KS3 CCEA Science: Core Knowledge Overview | KS3 CCEA 科学：核心知识点梳理

📚 KS3 CCEA Science: Core Knowledge Overview | KS3 CCEA 科学：核心知识点梳理

Welcome to your essential KS3 CCEA Science revision guide. The CCEA Key Stage 3 curriculum builds a strong foundation across biology, chemistry and physics. You will explore how living organisms function, how materials behave, and how the physical world works through hands-on investigations and scientific thinking. This article brings together the core knowledge you need, explained clearly in both English and Chinese to support your learning.

欢迎阅读 KS3 CCEA 科学核心复习指南。CCEA 关键阶段 3 课程为你打下生物学、化学和物理学的坚实基础。你将通过动手探究和科学思维，探索生物如何运作、物质如何变化以及物理世界如何运行。本文用中英双语清晰梳理了必须掌握的核心知识点，帮助你高效备考。

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1. Cells and Organisation | 细胞与组织

All living things are made of cells. Cells are the basic units of life. Animal cells contain a nucleus, cytoplasm and cell membrane, while plant cells have these plus a cell wall, chloroplasts and a permanent vacuole.

所有生物都由细胞构成，细胞是生命的基本单位。动物细胞包含细胞核、细胞质和细胞膜，而植物细胞除了这些，还有细胞壁、叶绿体和中央大液泡。

The nucleus controls the cell and contains genetic material. Cytoplasm is where chemical reactions take place. The cell membrane controls what enters and leaves the cell.

细胞核控制细胞活动并含有遗传物质。细胞质是化学反应发生的场所。细胞膜控制物质的进出。

In multicellular organisms, cells specialise to carry out particular jobs. Groups of similar cells form tissues, tissues work together to form organs, and organs form organ systems.

在多细胞生物中，细胞分化以执行特定功能。一群相似的细胞构成组织，组织组合形成器官，器官进一步构成器官系统。

Examples of specialised animal cells include red blood cells (carry oxygen), nerve cells (transmit signals) and muscle cells (contract for movement). In plants, root hair cells absorb water, and xylem vessels transport water.

特化的动物细胞例子有红细胞（运输氧气）、神经细胞（传递信号）和肌肉细胞（收缩产生运动）。植物中，根毛细胞吸收水分，木质部导管运输水分。

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2. Body Systems: Digestion and Respiration | 身体系统：消化与呼吸

The digestive system breaks down large food molecules into small, soluble substances that can be absorbed into the blood. Key organs include the mouth, oesophagus, stomach, small intestine, large intestine and pancreas.

消化系统将大分子食物分解成可溶的小分子物质，以便被血液吸收。主要器官包括口腔、食道、胃、小肠、大肠和胰腺。

Digestive enzymes speed up the breakdown of nutrients. Amylase breaks down starch into sugars, protease digests proteins into amino acids, and lipase converts fats into fatty acids and glycerol.

消化酶加速营养物质的分解。淀粉酶将淀粉分解成糖，蛋白酶将蛋白质消化为氨基酸，脂肪酶将脂肪转化为脂肪酸和甘油。

Absorption mainly happens in the small intestine, where villi provide a large surface area for nutrients to pass into the blood. The large intestine absorbs water, leaving faeces to be eliminated.

吸收主要发生在小肠，小肠绒毛提供了巨大的表面积，让营养物质进入血液。大肠吸收水分，剩余物质形成粪便排出体外。

The respiratory system provides oxygen for respiration and removes carbon dioxide. Air enters through the nose or mouth, passes down the trachea, into the bronchi and lungs, ending in tiny air sacs called alveoli.

呼吸系统为呼吸作用提供氧气并排出二氧化碳。空气通过鼻或口进入，沿气管下行，进入支气管和肺，最终到达称为肺泡的微小气囊。

Gas exchange occurs in the alveoli: oxygen diffuses into the bloodstream, and carbon dioxide diffuses out. Breathing involves the diaphragm and intercostal muscles changing the volume of the chest cavity.

