Year 12 Cambridge Physics: Key Terminology Mnemonic Guide | 剑桥物理AS术语速记指南

📚 Year 12 Cambridge Physics: Key Terminology Mnemonic Guide | 剑桥物理AS术语速记指南

Year 12 Cambridge Physics introduces a rich vocabulary that underpins both problem‑solving and conceptual understanding. This guide selects the most essential terms from the AS syllabus, pairs each English explanation with a Chinese translation, and provides short mnemonic devices to make memorisation faster and more enjoyable.

剑桥物理AS年级引入了大量支撑解题与概念理解的术语。本指南精选大纲核心词汇，以英文解释配中文翻译的形式呈现，并附上简洁的记忆口诀，帮助同学们更轻松、更高效地记住这些关键词。

1. Mechanics Foundations | 力学基础

Scalar vs Vector: A scalar has magnitude only (e.g. mass, time, temperature); a vector has both magnitude and direction (e.g. displacement, velocity, force). Remember: Vectors point where to go, like an arrow; Scalars are just a number, like the scale of a ruler.

标量与矢量：标量只有大小（如质量、时间、温度）；矢量既有大小又有方向（如位移、速度、力）。助记：矢量像箭头一样指向何方，标量只是刻度上的数字。

Displacement: The vector from the initial position to the final position. Symbol s or Δx. Think “dis‑place” — you move from your place; it is the shortest directed distance.

位移：从初位置指向末位置的矢量，符号 s 或 Δx。联想 “dis‑”（离开）+ “place”（位置）→ 离开原位的最短有向距离。

Velocity: Rate of change of displacement: v = Δs/Δt. It is a vector. Mnemonic: Vel‑o‑city — imagine a velodrome where cyclists always move with direction.

速度：位移的变化率：v = Δs/Δt，是矢量。助记：“velodrome”（自行车赛场）里的运动员总是在绕圈，运动总有方向。

Acceleration: Rate of change of velocity: a = Δv/Δt. Vector. Uniform acceleration equations apply when a is constant. Think: “accel‑erate” — you speed up or slow down, changing your velocity.

加速度：速度的变化率：a = Δv/Δt，矢量。匀加速度公式在加速度恒定时适用。联想：“加速”就是改变速度，就像踩油门或刹车。

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2. Forces and Newton’s Laws | 力与牛顿定律

Force: A push or pull that can cause acceleration. Measured in newtons (N). ∑F = ma. If you force a door open, you give it a push — that is force.

力：推或拉，能使物体加速，单位为牛顿 (N)。∑F = ma。推开门就是力在起作用。

Newton’s First Law (Inertia): An object stays at rest or moves with constant velocity unless a resultant force acts. Remember: “lazy” objects resist change — inertia sounds like inert (inactive).

牛顿第一定律（惯性）：物体在不受合外力时，静者恒静，动者恒做匀速直线运动。“惯性”就像“惰性”，物体不愿意改变自己的状态。

Newton’s Second Law: F = ma. The acceleration is proportional to the resultant force and inversely proportional to mass. F‑ma spells “F‑ma‑ous” — it is the famous equation!

牛顿第二定律：F = ma。加速度与合外力成正比，与质量成反比。F‑ma 读起来像“famous”，正是最著名的公式！

Newton’s Third Law: For every action there is an equal and opposite reaction. The forces act on different bodies. Mnemonic: “You push the wall, the wall pushes you back.”

牛顿第三定律：作用力与反作用力大小相等、方向相反，作用在不同物体上。口诀：“你推墙，墙推你。”

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3. Momentum and Collisions | 动量与碰撞

Momentum: p = mv. Vector quantity; unit kg m/s. Momentum is “mass in motion” — think of a moving lorry: it has lots of moment‑um because of its large mass and velocity.

动量：p = mv，矢量，单位kg·m/s。动量即“运动中的质量”——大卡车质量大、速度快，动量就大。

Impulse: Change in momentum, equal to FΔt. It explains why airbags reduce injury: they increase Δt, so force F decreases. Remember: impulse is the push that changes momentum in a short time.

冲量：动量的变化量，等于 FΔt。安全气囊延长了碰撞时间Δt，从而减小力。联想：“冲”就是短时间给一个力改变动量。

Conservation of Momentum: In a closed system, total momentum before collision = total momentum after. Use it for explosions and collisions. “Con‑serve” — you don’t throw momentum away, it stays.

