📚 Year 9 CIE Physics: Quick Memorisation Guide to Key Vocabulary and Terms | Year 9 CIE 物理：词汇术语速记指南
A strong grasp of physics vocabulary is the foundation of success in the Year 9 CIE course. This guide collects the essential terms you will encounter, pairs each with a clear definition, and adds memory tricks to help you recall them quickly during revision and exams. Use it to build confidence with the language of physics.
牢固掌握物理词汇是 Year 9 CIE 课程取得成功的基石。本指南汇集了你将遇到的核心术语，为每个词条配上了清晰的定义，并加入了记忆技巧，帮助你在复习和考试中快速回想。用它来建立你对物理语言的信心。
1. Measurement and Units | 测量与单位
Every observation in physics begins with measurement. Knowing the correct units and the difference between scalar and vector quantities allows you to describe the world with precision.
物理中的每一次观察都始于测量。了解正确的单位以及标量和矢量之间的区别，使你能够精确地描述世界。
Scalar quantity: at has only magnitude (size). Examples include distance, speed, mass and time. Memory tip: 'S'calar = 'S'ize only, no direction.
标量：只有大小（数值）的物理量。例如距离、速率、质量和时间。记忆技巧：标量的 '标' 联想到 '只标出大小'。
Vector quantity: A quantity that has both magnitude and direction, such as displacement, velocity, weight and force. Think of an arrow: the length shows magnitude, the arrowhead shows direction.
矢量：既有大小又有方向的量，如位移、速度、重量和力。想象一支箭：箭杆长度代表大小，箭头代表方向。
Distance: The total path length travelled by an object, a scalar. It is measured in metres (m).
路程：物体运动轨迹的总长度，是标量。单位是米 (m)。
Displacement: The length of the straight line from start to finish together with the direction; a vector. 'Displacement' sounds like 'dis-place' — you are only concerned with how place has changed.
位移：从起点指向终点的有向直线长度，是矢量。'位移' 顾名思义，只是位置改变的量。
Speed: The rate at which distance is covered, a scalar. Formula: v = d / t. Common units are m/s.
速率：物体运动路程与所用时间的比值，标量。公式：v = d / t。常用单位是米每秒 (m/s)。
Velocity: Speed in a stated direction, a vector. 'V' for velocity, 'V' for vector — use the same letter to remember the link.
速度：带有方向的速率，矢量。速记：velocity 和 vector 都以 'v' 开头。
Acceleration: ormula: a = Δv / Δt. Unit: m/s². When an object slows down, we often call it deceleration.
加速度：速度的变化率。公式：a = Δv / Δt。单位：米每二次方秒 (m/s²)。物体减速时常称为负加速度。
v = d / t | a = Δv / Δt
2. Motion and Forces | 运动与力
Forces control how objects move. Newton's laws of motion give us a framework for understanding everything from a stationary book to a rocket launch. Mastering these terms is vital for tackling mechanics problems.
力控制着物体的运动方式。牛顿运动定律为我们理解从静止的书本到火箭发射的万事万物提供了框架。掌握这些术语对解决力学问题至关重要。
Force: A push or pull that can change an object's speed, shape or direction. Measured in newtons (N).
力：能改变物体速度、形状或方向的推力或拉力。单位是牛顿 (N)。
Inertia: The tendency of an object to resist a change in its motion. More mass means more inertia. 'Inertia' sounds like 'inert' — unwilling to move.
惯性：物体反抗其运动状态被改变的性质。质量越大，惯性越大。惯性让人联想到“惰性”——不愿改变。
Newton's First Law: An object continues in a state of rest or uniform motion in a straight line unless acted upon by a resultant force. Think of a cup on a table – it won’t slide unless pushed.
牛顿第一定律：一切物体在没有受到合力作用时，总保持静止或匀速直线运动状态。想象桌上的杯子——不被推就不会滑走。
Newton's Second Law: portional to the resultant force and inversely proportional to its mass. Formula: F = m a.
牛顿第二定律：物体的加速度与所受合力成正比，与物体质量成反比。公式：F = m a。
Newton's Third Law: For every action force there is an equal and opposite reaction force, but the forces act on different bodies. Example: while walking, your foot pushes back on the ground; the ground pushes you forward.
牛顿第三定律：相互作用的两个物体产生一对大小相等、方向相反、作用在不同物体上的力。例：走路时脚向后蹬地，地向前推你。
Resultant force: The single force that has the same effect as all the original forces acting together. If it is zero, the object is in equilibrium.
合力：与所有原作用力共同效果等效的单个力。合力为零时，物体处于平衡状态。
Friction: A force that opposes motion between two surfaces in contact. It can be useful (walking) or unwanted (engine wear).
摩擦力：接触面之间阻碍相对运动的力。它可能是有益的（如行走），也可能是有害的（如发动机磨损）。
Air resistance: A type of friction caused by air particles colliding with a moving object. It increases with speed and surface area.
空气阻力：空气粒子与运动物体碰撞产生的摩擦阻力。随速度和迎风面积增大而增大。
Terminal velocity: The constant maximum speed reached by a falling object when air resistance equals weight. The forces are balanced, so acceleration becomes zero.
