📚 GCSE AQA Physics: Last-Minute Revision Notes | GCSE AQA 物理：考前冲刺笔记
This comprehensive revision guide covers the most essential topics, equations, and practical skills for the AQA GCSE Physics exam. Use it to organise your final review, spot common mistakes, and reinforce key concepts. Each section pairs concise English explanations with Chinese translations so you can grasp the ideas quickly and accurately.
这份全面的复习指南涵盖了 AQA GCSE 物理考试最重要的主题、方程和实验技能。用它来整理考前回顾，发现常见错误，并巩固核心概念。每个部分都配以简洁的英文解释和中文翻译，帮助你迅速精准地掌握要领。
1. Energy Stores and Transfers | 能量储存与转移
Energy exists in different stores: kinetic, gravitational potential, elastic potential, thermal, chemical, magnetic, electrostatic, and nuclear. In any system change, energy moves between stores along four pathways – mechanical work, electrical work, heating, and radiation – but the total energy in a closed system never changes (conservation of energy).
能量以不同形式储存：动能、重力势能、弹性势能、热能、化学能、磁能、静电和核能。任何系统变化中，能量会通过四种途径——机械做功、电做功、加热和辐射——在储存库之间转移，但封闭系统中的总能量保持不变（能量守恒）。
When a force moves an object, work is done: W = F s. Rate of energy transfer is power: P = E / t. Kinetic energy depends on mass and speed squared, while gravitational potential energy rises with height.
力使物体移动时做功：W = F s。能量转移速率即功率：P = E / t。动能取决于质量和速度的平方，而重力势能随高度增加。
Kinetic energy: Ek = ½ m v² | Gravitational potential energy: Ep = m g h
Always convert to SI units: mass in kg, speed in m/s, height in m, force in N, energy in J. Sankey diagrams show useful and wasted energy as arrows of different widths.
务必转换为国际单位：质量用 kg，速度用 m/s，高度用 m，力用 N，能量用 J。Sankey 图用不同宽度的箭头显示有用能量和浪费能量。
2. Electricity and Circuits | 电学与电路
Electric current is the rate of flow of charge. In a single closed loop, the current is the same everywhere; potential difference (voltage) across the supply is shared between components in series. In parallel branches, the supply voltage appears across each branch while the total current splits.
电流是电荷流动的速率。在单一闭合回路中，各处电流相同；串联时电源电压在元件间分配。并联时，每条支路两端均为电源电压，总电流分叉。
Charge: Q = I t | Ohm’s law: V = I R | Power: P = I V = I² R
Resistance of a wire increases with length and decreases with cross-sectional area. Required practical: investigate how the length of a resistance wire affects its resistance using an ammeter, voltmeter, and variable resistor.
导线的电阻随长度增加而增大，随横截面积增大而减小。必做实验：采用电流表、电压表和滑动变阻器，探究电阻丝长度如何影响其电阻。
| Component | I–V characteristic |
|---|---|
| Resistor (constant temp.) | Straight line through origin – current proportional to voltage |
| Filament lamp | Curve flattening at high voltage – resistance increases as it heats up |
| Diode | Very high resistance in reverse – only conducts in forward bias above ~0.6 V |
元件：定值电阻（恒温）的 I–V 曲线为过原点的直线，电流与电压成正比；白炽灯丝曲线在高电压处变平，因为温度升高电阻增大；二极管反向电阻极大，仅在正向偏压约 0.6 V 以上导通。
In the UK, the mains supply is 230 V, 50 Hz alternating current. Live wire is brown, neutral blue, earth wire green-and-yellow. Fuses and circuit breakers prevent overheating.
英国市电为 230 V、50 Hz 交流电。火线棕色，零线蓝色，接地线黄绿色。保险丝和断路器防止过热。
3. Particle Model of Matter | 物质的粒子模型
Density measures how tightly packed the particles are. The particle model explains changes of state: melting, boiling, condensing, freezing, sublimation. During a change of state, the temperature stays constant while internal energy increases or decreases.
