📚 Year 7 WJEC Engineering: Unit Test Mock Paper Analysis | Year 7 WJEC 工程：单元测试模拟卷解析
This article walks through a typical Year 7 WJEC Engineering unit test mock paper, providing not only the correct answers but also clear explanations of the underlying concepts. By working through sample questions on workshop safety, material properties, technical drawing and electronics, you will build confidence for your real assessment. Each section includes a representative exam-style question and a step-by-step guide to achieving full marks.
本文详细解析一份典型的 Year 7 WJEC 工程单元测试模拟卷，不仅给出正确答案，还清晰解释背后的概念。通过练习工作坊安全、材料属性、技术绘图和电子等样题，你将建立起应对真实评估的信心。每个部分都包含一道代表性的考题样式以及获得满分的分步指南。
1. Identifying Workshop Hazards | 识别车间危险
Mock Question: Look at the diagram of a cluttered workbench. Identify three hazards and describe a control measure for each.
模拟试题：观察一张杂乱工作台的示意图。识别出三种危险，并为每种危险提出一项控制措施。
Answer: The first hazard is a loose craft knife left on the edge, which could fall and cut someone. The control measure is to retract the blade and store it in a designated rack after use. The second hazard is a trailing cable from a soldering iron, creating a trip risk. The control measure is to route cables away from walkways and use cable clips. The third hazard is a pile of oily rags near a heat source, which poses a fire risk. The control measure is to dispose of oily rags in a sealed metal bin.
解析：第一种危险是留在边缘的松脱美工刀，可能掉落割伤他人。控制措施是使用后收回刀片并放入指定刀架。第二种危险是电烙铁拖曳的电缆，造成绊倒风险。控制措施是将电缆布置在远离通道的地方并使用线夹。第三种危险是靠近热源的一堆油污抹布，有火灾风险。控制措施是将油污抹布丢入密封的金属垃圾桶。
2. Personal Protective Equipment (PPE) | 个人防护装备
Mock Question: When soldering electronic components, what PPE must be worn? Justify each item.
模拟试题：焊接电子元件时，必须穿戴哪些个人防护装备？为每件装备提供理由。
Answer: You must wear impact-resistant safety goggles to shield your eyes from hot solder splashes and trimming fragments. A heat-resistant apron or cotton overalls should be worn to protect skin and clothing from burns. Finally, closed-toe leather shoes are essential to prevent injuries from dropped hot irons or heavy components.
解析：必须佩戴防冲击护目镜，保护眼睛免受热焊料飞溅和修剪碎屑的伤害。应穿上耐热围裙或棉质工作服，保护皮肤和衣物不被烫伤。最后，必须穿封闭式皮革鞋，防止烙铁掉落或重元件砸伤脚部。
3. Recognising Common Hand Tools | 识别常见手动工具
Mock Question: Three tools are shown: a try square, a hacksaw, and a cross-pein hammer. Name each tool and state one specific engineering application.
模拟试题：展示了三种工具：直角尺、钢锯和羊角锤。命名每种工具并说明一项具体的工程用途。
Answer: The try square is used to mark lines at 90° to an edge and to check the squareness of a workpiece during marking out. The hacksaw, with a fine-toothed blade, is for cutting metal bars and plastic sheets. The cross-pein hammer is ideal for shaping sheet metal and driving tacks, as its wedge-shaped pein spreads metal in a line.
解析：直角尺用于在边缘划出90°的线条，并在划线时检查工件的垂直度。钢锯带有细齿锯条，用于切割金属棒和塑料板。羊角锤的楔形锤头可将金属沿一条线延展，非常适合钣金成形和敲打平头钉。
4. Properties of Engineering Materials | 工程材料的性能
Mock Question: Explain the difference between 'hardness' and 'toughness' using everyday examples. Suggest a test to compare the toughness of two plastics.
模拟试题：用日常例子解释“硬度”和“韧性”的区别。提出一种比较两种塑料韧性的试验方法。
Answer: Hardness is a material's ability to resist scratching or indentation; a diamond is extremely hard. Toughness is its ability to absorb energy and deform without breaking; a rubber tyre is tough. While a glass window is hard but not tough, a plastic bottle can be both. To test toughness, an engineer can perform an impact test: drop a weighted striker onto notched samples of the two plastics and measure how much energy each absorbs before fracturing.
