📚 Year 7 CCEA Science: Core Knowledge Checklist | CCEA 7年级科学：核心知识点梳理
This article brings together the essential knowledge for Year 7 CCEA Science. It is designed to help you review the key ideas in biology, chemistry, physics and scientific enquiry. Each section is presented in short English–Chinese pairs so you can strengthen your understanding in both languages. Make sure you can explain each point clearly and give real-world examples.
本文汇总了 CCEA 7年级科学的核心知识，帮助你梳理生物、化学、物理以及科学探究中的关键概念。每个小节都以英–中配对的形式呈现，便于你在两种语言中巩固理解。请确保你能清晰地解释每一个要点，并给出实际例子。
1. Living Things and Cells | 生物与细胞
All living organisms share seven life processes, often remembered by the acronym MRS GREN: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition.
所有生物都具有七种生命过程，常用首字母缩写 MRS GREN 来记忆：运动、呼吸、感应、生长、繁殖、排泄和营养。
Living things are made of cells. Animal cells contain a nucleus, cytoplasm and a cell membrane. Plant cells have the same parts plus a rigid cell wall, chloroplasts for photosynthesis and a large permanent vacuole filled with cell sap.
生物是由细胞构成的。动物细胞包含细胞核、细胞质和细胞膜。植物细胞除了这些结构之外，还有坚硬的细胞壁、进行光合作用的叶绿体，以及充满细胞液的中央大液泡。
Unicellular organisms such as bacteria and yeast are made of just one cell, while multicellular organisms like humans have many specialised cells. Microorganisms can be helpful (e.g. in making bread) or harmful (e.g. causing disease).
细菌和酵母等是单细胞生物，而人类等多细胞生物则拥有许多特化的细胞。微生物可能是有益的（如用于制作面包），也可能是有害的（如引发疾病）。
A simple food chain shows how energy passes from one organism to another. The arrows point from the food to the consumer: grass → rabbit → fox.
简单的食物链显示能量如何从一个生物体传递到另一个生物体。箭头从食物指向消费者：草 → 兔子 → 狐狸。
2. States of Matter | 物质的状态
Matter exists in three main states: solid, liquid and gas. The particle model describes how particles are arranged and how they move in each state.
物质主要以三种状态存在：固态、液态和气态。粒子模型描述了每种状态下粒子如何排列及如何运动。
In a solid, particles are held tightly in a regular pattern and only vibrate in fixed positions. In a liquid, particles are close together but can slip past each other, allowing the liquid to flow. In a gas, particles are far apart and move rapidly in all directions.
在固体中，粒子被紧紧固定在规则的排列中，只能在固定位置上振动。液体中的粒子紧密但可以相互滑过，因此能流动。气体中的粒子相距很远，朝各个方向快速运动。
Changes of state include melting (solid → liquid), freezing (liquid → solid), boiling or evaporation (liquid → gas) and condensation (gas → liquid). Sublimation is when a solid turns directly into a gas, such as solid carbon dioxide.
状态变化包括熔化（固态 → 液态）、凝固（液态 → 固态）、沸腾或蒸发（液态 → 气态）和凝结（气态 → 液态）。升华是指固体直接变成气体，例如固体二氧化碳。
The mass of a substance stays the same when it changes state because the number of particles does not change.
物质在状态改变时质量保持不变，因为粒子的数量没有变化。
3. Atoms, Elements and Compounds | 原子、元素和化合物
All substances are made from tiny particles called atoms. An element is a substance made of only one type of atom. Examples include oxygen, iron and helium.
所有物质都由称为原子的微小粒子构成。元素是只由一种原子组成的物质，例如氧、铁和氦。
Compounds form when two or more different elements chemically combine in fixed proportions. A compound has different properties from the elements it is made of. For instance, water (H₂O) is a liquid, but its elements hydrogen and oxygen are gases at room temperature.
化合物由两种或两种以上不同元素按固定比例化合而成。化合物的性质不同于其组成元素。例如水（H₂O）是液体，但组成它的氢和氧在室温下是气体。
Chemical formulas tell us the type and number of atoms in a compound. For example, CO₂ contains one carbon atom and two oxygen atoms.
化学式表示化合物中原子的种类和数量。例如，CO₂ 含有一个碳原子和两个氧原子。
The periodic table lists all known elements in order of increasing atomic number. Metals are mostly on the left, non-metals on the right.
