📚 Case Study Practical Exercises in KS3 OCR Engineering | KS3 OCR 工程：案例分析实战演练
Engineering at KS3 is all about learning how things work, designing solutions and testing ideas through hands-on projects. This article takes you through a series of case study practical exercises that mirror the OCR approach, helping you develop key skills in analysis, design, making and evaluation. By working through real-world inspired challenges, you will see how engineers think and how classroom activities connect to everyday technology.
KS3 阶段的工程课核心在于了解事物的运作原理、设计解决方案并通过动手项目测试想法。本文将通过一系列案例分析实战演练，反映 OCR 的课程思路，帮助你培养分析、设计、制作和评估的关键技能。通过完成这些源自真实世界的挑战，你将了解工程师的思维方式，并明白课堂活动如何与日常科技紧密相连。
1. What is an Engineering Case Study? | 什么是工程案例分析？
An engineering case study is a detailed investigation of a design challenge or a real-world product. In KS3 OCR Engineering, case studies are used to explore how a problem was solved, what materials were chosen and how testing informed improvements. They encourage you to think like an engineer by breaking down a project step by step.
工程案例分析是对某项设计挑战或现实产品进行详细探究。在 KS3 OCR 工程课中，案例分析用于探讨问题是如何解决的、选择了哪些材料，以及测试如何推动改进。它们鼓励你一步步拆解项目，像工程师一样思考。
A typical case study involves identifying requirements, researching existing solutions, generating ideas, building a prototype and evaluating its performance. This mirrors the engineering design process used in industry. For KS3, the scale is smaller, but the thinking is just as rigorous.
典型的案例分析包括明确需求、调研现有解决方案、生成创意、制作原型并评估其性能。这与工业界使用的工程设计流程一致。在 KS3 阶段，项目规模较小，但思维方式同样严谨。
2. Case Study 1: Designing a Paper Bridge | 案例1：设计一座纸桥
The paper bridge challenge is a classic KS3 engineering activity. Your task is to design and build a bridge using only A4 paper and masking tape that can span a 30 cm gap and support a set load, such as a 100 g mass. This case study teaches you about structures, forces and material efficiency.
纸桥挑战是一项经典的 KS3 工程活动。你的任务是仅用 A4 纸和纸胶带设计并建造一座能跨越 30 厘米间隙、支撑设定载荷（如 100 克质量）的桥。这一案例分析教你结构、力和材料效率。
Begin by researching beam, arch and truss bridge designs. Sketch your ideas and predict where compression and tension will occur. Use folding, rolling or layering techniques to strengthen the paper. Test your bridge by adding mass until failure, then record the maximum load.
首先研究梁桥、拱桥和桁架桥设计。画出你的想法并预测压缩和拉伸出现的位置。利用折叠、卷曲或层叠技巧增强纸张强度。通过增加质量直到破坏来测试你的桥，然后记录最大载荷。
| Bridge Type 桥型 | Typical Load (g) 典型载荷 | Material Used 用材 |
|---|---|---|
| Flat Beam 平板梁 | 50-150 | 4 sheets 4张纸 |
| Rolled Truss 卷制桁架 | 200-450 | 6 sheets 6张纸 |
| Accordion Fold 手风琴折叠 | 300-600 | 8 sheets 8张纸 |
Evaluate: why did certain shapes hold more weight? This case study reinforces the principle that geometric stiffness can be more important than material thickness alone.
评估：为什么某些形状能承受更多重量？这一案例分析强化了一个原理：几何刚度可能比单纯的材料厚度更重要。
3. Case Study 2: Building a Catapult | 案例2：制作一个投石机
In this case study, you design a small catapult that must launch a marshmallow or foil ball a set distance. The project introduces levers, energy storage and trajectory. It also requires accuracy and repeatability, just like a real engineering specification.
在这个案例中，你设计一个必须将棉花糖或锡箔球发射到设定距离的小型投石机。该项目引入杠杆、能量存储和弹道，同时要求精度和可重复性，就像真实的工程规范一样。
Use materials such as lolly sticks, elastic bands, plastic spoons and a base. The lever is a simple machine: the effort applied by the stretched elastic is transferred to the load (projectile). The mechanical advantage can be calculated using the lever ratio.
使用冰棍棒、橡皮筋、塑料勺子和底座等材料。杠杆是一种简单机械：拉伸橡皮筋施加的动力传递给负载（抛射物）。机械效益可用杠杆比率计算。
Moment = Force Distance from pivot 力矩 = 力 支点距离
Test different lever lengths and elastic tensions. Measure launch distance and draw a graph of angle versus range. Identify optimum settings. This mirrors how engineers tune parameters in product development.
