📚 Year 8 Cambridge Physics: Glossary & Memory Guide | 剑桥物理八年级词汇术语速记指南
Mastering the language of physics is the first step toward understanding how the universe works. This guide covers essential vocabulary for the Year 8 Cambridge Physics curriculum, linking each term to clear definitions and memorable learning tips. Use these pairs to build confidence before tests and to develop a habit of thinking in both English and scientific terms.
掌握物理语言是理解宇宙运行规律的第一步。这份指南覆盖了剑桥八年级物理课程的核心词汇，每个术语都配有清晰的定义和易记的学习提示。用这些双语搭配来建立考前信心，养成用英语和科学术语思考的习惯。
1. Forces and Motion | 力与运动
A force is a push or a pull that can change the speed, direction or shape of an object. The unit of force is the newton (N).
力是能改变物体速度、方向或形状的推或拉，力的单位是牛顿（N）。
Friction is a contact force that opposes motion between two surfaces. It can be reduced by lubricants or streamlined shapes.
摩擦力是一种阻碍两个表面相对运动的接触力，可以用润滑剂或流线型外形来减小。
Air resistance (drag) is a type of friction that slows objects moving through air. A skydiver feels less drag when curled up.
空气阻力（也称为拖曳力）是一种减慢物体在空气中运动速度的摩擦力。跳伞者蜷起身子时感受到的阻力较小。
Mass is the amount of matter in an object, measured in kilograms (kg). It does not change with location.
质量是物体所含物质的多少，以千克（kg）为单位，不随位置改变。
Weight ational field strength (W=mg). The gravitational field strength on Earth is about 10 N/kg.
重量是作用在质量上的重力，重量 = 质量 × 重力场强度（W=mg）。地球上的重力场强度约为 10 N/kg。
Speed travelled per unit time. Average speed = total distance ÷ total time, often given in m/s.
速度是单位时间内通过的路程，平均速度 = 总路程 ÷ 总时间，通常用米/秒（m/s）表示。
Acceleration is the rate at which speed changes. A negative acceleration (deceleration) means slowing down.
加速度是速度变化的快慢，负加速度（减速）意味着速度变慢。
Mnemonics: Think of 'FUN' for Forces: Friction, Upthrust, Normal. For W=mg, remember 'Weight is mass times gravity'.
记忆法：用力学的“推拉变形”来记忆力的效果；W=mg 记成“重量是质量乘以引力”。
2. Energy | 能量
Energy is the ability to do work. It is measured in joules (J) and cannot be created or destroyed, only transferred or transformed.
能量是做功的本领，以焦耳（J）为单位，能量既不会凭空产生也不会凭空消失，只能转移或转化。
Kinetic energy is the energy of motion. A moving car has more kinetic energy at higher speeds.
动能是物体由于运动而具有的能量，高速行驶的汽车具有更大的动能。
Gravitational potential energy (GPE) is energy stored due to an object's height. GPE = mgh.
重力势能是物体因高度而储存的能量，重力势能 = mgh。
Thermal energy transfers from hotter to cooler objects. It is linked to the random motion of particles.
热能从较热的物体传递到较冷的物体，与粒子的随机运动有关。
Conduction is the transfer of thermal energy through a solid without the substance moving. Metals are good conductors.
热传导是热能通过固体传递而物质本身不移动的过程，金属是良导体。
Convection is the transfer of heat in liquids and gases by the movement of the fluid itself. Hot fluid rises, cool fluid sinks.
热对流是液体和气体通过流体本身的运动来传递热量，热流体上升，冷流体下沉。
Radiation transfers energy by electromagnetic waves, such as infrared. It can travel through a vacuum.
热辐射通过电磁波（如红外线）传递能量，可以在真空中传播。
Renewable energy sources include solar, wind, hydroelectric and tidal power. They can be replenished.
可再生能源包括太阳能、风能、水力发电和潮汐能，可以自然补充。
Memory tip: Remember the energy circus – energy changes form as it moves through a system, like a light bulb converting electrical energy to light and heat.
