What do the GCSE Science command words actually mean?

What do the GCSE Science command words actually mean?

Many students know the science content well, but struggle to interpret exactly what exam questions are asking. This often makes it difficult to demonstrate their knowledge effectively.

One of the most common mistakes is confusing “describe” with “explain.”

• Describe means to state what you see or outline the process (what is happening) .

• Explain requires you to go further, giving the scientific reasoning behind why it happens.

To help with this, we’ve created a clear and comprehensive list of GCSE Science command words, complete with examples of what examiners expect in your answers.

Top tip: Always underline or highlight the command words in the question. It keeps you focused and makes sure your answer matches exactly what’s being asked.

You can download a pdf here

Balance
You must balance a chemical equation so the number of atoms of each element is the same on both sides.
Example (Chemistry):
Balance: __ H₂ + O₂ → H₂O
Answer: 2H₂ + O₂ → 2H₂O

Calculate
Use the numbers in the question to work out an answer.
Example (Physics):
Calculate the speed of a car that travels 150 m in 12 s.
Answer: Speed = distance ÷ time = 150 ÷ 12 =12.5 m/s

Choose
Pick the correct answer from options provided.
Example (Biology): Choose the organelle where aerobic respiration takes place.
A) Nucleus B) Ribosome C) Mitochondrion
Answer: C) Mitochondrion

Compare
Describe similarities and differences.
Example (Biology): Compare a motor neurone and a sensory neurone.
Answer: Both transmit electrical impulses.
Motor neurones carry impulses to muscles; sensory neurones carry impulses from receptors.

Complete
Fill in missing information in a table, sentence, or diagram.
Example (Chemistry): Complete the table by adding the relative formula mass (Mr) of CO₂.
Answer: Mr of CO₂ = 12 + (16 × 2) =44

Define
Give the precise meaning of a word.
Example (Biology): Define “diffusion.”
Answer: The movement of particles from an area of high concentration to an area of low concentration.

Describe
State the key facts —what happens.
Example (Physics): Describe how the velocity of an object changes when it accelerates.
Answer: Its velocity increases over time.

Design
Set out a clear plan or method.
Example (Biology): Design an investigation to test how light intensity affects photosynthesis.
Answer (short model): Use a lamp at different distances from pondweed. Count bubbles produced in 1 minute at each distance.
(Note this is usually 4-6 marks, the example above would only give you 1 mark)

Determine
Use the given data to find an answer.
Example (Physics): Determine the resistance of a component using a V–I graph.
Answer: Resistance = gradient = voltage ÷ current (value depends on the graph)

Draw
Produce or add to a diagram.
Example (Biology): Draw and label a bacterium.
Answer: Sketch showing cell wall, cell membrane, cytoplasm, plasmids, and circular DNA.

Estimate
Give an approximate value.

Example (Physics): Estimate the wavelength of the wave shown.
Answer:Approximately2 cm(value depends on diagram)

Evaluate
Give strengths, weaknesses, and a reasoned conclusion.
Example (Biology): Evaluate the use of vaccines to control disease.
Answer: Vaccines reduce spread and protect vulnerable people. They may have side effects and require high uptake. Overall, vaccines are highly effective in controlling disease.

Explain
Give reasons —why something happens.
Example (Chemistry): Explain why increasing temperature increases the rate of reaction.
Answer: Particles move faster, collide more often, and with more energy, increasing successful collisions.

Give
Short answer only.
Example (Biology): Give one function of red blood cells.
Answer: Transports oxygen.

Identify
Pick out or name the correct answer.
Example (Physics): Identify the energy store that decreases when a car brakes.
Answer: Kinetic energy store.

Justify
Use evidence to support your answer.
Example (Biology): Justify which habitat the organism is best adapted to using the data.
Answer: It is best adapted to Habitat B because the data shows higher survival and faster reproduction there.

Label
Add names to a diagram.
Example (Biology): Label the parts of the heart.
Answer: Right atrium, right ventricle, left atrium, left ventricle, aorta, vena cava, pulmonary artery, pulmonary vein.

Measure
Find a numerical value using a scale.
Example (Physics): Measure the spring’s extension from the graph.
Answer:4.0 cm (value depends on graph)

Name
Short answer — usually one word.
Example (Chemistry): Name the ion O²⁻.
Answer: Oxide ion.

Plan
Write a clear method.
Example (Physics): Plan an experiment to investigate how force affects acceleration.
Answer (short model): Use a trolley on a track with a force applied by hanging masses. Measure acceleration using a light gate.
(Note this is usually 4-6 marks, the example above would only give you 1 mark).

Plot
Place points accurately on a graph.
Example (Physics): Plot current–voltage data for a filament lamp.
Answer: Points plotted accurately; curve showing resistance increasing as current increases.

Predict
State what is likely to happen.
Example (Biology): Predict how photosynthesis changes if CO₂ concentration increases.
Answer: Rate will increase until another factor becomes limiting.

Show
Give steps or calculations.
Example (Physics): Show that the resultant force is 6 N.
Answer: If 10 N acts forward and 4 N acts backward: 10 – 4 =6 N

Sketch
Draw an approximate graph or diagram.
Example (Physics): Sketch the I–V graph for a diode.
Answer: Flat near zero (no current), then a steep rise after the threshold voltage.

Suggest
Apply your knowledge to a new situation.
Example (Chemistry): Suggest why gas pressure increases in a sealed container.
Answer: Particles move faster and collide with the walls more often.

Use
Use the information in the question.
Example (Biology): Use the graph to explain how body temperature changes during exercise.
Answer: According to the graph, body temperature rises steadily for 10 minutes, then levels off.

Write
Short answer only.
Example (Chemistry): Write the formula for magnesium chloride.
Answer: MgCl₂

“Failure is success if we learn from it.” – Malcolm Forbes