📚 AQA Year 9 Engineering: Quick Terminology Memorisation Guide | AQA 九年级工程：术语速记指南
This guide provides a quick memorisation aid for essential engineering vocabulary encountered in the AQA Year 9 Engineering curriculum. Mastering these terms will help you understand concepts in materials, mechanics, electronics, and design. Each term is explained with concise definitions and relevant examples to support your revision and classroom learning.
本指南为 AQA 九年级工程课程中遇到的基本工程词汇提供速记帮助。掌握这些术语将帮助你理解材料、力学、电子和设计等概念。每个术语都有简洁的定义和相关例子，以支持你的复习和课堂学习。
1. Materials and Their Properties | 材料与性能
Key terms describing the response of materials to forces: tensile strength is the maximum stress a material can withstand while being stretched before breaking; compressive strength is the ability to resist being squashed. Hardness measures resistance to indentation or scratching, while toughness indicates how much energy a material can absorb before fracturing. Ductility refers to the capacity to be drawn into a wire, and malleability is the ability to be hammered or rolled into thin sheets without cracking.
描述材料受力响应的关键术语：抗拉强度是材料在被拉断前能承受的最大应力；抗压强度是抵抗被压扁的能力。硬度衡量抵抗压痕或划痕的能力，而韧性表示材料在断裂前能吸收多少能量。延展性指被拉成丝的能力，可锻性是能被锤打或轧制成薄片而不开裂的能力。
Another vital distinction is between elasticity and plasticity. An elastic material returns to its original shape after the applied force is removed (e.g., rubber band), whereas a plastic material retains permanent deformation (e.g., clay). The point where a material changes from elastic to plastic behaviour is the yield point. Understanding these properties allows engineers to select appropriate materials for specific applications such as bridges, car bodies, and electronic casings.
另一个重要区分是弹性与塑性。弹性材料在撤去外力后恢复原状（如橡皮筋），而塑性材料会保持永久变形（如黏土）。材料从弹性行为转变为塑性行为的点称为屈服点。理解这些性能使工程师能够为特定应用选择合适的材料，如桥梁、汽车车身和电子外壳。
2. Forces and Loads | 力与载荷
In engineering, forces cause objects to move, deform, or stay at rest. A load is the force applied to a structure or component. Tension is a pulling force that stretches a material; compression is a pushing force that shortens it. Shear forces cause parts of a material to slide past each other, while torsion applies a twisting action. Bending combines tension on one side and compression on the other, producing curvature. These forces often act together in real structures.
在工程中，力使物体运动、变形或保持静止。载荷是施加在结构或部件上的力。拉伸力是一种拉伸材料的拉力；压缩力是使其缩短的推力。剪切力使材料各部分相对滑动，而扭转力施加扭转作用。弯曲结合了一侧的拉伸和另一侧的压缩，产生弧度。这些力在真实结构中常常共同作用。
Loads are also classified by how they vary over time. A static load remains constant, such as the weight of books on a shelf. A dynamic load changes in magnitude or direction, like traffic crossing a bridge. Stress is the internal force per unit area, measured in pascals (Pa), and strain is the deformation produced, expressed as a ratio (extension ÷ original length).
载荷也根据随时间变化的方式分类。静载荷保持恒定，例如书架上的书的重量。动载荷在大小或方向上变化，如通过桥梁的交通。应力是单位面积上的内力，单位为帕斯卡 (Pa)；应变是产生的变形，用比值表示（伸长量 ÷ 原始长度）。
3. Motion and Mechanical Systems | 运动与机械系统
Mechanisms convert one type of motion into another. Linear motion occurs in a straight line; rotary motion revolves around a fixed point; oscillating motion swings in an arc; and reciprocating motion moves back and forth in a straight line, like a piston. Levers are simple machines that magnify force or distance. All levers have a fulcrum (pivot), an effort (input force), and a load (output). They are classed as first, second, or third order depending on the arrangement of these three elements.
机构将一种运动转换为另一种。直线运动沿直线进行；旋转运动绕固定点转动；摆动在弧形中来回；往复直线运动如活塞一样前后直线运动。杠杆是能够放大作用力或距离的简单机械。所有杠杆都有一个支点、一个施力（输入力）和一个负载（输出）。根据这三者的排列，杠杆分为一类、二类或三类。
Gears transmit rotary motion and can change speed and torque. The driver gear provides input, the driven gear receives output, and an idler gear reverses direction without affecting the ratio. The gear ratio is calculated as number of teeth on driven ÷ number of teeth on driver. A large ratio increases torque (turning force) but reduces speed, and vice versa. Pulleys and sprockets work similarly with belts and chains.
齿轮传递旋转运动并可以改变速度和扭矩。主动轮提供输入，从动轮接收输出，惰轮改变转向而不影响传动比。齿轮比计算为从动轮齿数 ÷ 主动轮齿数。大的传动比能增大扭矩（转动力），但降低转速，反之亦然。带轮和链轮与皮带和链条工作原理类似。
4. Energy and Power | 能量与功率
Energy is the capacity to do work. Kinetic energy is possessed by moving objects; potential energy is stored energy, such as gravitational potential energy (due to height) and elastic potential energy (in stretched springs). Work force moves an object, calculated as force × distance. The unit of work and energy is the joule (J).
能量是做功的能力。动能由运动物体所具有；势能是储存的能量，如重力势能（因高度）和弹性势能（在拉长的弹簧中）。当力使物体移动时，就做了功，计算公式为力 × 距离。功和能量的单位是焦耳 (J)。
Power is the rate at which work is done, measured in watts (W). One watt equals one joule per second. Efficiency compares useful output energy to total input energy: efficiency (% ful energy output ÷ total energy input) × 100. Due to friction and heat, no machine is 100% efficient. The principle of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed.
功率是做功的速率，以瓦特 (W) 为单位，1瓦特等于每秒1焦耳。效率比较有用输出能量与总输入能量：效率 (%) = (有用能量输出 ÷ 总能量输入) × 100。由于摩擦和发热，没有机器能达到100%的效率。能量守恒定律指出能量不能被创造或消灭，只能被转移或转化。
5. Electronics and Circuits | 电子与电路
Basic electrical quantities: voltage (V) is the potential difference that pushes charge; current (I) is the flow of electric charge, measured in amperes (A); resistance (R) opposes current, measured in ohms (Ω). Ohm's Law links these: V = I × R. In a series circuit, components share the same current and the voltage divides; in a parallel circuit, components share the same voltage and the current splits.
基本电学物理量：电压 (V) 是推动电荷的电位差；电流 (I) 是电荷的流动，单位安培 (A)；电阻 (R) 阻碍电流，单位欧姆 (Ω)。欧姆定律联系三者：V = I × R。在串联电路中，元件流过相同的电流，电压被分配；在并联电路中，元件承受相同电压，电流分流。
Common components are summarised below:
常见元件总结如下：
| Component (English) | 中文名称 | symbol key |
|---|---|---|
| Resistor | 电阻器 | limits current / 限制电流 |
| Variable resistor / potentiometer | 可变电阻器 / 电位器 | adjustable resistance / 可调电阻 |
| Light-emitting diode (LED) | 发光二极管 | emits light when current flows / 通流发光 |
| Diode | 二极管 | allows current in one direction / 单向导电 |
