📚 Year 7 CIE Science: Case Study Practical Exercises | 七年级CIE科学：案例分析实战演练
Case studies are a vital part of Year 7 CIE Science, helping you apply scientific thinking to real-world scenarios. This guide walks you through the essential skills of observation, hypothesis, experimental design, data analysis, and evaluation, using practical examples tailored for Year 7 learners.
案例分析是七年级CIE科学的重要组成部分，帮助你运用科学思维解决现实问题。本指南将带领你逐步掌握观察、假设、实验设计、数据分析和评估等关键技能，并通过适合七年级学生的实例进行实战演练。
1. What is a Case Study in Science? | 科学中的案例分析是什么？
A case study in science examines a specific scenario or experiment in detail. It requires you to identify the problem, analyse given data, and draw conclusions based on evidence. In Year 7, these exercises build foundational skills for IGCSE sciences.
科学中的案例分析是详细审视某个特定情境或实验。你需要识别问题、分析提供的数据，并依据证据得出结论。在七年级，这些练习为IGCSE科学课程奠定基础技能。
2. The Scientific Method: A Quick Recap | 科学方法：快速回顾
The scientific method is the backbone of any case study. It starts with making observations, asking a question, forming a hypothesis, designing an experiment, collecting data, analysing results, and finally drawing a conclusion.
科学方法是所有案例分析的支柱。它从观察开始，提出问题，形成假设，设计实验，收集数据，分析结果，最后得出结论。
3. Observations and Asking Questions | 观察与提出问题
Good science begins with careful observations. In a case study, you might be given a description or data table. Always note the independent variable (what you change), dependent variable (what you measure), and control variables (what you keep the same). For example, a graph showing plant height over time: the question could be 'How does fertiliser affect growth?'
好的科学始于细心的观察。在案例分析中，你可能会得到一段描述或数据表。始终注意自变量（你改变的）、因变量（你测量的）和控制变量（保持不变的）。例如，一张植物高度随时间变化的图表：问题可能是“肥料如何影响生长？”
4. Forming a Testable Hypothesis | 形成可检验的假设
A hypothesis is an educated guess that links the independent and dependent variables. It should be clear and testable. Example: 'If more fertiliser is added, then the plant will grow taller.' Avoid vague statements. Use 'If… then…' structure for clarity.
假设是一个将自变量和因变量联系起来的科学猜测。它应该清晰且可检验。例如：“如果添加更多肥料，那么植物会长得更高。”避免模糊陈述。使用“如果……那么……”结构使其清晰。
5. Designing a Fair Experiment | 设计公平实验
A fair experiment changes only one variable at a time. Control variables must stay constant. In a case study, identify what should be controlled: temperature, light, amount of water, type of soil, etc. A well-designed experiment also includes a control group for comparison and repeats measurements for reliability.
公平实验每次只改变一个变量。控制变量必须保持不变。在案例分析中，找出应该控制的因素：温度、光照、水量、土壤类型等。精心设计的实验还需包括对照组以作比较，并重复测量以确保可靠性。
6. Collecting and Recording Data | 收集和记录数据
Data can be qualitative (descriptive) or quantitative (numerical). In Year 7 case studies, you often interpret tables and graphs. Learn to read values correctly and note the units. A typical table has columns for the independent variable and rows for repeated trials, with averages calculated at the end.
数据可以是定性的（描述性）或定量的（数值型）。在七年级的案例分析中，你经常需要解读表格和图表。学会准确读取数值并注意单位。典型表格将自变量放在列中，重复试验放在行中，最后计算平均值。
7. Analysing Data: Tables and Graphs | 分析数据：表格和图表
When analysing, look for patterns or trends. For a line graph, describe the relationship: 'As X increases, Y increases steadily.' For bar charts, compare categories. Calculate the mean of repeated trials and identify any anomalous results that don't fit the pattern. Use simple calculations like percentage change if needed.
