📚 Year 9 CCEA Physics: Vocabulary & Terminology Quick Memorisation Guide | Year 9 CCEA 物理：词汇术语速记指南
Mastering the language of physics is the first big step towards exam success. This guide breaks down the essential CCEA Year 9 physics terms into clear, memorable definitions, with paired English and Chinese explanations to support your revision and understanding of key ideas like forces, energy, electricity and waves.
掌握物理的语言是通向考试成功的第一步。这份指南将 CCEA Year 9 物理的核心术语分解为清晰、易记的定义，并配有对应的英文和中文解释，帮助你复习和理解力、能量、电学和波等关键概念。
1. Force | 力
A force is a push or a pull that acts on an object because of its interaction with another object. Forces are measured in newtons (N). A force can change an object's speed, direction or shape. Contact forces, such as friction and air resistance, act when objects touch. Non‑contact forces, like gravitational force and magnetic force, act at a distance.
力是一个物体因与另一个物体相互作用而受到的推或拉。力的单位是牛顿（N）。力可以改变物体的速度、方向或形状。接触力（如摩擦力和空气阻力）在物体相互接触时产生。非接触力（如重力和磁力）则可以在一定距离外起作用。
A quick memory trick: think of a football being kicked – the force of the boot changes the ball's motion. If forces on an object are balanced, it stays at rest or moves at a steady speed. If unbalanced, the object accelerates or decelerates.
快速记忆技巧：想象足球被踢了一脚——球鞋的力改变了球的运动状态。如果作用在一个物体上的力是平衡的，它将保持静止或匀速运动。如果不平衡，物体会加速或减速。
2. Mass and Weight | 质量与重量
Mass is the amount of matter in an object. It is measured in kilograms (kg) and does not change wherever you are in the universe. Weight is the force of gravity pulling on a mass. Weight is measured in newtons (N) and depends on the gravitational field strength (g).
质量是物体所含物质的多少，以千克（kg）为单位，无论你身在宇宙何处都不会改变。重量是作用在质量上的重力，以牛顿（N）为单位，并且取决于引力场强度（g）。
Weight = mass × gravitational field strength
W = m × g
ght of 5 × 10 = 50 N. The same bag on the Moon would have the same mass but only about one‑sixth of the weight because the Moon's gravitational field is weaker.
在地球上，g 约等于 10 N/kg。因此一袋 5 kg 的土豆所受重力为 5 × 10 = 50 N。同一袋土豆在月球上质量相同，但重量大约只有六分之一，因为月球的引力场更弱。
3. Speed and Velocity | 速率与速度
Speed tells you how fast an object is moving. It is a scalar quantity, meaning it has magnitude only. Speed is calculated as distance travelled divided by time taken.
速率表示物体运动的快慢。它是一个标量，只有大小。速率的计算公式为行驶距离除以所用时间。
speed = distance ÷ time
Velocity includes direction as well as speed, so it is a vector quantity. Two cars travelling at 30 m/s north have the same velocity, but if one goes north and the other south they have different velocities even though their speeds are equal.
速度不仅包含快慢还包含方向，因此是矢量。两辆车都以 30 m/s 向北行驶，速度相同；但如果一辆向北一辆向南，即使速率相同，它们的速度也不同。
Typical units are metres per second (m/s), kilometres per hour (km/h) or miles per hour (mph). When solving word problems, always check that your units match before substituting into the formula.
常用单位有米每秒（m/s）、千米每小时（km/h）或英里每小时（mph）。解应用题时，代入公式前务必检查单位是否一致。
4. Acceleration | 加速度
Acceleration is the rate at which an object's velocity changes. It is a vector quantity, measured in metres per second squared (m/s²). Positive acceleration means speeding up; negative acceleration (deceleration) means slowing down.
加速度是物体速度变化的快慢，是一个矢量，单位为米每二次方秒（m/s²）。正加速度表示加速；负加速度（减速）表示减慢速度。
acceleration = (final velocity – initial velocity) ÷ time
a = (v – u) ÷ t
For example, a cyclist who goes from 2 m/s to 8 m/s in 3 seconds has an acceleration of (8 – ². A constant acceleration produces a steady increase or decrease in velocity each second.
例如，一名骑车人在 3 秒内从 2 m/s 加速到 8 m/s，加速度为 (8 – 2) ÷ 3 = 2 m/s²。恒定的加速度会使速度每秒稳定地增加或减少。
5. Pressure | 压强
how concentrated a force is. The unit of pressure is the pascal (Pa), where 1 Pa = 1 N/m².