测试不同的杠杆长度和弹性张力。测量发射距离，绘制角度与射程关系图。找出最佳设置。这反映了工程师在产品开发中如何调校参数。
4. Case Study 3: Creating a Simple Alarm Circuit | 案例3：制作简易报警电路
This case study combines electronics with design. You are asked to produce a pressure-sensitive alarm mat that triggers a buzzer when someone steps on it. The circuit includes a battery, switch (made from foil contacts) and a buzzer in series.
这个案例分析将电子学与设计结合。你需要制作一个压力感应报警垫，当有人踩踏时触发蜂鸣器。电路包含电池、开关（由锡纸触点制成）和串联的蜂鸣器。
Draw the circuit diagram using standard symbols. Build the prototype on a cardboard base. The switch consists of two pieces of aluminium foil separated by a thin foam layer with a hole; pressure connects them. Test continuity with a multimeter.
用标准符号绘制电路图。在卡纸板上搭建原型。开关由两片铝箔构成，中间隔一层开孔的薄泡沫；受压时它们接触导通。用万用表测试通断。
Voltage (V) = Current (I) Resistance (R) 电压 (V) = 电流 (I) 电阻 (R)
Discuss how to make the mat more reliable and durable. Consider insulation, switch sensitivity and power consumption. This case study shows that even simple circuits need systematic testing.
讨论如何让报警垫更可靠、更耐用。考虑绝缘、开关灵敏度和功耗。这个案例表明，即便是简单电路也需要系统测试。
5. The Engineering Design Process | 工程设计流程
All case studies follow a structured design process: Define the problem, Research, Brainstorm ideas, Select the best solution, Build a prototype, Test and Evaluate, then Iterate. In OCR KS3 Engineering, you will use this cycle repeatedly.
所有案例分析都遵循结构化的设计流程：定义问题、调研、头脑风暴、选择最佳方案、搭建原型、测试与评估，然后迭代改进。在 OCR KS3 工程课中，你将反复使用这一循环。
Document each stage in a design portfolio. Write a brief, list specifications, sketch concepts and annotate them with reasons. Record test results and suggest modifications. This reflects how professional engineers work.
在设计作品集中记录每个阶段。撰写设计概要，列出规格，绘制概念草图并注释理由。记录测试结果并提出修改建议。这反映了专业工程师的工作方式。
6. Evaluating Success Criteria | 评估成功标准
Before starting a case study, you must define measurable success criteria. For the paper bridge, criteria might be ‘span 30 cm and hold at least 200 g’. For the catapult, ‘launch a 5 g ball exactly 1.5 m’. Evaluation is then based on data.
开始案例分析前，你必须定义可衡量的成功标准。对于纸桥，标准可能是“跨度30厘米并至少承载200克”。对于投石机，可能是“将5克球精确发射到1.5米处”。评估于是基于数据。
Good criteria are specific, observable and linked to the brief. They allow you to judge whether the design works and where improvements are needed. Use a simple table to track performance against each criterion.
好的标准具体、可观察且与设计概要相关。它们让你能判断设计是否可行以及何处需要改进。使用简单的表格追踪每个标准的达标情况。
7. Material Selection in Projects | 项目中的材料选择
Choosing the right material is a key engineering decision. In KS3 case studies, you compare properties such as strength, weight, flexibility and cost. For instance, paper, card and foam board each have different stiffness-to-weight ratios.
选择合适的材料是关键工程决策。在 KS3 案例分析中，你需要比较强度、重量、柔韧性和成本等特性。例如，纸张、卡纸和泡沫板各有不同的刚度重量比。
- Paper 纸: lightweight, easy to shape, weak in tension 轻、易造型、抗拉弱
- Card 卡纸: stiffer, good for bases, can delaminate 更硬挺、适合底座、可能分层
- Foam board 泡沫板: rigid for weight, cuts cleanly, used in architectural models 质轻而刚硬、切割整齐、用于建筑模型
- Wood dowel 木棒: strong, used for axles or levers 强度高、用于轴或杠杆
Justify your material choices in the design portfolio by linking them to the required properties. This builds evidence for the ‘research’ phase.
在设计作品集中说明选材理由，将其与所需特性挂钩。这为“调研”阶段积累证据。
8. Testing and Iteration | 测试与迭代改进
Testing is not the end of a project; it is the start of refinement. After measuring the bridge’s failure load, you might add gussets or change the cross-section. In the catapult, you might adjust the pivot position after seeing the scatter in distance.