解析：硬度是材料抵抗刮擦或压痕的能力；金刚石非常硬。韧性是吸收能量并发生形变而不断裂的能力；橡胶轮胎很有韧性。玻璃窗硬却不韧，而塑料瓶可以兼顾二者。工程师可进行冲击试验：将带重物的撞锤打到两种塑料的缺口试样上，测量各自断裂前吸收的能量，从而比较韧性。
5. Metals, Polymers and Smart Materials | 金属、聚合物与智能材料
Mock Question: Classify aluminium, acrylic and nitinol. Give one key property for each and suggest a real-world use.
模拟试题：把铝、亚克力和镍钛诺分类。给出每种材料的一个关键性能，并提出一种实际用途。
Answer: Aluminium is a non-ferrous metal; it is lightweight and corrosion-resistant, making it ideal for aircraft skins. Acrylic is a thermoplastic polymer; it is transparent and easy to thermoform, so it is often used for safety barriers. Nitinol is a shape-memory alloy; it can return to its original shape when heated, which is why it appears in medical stents and spectacle frames.
解析：铝是有色金属；它轻便且耐腐蚀，是飞机蒙皮的理想材料。亚克力是热塑性聚合物；它透明且易于热成型，常用于安全屏障。镍钛诺是一种形状记忆合金；加热后能恢复原始形状，因此应用于医疗支架和眼镜架中。
6. Measuring Instruments and Accuracy | 测量工具与精度
Mock Question: A design requires a 35 mm line to be scribed onto a piece of mild steel. Describe the procedure using a steel rule and a scriber. How do you ensure accuracy?
模拟试题：设计要求在一块低碳钢上划出一条35 mm的线条。描述使用钢尺和划线针的步骤。如何确保精度？
Answer: First, degrease the surface so the line is visible. Place the steel rule on the work with its edge flush against the reference edge. Locate the 35 mm mark on the rule and hold it firmly. Angle the scriber at about 45° and draw it along the rule's edge in one smooth motion. To ensure accuracy, always measure from the 1 cm mark rather than the worn end, and check the measurement twice before scribing.
解析：首先对表面脱脂，使线条清晰可见。将钢尺放在工件上，其边缘与基准边齐平。找到尺上的35 mm刻度并牢牢按住。将划线针倾斜约45°，沿尺边缘一次平稳划过。为确保精度，应从1 cm刻度开始测量而非磨损的尺端，划线前对测量值重复检查两次。
7. Orthographic Projection Basics | 正投影基础
Mock Question: A 3D sketch shows a simple stepped block. Draw the front, side and plan views in third-angle projection. How should hidden edges be shown?
模拟试题：一个三维草图展示了一块简单的台阶块。用第三角投影绘制主视图、侧视图和俯视图。隐藏边应如何表示？
Answer: In third-angle projection, the front view is placed in the centre, the side view to its right, and the plan view directly above. The stepped profile will appear as stacked rectangles. Any edge that cannot be seen directly, such as the back face of a step, must be drawn as a dashed line (hidden detail) with thin, evenly spaced dashes. Dimensions can be added to show step heights and widths.
解析：在第三角投影中，主视图放在中间，侧视图在其右方，俯视图在其正上方。台阶轮廓表现为堆叠的矩形。任何无法直接看到的边缘，如台阶背部，必须用虚线（不可见轮廓线）表示，即细、均匀的短划线。可添加尺寸标注台阶高度和宽度。
8. Isometric Drawing of a Simple Block | 简单积木的等轴测图
Mock Question: Draw an isometric view of a 40 mm cube with a square through-hole of 15 mm centred on one face. Describe the use of 30° lines and the isometric grid.
模拟试题：绘制一个边长40 mm立方体的等轴测图，其中一个面中心有一个15 mm的方通孔。说明30°线和等轴测网格的用法。
Answer: Begin by drawing two 30° lines from a point to form the front edges of the cube. Draw vertical lines for height. Use an isometric grid to keep all lines either vertical or at 30° to the horizontal. The square hole appears as a parallelogram in isometric view; its sides remain parallel to the cube's edges. Draw the visible inner edges of the hole with solid lines and, if needed, use dashed lines for the hidden back face.