密度衡量粒子排列的紧密程度。粒子模型解释物态变化：熔化、沸腾、凝结、凝固、升华。物态变化时温度保持不变，但内能增减。
Density: ρ = m ÷ V | Specific heat capacity: ΔE = m c Δθ
Specific latent heat is the energy needed to change state without changing temperature. Lf for fusion, Lv for vaporisation: E = m L.
比潜热是改变物态而不改变温度所需的能量。熔化潜热 Lf，汽化潜热 Lv：E = m L。
In a gas, pressure is caused by particles colliding with walls. If temperature is constant, doubling the volume halves the pressure – p V = constant. Increasing temperature at constant volume raises pressure because particles move faster and hit harder.
在气体中，压强由粒子撞击容器壁引起。恒温下，体积加倍则压强减半——p V = 常数。定容升温时，压强增大，因为粒子运动更快、撞击更猛烈。
4. Atomic Structure and Radioactivity | 原子结构与放射性
The atom contains a tiny, positively charged nucleus made of protons and neutrons, surrounded by electrons in energy levels. Atomic number Z = number of protons, mass number A = protons + neutrons. Isotopes share the same Z but differ in neutron number.
原子含有一个极小的带正电的原子核，由质子和中子组成，周围电子在能级上运动。原子序数 Z = 质子数，质量数 A = 质子 + 中子。同位素质子数相同而中子数不同。
Unstable nuclei emit radiation: alpha (α: ₂⁴He nucleus, heavy, strong ionisation, stopped by paper), beta (β⁻: fast electron, medium ionisation, stopped by thin aluminium), gamma (γ: electromagnetic wave, weak ionisation, reduced by thick lead). Radioactive decay is random and each isotope has a fixed half-life.
不稳定核素发出辐射：α 辐射（₂⁴He 核，重，电离性强，纸张可挡）、β⁻ 辐射（高速电子，中等电离，薄铝板可挡）、γ 辐射（电磁波，电离性弱，厚铅板可减弱）。放射性衰变是随机的，每种同位素具有固定的半衰期。
Nuclear equations balance total mass and atomic numbers. Applications include medical tracers, radiotherapy, and smoke alarms. Nuclear fission splits a large nucleus; nuclear fusion joins light nuclei – the Sun’s energy comes from fusion.
核方程须平衡总质量和原子序数。应用包括医疗示踪剂、放射治疗和烟雾报警器。核裂变使大核分裂；核聚变将轻核合并——太阳的能量来自聚变。
5. Forces and Motion | 力与运动
Scalars have magnitude only (speed, distance, energy). Vectors have magnitude and direction (velocity, displacement, force, momentum). A resultant force causes acceleration according to F = m a and weight is a force due to gravity: W = m g (g = 9.8 N/kg on Earth).
标量只有大小（速率、路程、能量）。矢量既有大小也有方向（速度、位移、力、动量）。合力产生加速度，遵循 F = m a；重力为重量：W = m g（地表 g = 9.8 N/kg）。
Velocity: v = s / t | Acceleration: a = Δv / t | Momentum: p = m v
In a closed system, momentum is conserved: total momentum before = total momentum after. Stopping distance = thinking distance + braking distance; factors include speed, reaction time, road conditions, and tyre state.
封闭系统中动量守恒：碰撞前后的总动量相等。制动距离 = 思考距离 + 刹车距离；影响因素有车速、反应时间、路面状况和轮胎状态。
For springs obeying Hooke’s law, extension is proportional to force up to the limit of proportionality: F = k e. Elastic potential energy: Ee = ½ k e². Required practical: measure force-extension for a spring and calculate the spring constant.
对遵守胡克定律的弹簧，在比例极限范围内伸长量与力成正比：F = k e。弹性势能：Ee = ½ k e²。必做实验：测量弹簧的力-伸长关系并计算劲度系数。
6. Waves and the Electromagnetic Spectrum | 波动与电磁波谱
Waves transfer energy without transferring matter. Transverse waves (e.g. light, water waves) vibrate perpendicular to energy transfer; longitudinal waves (e.g. sound) vibrate parallel. The wave equation links speed, frequency, and wavelength: v = f λ.