记忆提示：想象“能量马戏团”——能量在系统中不断变换形式，比如灯泡将电能转化为光能和热能。
3. Waves | 波
A wave is a disturbance that transfers energy from one place to another without transferring matter.
波是将能量从一个地方传递到另一个地方的扰动，而不传递物质。
Transverse waves have vibrations perpendicular to the direction of energy transfer. Light and water waves are transverse.
横波的振动方向与能量传递方向垂直，光波和水波是横波。
Longitudinal waves have vibrations parallel to the direction of energy transfer. Sound waves are longitudinal.
纵波的振动方向与能量传递方向平行，声波是纵波。
Amplitude is the maximum displacement from the rest position. Larger amplitude means louder sound or brighter light.
振幅是离开平衡位置的最大位移，振幅越大声音越响或光越强。
Wavelength is the distance between two consecutive crests or compressions.
波长是两个相邻波峰或相邻密部之间的距离。
Frequency is the number of complete waves passing a point per second, measured in hertz (Hz). High frequency means high pitch.
频率是每秒通过某点的完整波的数量，以赫兹（Hz）为单位，频率高则音调高。
Visual tip: Draw a slinky spring – push and pull to see longitudinal, flick sideways to see transverse. Amplitude is height, wavelength is crest-to-crest.
可视化技巧：画一个弹簧——推拉可看到纵波，侧向抖动能看到横波。振幅是高度，波长是相邻波峰间距。
4. Light and Sound | 光与声
Light travels in straight lines at a speed of 3 × 10⁸ m/s in a vacuum. Reflection and refraction are key behaviours.
光在真空中沿直线传播，速度为 3 × 10⁸ 米/秒，反射和折射是其主要行为。
Reflection g of is the bouncing of light off a surface. The law of reflection: angle of incidence = angle of reflection.
反射是光在表面弹回的现象，反射定律：入射角等于反射角。
Refraction is the bending of light as it passes from one medium to another due to a change in speed.
折射是光从一种介质进入另一种介质时因速度变化而发生的弯曲现象。
Dispersion splits white light into the colours of the spectrum (red, orange, yellow, green, blue, indigo, violet) using a prism. Rainbow!
色散用棱镜将白光分解成光谱颜色（红、橙、黄、绿、蓝、靛、紫），就像彩虹。
Sound is produced by vibrations and travels as a longitudinal wave. It needs a medium (solid, liquid or gas) to travel; sound cannot travel through a vacuum.
声音由振动产生，以纵波形式传播。声音需要介质（固体、液体或气体）传播，不能在真空中传播。
Pitch depends on frequency. A high-pitched sound has a high frequency, like a whistle.
音调取决于频率，高音调的声音频率高，比如口哨声。
Volume (loudness) depends on amplitude. Bigger vibrations create louder sounds.
音量（响度）取决于振幅，振动幅度越大声音越响。
Mnemonics: 'ROYGBIV' for colours of the rainbow. For reflection, 'i = r' always. Sound needs a 'medium machine' to move.
记忆法：用“ROYGBIV”记彩虹颜色顺序，反射角“i = r”永远相等，声音需要“介质机器”才能传播。
5. Electricity | 电学
Current is the flow of electric charge, measured in amperes (A). In a circuit, conventional current flows from positive to negative.
电流是电荷的定向移动，以安培（A）为单位。在电路中，惯例电流从正极流向负极。
Voltage (potential difference) is the push that drives charge around a circuit, measured in volts (V).
电压（电位差）是驱动电荷在电路中流动的“推力”，以伏特（V）为单位。
Resistance is the opposition to current flow, measured in ohms (Ω). Longer or thinner wires have higher resistance.
电阻是对电流流动的阻碍，以欧姆（Ω）为单位，导线越长或越细则电阻越大。
Ohm's law links them: voltage = current × resistance (V=IR).
