📚 Year 7 WJEC Engineering: Core Knowledge Points Review | Year 7 WJEC 工程：核心知识点梳理
Welcome to the core knowledge review for Year 7 WJEC Engineering. This article brings together the essential concepts you will encounter: from the engineering design process and material properties to basic electronics, mechanical systems, and sustainability. Each topic is presented with clear explanations in both English and Chinese, helping you build a solid foundation for hands-on projects and written assessments.
欢迎查阅 Year 7 WJEC 工程的核心知识梳理。本文汇集了你将接触到的关键概念：从工程设计流程和材料特性，到基础电子学、机械系统以及可持续发展。每个主题都配有清晰的中英文双语解释，帮助你为动手项目和书面评估打下扎实基础。
1. The Engineering Design Process | 工程设计流程
The engineering design process is a systematic approach used to solve problems and create new products. It always begins with identifying a clear need or problem.
工程设计流程是一种用于解决问题和创造新产品的系统方法。它始终从明确需求或问题开始。
After the problem is identified, engineers carry out research. They look at existing solutions, materials, costs, and constraints to build a design specification.
明确问题后，工程师会开展研究。他们考察现有解决方案、材料、成本和限制条件，以形成设计规格。
Ideation follows, where many possible solutions are brainstormed. The best ideas are selected, often through sketches and simple models, and developed into a detailed design.
接下来是构思阶段，团队进行头脑风暴，产出许多可能的解决方案。最佳创意通常通过草图和简单模型筛选出来，并发展为详细设计。
Next, a prototype or working model is constructed. This prototype is then tested against the specification to see if it solves the original problem effectively.
下一步是制作原型或工作模型。随后根据设计规格对原型进行测试，判断它是否能有效解决最初的问题。
Based on test results, engineers evaluate the design and make improvements. This cycle of prototyping, testing, and evaluation may repeat several times until the product meets all requirements.
依据测试结果，工程师评估设计并进行改进。原型制作、测试与评估的循环可能重复多次，直到产品满足所有要求。
2. Materials and Their Properties | 材料及其特性
Choosing the right material is vital in engineering. Materials are grouped into categories such as metals, polymers, ceramics, composites, and wood. Their selection depends on the required properties for a specific application.
选择合适的材料在工程中至关重要。材料分为金属、聚合物、陶瓷、复合材料和木材等类别。材料的选择取决于特定应用所需的特性。
| Material / 材料 | Key Properties / 关键特性 | Typical Uses / 典型用途 |
|---|---|---|
| Wood (Timber) 木材 | Lightweight, easy to cut and join, good thermal and electrical insulator, renewable 轻质、易于切割连接、良好的热和电绝缘体、可再生 | Furniture, construction frames, models, flooring 家具、建筑框架、模型、地板 |
| Steel (Carbon steel) 碳钢 | High strength, ductile, magnetic, electrically conductive, prone to rust without protection 高强度、延展性好、有磁性、导电、若无防护易生锈 | Bridges, car bodies, tools, structural beams 桥梁、汽车车身、工具、结构梁 |
| Aluminium alloy 铝合金 | Lightweight, corrosion-resistant, good strength-to-weight ratio, conductive 轻质、耐腐蚀、良好的强度重量比、导电 | Aircraft parts, drink cans, window frames, electronics casings 飞机部件、饮料罐、窗框、电子外壳 |
| Acrylic (PMMA) 亚克力 | Transparent, rigid, lightweight, easily scratched, can be thermoformed 透明、刚性、轻质、易刮伤、可热成型 | Displays, signage, aquariums, light covers 展示牌、标志、水族箱、灯罩 |
| PVC (Polyvinyl chloride) 聚氯乙烯 | Durable, chemical-resistant, can be rigid or flexible, electrical insulator 耐久、耐化学腐蚀、可硬可软、电绝缘 | Pipes, cable insulation, flooring, medical tubing 管道、电缆绝缘层、地板、医用软管 |
| Composite (e.g. GRP) 复合材料（如玻璃钢） | High strength, lightweight, corrosion-resistant, can be moulded into complex shapes 高强度、轻质、耐腐蚀、可模压成复杂形状 | Boat hulls, sports equipment, car panels, wind turbine blades 船体、运动器材、汽车板材、风力叶片 |
Important mechanical properties include hardness (resistance to indentation), tensile strength (resistance to pulling forces), ductility (ability to stretch into wires), and toughness (energy absorbed before breaking). Electrical and thermal conductivity are also critical in many designs.
重要的机械特性包括硬度（抗压痕能力）、抗拉强度（抵抗拉力的能力）、延展性（拉成丝的能力）和韧性（断裂前吸收能量的能力）。电气和热导率在许多设计中也至关重要。
3. Tools and Workshop Safety | 工具与工作坊安全
Safety is the number one priority in any engineering workshop. You must always wear personal protective equipment (PPE): safety goggles, an apron, and sturdy enclosed shoes.
安全是任何工程工作坊的头等大事。你必须始终佩戴个人防护装备：护目镜、围裙和结实的包趾鞋。
Before using any machine or tool, you must receive proper instruction. Never use a tool unless you are confident about how to operate it safely. Always clamp your workpiece securely and keep your hands behind the cutting edge.
使用任何机器或工具前，你必须接受适当的指导。除非你有把握安全操作，否则不要使用工具。始终将工件夹紧，并将双手保持在切割刃后方。
Long hair must be tied back, and loose clothing, jewellery, or ties should be removed. Keep the floor and benches free from clutter. Report any broken tools or spills to the teacher immediately.
长发必须扎起，取下宽松的衣物、首饰或领带。保持地面和工作台整洁无杂物。立即向老师报告任何损坏的工具或溢洒。
Common hand tools you will use include the hacksaw (for cutting metal/plastic), coping saw (for curved cuts in wood/plastic), flat and half-round files (for shaping and smoothing), bench vice, steel rule, try square, and cordless drill.
你将使用的常用手动工具包括钢锯（切割金属/塑料）、钢丝锯（在木材/塑料上切割曲线）、平锉和半圆锉（用于成形和打磨）、台钳、钢尺、直角尺和充电式电钻。
When using adhesives like PVA or solvent cement, always work in a well-ventilated area and avoid inhaling fumes. Wash hands after the session.
使用白乳胶或溶剂胶粘合剂时，始终在通风良好的区域作业，避免吸入烟雾。工作结束后洗手。
4. Basic Electronics: Circuits and Components | 基础电子：电路与元器件
An electrical circuit is a closed loop that allows current to flow from a power source, through conductors, and to a load such as a lamp, motor, or buzzer. If the loop is broken, current stops and the device switches off.
电路是一个闭合回路，允许电流从电源流出，经过导体，到达负载（如灯泡、电机或蜂鸣器）。如果回路断开，电流停止，设备关闭。
Key components include batteries (DC power supply), switches (to control the circuit), lamps and LEDs (to produce light), resistors (to limit current), buzzers (to make sound), and motors (to create movement).
关键元器件包括电池（直流电源）、开关（控制电路）、灯泡和发光二极管（发光）、电阻（限制电流）、蜂鸣器（发声）以及电机（产生运动）。
| Component / 元器件 | Symbol Description / 符号描述 | Function / 功能 |
|---|---|---|
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