
Calculate	Work out a numerical answer	Show all working, state the equation, include units	2–4
Determine	Use data or information to find an answer	May involve reading a graph, a table or carrying out a calculation	2–3
Evaluate	Judge the evidence or argument; weigh up strengths and weaknesses	Give advantages and disadvantages, then reach a reasoned conclusion	4–6
Justify	Give reasons to support a conclusion or decision	Back up your answer with evidence or scientific reasoning	2–3
Deduce	Draw a conclusion from the information given	Use the data provided — do not recall from memory alone	1–3
Estimate	Give an approximate value using your knowledge or data	Show your reasoning; an exact answer is not expected but the method must be sound	1–2
Sketch	Draw approximately; key features must be correct	Label axes (graphs) or key parts (diagrams); exact precision is not required	2–3
Plan	Write a method for an investigation	Include equipment, variables, measurements, how to make it a fair test	6
Predict	Give an expected result based on understanding	Use your scientific knowledge; you may or may not need to explain	1–2
Complete	Fill in gaps in a table, diagram or sentence	Check you fill in every gap — marks are often lost by missing one	1–3
Draw	Produce a diagram or graph with accuracy	Use a ruler for straight lines; label clearly	1–3
Label	Add names or values to a diagram	Use lines (not arrows) pointing to the exact feature	1–2
Plot	Mark data points on a graph	Use small, neat crosses (×); do not join them unless told to	2–3

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Common Mistakes with Command Words

Describe vs Explain

This is the single biggest source of lost marks.

Command word	What is needed	Example question	Good answer
Describe	Say what happens	"Describe what happens to the temperature."	"The temperature increases from 20 °C to 50 °C over 5 minutes, then remains constant."
Explain	Say what happens and why	"Explain why the temperature increases."	"The temperature increases because the reaction is exothermic, releasing energy to the surroundings."

Exam Tip: If a question says "describe", do not give reasons. If it says "explain", you must give reasons — a description alone will score zero on the "explain" marks.

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Compare — The Two-Sided Rule

When asked to compare, you must mention both items. A statement about only one will not score.

• Wrong: "A catalyst speeds up the reaction."
• Right: "A catalyst speeds up the reaction, whereas without a catalyst the reaction is slower."

Use linking words: whereas, however, both, but, on the other hand.

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Evaluate — Make a Judgement

"Evaluate" is the hardest command word. You need to:

1. List advantages (or evidence for).
2. List disadvantages (or evidence against).
3. Reach a conclusion — which side is stronger and why?

flowchart TD
    A["Read the question"] --> B["List advantages"]
    A --> C["List disadvantages"]
    B --> D["Weigh up both sides"]
    C --> D
    D --> E["Write a clear conclusion<br/>supported by your points"]

Exam Tip: In an "evaluate" question, students who forget the conclusion often drop from Level 3 to Level 2 in the mark scheme. Always finish with a sentence starting "Overall..." or "In conclusion...".

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Calculate — Show Every Step

For "calculate" questions, always:

1. Write the equation (from memory or the equation sheet).
2. Substitute the values with units.
3. Calculate the answer.
4. State the unit of your answer.

Even if you get the wrong final number, you can pick up marks for correct working.