波动传递能量而不传递物质。横波（如光波、水波）振动方向与能量传递方向垂直；纵波（如声波）振动方向平行。波动方程联系波速、频率和波长：v = f λ。
Electromagnetic waves form a continuous spectrum: radio, microwave, infrared, visible, ultraviolet, X-ray, gamma – in order of increasing frequency and decreasing wavelength. All travel at 3.0 × 10⁸ m/s in a vacuum.
电磁波形成连续谱：无线电波、微波、红外线、可见光、紫外线、X 射线、伽马射线——频率依次升高、波长依次变短。它们在真空中速度均为 3.0 × 10⁸ m/s。
Reflection follows the law: angle of incidence = angle of reflection. Refraction occurs when a wave crosses a boundary and changes speed. Convex lenses converge light to a real or virtual image depending on object distance.
反射遵循定律：入射角 = 反射角。波穿过界面发生折射，速度改变。凸透镜根据物距会聚光线形成实像或虚像。
Required practical: measure the speed of waves on water or in a solid, and investigate reflection and refraction with a ray box.
必做实验：测量水波或固体中的波速，并用光线盒研究反射和折射。
7. Magnetism and Electromagnetism | 磁学与电磁学
A current-carrying wire produces a magnetic field (right-hand grip rule). An electromagnet uses a soft iron core to strengthen the field. The motor effect: a conductor in a magnetic field experiences a force when current flows, given by Fleming’s left-hand rule.
通电导线产生磁场（右手螺旋定则）。电磁铁利用软铁芯增强磁场。电动机效应：处在磁场中的导体通电时会受到力，可用弗莱明左手定则判断方向。
Force on a conductor: F = B I L (when perpendicular)
Electromagnetic induction: moving a wire through a magnetic field (or changing the field) induces a potential difference. Generators rotate a coil in a magnetic field to produce alternating current; dynamos produce direct current via a split-ring commutator.
电磁感应：导线在磁场中移动（或磁场变化）会感应出电势差。发电机在磁场中旋转线圈产生交流电；通过裂环整流器产生直流电的称为直流发电机。
Transformers change the size of an alternating voltage. For an ideal transformer:
Vp / Vs = np / ns | Pp = Ps
Step-up transformers increase voltage and decrease current to minimise energy losses in the National Grid.
升压变压器提高电压、降低电流，以减小国家电网中的能量损耗。
8. Space Physics | 空间物理
Our solar system includes the Sun, planets, dwarf planets, moons, asteroids, and comets. Orbits result from the balance between gravitational pull and the object’s velocity. For a stable circular orbit, the gravitational force provides the centripetal force, and speed changes with radius.
太阳系包括太阳、行星、矮行星、卫星、小行星和彗星。轨道运动是引力与物体速度平衡的结果。稳定圆周轨道中，万有引力充当向心力，速度随轨道半径改变。
The life cycle of a star depends on its mass. A Sun-like star evolves: nebula → protostar → main sequence → red giant → white dwarf. More massive stars end as supernova then neutron star or black hole. Fusion in stars produces elements up to iron; heavier elements form in supernovae.
恒星的生命周期取决于质量。类似太阳的恒星演化：星云 → 原恒星 → 主序星 → 红巨星 → 白矮星。质量更大的恒星终结为超新星，然后形成中子星或黑洞。恒星内部聚变生成至铁的元素；更重的元素在超新星爆发中产生。
Redshift of light from distant galaxies shows they are moving away; more distant galaxies have greater redshift, revealing the Universe is expanding. This supports the Big Bang theory. Key evidence also includes cosmic microwave background radiation.
遥远星系的光谱红移表明它们正在远离；距离越远红移越大，说明宇宙在膨胀，这支撑了大爆炸理论。关键证据还包括宇宙微波背景辐射。
9. Key Required Practicals | 关键必做实验
| Practical | Core measurement / objective |
|---|---|
| Density | Measure mass and volume of regular/irregular solids and liquids; use displacement can for irregular shape. |
| Specific heat capacity | Heat a metal block, record Δθ, electrical energy input, calculate c = ΔE/(m Δθ). |
| Resistance of a wire | 更多咨询请联系16621398022（同微信）
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