压强是垂直作用于单位面积上的力。它告诉我们力的集中程度。压强的单位是帕斯卡（Pa），1 Pa = 1 N/m²。
pressure = force ÷ area
P = F ÷ A
A sharp knife cuts easily because the force is concentrated over a tiny area, producing high pressure. Snowshoes stop you sinking into snow by spreading your weight over a large area, which lowers the pressure.
锋利的刀容易切割是因为力集中在极小的面积上，产生高压强。雪鞋通过将体重分散到较大面积来降低压强，防止你陷入雪中。
In liquids, pressure increases with depth. The pressure at a point in a liquid depends on the density of the liquid, the gravitational field strength and the depth below the surface.
在液体中，压强随深度增加而增大。液体中某一点的压强取决于液体的密度、引力场强度和该点距液面的深度。
6. Density | 密度
Density is the mass per unit volume of a substance. It describes how tightly packed the particles are. Dense materials feel heavy for their size. The SI unit is kilograms per cubic metre (kg/m³), though g/cm³ is often used in the lab.
密度是物质单位体积的质量，描述粒子排列的紧密程度。密度大的材料相对于其体积感觉更重。国际单位是千克每立方米（kg/m³），实验室也常用克每立方厘米（g/cm³）。
density = mass ÷ volume
ρ = m ÷ V
Water has a density of about 1 g/cm³ or 1000 kg/m³. Objects with a density less than water will float; those with a higher density will sink. This is why an iron nail sinks while a ship made of steel can float – the ship's overall density is reduced by the air‑filled hull.
水的密度约为 1 g/cm³ 或 1000 kg/m³。密度小于水的物体会漂浮；密度大于水的会下沉。这就是铁钉下沉而钢制轮船却能浮在水面的原因——船舱中的空气降低了整体的平均密度。
7. Energy Stores and Transfers | 能量储存与转移
Energy is the ability to do work. It is measured in joules (J). Energy can exist in different stores: kinetic energy (movement), gravitational potential energy (position in a gravitational field), thermal energy (heat), chemical energy, elastic potential energy and nuclear energy.
能量是做功的能力，以焦耳（J）为单位。能量可以储存为不同形式：动能（运动）、重力势能（在引力场中的位置）、热能、化学能、弹性势能和核能。
Energy can be transferred from one store to another by forces doing work, by heating or by radiation. The principle of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed.
能量可以通过力做功、加热或辐射等方式在不同的储存形式间转移。能量守恒定律指出，能量不能凭空产生或消失，只能转移或转化。
Kinetic Energy: Eₖ = ½ m v²
Gravitational Potential Energy: Eₚ = m g h
In any closed system, the total energy before a transfer equals the total energy after. Learning to identify the stores involved – for example, a ball thrown upwards loses kinetic energy and gains gravitational potential energy – makes problem solving easier.
在任何封闭系统中，转移前的总能量等于转移后的总能量。学会辨识涉及的能量储存形式——例如，向上抛出的球动能减少、重力势能增加——能让解题变得更容易。
8. Electrical Current, Voltage and Resistance | 电流、电压与电阻
Electric current is the flow of electric charge, usually carried by electrons moving through a wire. Current is measured in amperes (A or amps). In a single closed loop, the current is the same at every point.
电流是电荷的流动，通常由电子在导线中移动形成。电流的单位是安培（A）。在单一闭合回路中，各点的电流处处相等。
Voltage (potential difference) is the push that drives the charge around a circuit. It is measured in volts (V). A higher voltage provides more energy to each unit of charge. Resistance is a measure of how difficult it is for current to flow, measured in ohms (Ω).
电压（电势差）是驱动电荷在电路中流动的推动力，单位为伏特（V）。电压越高，提供给每单位电荷的能量就越多。电阻衡量电流流动的难易程度，单位为欧姆（Ω）。
Voltage = Current × Resistance
V = I × R
A useful analogy is a water pipe: voltage is like the water pressure, current is the flow rate, and resistance is the pipe's narrowness. Thin wires have higher resistance because there are more collisions between electrons and atoms.
一个形象的类比是水管：电压好比水压，电流好比水流速度，电阻好比管道的粗细。细导线电阻更大，因为电子与原子间的碰撞更多。
9. Series and Parallel Circuits | 串联与并联电路
In a series circuit, components are connected end‑to‑end in a single loop. The current is the same at all points. The total voltage is shared across the components, and if one component breaks, the entire circuit stops working.
在串联电路中，元件首尾相接形成单一路径。各点的电流相同，总电压由各元件分担，若任一元件断开，整个电路停止工作。
In a parallel circuit, components are connected on separate branches. The voltage across each branch is the same as the supply voltage. The total current is the sum of the currents in all branches. A break in one branch does not stop the others.