元素周期表按原子序数递增的顺序列出了所有已知元素。金属大多在左侧，非金属在右侧。
4. Mixtures and Separation Techniques | 混合物与分离技术
A mixture contains two or more substances that are not chemically joined. The components keep their own properties and can be separated by physical methods.
混合物包含两种或两种以上未发生化学结合的物质。各组分保持自身的性质，可以通过物理方法分离。
Filtration is used to separate an insoluble solid from a liquid, for example sand from water. The solid stays on the filter paper while the liquid passes through.
过滤用于将不溶性固体与液体分离，例如将沙子从水中分离。固体留在滤纸上，液体穿过滤纸。
Evaporation can separate a soluble solid from a solution by heating the solution until the liquid turns into a gas, leaving the solid behind. Crystallisation is a gentler method that forms large crystals.
蒸发可通过加热溶液使液体变成气体，从而将可溶性固体从溶液中分离出来。结晶是更温和的方法，能形成较大的晶体。
Simple distillation separates a solvent from a solution. The solvent is boiled, condensed and collected as pure liquid. Chromatography separates mixtures of coloured substances, such as the dyes in ink.
简单蒸馏能将溶剂从溶液中分离出来。溶剂沸腾、冷凝后作为纯液体被收集。色谱法用于分离有色物质的混合物，例如墨水中的染料。
A pure substance has a sharp melting point and a sharp boiling point, while a mixture often melts or boils over a range of temperatures.
纯物质具有尖锐的熔点和沸点，而混合物往往在一个温度区间内熔化或沸腾。
5. Acids and Alkalis | 酸和碱
Acids are substances with a pH less than 7. Common laboratory acids include hydrochloric acid, sulfuric acid and nitric acid. Alkalis are soluble bases with a pH greater than 7, such as sodium hydroxide.
酸是 pH 值小于 7 的物质。实验室常见的酸包括盐酸、硫酸和硝酸。碱是可溶的、pH 值大于 7 的物质，如氢氧化钠。
Indicators are dyes that change colour in acid, alkaline or neutral solutions. Universal indicator shows a range of colours across the pH scale: red for strong acids, green for neutral and purple for strong alkalis.
指示剂是一种能在酸性、碱性或中性溶液中变色的染料。通用指示剂在整个 pH 范围内显示不同颜色：强酸呈红色，中性呈绿色，强碱呈紫色。
A neutralisation reaction occurs when an acid reacts with an alkali, producing salt and water. The general equation is:
acid + alkali → salt + water
酸碱中和反应生成盐和水。通式如下：酸 + 碱 → 盐 + 水
Everyday examples of neutralisation include treating indigestion with antacids and applying toothpaste to neutralise mouth acid.
生活中的中和反应例子包括用抗酸剂治疗胃灼热，以及用牙膏中和口腔酸性。
6. Energy and Its Transfers | 能量及其转移
Energy is the ability to do work. It can exist in many forms: kinetic, thermal, light, sound, electrical, chemical and gravitational potential energy.
能量是做功的能力。它可以有多种形式：动能、热能、光能、声能、电能、化学能和重力势能。
Energy can be stored or transferred, but it is never created or destroyed. This is the principle of conservation of energy.
能量可以被储存或转移，但永远不会被创造或消灭。这就是能量守恒定律。
Energy transfers can be shown using simple flow diagrams. For example, in a torch: chemical energy (battery) → electrical energy (wires) → light energy + thermal energy.
能量转移可以用简单的示意图表示。例如手电筒：化学能（电池）→ 电能（导线）→ 光能 + 热能。
Heat energy travels from hotter objects to cooler ones by conduction, convection and radiation. Conduction occurs mainly in solids, convection in liquids and gases, and radiation can travel through empty space.
热能通过传导、对流和辐射从高温物体传向低温物体。传导主要发生在固体中，对流发生在液体和气体中，辐射可以在真空中传播。
Fuels store chemical energy that is released when they burn. Renewable energy resources such as solar, wind and hydroelectric are alternatives to fossil fuels.
燃料储存的化学能在燃烧时释放。太阳能、风能和水力等可再生能源是化石燃料的替代品。
7. 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) using a force meter.
力是一种推或拉的作用，能改变物体的速度、方向或形状。力的单位是牛顿（N），可用测力计测量。
Gravity is a force that pulls objects towards the centre of the Earth. Weight is the force of gravity acting on a mass. Weight (N) = mass (kg) × gravitational field strength, where on Earth
weight = mass × 10 N/kg
重力是将物体拉向地球中心的力。重量是重力作用在质量上的力。重量（N）= 质量（kg）× 重力场强度，在地球上约为：重量 = 质量 × 10 N/kg。
Friction is a force that opposes motion between two surfaces in contact. It can be useful (e.g. for gripping) or unwanted (e.g. causing wear). Lubricants reduce friction.