终极速度：物体下落时，当空气阻力等于重力时达到的恒定最大速度。此时合力为零，加速度为零。
F = m a
3. Energy, Work and Power | 能量、功和功率
Energy is the currency of physics. The principle of conservation of energy states that energy cannot be created or destroyed, only transferred between forms or stored. Understanding these energy terms helps you analyse any system.
能量是物理学的“货币”。能量守恒原理指出能量不能凭空产生或消灭，只能在不同形式之间转移或储存。理解这些能量术语能帮你分析任何系统。
Kinetic energy (KE): possesses due to its motion. KE = ½ m v². The v-squared term means speed has a huge effect — doubling speed quadruples the kinetic energy.
动能 (KE)：物体由于运动而具有的能量。KE = ½ m v²。速度的平方项说明速度的影响极大——速度加倍，动能变为原来的四倍。
Gravitational potential energy (GPE): Energy stored in an object because of its height above the Earth's surface. GPE = m g h, where g is gravitational field strength (~9.8 N/kg on Earth).
重力势能 (GPE)：物体因其高于地面的位置而储存的能量。GPE = m g h，其中 g 是重力场强度（地球约 9.8 N/kg）。
Work done: e moves an object through a distance. W = F d, unit: joule (J). 1 joule is 1 newton-metre.
做功：力作用于物体并使物体在力的方向上移动一段距离，就做了功。W = F d，单位：焦耳 (J)。1 焦耳等于 1 牛·米。
Power: y is : The rate at which work is done or energy is transferred. P = W / t, unit: watt (W). A 60 W bulb transfers 60 joules every second.
功率：做功或能量转移的快慢。P = W / t，单位：瓦特 (W)。一个 60 W 的灯泡每秒转移 60 焦耳能量。
Efficiency: rgy, often given as a percentage. Efficiency = (useful energy out / total energy in) × 100%.
效率：有用输出能量与总输入能量之比，通常表示为百分比。效率 = (有用输出能 / 总输入能) × 100%。
Conservation of energy: Energy cannot be created or destroyed; it can only be transferred from one form to another. In a falling object, GPE converts to KE, but total mechanical energy decreases if friction is present.
能量守恒：能量不会凭空产生或消失，只会从一种形式转换为另一种形式。在下落的物体中，GPE 转化为 KE，若有摩擦，总机械能减少，但总能量仍然守恒。
Renewable energy: Energy sources that won't run out, such as solar, wind, tidal and hydroelectric power. They are often cleaner but can depend on weather.
可再生能源：不会耗尽的能源，如太阳能、风能、潮汐能和水力发电。它们通常更清洁，但依赖天气条件。
KE = ½ m v² | GPE = m g h | W = F d | P = W / t
4. Thermal Physics | 热物理学
Heat transfer and temperature are central to thermal physics. Understanding conduction, convection and radiation helps explain everyday phenomena, from cooking to weather.
传热和温度是热物理学的核心。理解传导、对流和辐射有助于解释从烹饪到天气的日常现象。
Temperature: A measure of the average kinetic energy of the particles in a substance. Higher temperature means particles move faster. Unit: degrees Celsius (°C) or kelvin (K).
温度：物质中粒子平均动能的量度。温度越高，粒子运动越快。单位：摄氏度 (°C) 或开尔文 (K)。
Conduction: Transfer of thermal energy through a solid without the material itself moving. Metals are good conductors because of free electrons. 'Conduction' touches — think of direct contact.
导热：热能不伴随物质移动而通过固体传递的过程。金属因自由电子而成为良导体。'导热' 必须接触——联想直接传导。
Convection: Transfer of heat through fluids (liquids and gases) by the movement of the fluid itself. Warm fluid rises, cool fluid sinks, creating a convection current. Picture soup bubbling in a pot.
对流：通过流体（液体和气体）自身的流动传递热量。热流体上升，冷流体下沉，形成对流环流。想象锅里翻滚的汤。
Radiation: Transfer of energy by electromagnetic waves, mostly infrared. It can travel through a vacuum, which is why the Sun's energy reaches Earth. No particles are involved.
辐射：通过电磁波（主要是红外线）传递能量。它能在真空中传播，因此太阳能抵达地球。不依赖粒子。
Melting and boiling: Melting is the change from solid to liquid at the melting point. Boiling is the change from liquid to gas throughout the liquid at the boiling point. Both require energy but temperature stays constant during the change.
熔化和沸腾：熔化是固体在熔点时变为液体的过程。沸腾是液体在沸点整体变为气体的过程。两者都需要吸收能量，但相变期间温度保持不变。
Evaporation: Change from liquid to gas that occurs only at the surface and at any temperature. Faster evaporation happens with higher temperature, larger surface area or a breeze.
蒸发：仅在液体表面发生且可在任何温度下进行的由液变气的过程。温度越高、表面积越大或有风时蒸发越快。
Condensation: Change from gas to liquid, often seen on cold windows. It releases thermal energy.