欧姆定律将三者联系起来：电压 = 电流 × 电阻（V=IR）。
Series circuit: there is only one path for current; components share the voltage but the current is the same everywhere.
串联电路：电流只有一条通路，用电器共享电压，但各处电流相等。
Parallel circuit: there are multiple branches; the voltage across each branch is the same, but the current divides.
并联电路：有多条支路，每条支路电压相同，但电流会分流。
Conductor allows charge to flow easily (e.g. copper). Insulator doesn't (e.g. plastic).
导体容易让电荷通过（如铜），绝缘体不容易（如塑料）。
Memory aid: Think of electricity like water flow – voltage is pressure, current is flow rate, resistance is pipe width.
记忆辅助：把电想象成水流——电压是水压，电流是流率，电阻是管道粗细。
6. Magnetism | 磁学
A magnet has two poles: north and south. Like poles repel, unlike poles attract.
磁体有两个磁极：北极和南极，同名磁极相互排斥，异名磁极相互吸引。
Magnetic field is the region around a magnet where magnetic forces act. Field lines go from north to south outside the magnet.
磁场是磁体周围存在磁力作用的区域，磁感线在磁体外部从北极指向南极。
Electromagnet is a coil of wire (solenoid) with an iron core that becomes magnetic when current flows. It can be turned on and off.
电磁铁是一个绕有线圈（螺线管）并带有铁芯的装置，通电时产生磁性，可以随时开关。
Permanent magnet keeps its magnetism, e.g. steel. Temporary magnet loses it easily, e.g. soft iron.
永磁体能保持磁性，如钢；临时磁体容易失磁，如软铁。
Magnetic materials include iron, nickel, cobalt and their alloys. Not all metals are magnetic.
磁性材料包括铁、镍、钴及其合金，并非所有金属都有磁性。
Use the phrase 'Never Lower Cows' for poles? Better: 'NN-SS repel, NS-SN attract.' Or simply draw a compass.
记忆：同名极相斥、异名极相吸，画一个小磁针就能记住磁场方向。
7. Matter and Density | 物质与密度
Matter is anything that has mass and takes up space. It exists in three common states: solid, liquid and gas.
物质是任何具有质量并占据空间的东西，通常以三种状态存在：固态、液态和气态。
Particle model: solids have fixed, closely packed particles; liquids have particles that can slide past each other; gases have widely spaced, fast-moving particles.
粒子模型：固体的粒子排列紧密且固定；液体的粒子可以相对滑动；气体的粒子间距大且快速运动。
Density is mass per unit volume. Formula: density = mass ÷ volume (ρ = m/V). Unit: kg/m³ or g/cm³.
密度是单位体积的质量，公式：密度 = 质量 ÷ 体积（ρ = m/V），单位是 kg/m³ 或 g/cm³。
Expansion occurs when matter is heated; particles vibrate more and take up more space. Contraction happens when cooled.
热膨胀是物质受热时粒子振动加剧从而占据更大空间的现象，冷却时会收缩。
Changes of state: melting (solid to liquid), freezing (liquid to solid), boiling/evaporation (liquid to gas), condensation (gas to liquid), sublimation (solid to gas).
物态变化：熔化（固→液）、凝固（液→固）、沸腾/蒸发（液→气）、冷凝（气→液）、升华（固→气）。
Remember mass is conserved during changes of state. 'Dense as a brick' reminds us that density is heaviness for its size.
物态变化中质量守恒。“像砖块一样密实”帮助你记住密度是单位体积的重量感。
8. Space Physics | 空间物理
Gravity is the force of attraction between masses. The larger the mass, the stronger the pull. It keeps planets in orbit around the Sun.
万有引力是质量之间相互吸引的力，质量越大引力越强。它使行星绕太阳运转。
Orbit is the curved path of one object around another due to gravity, like the Moon around Earth.