分析时，要寻找模式或趋势。对于折线图，描述关系：“当X增加时，Y稳定增加。”对于条形图，比较各类别。计算重复试验的平均值，并找出不符合规律的异常结果。必要时可进行简单的百分比变化计算。
8. Drawing Conclusions | 得出结论
A conclusion states whether the results support the hypothesis. It should refer to the data: 'The average height increased from 5 cm to 18 cm with more fertiliser, so the hypothesis is supported.' Never claim to 'prove' a hypothesis; use 'support' or 'refute'. Also, suggest how the experiment might affect the real world.
结论说明结果是否支持假设。它应该引用数据：“随着肥料增加，平均高度从5厘米增至18厘米，因此假设得到支持。”永远不要声称“证明”了一个假设，应使用“支持”或“反驳”。此外，还可以说明实验对现实世界可能产生的影响。
9. Evaluating the Experiment | 评估实验
Evaluation identifies limitations and suggests improvements. Was the range of the independent variable wide enough? Were there enough repeats? Could human error have affected measurements? For example, 'Using a ruler to measure plant height might have introduced parallax error; using a calibrated sensor would improve accuracy.'
评估部分要指出局限性并提出改进建议。自变量的范围够宽吗？重复次数够多吗？人为误差是否影响了测量？例如，“用尺子测量植物高度可能引入视差误差；使用校准传感器会提高准确性。”
10. Case Study Walkthrough: Salt Dissolving | 案例分析实战：盐的溶解
40°C, 60°C, and 80°C, stirring at the same rate. She records the time until no solid is visible. Her results: 20°C → 120 s, 40°C → 85 s, 60°C → 55 s, 80°C → 45 s. Now answer: what is the independent variable? What pattern is shown? Is the 45 s reading reliable? How could she improve the experiment?
阅读以下情境：一名学生研究水温如何影响5克盐的溶解时间。她使用100毫升水，温度分别为20°C、40°C、60°C和80°C，并以相同速率搅拌。她记录直至看不到固体的时间。结果：20°C → 120秒，40°C → 85秒，60°C → 55秒，80°C → 45秒。请回答：自变量是什么？显示出什么规律？45秒的读数可靠吗？她如何改进实验？
Independent variable: water temperature. Pattern: as temperature increases, dissolving time decreases. The 45 s data point fits the trend but only one trial was done; repeating each temperature three times would reveal any outliers and allow calculation of an average. To improve, use a thermometer accurate to 0.5°C and stopwatch with repeat timings.
自变量：水温。规律：随着温度升高，溶解时间减少。45秒的数据点符合趋势，但只进行了一次试验；每个温度重复三次可以发现异常值并计算平均值。改进方法：使用精确至0.5°C的温度计，并用秒表重复计时。
11. Common Mistakes to Avoid | 要避免的常见错误
Many students confuse independent and dependent variables. Remember: independent is what you deliberately change; dependent is what you measure as a result. Also, avoid drawing a conclusion that goes beyond the data. Finally, don't forget to label axes on graphs and include units for all measurements.
许多学生会混淆自变量和因变量。记住：自变量是你有意改变的，因变量是你测量的结果。此外，避免得出超出数据范围的结论。最后，别忘了在图表上标记坐标轴，并为所有测量值加上单位。
12. Practice Tips for Success | 成功练习技巧
To excel in case study questions, practise with past papers or create your own mini-investigations. For any data set, ask yourself: 'What is the question? What remains constant? Is there a control? Can I spot an anomaly?' Reviewing these steps regularly will make your analysis faster and more accurate during tests.
要在案例分析题中脱颖而出，请使用历年真题进行练习，或自行设计小型探究。对于任何一组数据，问自己：“问题是什么？哪些保持不变？有对照组吗？我能发现异常值吗？”定期复习这些步骤，你在考试中的分析将更快、更准确。
Published by TutorHao | Science Revision Series | aleveler.com
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