冷凝：气体变为液体的过程，常见于冰冷玻璃窗上。冷凝会释放热能。
Conduction → solids | Convection → fluids | Radiation → vacuum allowed
5. Waves: Sound and Light | 波：声与光
Waves transfer energy without transferring matter. Sound and light dominate this topic, and being able to label a wave diagram and use the wave equation is essential.
波传递能量却不传递物质。声音与光占据了本专题的核心，能够标注波形图并使用波速方程至关重要。
Transverse wave: A wave in which particle vibrations are perpendicular to the direction of energy transfer. Light and water ripples are transverse. Think of a 'T' — the top line is perpendicular to the stem.
横波：粒子的振动方向与能量传递方向垂直的波。光波和水波都是横波。联想字母 'T' 的横竖垂直。
Longitudinal wave: A wave where particle vibrations are parallel to the energy transfer direction. Sound is a longitudinal wave; compressions and rarefactions move along the spring-like path. 'Longitudinal' contains 'long' — vibrations travel along.
纵波：粒子振动方向与能量传递方向平行的波。声波是纵波，压缩区与稀疏区沿传导路径移动。'纵波' 的 '纵' 包含 '沿着' 之意。
Amplitude: The maximum displacement of a wave from its rest position. Related to loudness of sound and brightness of light. Bigger amplitude, more energy carried.
振幅：波离开平衡位置的最大位移。与声音的响度和光的亮度相关。振幅越大，携带能量越多。
Wavelength: The distance between two consecutive crests (or compressions). Symbol: λ (lambda). Unit: metre (m).
波长：两个相邻波峰（或压缩区）之间的距离。符号：λ (lambda)。单位：米 (m)。
Frequency: second. Unit: hertz (Hz). 1 Hz = 1 wave per second. High frequency sound is high-pitched.
频率：每秒通过某点的完整波数。单位：赫兹 (Hz)。1 Hz = 每秒 1 个波。频率高的声音音调高。
Wave speed: : How fast the wave travels. Formula: v = f λ. This equation works for sound, light and water waves.
波速：波传播的快慢。公式：v = f λ。此方程适用于声波、光波和水波。
Reflection: The bouncing back of a wave when it hits a boundary. Law of reflection: angle of incidence equals angle of reflection. Echo is reflected sound.
反射：波遇到界面时返回原介质的现象。反射定律：入射角等于反射角。回声就是声波的反射。
Refraction: The bending of a wave as it passes from one medium to another due to a change in speed. A straw in water looks broken because of refraction.
折射：波由于速度变化而通过不同介质时发生弯曲的现象。水中的吸管看起来像是断了，正是折射的效果。
v = f λ
6. Electricity | 电学
Electricity powers our modern world. Year 9 students need to know current, voltage and resistance, and be able to compare series and parallel circuits.
电驱动着现代世界。Year 9 学生需要了解电流、电压和电阻，并能比较串联与并联电路。
Current (I): The rate of flow of electric charge. Measured in amperes (A). In a single loop, current is the same everywhere.
电流 (I)：电荷流动的速率。单位是安培 (A)。在单一回路中，各处的电流相同。
Voltage (potential difference, V): The energy transferred per unit charge between two points. Think of it as the 'push' that drives current around the circuit. Unit: volt (V).
电压（电势差, V）：单位电荷在两点的能量转移量。可看作推动电荷绕电路移动的“推力”。单位：伏特 (V)。
Resistance (R): The opposition to the flow of current. It depends on the material, length and thickness of the conductor. Unit: ohm (Ω).
电阻 (R)：对电流流动的阻碍作用。它取决于导体的材料、长度和粗细。单位：欧姆 (Ω)。
Ohm's law: nstant temperature is directly proportional to the voltage across it. V = I R. Memory aid: 'V' is 'very large I times R'.
欧姆定律：在温度不变时，通过电阻的电流与其两端电压成正比。V = I R。助记：把 V I R 当作一个缩写词记住。
Series circuit: Components connected one after another in a single loop. Current is the same everywhere; voltage is shared. If one bulb fails, the circuit is broken.
串联电路：元件依次首尾相连的单一环路。电流处处相等；电压被分配。若一个灯泡熄灭，整个电路断开。
Parallel circuit: Components connected on separate branches. Voltage across each branch is identical; currents add up to the total. If one bulb fails, others remain on.
并联电路：元件接在不同支路上。各支路电压相等；干路电流等于各支路电流之和。一个灯泡坏了不影响其他灯泡。
Conductor and insulator: Conductors (e.g., copper) allow charge to flow easily; insulators (e.g., plastic) do not. Key for safety.
导体和绝缘体：导体（如铜）允许电荷自由流动；绝缘体（如塑料）阻止电荷流动。这对安全至关重要。
V = I R | Series: I same, V shared | Parallel: V same, I branches
7. Magnetism | 磁学
Magnetism involves invisible fields that exert forces. From permanent magnets to electromagnets, these concepts appear in everything from compasses to electric bells.
磁学涉及施加力的无形场。从永磁体到电磁铁，这些概念存在于从指南针到电铃的各种装置中。
Magnetic pole: The region of a magnet where the magnetic force is strongest
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