📚 9630 International A-Level Physics Command Words Explained | 9630国际A-Level物理命令词解析
Command words in Edexcel International A-Level Physics (9630) are the instructional terms that tell you exactly what the examiner expects in your answer. Misreading a single word – for example, writing a description where an explanation is required – can lose marks even when your physics knowledge is sound. This guide breaks down every core command word, pairs it with a clear definition of the response depth, and provides physics-specific examples so that you can tackle any question with precision and confidence.
指令词是爱德思国际A-Level物理(9630)试卷中告诉考生应该如何作答的关键术语。如果误读一个词——比如把“解释”当成“描述”——就算物理概念正确也可能丢分。本指南逐一拆解核心命令词，给出每个词所要求的答题深度，并配以物理场景示例，帮助你有条理、准确地应对每一道考题。
1. What are Command Words? | 什么是命令词？
Command words are the active verbs placed at the start of a question or task. They define the cognitive skill being tested – from simple factual recall to high-level evaluation. In 9630 Physics papers, these words are used consistently across all units (Mechanics, Electricity, Waves, Fields, Nuclear Physics, etc.) and across multiple choice, short-answer and long-answer questions. Understanding them is as important as knowing the equations.
命令词是题目开头出现的动词，界定了要考查的认知层次——从简单的知识再现到高阶评价。在9630物理试卷中，这些词贯通力学、电学、波动、场、核物理等所有单元，在选择题、简答题和长答题中重复出现。理解命令词与掌握公式同等重要。
For example, a question may ask you to state Hooke's law, describe an experiment to measure the Young modulus, or evaluate the accuracy of a student's data. Each task demands a completely different type of response. If you treat them equally, you will lose the depth marks that distinguish A* candidates from B candidates.
例如，一道题可能要求你“陈述”胡克定律，“描述”测量杨氏模量的实验，或者“评价”某学生数据的准确度。这些任务要求的回答方式完全不同。如果一概而论，你就会丢掉那些区隔A*与B等级的关键深度分。
2. State and Define | 陈述与定义
State asks for a concise factual answer. No explanation, no reasoning – just the final result, law, or quantity. In physics, you often state a law, a value read from a graph, or a simple outcome.
陈述 (State) 要求给出简洁的事实答案，无需解释或推理，只需给出最终结果、定律或物理量。物理题中常用来陈述定律、从图上读出的数值或简单结论。
Example: “State the principle of conservation of momentum.” Answer: The total momentum of a closed system remains constant provided no external forces act.
例题：“陈述动量守恒定律。”答案：在无外力作用的封闭系统中，总动量保持不变。
Define asks for the precise meaning of a term or quantity. You should give a formal definition, often including the key equation in words or symbols.
定义 (Define) 要求给出术语或物理量的准确含义，通常需要包含口头表述或符号式的关键公式。
Example: “Define electric field strength.” Answer: Electric field strength at a point is the force per unit positive charge experienced by a small test charge placed at that point, given by E = F/q.
例题：“定义电场强度。”答案：电场中某点的电场强度等于放置在该点的单位正电荷所受的力，数学表示为 E = F/q。
3. Describe and Outline | 描述与概述
Describe requires you to give a detailed account of what happens, what you observe, or how an experiment is set up. You do not need to explain why it happens unless the question explicitly adds “and explain”. In a practical context, you should include any precautions and measurements, but not the physics theory behind them.
描述 (Describe) 要求详细叙述发生了什么、观察到什么现象，或实验如何搭建。除非题目明确要求“并解释”，否则无需说明原因。在实验题中，应写明步骤、测量量和注意事项，而不必细述背后的物理理论。
Example: “Describe an experiment to determine the acceleration of free fall using a pendulum.” Your answer should mention the length of the string, timing for multiple oscillations, and how to plot T² against l.
例题：“描述利用单摆测定重力加速度的实验。”答案应提及绳长、多次摆动计时，以及如何绘制 T²-l 图像。
Outline is a lighter version of describe – you only need the main steps or key points, without fine detail.
概述 (Outline) 是“描述”的简化版，只需要写出主要步骤或要点，无需细致展开。
4. Explain and Discuss | 解释与讨论
Explain asks you to give reasons or mechanisms. You must link causes to effects, often using physical principles, equations, or energy transfers. Explanations in physics typically follow a logical chain: “because… therefore…”.