动量守恒：孤立系统中碰撞前总动量等于碰撞后总动量。用于爆炸和碰撞问题。记住“守恒”——动量不会凭空消失，总是保持总量。

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4. Work, Energy and Power | 功、能和功率

Work: W = F d cosθ, where d is displacement in the direction of the force. Unit: joule (J). When you do work, you transfer energy by moving something. Think: “work = force × distance actually moved in force’s direction.”

功：W = F d cosθ，d 为力方向上的位移。单位焦耳(J)。做功就是通过移动物体来转移能量。记住“功 = 力 × 沿力方向的位移”。

Kinetic Energy: Eₖ = ½ m v². The energy an object has due to its motion. “Kin‑etic” shares the root with “cinema” (movement) — moving pictures = moving energy.

动能：Eₖ = ½ m v²，物体因运动而具有的能量。“kinetic”与“cinema”（电影）同根，都带有“运动”的含义。

Gravitational Potential Energy: Eₚ = m g h. Stored energy due to height. Think: “potential” — it has the potential to fall and do work.

重力势能：Eₚ = m g h，因高度而储存的能量。“势”就是潜在的做功能力，一旦落下即可释放。

Power: Rate of doing work: P = W/t or P = F v. Unit watt (W). A powerful engine does work quickly. Mnemonic: “Power = work per time”.

功率：做功的快慢：P = W/t 或 P = F v，单位瓦特(W)。强大的引擎做功快。“功率”就是单位时间做的功。

Conservation of Energy: Energy cannot be created or destroyed, only transferred or transformed. Total energy in an isolated system remains constant. “Energy conservation” — like keeping money in a closed wallet.

能量守恒：能量既不能创造也不能消灭，只能转移或转化。孤立系统总能量不变。就像钱包里的钱，只会转换形式，不会凭空消失。

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5. Materials and Deformation | 材料与形变

Density: ρ = m/V. Mass per unit volume. Unit kg/m³. “Dense” objects feel heavy for their size; lead is dense, foam is not.

密度：ρ = m/V，单位体积的质量，单位kg/m³。铅密度大，摸起来沉；泡沫密度小，轻飘飘。

Hooke’s Law: F = k x, where x is extension and k is spring constant. Valid only up to the limit of proportionality. Hooke the springs man — “Hooke’s law keeps the spring hooked to a straight line.”

胡克定律：F = k x，x为伸长量，k为劲度系数。仅在线性范围内成立。胡克就像弹簧一样，把力和伸长牢牢“勾”成直线关系。

Stress: σ = F/A. Force per unit cross‑sectional area, unit Pa. Stress is the “pressure” inside a material when pulled.

应力：σ = F/A，单位横截面积上的力，单位Pa。应力就是材料内部受到的“压强”，拉伸时内部紧绷。

Strain: ε = ΔL/L₀. Fractional extension, dimensionless. Strain rhymes with “gain” — you gain length when you stretch.

应变：ε = ΔL/L₀，相对伸长量，无量纲。应变和“伸长”押韵，一拉就变长。

Young Modulus: E = stress/strain, a measure of stiffness. Steep stress‑strain graph means high E. “Young’s modulus tells if the material is young and stiff or old and flexible.”

杨氏模量：E = 应力/应变，衡量材料刚度。应力‑应变曲线斜率越大，杨氏模量越大。杨氏模量就像材料的“年轻度”，越年轻越硬挺。

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6. Wave Phenomena | 波的现象

Transverse and Longitudinal Waves: In transverse waves, vibrations are perpendicular to wave travel (light, water). In longitudinal waves, vibrations are parallel (sound). Transverse – think “across”; longitudinal – think “along”.

横波与纵波：横波振动方向与传播方向垂直（光、水波）；纵波振动方向平行于传播方向（声波）。“横”是横跨，“纵”是纵向。

Frequency (f) and Period (T): f = 1/T. Frequency is number of oscillations per second, unit hertz (Hz). A frequent visitor comes often — high frequency means many cycles per second.

频率 (f) 与周期 (T)：f = 1/T，频率是每秒振动次数，单位赫兹(Hz)。“频繁”就是经常来，频率高就是每秒震动多次。

Wavelength (λ): Distance between two consecutive points in phase, e.g. crest to crest. “Wave‑length” — the length of one full wave cycle.

