📚 Quick Guide to Memorising Year 9 OCR Physics Terms | Year 9 OCR 物理：词汇术语速记指南
Mastering physics vocabulary in Year 9 is not just about memorising definitions – it's about connecting terms to real-world ideas, spotting patterns in word roots, and using simple memory tricks. This guide organises the most important OCR physics terms into ten themed sections, each packed with English–Chinese paired explanations, mnemonic tips and carefully presented equations. You will build confidence for tests and practical work while avoiding the most common mix-ups.
Year 9 物理术语的学习并非死记硬背，而是要把词汇与真实现象联系起来、发现词根规律并掌握巧记方法。本指南将 OCR 物理最关键的概念分成十个主题，每个板块都采用中英对照讲解，搭配记忆锦囊和清晰呈现的公式。通过阅读和实践，你能在考试与实验课中更自信，并避开最常见的混淆点。
1. Forces and Motion | 力与运动
A force is a push or a pull, measured in newtons (N). It is a vector quantity, meaning it has both magnitude and direction. Imagine an arrow: the tail shows the application point, the length shows size, and the arrowhead shows direction.
力是推或拉，单位是牛顿 (N)。力是矢量，既有大小也有方向。想象一支箭：箭尾表示作用点，长度表示大小，箭头指示方向。
Weight is the downward pull of gravity on a mass, not the same as mass itself. Mass (in kg) tells you how much matter an object contains and stays the same everywhere. Weight changes with gravity: on the Moon your weight would be about one-sixth of that on Earth, but your mass would be unchanged. The equation is W = m × g
重量是重力对质量的向下拉力，不同于质量本身。质量（单位 kg）表示物体所含物质的多少，在任何地方都不变。重量随重力变化：在月球上你的重量约为地球的六分之一，但质量不变。公式为 W = m × g
Friction and air resistance are forces that oppose motion. They can be useful (walking, brakes) or a nuisance (engine wear). When forces on an object are balanced, it stays at rest or moves at constant speed; when unbalanced, the object accelerates or decelerates.
摩擦力和空气阻力是阻碍运动的力，既有用（行走、刹车）也有害（发动机磨损）。当物体受力平衡时，保持静止或匀速运动；受力不平衡时，会加速或减速。
Speed is a scalar (just a number with a unit), whereas velocity is a vector (speed in a given direction). Acceleration is any change in velocity – speeding up, slowing down or changing direction. The formula linking initial velocity (u), final velocity (v), acceleration (a) and time (t) is v = u + a t
速率是标量（只有数值和单位），而速度是矢量（带方向的速率）。加速度指速度的任何变化——变快、变慢或改变方向。联系初速度 (u)、末速度 (v)、加速度 (a) 和时间 (t) 的公式是 v = u + a t
Memory tip: 'Scalar' and 'Speed' both start with S, and both are simple. 'Vector' and 'Velocity' both start with V, and both involve direction. Think 'S for Speed, V for Velocity with an arrow'.
记忆法：‘Scalar’ 和 ‘Speed’ 都以 S 开头，都单纯；‘Vector’ 和 ‘Velocity’ 都以 V 开头，都涉及方向。联想“S 是速度值，V 是带箭头的速度”。
2. Energy Types and Transfers | 能量类型与转化
Energy is the ability to do work and is measured in joules (J). It can be stored (potential) or moving (kinetic). The principle of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed.
能量是做功的本领，单位是焦耳 (J)。能量可储存（势能）或处于运动中（动能）。能量守恒定律指出能量无法被创造或消灭，只能转移或转化。
Kinetic energy depends on mass and speed: KE = ½ m v² Notice that doubling the speed quadruples the kinetic energy – that is why high-speed collisions are so dangerous.
动能取决于质量和速率：KE = ½ m v² 速率加倍，动能变为四倍——这正是高速碰撞十分危险的原因。
Gravitational potential energy (GPE) is the energy an object has because of its height above the ground: GPE = m g h where h is the vertical height. Lifting a book onto a shelf increases its GPE; dropping it converts GPE to KE.
