📚 Year 7 WJEC Science: Case Study Practical Exercises | 七年级WJEC科学：案例分析实战演练
In Year 7 WJEC Science, case studies are a common way to test your investigative skills. You are given a real-world experimental scenario and asked to think about variables, data and improvements. This type of question pushes you to work like a practising scientist, not just recall facts. In this article, we will work through a detailed case study together and then give you some practice tasks to build your confidence.
在七年级WJEC科学中，案例分析是测试你探究技能的常见方式。你会看到一个真实世界的实验情景，并被要求思考变量、数据和改进之处。这类问题推动你像真正的科学家一样工作，而不仅仅是回忆事实。在本文中，我们将一起详细分析一个案例，然后给你一些练习任务来建立信心。
1. Introduction to Case Studies in Science | 科学案例分析简介
A scientific case study is a short story about an experiment. Your job is to read it carefully, extract the key information and answer questions about how the investigation was designed, whether it was a fair test and what the results can tell us. Marks are given for using correct scientific words and for linking your ideas to the specific context.
科学案例分析是一段关于实验的简短故事。你的任务是仔细阅读，提取关键信息，并回答关于实验设计、是否公平测试以及结果能告诉我们什么的问题。评分依据包括使用正确的科学词汇以及将你的想法与具体情境联系起来。
In WJEC assessments, typical case study questions ask you to identify the independent variable (the one you change), the dependent variable (the one you measure) and at least two control variables (things you keep the same). You may need to spot mistakes in the method, complete a results table, draw a graph, write a conclusion and suggest improvements. The more you practise, the easier it becomes to spot these details quickly.
在WJEC评估中，典型的案例分析问题会要求你识别自变量（你改变的变量）、因变量（你测量的变量）以及至少两个控制变量（你保持不变的因素）。你可能需要找出方法中的错误、完成结果表、绘制图表、写出结论并提出改进建议。练习越多，你就能越快地发现这些细节。
2. The Scenario: Salty Seeds Experiment | 案例情景：盐水种子实验
Alex was curious about how salt in soil might affect plants. She decided to investigate the effect of different concentrations of salt water on the germination of mung bean seeds. She prepared four solutions: 0% salt (pure water), 5%, 10% and 15% salt by mass. For each concentration, she placed a piece of damp paper towel into a Petri dish, added exactly 10 mung bean seeds and poured in 15 ml of the solution. The dishes were labelled and placed on the same windowsill at room temperature. Every day she checked the dishes and added a little more of the same solution if the paper towel looked dry. After 5 days, she counted the number of seeds that had produced a visible root. Alex repeated the entire experiment three times to check her results.
Alex好奇土壤中的盐分会如何影响植物。她决定研究不同浓度的盐水对绿豆种子发芽的影响。她配制了四种溶液：0%盐（纯水）、5%、10%和15%盐（按质量计）。对于每种浓度，她将一片湿纸巾放入培养皿中，放入恰好10粒绿豆种子，并倒入15毫升溶液。培养皿被贴上标签并放在同一个室温的窗台上。每天她检查培养皿，如果纸巾看起来干了就再添加少量同种溶液。5天后，她数出已长出可见根的种子数量。Alex将整个实验重复了三次，以核对她的结果。
3. Identifying the Aim and Hypothesis | 确定目的与假设
The aim is a simple statement of purpose. Here, the aim was: 'To investigate how salt concentration affects the germination of mung bean seeds.' A hypothesis is a testable prediction. You can write it in the 'If... then... because...' format to show your scientific reasoning. For example, Alex could have written: 'If the concentration of salt is increased, then fewer seeds will germinate because salt reduces the ability of seeds to absorb the water they need for growth.'
目的是一句简单的意图陈述。这里的目的是：“探究盐浓度如何影响绿豆种子的发芽。”假设是一个可检验的预测。你可以用“如果……那么……因为……”的格式来写，以展示你的科学推理。例如，Alex可以这样写：“如果盐浓度升高，那么发芽的种子会更少，因为盐降低了种子吸收生长所需水分的能力。”
In a WJEC answer, you must state your hypothesis clearly and make sure it links the independent and dependent variables. Avoid saying 'I think' - instead, phrase it as an expected outcome based on science.
在WJEC的答案中，你必须清楚地陈述假设，并确保它将自变量和因变量联系起来。避免使用“我想
Published by TutorHao | Year 7 Science Revision Series | aleveler.com
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