波长 (λ)：相邻同相位点之间的距离，如波峰到波峰。“波长”就是完整一个波的长度。

Phase Difference: The fraction of a cycle by which one wave leads or lags another, expressed in degrees or radians. Two points in step are in phase; opposite are in antiphase. “Phase” is like being in step while dancing.

相位差：一列波相对于另一列波超前或落后的周波分数，用角度或弧度表示。步调一致为同相，相反为反相。就像跳舞时步伐的先后。

Superposition: When two or more waves meet, the resultant displacement is the vector sum of individual displacements. Super + position = waves placed on top of each other simply add up.

叠加原理：两列波相遇时，合位移等于各分位移的矢量和。“叠”就是一摞一摞加起来。

Interference: The pattern of reinforcement and cancellation resulting from superposition. Constructive (in phase) gives bright fringes; destructive (antiphase) gives dark. Interfere means waves “get in each other’s way” and create a pattern.

干涉：叠加产生的加强和减弱图样。相长干涉（同相）产生亮纹；相消干涉（反相）产生暗纹。干涉就像两列波“互相打扰”，形成了条纹。

Diffraction: Spreading of waves when they pass through a gap or around an obstacle. Significant when gap size ≈ λ. Diffraction sounds like “detract” — waves bend away from the straight‑line path.

衍射：波穿过狭缝或绕过障碍物时发生展宽。缝宽与波长相近时衍射显著。衍射就是波不再走直线，“绕弯”了。

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7. Electricity and Circuits | 电学与电路

Current (I): Rate of flow of charge: I = ΔQ/Δt. Unit ampere (A). Conventional current flows from positive to negative. Think: current like water current — flow of electrons (or charge).

电流 (I)：电荷流动的速率：I = ΔQ/Δt，单位安培(A)。电流方向为正电荷流向。像水流一样，电流就是电荷的流动。

Potential Difference (V): Energy transferred per unit charge: V = W/Q. Unit volt (V). Also called voltage. It “pushes” charge around a circuit. Mnemonic: “Potential to do work” on each coulomb.

电势差 (V)：单位电荷转移的能量：V = W/Q，单位伏特(V)。也叫电压，驱动电荷在回路中移动。每个库仑都具有“做功的潜力”。

Resistance (R): R = V/I. Opposition to current flow. Unit ohm (Ω). A resistor resists the flow, like a narrow pipe resists water.

电阻 (R)：R = V/I，对电流的阻碍作用，单位欧姆(Ω)。电阻就像水管变窄，阻碍水流通过。

Ohm’s Law: For an ohmic conductor at constant temperature, V ∝ I, so R = constant. “V = I R” — Very Important Rule!

欧姆定律：对欧姆导体，温度不变时 V ∝ I，R为常数。记住“V=IR”，非常重要的规则！

Kirchhoff’s Laws: Junction rule: total current into a junction = total current out (charge conservation). Loop rule: sum of e.m.f. around any loop = sum of p.d. drops (energy conservation). Kirchhoff reminds you to conserve both charge and energy.

基尔霍夫定律：节点定律：流入节点的电流之和等于流出之和（电荷守恒）。回路定律：回路中电动势之和等于电压降之和（能量守恒）。基尔霍夫要求你同时守住电荷和能量。

Internal Resistance (r): The resistance inside a cell causing lost volts: V_terminal = ε – I r. “Internal” — the battery’s own tiny resistor inside that eats some energy.

内阻 (r)：电池内部的电阻，导致端电压降低：V_端 = ε – I r。电池内部自带小电阻，会吃掉一部分能量。

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8. Quantum Physics | 量子物理

Photon: A quantum of electromagnetic radiation with energy E = h f. Light comes in packets. “Photo‑n” — photo means light, and ‑n suggests a tiny particle.

光子：电磁辐射的量子，能量为 E = h f。光是以小份能量包的形式传播的。光子即“光粒子”，像一颗颗小炮弹。

Photoelectric Effect: Emission of electrons from a metal surface when light of frequency above the threshold frequency shines on it. Evidence for particle nature of light. One photo‑n kicks out one electro‑n.

光电效应：当频率高于截止频率的光照射金属表面时，电子逸出的现象。证明了光的粒子性。一个光子打出一个电子，一对一。

Threshold Frequency (f₀): Minimum frequency of light required to eject electrons from a metal. If f < f₀, no electrons are emitted however intense the light. “Threshold” — you must cross the doorstep to enter the house.

