April 14, 2026 • By KayScience
GCSE science command words determine exactly how students should answer a question, and misunderstanding them is one of the most common reasons marks are lost in exams. Examiners across AQA, Edexcel and OCR design questions so that each command word requires a specific type of response, and failing to match this leads to incomplete or incorrect answers.
In practice, this means students can know the content but still lose marks if they do not respond in the way the mark scheme expects.
Definition: GCSE science command words are the key instructions in exam questions (e.g. describe, explain, evaluate) that tell students how to structure their answers to gain marks.
Understanding command words is essential for applying knowledge correctly across GCSE Biology, Chemistry and Physics. Students should reinforce this alongside content revision using the [GCSE Science Revision Hub].
Each command word signals a different expectation in the mark scheme.
Describe → state what happens
Explain → give reasons why something happens
Evaluate → assess strengths, weaknesses and improvements
Compare → identify similarities and differences
Calculate → use a formula and show working
Students often treat these as interchangeable, which leads to lost marks.
For example:
describing when the question asks for explanation limits marks
explaining when only description is needed wastes time
Examiners mark strictly based on the command word.
Understanding how command words appear in real questions is critical.
Example GCSE Question (Chemistry):
Explain how increasing temperature affects the rate of reaction. (4 marks)
As temperature increases, particles gain more kinetic energy. This results in more frequent collisions and a greater number of successful collisions, increasing the rate of reaction.
This answer gains full marks because it:
follows the “explain” command
uses correct terminology (kinetic energy, collisions)
links cause and effect clearly
A common mistake is writing:
“The rate of reaction increases when temperature increases.”
This is a description, not an explanation, and would only gain partial marks.
Students must match the command word precisely.
Students frequently lose marks by misunderstanding what the question requires.
answering a “describe” question with explanations
failing to evaluate in “evaluate” questions
not showing working in “calculate” questions
missing comparisons when asked to compare
Example mistake:
Question: Evaluate a method.
Weak answer:
“The method works well.”
This is insufficient because evaluation requires:
strengths
limitations
improvements
Correct approach:
“The method is valid because it controls variables, but accuracy may be limited due to measurement error. This could be improved by using digital sensors.”
Students should apply a structured method depending on the command word.
give factual statements
no need for reasons
use cause and effect
link ideas logically
identify limitation
explain impact
suggest improvement
state similarities and differences
use comparative language
write formula
show working
include units
A simple but effective strategy is to:
Read the question
Identify the command word
Decide the structure before writing
For example:
“Explain” → plan a chain of reasoning
“Evaluate” → include strengths and weaknesses
This prevents irrelevant answers and improves accuracy.
Students who consistently apply this approach perform better across all question types.
Command words determine how marks are awarded in GCSE science exams.
Students who:
match their answer to the command word
use correct structure
include required detail
are more likely to gain full marks.
Students who ignore command words often:
lose marks despite correct knowledge
write incomplete answers
fail to reach higher mark bands
This is particularly important in extended-response questions, where structure is essential.
Understanding GCSE science command words is only effective if students practise applying them in exam conditions.
Structured tuition provides:
targeted practice across different command words
feedback aligned with mark schemes
correction of common mistakes
reinforcement of exam technique
Students who improve their response structure can gain 10–15 additional marks per paper, which often results in a full grade improvement.
With mock exams approaching, refining how students respond to command words is one of the most effective ways to improve results quickly.
For parents seeking a system that develops both knowledge and exam performance, structured programmes such as [GCSE Science Tuition] provide a more reliable pathway.
What are GCSE science command words?
They are instructions in exam questions that tell students how to answer, such as describe, explain and evaluate.
Do command words affect marks?
Yes. Marks are awarded based on how well the response matches the command word.
How can students improve quickly?
By practising exam questions and focusing on structuring answers correctly.