在并联电路中，元件连接在不同的分支上。每个支路两端的电压与电源电压相等。总电流等于各支路电流之和。某一支路断开不影响其他支路工作。
| Feature | Series Circuit | Parallel Circuit |
|---|---|---|
| Current | Same everywhere | Shared; total = sum of branches |
| Voltage | Shared across components | Same across each branch |
| Total resistance | Increases as more components added | Decreases as more branches added |
中文对照：
| 特性 | 串联电路 | 并联电路 |
|---|---|---|
| 电流 | 处处相等 | 总电流为各分支之和 |
| 电压 | 各元件分担 | 每个支路电压相同 |
| 总电阻 | 增加元件总电阻增大 | 增加支路总电阻减小 |
10. Waves: Amplitude, Frequency and Wavelength | 波：振幅、频率与波长
Waves transfer energy without transferring matter. In transverse waves, such as light and ripples on water, the oscillations are perpendicular to the direction of energy travel. In longitudinal waves, such as sound, the oscillations are parallel to the direction of energy travel.
波传递能量而不传递物质。在横波（如光和水面涟漪）中，振动方向与能量传播方向垂直。在纵波（如声波）中，振动方向与能量传播方向平行。
The amplitude is the maximum displacement from the rest position – the taller the wave, the more energy it carries. Wavelength (λ) is the distance between two consecutive crests or compressions. Frequency (f) is the number of complete waves passing a point per second, measured in hertz (Hz).
振幅是偏离平衡位置的最大位移——波越高，携带的能量越多。波长（λ）是两个相邻波峰或压缩区之间的距离。频率（f）是每秒通过某点的完整波的数量，单位为赫兹（Hz）。
wave speed = frequency × wavelength
v = f × λ
sound wave of frequency 440 Hz and wavelength 0.78 m travels at 440 × 0.78 ≈ 343 m/s. High‑frequency sounds are high‑pitched; low‑frequency sounds are low‑pitched.
例如，频率 440 Hz、波长 0.78 m 的声波速度为 440 × 0.78 ≈ 343 m/s。高频声音音调高，低频声音音调低。
11. Reflection and Refraction | 反射与折射
Reflection occurs when a wave bounces off a surface. The law of reflection states that the angle of incidence equals the angle of reflection. These angles are measured between the ray and the normal – an imaginary line perpendicular to the surface at the point of incidence.
反射是指波从表面弹回的现象。反射定律指出，入射角等于反射角。这些角是光线与法线（在入射点处垂直于表面的假想线）之间的夹角。
Refraction is the bending of a wave as it passes from one medium into another where its speed changes. When light enters a denser medium (e.g. from air to glass), it slows down and bends towards the normal. When it enters a less dense medium, it speeds up and bends away from the normal.
折射是波从一种介质斜射入另一种速度不同的介质时发生的弯曲现象。光进入光密介质（如从空气到玻璃）时速度变慢，并向法线靠拢；进入光疏介质时速度变快，并偏离法线。
The change in speed causes the change in direction unless the wave hits the boundary along the normal. Practical demonstrations with a glass block and a ray of light are classic CCEA experiments to investigate refraction.
速度变化导致了方向的改变，除非波沿法线方向入射。使用玻璃块和光线进行折射实验是 CCEA 经典的探究内容。
12. States of Matter and Changes | 物质状态与变化
Matter exists as a solid, liquid or gas. In a solid, particles are held in a fixed, regular pattern and only vibrate in place. They have the least energy. In a liquid, particles are still close together but can slide past each other, taking the shape of the container. In a gas, particles move rapidly in all directions and are far apart.
物质以固态、液态或气态存在。固态时，粒子固定在规则排列的位置上，仅能在原位振动，能量最低。液态时，粒子仍然紧密相邻，但可以相互滑过，呈容器的形状。气态时，粒子快速地向各个方向运动，且彼此相距很远。
as → liquid), and sublimation (solid ↔ gas directly). During a change of state, the temperature remains constant while the substance absorbs or releases latent heat.
状态变化是物理变化：熔化（固→液）、凝固（液→固）、沸腾/蒸发（液→气）、冷凝（气→液）以及升华（固↔气直接转变）。在状态变化过程中，温度保持不变，物质吸收或释放潜热。
The particle model explains why a balloon filled with air can be compressed: gas particles have large spaces between them. It also explains why solids keep a fixed shape and why liquids flow.
粒子模型可以解释为什么充气气球可以被压缩：气体粒子之间有较大的空隙。它也能解释固体为什么能保持固定形状，而液体为什么会流动。
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