截止频率 (f₀)：使金属发射电子的最低频率。低于该频率，无论光强多大都不会发射电子。门槛频率，不过门槛休想进门。

Work Function (Φ): Minimum energy needed to remove an electron from the metal surface: Φ = h f₀. “Work function” — the work you must do to free an electron.

逸出功 (Φ)：从金属表面移除一个电子所需的最小能量：Φ = h f₀。逸出功就是把电子“拉出来”必须做的功。

Wave‑Particle Duality: Objects can exhibit both wave‑like and particle‑like behaviour. Light shows interference (wave) and photoelectric effect (particle). Electrons diffract and interfere. “Dual” means two‑faced: light plays both roles.

波粒二象性：物质既能表现波动性又能表现粒子性。光有干涉（波）和光电效应（粒子）；电子也能衍射。双重性格——光可以一会儿是波，一会儿是粒子。

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9. Nuclear and Particle Physics | 核与粒子物理

Nuclide Notation: ᴬ₂X, where A = mass number (protons + neutrons) and Z = atomic number (protons). Massive A includes all the massive nucleons.

核素符号：ᴬ₂X，A为质量数（质子+中子），Z为原子序数（质子数）。质量数A包含了所有大块头的核子。

Isotopes: Atoms of the same element with same Z but different A. They have different numbers of neutrons. Iso‑ means same; ‑tope means place — same place in the periodic table.

同位素：同一元素中质子数(Z)相同但质量数(A)不同的原子，中子数不同。同位即“同一位置”，在周期表中占据同一格。

Radioactive Decay: Unstable nuclei emit particles or radiation to become more stable. Alpha (⁴₂He), beta⁻ (electron), beta⁺ (positron), gamma (photon). Radio as in “radio waves” — radiation is emitted invisibly.

放射性衰变：不稳定的原子核通过发射粒子或辐射趋向稳定。包括α衰变(⁴₂He)、β⁻衰变(电子)、β⁺衰变(正电子)、γ辐射(光子)。“放射”就像广播发射看不见的波。

Half‑Life (T½): Time taken for half the radioactive nuclei in a sample to decay. It is constant for a given isotope. “Half‑life” means after one half‑life, half of the atoms remain.

半衰期 (T½)：样品中一半放射性原子核衰变所需的时间。对特定同位素为常数。过一个半衰期就剩一半，再过一半又剩一半。

Quarks and Leptons: Fundamental particles. Protons and neutrons consist of up (u) and down (d) quarks. Electrons are leptons. “Quark” sounds like a cork in wine — it’s inside the nucleon bottle.

夸克与轻子：基本粒子。质子和中子由上夸克(u)和下夸克(d)组成。电子属于轻子。夸克就像软木塞，塞在核子瓶子里。

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10. Experimental Skills and Error Terms | 实验技能与误差术语

Accuracy: How close a measurement is to the true value. High accuracy means near the bullseye. “Accurate” -> “accurate as a sharpshooter”.

准确度：测量值接近真值的程度。准确度高就像打靶命中靶心。准确如同神枪手。

Precision: How close repeated measurements are to each other, without regard to the true value. A precise set of data clusters tightly together. “Precision” — many darts in a small group, even if not in the centre.

精密度：多次测量值彼此接近的程度，不考虑真值。精密度高的一组数据聚集紧密。就像飞镖全扎在一小撮，即使未中靶心。

Systematic Error: An error that shifts all readings in one direction (e.g. zero error on a voltmeter). It affects accuracy but not necessarily precision. “Systematic” means it follows a system — consistent bias.

系统误差：使所有读数向同一方向偏移的误差（如电压表零点误差）。影响准确度，但不一定影响精密度。系统误差是“系统性的”偏置。

Random Error: Unpredictable fluctuations that scatter readings about the true value. Reduced by averaging many readings. Random like rolling dice — you never know which way they’ll go.

随机误差：不可预测的波动使读数围绕真值分散。通过多次测量取平均值来减小。随机好比掷骰子，结果不定。

Uncertainty: The interval within which the true value is expected to lie, often expressed as ± half the smallest scale division or standard deviation. “Uncertainty” — you are not 100% certain, so you give a range.

不确定度：真值预期落在一个区间内，通常以最小分度的一半或标准差表示。不确定就是没有百分之百的把握，所以给一个范围。

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