气体交换在肺泡进行：氧气扩散进入血液，二氧化碳扩散排出。呼吸需要膈肌和肋间肌改变胸腔容积来完成。

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3. Photosynthesis and Ecosystems | 光合作用与生态系统

Photosynthesis is the process plants use to make their own food. It takes place in chloroplasts using light energy to convert carbon dioxide and water into glucose and oxygen.

光合作用是植物制造自身养料的过程。它在叶绿体中进行，利用光能将二氧化碳和水转化成葡萄糖和氧气。

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

The rate of photosynthesis is affected by light intensity, carbon dioxide concentration and temperature. A lack of any of these can limit the rate.

光合作用速率受光照强度、二氧化碳浓度和温度的影响。任何一种因素的缺乏都会限制光合作用的速率。

Plants are producers in food chains. Energy passes from producers to primary consumers, then to secondary consumers and so on. Arrows in a food chain show the direction of energy transfer.

植物是食物链中的生产者。能量从生产者传递到初级消费者，再传递给次级消费者，依此类推。食物链中的箭头表示能量传递的方向。

Toxic materials can accumulate as they move up a food chain, a process called bioaccumulation. Predators at the top of the chain often have the highest concentration of toxins.

有毒物质在食物链中向上传递时会不断积累，这一过程称为生物累积。位于食物链顶端的捕食者体内毒素浓度往往最高。

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4. Particle Model and States of Matter | 粒子模型与物质状态

All matter is made of tiny particles. The particle model explains the properties of solids, liquids and gases. In solids, particles are held tightly in a fixed arrangement and only vibrate. In liquids, particles are close but can move past each other. In gases, particles are far apart and move quickly in all directions.

所有物质都由微小粒子构成。粒子模型解释了固体、液体和气体的性质。固体中粒子紧密排列在固定位置，只做振动；液体中粒子靠近但能互相滑动；气体中粒子间距大，朝各个方向快速运动。

Changes of state, such as melting, freezing, boiling, condensing and sublimation, are physical changes. The mass stays the same because the number of particles does not change.

状态变化，如熔化、凝固、沸腾、冷凝和升华，都是物理变化。由于粒子总数不变，物质的质量保持不变。

Diffusion is the movement of particles from an area of high concentration to an area of low concentration. It happens faster in gases and at higher temperatures because particles have more kinetic energy.

扩散是粒子从高浓度区域向低浓度区域运动的过程。在气体中扩散更快，温度越高扩散越快，因为粒子具有更大的动能。

Gas pressure is caused by particles colliding with the walls of their container. Increasing the temperature makes particles move faster and hit the walls harder, raising the pressure.

气体压强由粒子碰撞容器壁产生。升高温度使粒子运动加快、撞击更猛烈，导致压强增大。

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5. Atoms, Elements and Compounds | 原子、元素和化合物

All substances are made of atoms. An element is a substance made of only one type of atom. The periodic table lists all known elements, arranged in order of increasing atomic number.

所有物质都由原子构成。元素是只含一种原子的物质。元素周期表列出了所有已知元素，并按原子序数递增排列。

Atoms have a central nucleus containing protons and neutrons, surrounded by electrons in energy levels. In a neutral atom, the number of electrons equals the number of protons.

原子中央是包含质子和中子的原子核，电子分层排布在核外。在电中性原子中，电子数等于质子数。

Compounds form when atoms of two or more different elements chemically combine. A compound has properties different from the elements it contains. For example, sodium is a reactive metal, chlorine is a toxic gas, but together they make sodium chloride (common table salt).

当两种或多种不同元素的原子通过化学结合时会形成化合物。化合物的性质不同于组成它的元素。例如钠是活泼金属，氯是毒气，但它们结合成氯化钠（食盐）。

Chemical formulas show the elements in a compound and the ratio of atoms. For example, water H₂O has two hydrogen atoms for every oxygen atom. Carbon dioxide CO₂ has one carbon atom and two oxygen atoms.

化学式表示化合物中所含的元素及其原子个数比。例如水 H₂O 中氢氧原子个数比为 2:1，二氧化碳 CO₂ 中碳氧原子个数比为 1:2。

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6. Chemical Reactions and Equations | 化学反应与方程式

In a chemical reaction, new substances are formed. Signs of a reaction include colour change, temperature change, gas production or formation of a precipitate. During a reaction, atoms are rearranged; no atoms are created or destroyed.

