📚 Year 7 AQA Physics: Core Knowledge Summary | 七年级AQA物理：核心知识点梳理
Year 7 Physics introduces you to the fundamental rules that govern how our universe works. From forces that keep your feet on the ground to the energy that lights your home, these core topics build the foundation for all future science study. This guide walks you through every essential concept in the AQA Year 7 Physics curriculum, pairing clear English explanations with their Chinese translations so you can study confidently in either language.
七年级物理带你认识支配宇宙运行的基本规律。从让你脚踏实地的作用力到点亮家中的能量，这些核心主题构建了未来所有科学学习的基础。本指南梳理了AQA七年级物理课程中的每一个关键概念，将清晰的英文解释与对应的中文翻译配对呈现，帮助你自信地使用任意一种语言进行学习。
1. Introduction to Physics and Scientific Skills | 物理与科学技能入门
Physics is the study of matter, energy and the interactions between them. In Year 7, you develop practical skills like making measurements, recording data in tables, and plotting graphs. You also learn to identify variables: the independent variable you change, the dependent variable you measure, and the control variables you keep the same. Safety in the lab is always the first priority – always listen to your teacher and wear goggles when instructed.
物理学是研究物质、能量及其相互作用的学科。在七年级，你需要培养实用技能，例如进行测量、用表格记录数据以及绘制图表。你还要学会识别变量：你改变的独立变量、你测量的因变量，以及你保持不变的受控变量。实验室安全始终是第一要务——始终听从老师的指导，并在要求时佩戴护目镜。
- A fair test changes only one variable at a time.
- 公平实验一次仅改变一个变量。
- Units like metre (m), kilogram (kg), second (s) are standard in physics.
- 物理学中使用的标准单位有米（m）、千克（kg）、秒（s）等。
2. Forces and Motion | 力与运动
A force is a push or a pull that can change an object's speed, direction or shape. Forces are measured in newtons (N). Contact forces, like friction and air resistance, require objects to touch; non‑contact forces, such as gravity and magnetism, act at a distance. If forces on an object are balanced, its motion stays the same – it remains still or continues moving at a steady speed. An unbalanced force causes acceleration or deceleration.
力是一种推或拉，可以改变物体的速度、方向或形状。力的单位是牛顿（N）。接触力（如摩擦力和空气阻力）需要物体相互接触；非接触力（如重力和磁力）可以隔空作用。如果作用在物体上的力是平衡的，其运动状态保持不变——保持静止或匀速直线运动。不平衡的力则会导致加速或减速。
Weight (N) = mass (kg) × gravitational field strength (N/kg)
重量（牛）= 质量（千克） × 重力场强度（牛/千克）
- Gravity on Earth gives a field strength of about 10 N/kg.
- 地球的重力场强度约为10 N/kg。
- Speed = distance ÷ time; average speed is total distance divided by total time.
- 速度 = 距离 ÷ 时间；平均速度是总距离除以总时间。
3. Energy Forms and Transfers | 能量的形式与转化
Energy is the ability to do work and is measured in joules (J). It comes in many forms: kinetic (movement), thermal (heat), chemical (stored in food and fuel), gravitational potential (height), elastic potential (stretched or compressed springs), light, sound and electrical. Energy can be transferred from one store to another but is never created or destroyed – this is the principle of conservation of energy.
能量是做功的能力，单位是焦耳（J）。能量有多种形式：动能（运动）、热能、化学能（储存在食物和燃料中）、重力势能（高度）、弹性势能（拉伸或压缩的弹簧）、光能、声能和电能。能量可以从一个储存库转移到另一个，但既不会凭空产生也不会凭空消失——这就是能量守恒定律。
| Energy Store 能量储存库 | Example 示例 |
|---|---|
| Kinetic 动能 | A moving car 行驶的汽车 |
| Thermal 热能 | Hot cup of tea 热茶 |
| Gravitational potential 重力势能 | A book on a high shelf 高处书架上的书 |
| Chemical 化学能 | Battery or sandwich 电池或三明治 |
4. Energy Resources and Power | 能源与功率
electricity using energy resources. Fossil fuels (coal, oil, gas) and nuclear fuel are non‑renewable – ages and disadvantages related to cost, reliability and environmental impact. Power is the rate of energy transfer, calculated as energy transferred divided by time taken. A more powerful device transfers more joules per second (1 watt = 1 J/s).