解释 (Explain) 要求给出原因或机理，必须用物理原理、方程或能量转化将因果联系起来。物理解释通常遵循逻辑链：“因为……所以……”。
Example: “Explain why a satellite in a higher orbit has a longer period.” You should refer to v = √GM/r and the circumference, or directly to Kepler's third law T² ∝ r³.
例题：“解释为什么较高轨道的卫星周期更长。”你需要引用 v = √GM/r 和轨道周长，或直接用开普勒第三定律 T² ∝ r³ 来说明。
Discuss goes further: it usually asks you to present both sides of an argument, identify advantages and disadvantages, or explore the validity of a model. An answer without any critical balance rarely scores full marks.
讨论 (Discuss) 要求更高：通常需要呈现双方观点、分析优缺点或审视模型的有效性。缺乏辩证平衡的答案很少能得满分。
5. Calculate and Determine | 计算与确定
Calculate means you must perform a numerical computation, showing your working clearly. The final answer should include the correct unit and appropriate significant figures. Substitutions into a formula must be explicit.
计算 (Calculate) 要求你进行数值运算，并清晰展示步骤。最终答案需包含正确单位和合理的有效数字。代入公式的过程必须明确写出。
Example: “Calculate the de Broglie wavelength of an electron accelerated through 100 V.” Start with λ = h/p, then p = √2meV, and substitute values to reach about 1.2 × 10⁻¹⁰ m.
例题：“计算被100 V电压加速的电子的德布罗意波长。”从 λ = h/p 入手，再由 p = √2meV 代入数值，得到约 1.2 × 10⁻¹⁰ m。
Determine is broader: it can include reading a graph, using an intercept, or applying geometric reasoning to find a quantity. You should still show the method, even if the calculation is simple.
确定 (Determine) 含义更广，可包括从图上读取、利用截距或通过几何推理找出某个量。即便计算简单，也需显示方法。
6. Show that and Prove | 证明与推导
Show that asks you to derive a given result, usually step by step. You must convince the examiner that you can replicate the logic, not just write the final line. All algebraic manipulation must be shown; omission of a key step will lose marks.
证明 (Show that) 要求一步步推导出给定结果。你必须让考官看到完整的逻辑再现，而非仅仅写出最后一行。所有代数操作需呈现，遗漏关键步骤会失分。
Example: “Show that the centripetal acceleration is given by a = v²/r.” Use vector diagrams or small-angle approximations for the change in velocity over a short time.
例题：“证明向心加速度表达式为 a = v²/r。”使用矢量图或小角度近似导出短时间内速度的变化。
Prove is rarer and usually appears in mathematical modules; in physics it demands a rigorous derivation, often from first principles. Treat it like “show that” but be extra thorough.
推导 (Prove) 较少见，通常在数学模块出现；在物理中要求从第一性原理出发进行严格论证。视同“证明”，但需更全面。
7. Compare and Contrast | 比较与对比
Compare asks you to identify similarities and differences between two or more things. A table can be an efficient way to present comparative features, but you must still write at least one summarizing sentence that highlights the key distinctions.
比较 (Compare) 要求指出两个或多个事物之间的相似与相异。用表格呈现对比项效率很高，但至少仍须写出一句总结性的关键差异。
Example: “Compare the gravitational field and the electric field due to a point mass and a point charge.” Mention both follow inverse-square laws, but gravitational field is always attractive while electric field can be attractive or repulsive.
例题：“比较点质量产生的引力场与点电荷产生的电场。”既要提及二者均遵循平方反比定律，又要指出引力场只有吸引，电场可吸引可排斥。
Contrast focuses exclusively on the differences. If a question says “compare and contrast”, you must cover both aspects.
对比 (Contrast) 只聚焦于差异。若题目要求“比较与对比”，则两方面均须覆盖。
8. Evaluate and Assess | 评估与评价
Evaluate is a high-order skill. You must make a judgement, backed by evidence and physical reasoning. In an experiment, this might involve commenting on sources of error, reliability, and whether a conclusion is supported by the data. Use phrases like “this is valid because… however, a limitation is…”.
评估 (Evaluate) 属高阶能力。你必须给出判断，并以证据和物理推理支撑。在实验中可能涉及误差来源、信度和数据是否支持结论。用诸如“这成立因为……但其局限是……”的结构。
Example: “Evaluate the student's claim that the pendulum period does not depend on mass.” Discuss the independence in simple harmonic motion, but note the possible effect of air resistance or the mass of the string if not ideal.