轨道是物体在引力作用下围绕另一个物体运行的弯曲路径，如月球绕地球公转。
Solar System consists of the Sun and all objects bound by its gravity: eight planets, dwarf planets, moons, asteroids and comets.
太阳系由太阳及其引力束缚的所有天体组成：八大行星、矮行星、卫星、小行星和彗星。
Planet (IAU definition): orbits the Sun, has enough mass to be nearly round, and has cleared its orbital neighbourhood. Earth is the third planet.
行星（IAU定义）：绕太阳运行，质量足够大致呈球形，且已清空其轨道附近区域。地球是第三颗行星。
Light-year stance light travels in one year, about 9.46 × 10¹⁵ m. It is a unit of distance, not time.
光年是光在一年中传播的距离，约 9.46 × 10¹⁵ 米，是距离单位，不是时间单位。
Day and night are caused by Earth's rotation on its axis. One full rotation takes about 24 hours.
昼夜交替是由地球自转引起的，自转一圈约需 24 小时。
Seasons arise from the tilt of Earth's axis as it revolves around the Sun, not from distance changes.
四季是由地球绕太阳公转时地轴的倾斜引起的，并非距离变化所致。
Memory: 'My Very Educated Mother Just Served Us Noodles' for the order of planets (Mercury to Neptune).
记忆：“我非常有学问的妈妈刚给我们上面条”帮记行星顺序（水星到海王星）。
9. Key Measurement Terms | 关键测量术语
Physical quantity is a property that can be measured, e.g. length, mass, time, temperature, current, voltage.
物理量是可以测量的属性，如长度、质量、时间、温度、电流、电压。
Accuracy is how close a measurement is to the true value. Precision is how closely repeated measurements agree with each other. They are different!
准确度指测量值接近真实值的程度；精密度指重复测量结果彼此接近的程度，两者不同。
Zero error occurs when an instrument does not read zero when it should, leading to systematic errors.
零误差是仪器本该指零时未指零而导致的系统误差。
Unit conversion often uses prefixes: kilo- (1000), mega- (1 000 000), centi- (1/100), milli- (1/1000), micro- (1/1 000 000).
单位换算常用词头：千（1000）、兆（1 000 000）、厘（1/100）、毫（1/1000）、微（1/1 000 000）。
Scalar quantities have magnitude only, e.g. speed, distance, mass. Vector quantities have both magnitude and direction, e.g. velocity, force, displacement.
标量只有大小，如速率、路程、质量；矢量既有大小又有方向，如速度、力、位移。
Think: 'Speed with a direction is velocity.' 'Mass with direction? No – that's a vector no-no.'
记住：“速率加上方向就是速度。”质量有方向吗？没有——矢量可得小心区分。
10. General Scientific Vocabulary | 通用科学词汇
Hypothesis – a testable prediction based on prior knowledge. Variable – a factor that can change in an experiment. Independent variable (you change), dependent variable (you measure), control variables (kept the same).
假设——基于已有知识的可检验预测。变量——实验中可以改变的因素：自变量（你改变的）、因变量（你测量的）、控制变量（保持不变的）。
Validity – an experiment is valid if it tests what it claims to, with only the independent variable affecting the dependent variable. Reliability – results are reliable if repeat measurements are consistent.
有效性——实验如果只让自变量影响因变量并检验预期，则有效。可靠性——重复测量结果一致则可靠。
Friction often reduces efficiency by converting useful energy into thermal energy.
效率降低常因摩擦将有用能量转化为热能。
Work done × distance moved in direction of force. When you lift a book, you do work against gravity.
做功 = 力 × 沿力方向移动的距离，提起书本就是克服重力做功。
Power is the rate of doing work, measured in watts (W). Power = work done ÷ time taken.
功率是做功的快慢，以瓦特（W）为单位，功率 = 做功 ÷ 所用时间。
'Fast work is powerful.' 'If you lift the book quickly, your power is higher.'
“做得快就是功率大”，“快速举起书本时你的功率更大。”
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