我们利用能源来发电。化石燃料（煤、石油、天然气）和核燃料是不可再生的——它们终有一天会耗尽。可再生资源包括太阳能、风能、潮汐能、波浪能、水力能、地热能和生物质能。每种资源在成本、可靠性和环境影响方面都有各自的优缺点。功率是能量转移的速率，计算方法为转移的能量除以所用时间。功率越大的设备每秒传递的焦耳越多（1瓦特 = 1焦耳/秒）。
Power (W) = energy transferred (J) ÷ time (s)
功率（瓦）= 转移的能量（焦） ÷ 时间（秒）
- Efficiency = (useful output energy ÷ total input energy) × 100%.
- 效率 =（有用输出能量 ÷ 总输入能量）× 100%。
- Wind turbines use kinetic energy of moving air; solar cells use light.
- 风力涡轮机利用流动空气的动能；太阳能电池利用光能。
5. Particle Model of Matter | 物质的粒子模型
All substances are made of tiny particles. In solids, particles are tightly packed in fixed positions, vibrating slightly – this explains why solids have a fixed shape and volume. Liquid particles are close together but can slide past each other, so liquids flow and take the shape of their container while keeping a constant volume. Gas particles are far apart, moving quickly in all directions; gases have no fixed shape or volume and can be compressed easily because there is plenty of space between particles.
所有物质都由微小粒子组成。固体中的粒子紧密排列在固定位置上，仅轻微振动——这解释了为什么固体有固定的形状和体积。液体中的粒子彼此靠近但可以相互滑动，因此液体可以流动并呈现容器的形状，同时保持恒定的体积。气体粒子则相距很远，向各个方向快速运动；气体没有固定的形状和体积，并且由于粒子间有大量空间，很容易被压缩。
- Heating increases the energy of particles; they move or vibrate faster.
- 加热会增加粒子的能量；它们运动或振动得更快。
- Diffusion is the random spreading of particles from an area of high concentration to low concentration.
- 扩散是粒子从高浓度区域向低浓度区域的随机扩散过程。
6. Changes of State and Density | 状态变化与密度
When a solid is heated, its particles gain energy and eventually break free from their fixed positions – this is melting. Further heating turns the liquid into a gas through evaporation or boiling. Condensing is the reverse of boiling: a gas cools, particles lose energy, come closer together and form a liquid. Freezing turns liquid to solid. During a change of state, temperature remains constant because energy is used to break or form particle bonds, not to raise temperature. Density tells us how much mass is packed into a certain volume; denser materials have more particles in the same space.
当固体受热时，粒子获得能量，最终脱离固定位置——这就是熔化。进一步加热会使液体通过蒸发或沸腾变为气体。凝结是沸腾的逆过程：气体冷却，粒子损失能量并聚拢形成液体。凝固则使液体变为固体。在状态变化期间，温度保持不变，因为能量用于打破或形成粒子间的键，而不是用于提升温度。密度告诉我们一定体积内包含多少质量；密度较大的材料在相同空间内含有更多的粒子。
Density (kg/m³) = mass (kg) ÷ volume (m³)
密度（千克/米³）= 质量（千克） ÷ 体积（米³）
- Ice is less dense than liquid water, so it floats.
- 冰的密度比液态水小，所以会浮在水面。
- Mass is conserved during physical and chemical changes.
- 在物理变化和化学变化中，质量是守恒的。
7. Waves: Sound and Light | 波：声与光
Waves transfer energy without transferring matter. Sound waves are longitudinal vibrations that travel through solids, liquids and gases but cannot travel through a vacuum. The speed of sound in air is about 340 m/s. Light waves are transverse electromagnetic waves that can travel through a vacuum at 300,000 km/s. Light travels in straight lines, and we see objects because light reflects off them into our eyes. The law of reflection says the angle of incidence equals the angle of reflection, measured from an imaginary normal line.
波传递能量而不传递物质。声波是一种纵波，可以在固体、液体和气体中传播，但不能在真空中传播。声音在空气中的传播速度约为340米/秒。光波是横波电磁波，可以在真空中以30万千米/秒的速度传播。光沿直线传播，我们之所以能看见物体，是因为光从物体反射到我们的眼睛中。反射定律指出，入射角等于反射角，这两个角都是从假想的法线量起的。
- Frequency is the number of waves per second, measured in hertz (Hz).
- 频率是每秒的波数，单位是赫兹（Hz）。
- Amplitude is the height of a wave from its rest position; affecting loudness for sound and brightness for light.
