How to Use Command Terms Correctly

Why Command Terms Decide Your Grade

Every IB Physics question begins with a command term. That term tells you exactly what the examiner expects. Misinterpreting it is like answering a different question — you’ll write correct physics but receive zero marks.

The IB categorises command terms into three Assessment Objective levels:

AO1: Knowledge and Understanding

These command terms ask you to recall information:

State

Give a specific name, value, or brief answer. No explanation needed.

• ✅ “State Newton’s third law.” → “When body A exerts a force on body B, body B exerts an equal and opposite force on body A.”
• ❌ Writing a paragraph about Newton’s laws (wastes time, no extra marks)

Define

Give the precise meaning of a word, term, or concept, ideally in the form used in the IB Physics syllabus.

• ✅ “Define specific heat capacity.” → “The energy required to raise the temperature of 1 kg of a substance by 1 K.”
• ❌ Giving an example instead of a definition

List

Give a sequence of brief answers with no explanation. Think bullet points.

Draw / Label

Produce or add to a diagram. Must be accurate, neat, and labelled where required.

AO2: Application and Analysis

These require you to use your knowledge:

Calculate

Find a numerical answer showing your working. The expected structure:

1. State the equation
2. Substitute values with units
3. Give the final answer with correct units and appropriate significant figures

Determine

Similar to “calculate” but you must first extract information from a graph, table, or diagram before performing the calculation.

Estimate

Make an approximate calculation. You may need to make reasonable assumptions (e.g., mass of a person ≈ 70 kg). State your assumptions explicitly.

Sketch

Draw a graph showing the general shape and key features (intercepts, asymptotes, maxima/minima). Exact values are not required unless specified.

Show that

Prove a given result using logical steps. You must show every step — the answer is already given, so the marks are entirely for your working.

Critical: Use at least one more significant figure than the given answer in your intermediate steps.

AO3: Synthesis and Evaluation

These require the deepest thinking:

Explain

Give a detailed account including reasons or causes. An explanation must contain a causal chain:

Template: [Physics principle] → [How it applies here] → [What happens as a result]

• ✅ “The current decreases because the resistance of the filament increases as temperature rises (R ∝ T for metals), and since V is constant, I = V/R must decrease.”
• ❌ “The current decreases because resistance increases.” (No causal mechanism — earns 1/3 at best)

Discuss

Present multiple viewpoints or consider different aspects. A strong “discuss” answer includes:

1. Arguments for and against
2. Advantages and limitations
3. A concluding statement weighing the evidence

Evaluate

Make an appraisal by weighing up strengths and limitations. Common in experimental contexts:

• Identify sources of error (systematic and random)
• Assess whether the data supports the hypothesis
• Suggest specific, practical improvements

Analyse

Break down information into component parts, find patterns, and identify relationships. Often requires calculations to support your analysis.

Deduce

Reach a conclusion by considering the given information logically. Your reasoning must be explicit.

The Command Term Decision Matrix

When you read a question, ask yourself:

Common Pitfalls

1. Over-answering “State” questions: Writing 5 sentences when 1 is needed. You waste time and gain no extra marks.

2. Under-answering “Explain” questions: Writing “because the force increases” without saying why. Always complete the causal chain.

3. Treating “Determine” like “Calculate”: Forgetting to show how you extracted values from the graph or data.

4. Ignoring “Suggest”: “Suggest” means the answer isn’t directly in the syllabus. You need to apply your knowledge creatively. There may be multiple acceptable answers.

5. Panicking at “Deduce”: This just means “figure it out from the information given.” Take a breath, read the data, and reason logically.