重力势能 (GPE) 是物体因处于高处而具有的能量：GPE = m g h h 为垂直高度。把书举到书架上增加其 GPE；松手后 GPE 转化为动能。
Work done and energy transferred are the same thing: W = F × d Power is the rate of doing work: P = W / t A powerful motor does the same work in less time. Remember: 'Power' and 'Pace' both relate to how fast something happens.
做的功与转移的能量是一回事：W = F × d 功率是做功的速率：P = W / t 大功率的马达能在更短时间内做同样多的功。记住：‘Power’ 和 ‘Pace’（步速）都与快慢有关。
3. Waves – Sound and Light | 波 – 声音与光
Waves transfer energy without transferring matter. In transverse waves, such as light and water ripples, the oscillations are perpendicular to the direction of energy travel. In longitudinal waves, such as sound, the particles vibrate parallel to the wave direction, producing compressions and rarefactions.
波传递能量而不传递物质。横波（如光波、水波）的振动方向与能量传播方向垂直。纵波（如声波）的粒子振动方向平行于传播方向，形成疏密部。
Amplitude is the maximum displacement from the rest position – it determines loudness in sound and brightness in light. Wavelength (λ) is the distance between two identical points on consecutive waves. Frequency (f) is the number of complete waves passing a point per second, measured in hertz (Hz). Period (T) is the time for one complete wave: T = 1 / f
振幅是离开平衡位置的最大位移——它决定声音的响度和光的亮度。波长 (λ) 是相邻波上两个相同点之间的距离。频率 (f) 是每秒通过某点的完整波数，单位是赫兹 (Hz)。周期 (T) 是一个完整波所需的时间：T = 1 / f
The wave speed equation links all three: v = f λ 340 m/s in air; light travels nearly a million times faster. To remember the order, think 'Very Fast Light' – V = f λ, and 's' in 'sound' is slower.
波速方程把三个量联系起来：v = f λ 声音在空气中约 340 m/s；光速比声速快近百万倍。助记：‘Very Fast Light’ 对应 v = f λ，而 ‘sound’ 里的 s 暗示 slower。
4. Electricity – Circuits and Components | 电 – 电路与元件
Electric current (I) is the flow of electric charge, measured in amperes (A). In a metal wire, current is a flow of negative electrons. Conventional current is drawn from positive to negative, but electrons actually move the opposite way – just remember 'electron flow is the real show'.
电流 (I) 是电荷的流动，单位是安培 (A)。在金属导线中，电流是负电子的流动。约定的电流方向是正到负，但电子实际运动方向相反——记住‘电子流向才是真实的’。
Potential difference (voltage, V) is the push that drives the current. It is measured in volts (V) and can be thought of as the energy given to each coulomb of charge. Resistance (R) in ohms (Ω) opposes the flow. Ohm's law states: V = I × R If you increase resistance, less current flows for the same voltage – like squeezing a hose.
电势差（电压 V）是驱动电流的‘推力’，单位是伏特 (V)，可理解为每库仑电荷获得的能量。电阻 (R) 单位为欧姆 (Ω)，阻碍电流。欧姆定律为：V = I × R 提高电阻，相同电压下电流减小——就像捏紧水管。
In a series circuit the current is the same everywhere, but the supply voltage is shared across components. In a parallel circuit the voltage across each branch is the same, but the currents through the branches add up to the total current. Memory aid: 'Series shares voltage, parallel shares current.'
串联电路中电流处处相等，电源电压被各元件分摊。并联电路中各支路两端电压相同，支路电流之和等于总电流。助记：‘串联分压，并联分流。’
5. Magnetism and Electromagnets | 磁与电磁铁
A magnet has a north pole and a south pole. Like poles repel; unlike poles attract. A magnetic field is the region around a magnet where it can exert a force. Field lines point from north to south and are closest together where the field is strongest. Remember: 'North to South on paper, but inside the magnet it goes South to North.'