例题：“评价学生关于单摆周期与质量无关的说法。”讨论简谐运动中的无关性，但指出非理想情况下空气阻力或绳子质量的可能影响。
Assess is similar; it asks you to weigh up the importance or reliability of something and offer a reasoned conclusion.
评价 (Assess) 类似，要求你权衡某事物的重要性或可靠性，并给出有依据的结论。
9. Suggest and Predict | 建议与预测
Suggest usually appears in unfamiliar contexts or practical problems. You are expected to apply your physics knowledge creatively to propose a plausible explanation or method. There is often no single “right” answer, but your reasoning must be physically sound.
建议 (Suggest) 常出现在陌生情境或实际问题中。你需要创造性地运用物理知识提出合理的解释或方法。没有唯一标准答案，但推理必须符合物理原理。
Example: “Suggest why the resistance of a filament lamp increases with current.” Your answer can refer to lattice vibrations, increased collisions, and temperature dependence.
例题：“建议说明为什么白炽灯灯丝的电阻随电流增大而增大。”答案可提及晶格振动加剧、碰撞增加及温度依赖性。
Predict requires you to state what will happen under given conditions, often using a trend in a graph or an equation. Support your prediction with a brief reason.
预测 (Predict) 要求你指出在给定条件下会发生什么，常基于图表趋势或方程，并用简短的原理佐证。
10. Sketch, Draw and Plot | 草图、绘制与描点
Sketch a graph means you do not need to plot exact points, but you must show the overall shape, axes labels, and key features such as intercepts, asymptotes or turning points. In physics, sketching also includes indicating the correct curvature (e.g., exponential decay vs. straight line).
草图 (Sketch) 图像无需精确描点，但必须显示整体形状、坐标轴标签和关键特征，如截距、渐近线或极值点。物理作图中还要体现正确的曲率走向（如指数衰减还是直线）。
Draw can refer to a diagram (like a free-body force diagram) or a precisely plotted graph. When drawing vector diagrams, arrows must be to scale where possible and labelled clearly.
绘制 (Draw) 可指示意图（如受力分析图）或精确绘制的图像。画矢量图时，箭头尽可能按比例，并清晰标注。
Plot specifically tells you to transfer data points onto a grid, usually with crosses or dots, and often to draw a best-fit line afterwards.
描点 (Plot) 专指将数据点标记在网格纸上，通常用叉号或圆点，并常要求随后画出最佳拟合线。
11. Analyse and Deduce | 分析与推断
Analyse requires you to break down information or data into components, identify patterns, and relate them to physical principles. You may need to calculate gradients, use the area under a graph, or interpret logarithmic plots. The outcome is typically a reasoned interpretation, not just raw numbers.
分析 (Analyse) 要求你将信息或数据拆解为组成部分、识别规律并与物理原理相联系。可能需要计算斜率、使用图像下方面积或解读对数坐标图。最终应给出有理有据的解读，而非仅罗列原始数值。
Example: “Analyse the motion of a ball thrown vertically upwards from a velocity–time graph.” State where acceleration is constant, where velocity is zero, and link area to displacement.
例题：“分析竖直上抛小球的速度–时间图像。”指出何处加速度恒定、何处速度为零，并将面积与位移关联。
Deduce means you are to reach a conclusion from given data or a statement, using physics reasoning. It is a stepping-stone between “calculate” and “explain”.
推断 (Deduce) 指根据给定数据或陈述，利用物理推理得出一个结论。它是“计算”与“解释”之间的桥梁。
12. Justify and Comment | 论证与评论
Justify demands that you give evidence or reasoning to support a decision, design choice, or conclusion. It goes beyond a simple explanation by adding a layer of persuasion: why your chosen method is suitable, or why a particular assumption is acceptable.
论证 (Justify) 要求你用证据或推理支撑一个决定、设计选择或结论。它超越简单解释，上升为说服力：为什么你选的方法合适，或为什么某个假设可以接受。
Example: “A student uses a motion sensor connected to a data logger to measure the acceleration of a trolley. Justify the use of this equipment.” Mention high sampling rate, reduction of human reaction time error, and immediate graph plotting.
例题：“某学生用连接到数据记录器的运动传感器测量小车的加速度。论证这一设备的使用。”提及高采样率、减少人为反应时间误差和即时绘图功能。
Comment is a lighter version of evaluate; it asks you to note observations or make a brief judgement, usually linked to a given statement or graph.
评论 (Comment) 是评估的轻量版，要求你指出观察结果或给出简短判断，常联系给定的陈述或图像。
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