- 振幅是波从平衡位置起的高度；影响声音的响度和光的亮度。
- Refraction occurs when light bends as it passes from one transparent material to another due to a change in speed.
- 当光从一种透明介质进入另一种介质时，由于速度变化而发生折射。
8. Electric Circuits and Components | 电路与元件
An electric circuit needs a complete loop of conducting material for current to flow. Current is the flow of electric charge, measured in amperes (A). Voltage (potential difference) is the push that drives current, measured in volts (V). Components like cells, bulbs, switches, buzzers, motors and resistors can be connected in series (one loop) or parallel (more than one path). In a series circuit, the same current flows through all components; in parallel, the current splits but the voltage across each branch is the same.
电路需要由导电材料构成的完整回路，电流才能流动。电流是电荷的流动，单位是安培（A）。电压（电位差）是推动电流的驱动力，单位是伏特（V）。电池、灯泡、开关、蜂鸣器、电机和电阻器等元件可以串联（单一回路）或并联（多条路径）连接。在串联电路中，流过所有元件的电流相同；在并联电路中，电流分流，但每个支路两端的电压相同。
| Component 元件 | Symbol Function 符号与功能 |
|---|---|
| Cell 电池 | Long line positive, short line negative; provides energy. 长线为正，短线为负；提供能量。 |
| Bulb 灯泡 | Circle with a cross; lights up when current flows. 圆形内有叉号；有电流通过时发光。 |
| Resistor 电阻器 | Rectangle; reduces current. 矩形；限制电流。 |
Resistance (Ω) = voltage (V) ÷ current (A)
电阻（欧）= 电压（伏） ÷ 电流（安）
9. Magnetism and Electromagnets | 磁与电磁
A magnet has a north and a south pole. Like poles repel, unlike poles attract. Permanent magnets are always magnetic; induced magnets become magnetic only when placed in a magnetic field. The Earth itself behaves as a huge magnet, which is why a compass needle points north. An electromagnet is created by wrapping a coil of wire around an iron core and passing a current through the wire. The strength of an electromagnet can be increased by using more coils, a larger current, or an iron core.
磁铁有北极和南极。同极相斥，异极相吸。永磁体总是具有磁性；而感应磁体仅在置于磁场中时才显现磁性。地球本身就像一个巨大的磁体，这就是指南针指向北方的原因。电磁铁是通过将线圈缠绕在铁芯上，并在线圈中通入电流而制成的。增加线圈匝数、增大电流或使用铁芯都可以增强电磁铁的强度。
- Magnetic materials include iron, nickel, cobalt and their alloys.
- 磁性材料包括铁、镍、钴及其合金。
- An electric bell and relay use electromagnets to convert electrical energy into mechanical movement.
- 电铃和继电器利用电磁铁将电能转换为机械运动。
10. The Solar System and Beyond | 太阳系与宇宙
Our Solar System consists of the Sun, eight planets, their moons, and smaller objects like asteroids and comets. Gravity keeps the planets in orbit around the Sun. The inner planets (Mercury, Venus, Earth, Mars) are rocky and relatively small; the outer planets (Jupiter, Saturn, Uranus, Neptune) are gas giants, much larger and colder. The Sun is a medium‑sized star that produces light and heat through nuclear fusion. Beyond our solar system sit billions of other stars grouped into galaxies; we live in the Milky Way galaxy.
我们的太阳系由太阳、八颗行星、它们的卫星以及小行星和彗星等较小天体组成。引力使行星保持在围绕太阳的轨道上。内行星（水星、金星、地球、火星）是岩石质且较小的；外行星（木星、土星、天王星、海王星）是气态巨行星，体积更大且温度更低。太阳是一颗中等大小的恒星，通过核聚变产生光和热。在我们太阳系之外，存在着数以十亿计的其他恒星，它们聚集形成星系；我们生活在银河系中。
- Day and night occur because Earth rotates on its axis once every 24 hours.
- 昼夜交替是因为地球每24小时绕轴自转一圈。
- Seasons are caused by the tilt of Earth's axis as it orbits the Sun.
- 四季是由地球绕太阳公转时地轴倾斜所致。
- Light from the Sun takes about 8 minutes to reach Earth; light from the next nearest star takes over 4 years.
- 阳光到达地球大约需要8分钟；距离最近的恒星发出的光则需要4年多才能抵达。
Published by TutorHao | Physics Revision Series | aleveler.com
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