磁铁有 N 极和 S 极。同名极相斥，异名极相吸。磁场是磁体周围能产生磁力的区域。磁感线从 N 指向 S，线密集处磁场最强。记住：‘纸面上 N 到 S，但磁体内部 S 到 N 形成闭合回路。’
An electromagnet is created by wrapping a wire into a coil (solenoid) and passing a current through it. The strength can be increased by adding an iron core, increasing the current, or adding more turns of wire. Electromagnets are temporary – switch off the current and the magnetism disappears. They are used in relays, electric bells and scrapyard cranes.
电磁铁是将导线绕成线圈（螺线管）并通以电流制成。加入铁芯、增大电流或增加线圈匝数都能增强磁性。电磁铁是临时的——切断电流磁性立即消失。它们被用于继电器、电铃和废铁场吊车。
6. Matter – Particle Model and Density | 物质 – 粒子模型与密度
All matter is made of tiny particles that are in constant random motion. In solids, particles vibrate in fixed positions; in liquids, they slide past each other; in gases, they move rapidly and fill any container. The word 'random' here means particles have no set path – just like a buzzing crowd.
一切物质都由永不停歇地做无规则运动的微粒组成。固体中粒子在固定位置振动；液体中粒子相互滑过；气体中粒子快速移动并充满整个容器。‘无规则’指粒子没有固定路线——就像热闹人群中乱走的人。
Density (ρ) tells you how much mass is packed into a given volume: ρ = m / V A kilogram of feathers takes up far more space than a kilogram of iron, so feathers have a much lower density. Water has a density of 1 g/cm³ (1000 kg/m³); objects with density less than water float.
密度 (ρ) 表示单位体积所含的质量：ρ = m / V 1 kg 羽毛比 1 kg 铁占据的空间大得多，因此羽毛密度低。水的密度是 1 g/cm³（1000 kg/m³）；密度小于水的物体会上浮。
Pressure in fluids acts equally in all directions. Pressure increases with depth because of the weight of the fluid above. A sharp knife has a small area, so it exerts high pressure for the same force – that is why it cuts easily.
流体中的压强朝各个方向等大传递。深度越深，压强越大，因为上方的液体重量更大。锋利的刀受力面积小，相同力下压强很高，因此容易切割。
7. Space Physics | 空间物理
Gravity is the attractive force between any two masses. On Earth it gives everything weight. The gravitational field strength (g) is about 9.8 N/kg at the Earth's surface, but it decreases the further you go from the planet. 'g' is not gravity itself – it is the force per kilogram.
万有引力是任意两个质量之间的吸引力。地球上它赋予万物重量。地表附近的重力场强度 (g) 约为 9.8 N/kg，离地球越远，g 值越小。注意 g 并非引力本身，而是每千克受到的引力。
Our Solar System consists of the Sun, eight planets, moons, dwarf planets, asteroids and comets. The planets move in elliptical orbits around the Sun. A light-year is a unit of distance, not time – it is how far light travels in one year (about 9.5 trillion kilometres). Think: 'A light-year is how far light runs in a year – distance, not duration.'
太阳系由太阳、八大行星、卫星、矮行星、小行星和彗星组成。行星沿椭圆轨道绕日运行。光年是距离单位而非时间——它是光在一年中走过的距离（约 9.5 万亿千米）。联想：‘光跑一年跑出的路程是光年——是距离不是时间。’
8. Key Measuring Instruments and Units | 关键测量工具与单位
Physics relies on standard SI units: metre (m) for length, kilogram (kg) for mass, second (s) for time, ampere (A) for electric current, kelvin (K) for temperature, mole (mol) for amount of substance, and candela (cd) for luminous intensity. All other units are derived from these seven base units.
物理依赖标准国际单位制 (SI)：长度用米 (m)，质量用千克 (kg)，时间用秒 (s)，电流用安培 (A)，温度用开尔文 (K)，物质的量用摩尔 (mol)，发光强度用坎德拉 (cd)。其他所有单位均由这七个基本单位导出。
Common measuring tools: a metre ruler or tape measure for length, a stopwatch for time, a top-pan balance for mass, a newton meter (spring scale) for force, an ammeter for current (connected in series), and a voltmeter for voltage (connected in parallel). The ammeter 'A' is Always in line (series); the voltmeter 'V' is placed aCross (V for across) – 'A in line, V across.'