测试不是项目的终点，而是优化的起点。测出纸桥的破坏载荷后，你可以增加角撑板或改变截面。在投石机中，观察距离离散度后可调整支点位置。
Use a fair test approach: change only one variable at a time. Record results and compare them to the success criteria. Each iteration should bring the design closer to the target specification.
采用公平测试方法：每次只改变一个变量。记录结果并与成功标准比较。每次迭代应使设计更接近目标规格。
Iteration is a hallmark of engineering. Even the best products go through many versions before launch. Document your changes clearly to show development.
迭代是工程学的标志。即使最好的产品在发布前也经历多个版本。清楚记录你的修改以展示开发过程。
9. Problem-Solving Strategies | 问题解决策略
When a prototype fails, engineers analyse why. In KS3, use simple tools like the ‘5 Whys’, fishbone diagrams or fault-tree analysis. For the alarm circuit, if the buzzer does not sound, check each component: battery voltage, switch contact, buzzer polarity.
原型失败时，工程师会分析原因。在 KS3，使用“五个为什么”、鱼骨图或故障树分析等简单工具。对于报警电路，如果蜂鸣器不响，检查每个元件：电池电压、开关触点、蜂鸣器极性。
Break the problem into smaller parts. Test subsystems separately before integrating. This modular thinking reduces frustration and leads to logical solutions. Record what you tried, even if it did not work.
将问题分解为更小部分。在集成之前分别测试子系统。这种模块化思维能减少挫折并得出合乎逻辑的解决方案。记录你尝试过的方法，即使没有成功。
10. Teamwork and Communication | 团队合作与沟通
Engineering is rarely a solo activity. In case study exercises, you often work in small teams. Assign roles such as designer, builder, tester and scribe. Effective teams share ideas, listen to each other and combine strengths.
工程很少是单打独斗。在案例分析练习中，你常以小组形式工作。分配角色，如设计师、建造者、测试员和记录员。高效团队分享想法、互相倾听并整合优势。
Communication is tested when you present your case study findings. Use labelled diagrams, simple data tables and clear explanations. Explain why you chose a particular design and how you would improve it next time. This mirrors a professional design review.
当你展示案例分析成果时，沟通能力受到检验。使用带标注的示意图、简单的数据表和清晰的解释。说明为何选择某种设计以及下次如何改进。这模拟了专业设计评审。
11. Applying Maths and Science | 数学与科学的应用
Engineering case studies make maths and science tangible. You calculate areas when reinforcing a bridge deck, use ratios for lever arms, and apply Ohm’s law in circuits. These skills directly support the OCR KS3 curriculum and build confidence for GCSE.
工程案例分析让数学和科学变得具体可感。在加强桥面时计算面积，利用杠杆臂的比例，在电路中应用欧姆定律。这些技能直接支持 OCR KS3 课程，并为 GCSE 建立信心。
In the catapult case, measure angles with a protractor and plot a scatter graph of launch distance. Calculate mean values and discuss variation. Ask ‘how does the applied force change if the elastic is stretched twice as far?’ This brings energy stores to life.
在投石机案例中，使用量角器测量角度并绘制发射距离的散点图。计算平均值并讨论差异。思考“如果橡皮筋拉伸距离加倍，施加的力如何变化？”这使能量存储概念变得生动。
12. Real-World Engineering Links | 现实世界的工程联系
Every KS3 case study links to real engineering. The paper bridge connects to civil engineers designing spans over rivers. The catapult relates to aerospace engineers testing launch mechanisms. The alarm circuit mirrors burglar alarms and pressure sensors in industry.
每个 KS3 案例分析都与实际工程相联系。纸桥对应土木工程师设计跨越河流的桥梁。投石机对应航空工程师测试发射机构。报警电路反映工业中的防盗报警器和压力传感器。
Research these links to enrich your portfolio. For example, the Millau Viaduct in France used computer modelling to optimise its cable-stayed design, just as you optimised your paper truss. This shows that the core principles are scale-independent.
研究这些联系以丰富你的作品集。例如，法国米约高架桥使用计算机建模优化其斜拉设计，正如你优化纸桁架一样。这表明核心原理与规模无关。
By completing these case studies, you are not just making models; you are practising the engineering habits of mind that will carry through to further study and careers. Record, reflect and redesign – that’s the engineer’s way.
通过完成这些案例分析，你不只是制作模型；你在培养工程思维习惯，这将贯穿后续学习和职业生涯。记录、反思、再设计——这就是工程师之道。
Published by TutorHao | Engineering Revision Series | aleveler.com
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