解析：先从一个点出发画两条30°线，构成立方体的前棱边。垂直线表示高度。利用等轴测网格确保所有线条要么垂直、要么与水平线呈30°。方孔在等轴测视图中看起来像个平行四边形；其各边依然平行于立方体的棱边。用实线画出孔内可见棱边，必要时用虚线表示隐藏的背面边缘。
9. Types of Forces and Structures | 力的类型与结构
Mock Question: A truss bridge experiences tension, compression and torsion. Define each force and identify which truss members are in compression when a load is applied.
模拟试题：一座桁架桥承受拉力、压力和扭力。定义每种力，并指出施加荷载时哪些桁架构件受压。
Answer: Tension is a pulling force that stretches a member; compression is a pushing force that squashes it; torsion is a twisting force. In a simply supported truss bridge under a central load, the top chord members are in compression while the bottom chord is in tension. The diagonal web members alternate between tension and compression depending on their orientation.
解析：拉力是拉伸构件的牵引力；压力是压碎构件的推进力；扭力是扭转力。在一座简支桁架桥承受中央荷载时，上弦杆受压，下弦杆受拉。斜腹杆根据方向交替承受拉力或压力。
10. Introducing Electronic Components | 基础电子元件介绍
Mock Question: Identify the circuit symbols for a battery, an LED, a fixed resistor and a push-to-make switch. Draw a circuit where pressing the switch lights the LED. If the LED runs at 2 V and 20 mA from a 5 V supply, calculate the required series resistor using Ohm's law.
模拟试题：辨识电池、发光二极管、固定电阻和按钮开关的电路符号。绘制一个按下开关就能点亮LED的电路。若LED在5 V电源下工作电压为2 V、电流20 mA，请用欧姆定律计算所需串联电阻。
switch is pressed, current flows. To calculate the resistor: voltage across resistor = 5 V – g R = V ÷ I, R = 3 ÷ 0.02 = 150 Ω. Therefore, a 150 Ω resistor should be placed in series.
解析：电路由电池、开关、电阻和LED串联组成（注意LED箭头方向）。按下开关时电流通过。计算电阻：电阻两端电压 = 5 V – 2 V = 3 V。电流 I = 20 mA = 0.02 A。使用 R = V ÷ I，R = 3 ÷ 0.02 = 150 Ω。因此，应串联一个150 Ω的电阻。
11. The 6Rs of Sustainable Design | 可持续设计的6R原则
Mock Question: List and explain the 6Rs of sustainability. Provide a practical engineering example for 'Rethink'.
模拟试题：列举并解释可持续发展的6R原则。为“重新思考”提供一个工程实例。
Answer: The 6Rs are: Reduce – use fewer resources and less energy during manufacture; Reuse – use a product again for the same purpose without reprocessing; Recycle – break down materials to make new products; Rethink – reconsider how a function can be provided in a more sustainable way; Refuse – avoid using materials that are damaging to the environment; Repair – fix a faulty product to extend its life. An engineering example for Rethink is designing a public bicycle-sharing system instead of manufacturing more private cars for short trips.
解析：6R原则是：减少——制造中使用更少资源和能源；重用——同一产品不经再处理直接再次使用；回收——分解材料以制造新产品；重新思考——重新考量如何用更可持续的方式提供某项功能；拒绝——避免使用对环境有害的材料；维修——修复故障产品以延长寿命。重新思考的工程实例：设计公共自行车共享系统，取代为短途出行制造更多私家车。
12. Evaluating a Product or Model | 评估产品或模型
Mock Question: You have made a wooden phone holder. Suggest three evaluation criteria and describe a test for each.
模拟试题：你制作了一个木制手机支架。提出三项评估准则，并描述每项准则的测试方法。
Answer: Criterion 1: Stability – place a phone of maximum weight on the holder, tilt the base to 15°, and check if it stays upright. Criterion 2: Fit for purpose – insert three different phone sizes and verify that the viewing angle remains comfortable without the device slipping. Criterion 3: Finish quality – run a clean cloth over all surfaces; there should be no splinters, sharp edges or uneven varnish. Record the results in a table and suggest improvements.
解析：准则1：稳定性——将最大重量的手机放在支架上，将底座倾斜至15°，检查手机是否保持直立。准则2：适用性——插入三种不同尺寸的手机，验证视角是否舒适且设备不会滑动。准则3：表面处理质量——用干净软布擦拭所有表面；不应有木刺、锋利边缘或不均匀的清漆。将结果记录在表中并提出改进建议。
Published by TutorHao | Engineering Revision Series | aleveler.com
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