常见测量工具：米尺或卷尺测长度，秒表计时，托盘天平测质量，牛顿计（弹簧秤）测力，电流表串联测电流，电压表并联测电压。记忆：电流表 ‘A’ 总是串联 (in line)，电压表 ‘V’ 跨接 (across)——‘A 串 V 并’。
9. Prefixes and Suffixes in Physics | 物理词缀速记
re built from Greek and Latin roots. Learning these will help you decode unfamiliar words. 'kilo-' means thousand (1 kg = 1000 g), 'centi-' means hundredth, 'milli-' means thousandth, 'micro-' (μ) means millionth. 'Photo-' relates to light, 'therm-' to heat, 'electro-' to electricity, '-'meter' means measuring device.
大量物理术语源自希腊和拉丁词根，掌握它们能帮你推测生词。‘kilo-’ 表示千（1 kg = 1000 g），‘centi-’ 是百分之一，‘milli-’ 是千分之一，‘micro-’ 是百万分之一。‘photo-’ 与光有关，‘therm-’ 与热有关，‘electro-’ 与电有关，‘-meter’ 表示测量仪表。
Suffixes are equally helpful: '-scope' means 'to look at' (telescope, microscope), '-graph' means 'to write or record' (telegraph, barograph), '-ics' means 'science of' (physics, dynamics). 'Tension' and 'pressure' both end with '-sure', hinting at a steady influence. The more roots you know, the lighter your memory load becomes.
后缀同样有用：‘-scope’ 意为‘观察’（望远镜、显微镜），‘-graph’ 意为‘记录’（电报、气压记录仪），‘-ics’ 表示‘…学’（物理学、动力学）。‘Tension’（张力）和 ‘Pressure’（压强）都以 ‘-sure’ 结尾，暗示一种持续的作用。掌握词根越多，记忆负担越轻。
10. Common Confusions | 常见易混淆术语辨析
Mass vs. weight: Mass is the amount of 'stuff' (kg), constant everywhere. Weight is a force (N) caused by gravity. Think of an astronaut – her mass is the same in space, but she is weightless because she feels no support force. 'Weight = mass × gravity, Weight is wobbly, Mass is mellow.'
质量与重量：质量是‘物的多少’(kg)，处处不变。重量是重力产生的力 (N)。想象宇航员——她在太空中质量不变，但因不受支持力而‘失重’。‘重量随重力摇摆，质量始终沉稳。’
Speed vs. velocity: Speed says 'how fast?' Velocity says 'how fast and which way?' A car going around a roundabout at constant speed is constantly changing velocity because its direction changes. 'Speed is the size, velocity is the size and direction.'
速率与速度：速率问‘多快？’速度问‘多快、朝哪？’汽车匀速绕环岛时，速率不变，但因方向持续改变，速度一直在变。‘速率只问快慢，速度还要问方向。’
Heat vs. temperature: Temperature (in °C or K) tells you how hot or cold something is on a chosen scale. Heat (in joules) is the thermal energy transferred from a hotter object to a cooler one due to the temperature difference. A huge iceberg may have a low temperature but contains far more heat energy than a cup of boiling water.
热量与温度：温度（单位 °C 或 K）表示物体在给定标度上的冷热程度。热量（单位焦耳）是由于温差而从高温物体传递到低温物体的热内能。一座巨大的冰山温度很低，但它含有的热能远多于一杯沸水。
Series vs. parallel circuits: In a series circuit there is only one path for current; if one bulb breaks, all bulbs go out. In a parallel circuit each bulb has its own branch, so the others stay lit. Think of a string of fairy lights – older sets were series and went dark together; modern sets are often parallel so one broken bulb does not ruin the show.
串联与并联：串联电路只有一条电流通路，一盏灯坏掉全部熄灭。并联电路中每个灯有自己的支路，其余灯仍亮。联想一串彩灯——老式串联灯会一起灭；现代灯多为并联，一粒坏掉不影响整体。
Published by TutorHao | Physics Revision Series | aleveler.com
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