📚 AS Physics Unit 2 Mark Scheme June 2019: Experiment and Investigation Skills | AS 物理 Unit 2 2019年6月评分标准：实验探究技巧
For many students, the experiment-based questions in AS Physics Unit 2 are the most challenging part of the exam. The June 2019 mark scheme offers a clear window into exactly what examiners reward: precise scientific vocabulary, logical sequencing of steps, and a rigorous approach to uncertainties. This article unpacks the experimental skills assessed in that session and shows you how to turn a good experiment description into high marks.
对许多学生来说，AS物理单元2中的实验题是考试中最具挑战性的部分。2019年6月的评分标准清晰地展示了考官究竟给分在哪儿：精确的科学用语、步骤的逻辑顺序以及对不确定度的严谨处理。本文剖析了那次考试中评估的实验技能，并教你如何将一段不错的实验描述转化为高分答案。
1. Overview of the June 2019 Unit 2 Mark Scheme | 2019年6月单元2评分标准概览
The Unit 2 mark scheme from June 2019 is structured around three assessment objectives: knowledge of experimental procedures, handling and analysing data, and evaluating evidence. Marks are allocated for specific details rather than vague intentions. For instance, saying 'measure the diameter' may score zero, but 'measure the diameter in three perpendicular directions using a micrometer screw gauge' earns the precision mark.
2019年6月单元2评分标准围绕三个评价目标构建：实验流程的知识、数据的处理与分析、证据的评估。分数是按具体的细节而非笼统的意图给出的。比如，说“测量直径”可能得零分，而“用千分尺在三个相互垂直的方向上测量直径”就能拿到精确测量的分数。
2. Understanding the Experiment Question Structure | 理解实验题结构
A typical experiment question in this paper is split into three parts: planning (designing a valid method), implementation (recording and processing results), and evaluation (identifying sources of uncertainty and suggesting improvements). The mark scheme shows that each part follows a tightly defined hierarchy of marks, where later points often depend on earlier ones.
典型的实验题通常分成三个部分：设计（设计合理的方法）、实施（记录并处理结果）和评估（识别不确定度来源并提出改进）。评分标准显示，每个部分都遵循严格定义的分值层级，后面的得分点往往依赖于前面的得分点。
3. Key Command Words in Mark Schemes | 评分方案中的关键指令词
Command words such as 'describe', 'explain', 'determine', and 'evaluate' each trigger a different expected response. The June 2019 mark scheme expects a 'describe' answer to list steps with instruments, an 'explain' to give a physical reason, and an 'evaluate' to discuss both strengths and weaknesses. Misreading a command word is one of the most common reasons for losing marks even when the physics is correct.
像“描述”、“解释”、“确定”和“评估”这样的指令词，各自对应不同的预期回答。2019年6月的评分标准要求，“描述”要列出带有仪器的步骤，“解释”要给出物理上的理由，“评估”则要讨论优缺点。即使物理内容正确，误解指令词也是最常见的丢分原因之一。
4. Designing an Experiment: Variables and Controls | 设计实验：变量与控制
A high-scoring plan identifies the independent, dependent, and control variables unambiguously. The June 2019 mark scheme rewards statements like 'keep the length of the wire constant at 1.000 m measured by a metre rule' over just 'keep length constant'. It also insists on a method that produces a linear relationship, such as plotting T² against L for a pendulum, so that a straight-line graph can verify the theory.
一份高分实验设计会明确地指出自变量、因变量和控制变量。2019年6月的评分标准给分给的是“用米尺测量，使金属丝长度恒定为1.000米”这样的表述，而不是简单的“保持长度不变”。它还要求方法能产生线性关系，例如绘制单摆的T²-L图，从而用直线图像验证理论。
5. Measurement Techniques and Precision | 测量技术与精度
Examiners look for the most appropriate instrument for each quantity. In the June 2019 scheme, using a micrometer for thickness (0.01 mm resolution), a digital calliper for diameter, and a travelling microscope for small displacements all appear as credited answers. Stating the instrument alone is not enough; you must also describe how to use it to reduce random error, such as taking repeat readings and averaging.
考官寻找每个量所用的最合适的仪器。在2019年6月的评分标准中，使用千分尺测厚度（0.01毫米分辨率）、用数显卡尺测直径、用移测显微镜测微小位移，这些都属于得分点。仅写出仪器是不够的，你还必须描述如何使用它来减少随机误差，例如多次读数取平均值。
6. Data Recording and Table Design | 数据记录与表格设计
The mark scheme explicitly checks that tables have correct headings with units separated by a solidus or brackets, e.g. 'd / mm' or 'd (mm)'. All raw data must be recorded to the instrument's precision, and repeated readings columns must be present. Consistent significant figures in calculated quantities are also essential. A mark can be lost if a value of 0.020 is incorrectly written as 0.02 when the instrument reads to three decimal places.