在化学反应中会生成新物质。反应的迹象包括颜色变化、温度变化、产生气体或生成沉淀。反应中原子重新排列，原子不会被创造也不会被消灭。

Word equations and symbol equations describe reactions. The Law of Conservation of Mass says the total mass of the reactants equals the total mass of the products. Equations must be balanced to show this.

文字方程式和符号方程式用来描述化学反应。质量守恒定律指出反应物的总质量等于生成物的总质量，因此化学方程式需要配平。

CH₄ + 2O₂ → CO₂ + 2H₂O

Common reaction types include combustion, thermal decomposition, neutralisation and displacement. Combustion burns a fuel in oxygen to release energy. Neutralisation is a reaction between an acid and an alkali, producing salt and water.

常见的反应类型有燃烧、热分解、中和及置换反应。燃烧是燃料在氧气中燃烧释放能量。中和是酸与碱反应生成盐和水。

HCl + NaOH → NaCl + H₂O

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7. Forces and Motion | 力与运动

A force is a push or pull acting on an object. Forces can change the speed, direction or shape of an object. They are measured in newtons (N). Common forces include gravity, friction, air resistance and upthrust.

力是作用在物体上的推力或拉力。力可以改变物体的速度、方向或形状。力的单位是牛顿（N）。常见的力有重力、摩擦力、空气阻力和浮力。

Balanced forces mean an object stays at rest or moves at a constant speed. Unbalanced forces cause acceleration, deceleration or a change in direction. This is linked to Newton’s laws of motion at a descriptive level.

平衡力使物体保持静止或匀速直线运动。非平衡力导致物体加速、减速或改变方向。这可以感性地与牛顿运动定律联系起来。

Speed is how fast something moves. It can be calculated using:

速度表示物体运动的快慢，可用以下公式计算：

speed = distance ÷ time

Distance–time graphs show motion. A straight horizontal line means the object is stationary, a straight sloping line indicates constant speed, and a steeper slope means faster speed.

距离-时间图表示运动状态。水平直线表示物体静止，倾斜直线表示匀速运动，斜率越大速度越快。

Friction is a force that opposes motion. It can be useful (e.g. grip on shoes) or unwanted (e.g. causing wear). Lubricants reduce friction between surfaces.

摩擦力是阻碍运动的力。它可能是有益的（如鞋底的抓地力），也可能是有害的（如造成磨损）。润滑剂可以减少接触面之间的摩擦。

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8. Energy: Forms and Transfers | 能量：形式与转换

Energy is the ability to do work. It exists in many forms: kinetic, thermal, light, sound, electrical, chemical, elastic potential and gravitational potential. Energy is measured in joules (J).

能量是做功的能力。能量以多种形式存在：动能、热能、光能、声能、电能、化学能、弹性势能和重力势能。能量的单位是焦耳（J）。

The law of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed from one form to another. In any process, total energy stays the same.

能量守恒定律指出能量不能被创造或消灭，只能从一种形式转移或转化为另一种形式。在任何过程中，总能量保持不变。

Energy transfers can be shown using energy flow diagrams. For example, a lamp transfers electrical energy into light energy, but some energy is wasted as thermal energy.

能量传递可以用能量流程图表示。例如灯泡将电能转化为光能，但部分能量以热能的形式浪费掉。

Thermal energy can be transferred by conduction, convection and radiation. Conduction happens best in solids, especially metals. Convection occurs in fluids (liquids and gases). Radiation can travel through a vacuum.

热能可以通过传导、对流和辐射传递。传导在固体中效果最好，尤其是金属。对流发生在流体中（液体和气体）。辐射可以在真空中传播。

Renewable energy resources include solar, wind, hydroelectric, wave, tidal and biomass. Non-renewable resources include coal, oil and natural gas. Using more renewables helps reduce carbon emissions.