评分标准会明确检查表格是否有正确的表头，单位用斜线或括号隔开，例如“d / mm”或“d (mm)”。所有原始数据必须记录到仪器的精度，并且必须有重复读数的列。计算量的有效数字前后一致也至关重要。如果仪器读数精度到三位小数，把0.020错误地写成0.02，就可能丢分。
7. Graph Plotting and Analysis | 绘图与数据分析
Graph work in the June 2019 mark scheme is marked against several criteria: axes labelled with quantities and units, sensible scales that use more than half the grid, accurately plotted points, and a best-fit straight line or smooth curve. When determining the gradient, the scheme requires a large triangle with coordinates read from the line, not from data points, and the final gradient stated with appropriate units.
2019年6月评分标准中的图形题按照几个标准评分：坐标轴标有物理量和单位、合理的标尺能使用一半以上的网格、点描画准确、以及一条最佳拟合直线或光滑曲线。在计算斜率时，标准要求取一个大三角形，坐标从线上读取，而不是来自数据点，最后给出带有适当单位的斜率值。
8. Calculating Uncertainties and Percentage Errors | 计算不确定度与百分误差
ent, add percentage uncertainties; for a power, multiply by the power. If the measurement is the diameter of a wire and the cross-sectional area is needed, the mark scheme expects the percentage uncertainty in area to be twice that in diameter, e.g. if Δd/d = 2%, then ΔA/A = 4%.
试题经常要求计算导出量的百分不确定度。评分标准接受的是不确定度的合成：对于乘除运算，百分不确定度相加；对于乘方，乘以指数。如果测量的是导线直径而需要横截面积，评分标准期望面积的不确定度百分比是直径的两倍，例如若Δd/d = 2%，则ΔA/A = 4%。
9. Evaluating the Experiment: Limitations and Improvements | 评估实验：局限性与改进
Evaluation marks hinge on linking a specific limitation to a specific improvement. Saying 'there was a parallax error' only scores if you then suggest 'use a set square to align the eye perpendicular to the scale' or 'use a digital sensor'. The June 2019 mark scheme frequently awards marks for practical, implementable suggestions rather than unrealistic ones like 'do the experiment in a vacuum'.
评估部分的得分取决于能否将具体的局限性联系到具体的改进措施上。说“存在视差误差”只有在紧接着提出“用三角尺使视线垂直于刻度”或“使用数字传感器”时才得分。2019年6月评分标准常常给那些实用、可操作的建议加分，而不是像“在真空中实验”这类不现实的建议。
10. Common Pitfalls Highlighted by Mark Schemes | 评分标准揭示的常见错误
June 2019 examiner reports reveal that students frequently lose marks by omitting units from calculated values, failing to check that a wire is horizontal before measuring, or describing a method that does not actually vary the independent variable systematically. The mark scheme explicitly withholds marks for 'several' or 'different' values without specifying a range and number, such as 'take readings for at least six lengths from 0.200 m to 1.000 m'.
2019年6月的考官报告揭露，学生经常因遗漏计算值的单位、测量前未检查导线是否水平，或描述的方法并未系统地改变自变量而丢分。评分标准明确不会给“几个”或“不同的”数值加分，除非具体说明了范围和数量，例如“至少对0.200米到1.000米之间的六个长度进行读数”。
11. Using the Mark Scheme for Effective Revision | 利用评分标准高效复习
Active revision with a mark scheme means recreating perfect answers. Read a past paper experiment question, attempt a plan, then compare your language with the mark scheme's phrasing. Notice how the scheme uses phrases like 'measure the angle using a protractor with a resolution of 1°' and how it structures logical sequencing. Gradually, you internalise the vocabulary that consistently appears, such as 'light gate', 'fiducial marker', 'repeat and calculate mean'.
带着评分标准主动复习，意味着要还原出完美的答案。读一道往年实验题，试着自己设计，然后将你的用语与评分标准的措辞进行比较。注意评分标准如何使用“用量角器测量角度，分辨率为1°”这样的短语，以及它如何安排逻辑顺序。渐渐地，你就会内化那些频繁出现的词汇，比如“光闸”、“参考标记”、“重复并计算平均值”。
12. Conclusion: Mastering Experimental Skills for Top Marks | 结语：掌握实验技能取得高分
The June 2019 Unit 2 mark scheme confirms that experimental questions are not a test of creativity but of precision, clarity, and systematic thinking. By learning the examiner's language and understanding exactly what each marking point demands, you can turn these questions from a source of anxiety into a highly predictable opportunity to secure full marks.
2019年6月单元2的评分标准证实了，实验题不是在考创意，而是在考精确性、清晰度和系统思维。通过学习考官的语言并确切理解每个得分点的要求，你可以把这些题目从焦虑的来源转变为完全可以预测的获得满分的机会。
Published by TutorHao | Physics Revision Series | aleveler.com
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