可再生能源包括太阳能、风能、水力发电、波浪能、潮汐能和生物质能。不可再生能源包括煤、石油和天然气。更多地使用可再生能源有助于减少碳排放。

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9. Electric Circuits and Current | 电路与电流

An electric circuit needs a complete loop for current to flow. It typically includes a power source (cell or battery), wires and components like bulbs, buzzers or motors.

电路需要一个完整的回路才能让电流通过。电路通常包括电源（电池）、导线和灯泡、蜂鸣器或电动机等元件。

Electric current is the flow of electric charge. In a single closed loop, the current is the same everywhere. Current is measured in amperes (A) using an ammeter connected in series.

电流是电荷的流动。在单个闭合回路中，各处电流相等。电流的单位是安培（A），用串联在电路中的安培表测量。

Voltage, measured in volts (V), is the energy transferred per unit charge. It can be thought of as the ‘push’ driving the current around the circuit. A voltmeter is connected in parallel across a component.

电压的单位是伏特（V），表示单位电荷传递的能量。可以把电压想象成推动电流绕电路流动的“推力”。伏特表并联在元件两端进行测量。

In a series circuit, components are connected one after another. If one bulb breaks, the circuit is broken and all bulbs go out. The total voltage across the components adds up to the battery voltage.

在串联电路中，元件依次连接。如果一只灯泡损坏，电路断开，所有灯泡都会熄灭。各元件两端的电压之和等于电池电压。

In a parallel circuit, components are connected on separate branches. If one branch breaks, the others continue working. The voltage across each branch is the same as the battery voltage, but the current splits between branches.

在并联电路中，元件连接在不同支路上。如果一条支路断开，其他支路继续工作。各支路两端电压与电池电压相等，但电流在支路间分流。

Conductors allow electricity to flow easily (e.g. copper). Insulators do not allow electricity to flow (e.g. rubber). Always follow safety rules: never touch sockets with wet hands and keep water away from electrical devices.

导体（如铜）能让电流轻易通过。绝缘体（如橡胶）阻止电流通过。请始终遵守安全规则：不用湿手触摸插座，并让电器远离水。

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10. Earth and Space Resources | 地球与太空资源

The Earth is made up of three main layers: the crust, mantle and core. The crust is the thin, solid outer layer. Below it, the mantle is semi-solid and can flow very slowly. The core is made mostly of iron and nickel.

地球主要由三层构成：地壳、地幔和地核。地壳是薄而坚固的外层。下面的地幔呈半固态，可以非常缓慢地流动。地核主要由铁和镍组成。

Rocks are classified into three types based on how they are formed. Igneous rocks form when magma or lava cools and solidifies. Sedimentary rocks form from layers of sediment compacted over time. Metamorphic rocks form when existing rocks are changed by heat and pressure.

岩石根据形成方式分为三类。火成岩由岩浆或熔岩冷却凝固形成。沉积岩由沉积物层层压实形成。变质岩由原有岩石在高温高压下变质形成。

The rock cycle describes how rocks are continuously recycled between these types through processes such as melting, cooling, weathering, erosion, compaction and metamorphism.

岩石圈描述了岩石如何通过熔化、冷却、风化、侵蚀、压实和变质等过程在三种类型之间持续循环转化。

The Earth’s resources include air, water, minerals and fossil fuels. Fossil fuels such as coal, oil and natural gas are formed from the remains of ancient organisms over millions of years. They are finite and their burning releases carbon dioxide.

地球资源包括空气、水、矿物和化石燃料。煤、石油和天然气等化石燃料是由远古生物遗体经过数百万年形成的。它们是有限资源，燃烧时会释放二氧化碳。

In the solar system, the Earth orbits the Sun. The Moon orbits the Earth. Day and night are caused by the Earth spinning on its axis once every 24 hours. The seasons result from the tilt of the Earth’s axis as it orbits the Sun, leading to varying sunlight intensity across the year.

在太阳系中，地球绕太阳公转，月球绕地球转动。地球每 24 小时自转一周，产生了昼夜交替。四季更替是由于地轴倾斜，使得地球在公转时不同地区接收的太阳光照强度随一年变化。

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