摩擦力是阻碍两个接触表面相对运动的力。它可能有用（如抓握），也可能带来麻烦（如导致磨损）。润滑剂可以减少摩擦。
When forces are balanced, an object stays at rest or moves at a constant speed in a straight line. Unbalanced forces cause a change in speed or direction.
当力达到平衡时，物体保持静止或沿直线匀速运动。不平衡的力会导致速度或方向改变。
Speed is the distance travelled per unit of time. Average speed can be calculated as:
average speed = total distance ÷ total time
速度是单位时间内移动的距离。平均速度计算公式：平均速度 = 总距离 ÷ 总时间。
8. Electricity and Circuits | 电与电路
An electric current is a flow of electric charge, usually through wires. A complete circuit is needed for current to flow. Circuit components include cells, bulbs, buzzers, motors and switches.
电流是电荷的流动，通常通过导线。电流的流通需要一个完整回路。电路元件包括电池、灯泡、蜂鸣器、电动机和开关。
Conductors, such as copper and aluminium, allow electricity to pass through easily. Insulators, like plastic and rubber, do not. Wires are coated with insulators for safety.
铜和铝等导体容易让电流通过。塑料和橡胶等绝缘体则不让电流通过。为了安全，电线都包裹着绝缘体。
In a series circuit, there is only one loop for current. If one bulb breaks, all go out. In a parallel circuit, each component sits on its own branch, so others keep working if one fails.
在串联电路中，电流只有一条回路。如果一个灯泡坏了，所有灯泡都会熄灭。在并联电路中，每个元件都有自己的分支，因此一个损坏不影响其他元件工作。
Adding more bulbs in series makes them dimmer because the voltage is shared. In parallel, each bulb gets the full voltage and shines brightly.
串联电路中增加更多灯泡会使灯泡变暗，因为电压被分摊。并联电路中每个灯泡都能获得全部电压，因而保持明亮。
Current is measured in amperes (A) using an ammeter placed in series. Voltage is measured in volts (V) using a voltmeter placed in parallel.
电流用安培（A）计量，电流表串联在电路中。电压用伏特（V）计量，电压表并联在电路中。
9. Earth and Space | 地球与太空
The Solar System consists of the Sun, eight planets, dwarf planets, moons, asteroids and comets. The planets in order from the Sun are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
太阳系由太阳、八大行星、矮行星、卫星、小行星和彗星组成。行星距离太阳由近及远依次为：水星、金星、地球、火星、木星、土星、天王星、海王星。
The Earth rotates on its axis once every 24 hours, causing day and night. It orbits the Sun once every 365¼ days, giving us a year and the seasons.
地球每 24 小时自转一周，形成昼夜。它绕太阳公转一周约为 365¼ 天，形成一年的长度和四季变化。
The Moon orbits the Earth roughly every 28 days. Its changing appearance—the phases—is due to the portion of its illuminated side we can see from Earth.
月球大约每 28 天绕地球运行一周。我们看到的月相变化是由于从地球上看到月球照亮部分的不同。
The Earth has a layered structure: a solid inner core, liquid outer core, mantle and thin crust. Rocks are classified into three types: igneous (formed from cooling magma), sedimentary (compacted layers of sediment) and metamorphic (changed by heat and pressure).
地球内部具有层状结构：固态内核、液态外核、地幔和薄的地壳。岩石分为三大类：火成岩（由冷却的岩浆形成）、沉积岩（由沉积物压实形成）和变质岩（在热和压力下变质而成）。
10. Working Scientifically | 科学探究方法
When planning an investigation, we identify the independent variable (the one we change), the dependent variable (the one we measure) and control variables (the ones we keep the same) to make it a fair test.
设计探究实验时，我们要确定自变量（我们改变的变量）、因变量（我们测量的变量）和控制变量（保持不变的变量），以便进行公平测试。
We present results clearly in tables and graphs. A line graph is used for continuous data, while a bar chart suits categories. Always label axes and include units.
我们要清晰地用表格和图表展示结果。连续数据适合用折线图，类别数据适合用柱状图。务必标注坐标轴并写出单位。
Evaluating the experiment means looking at whether the results are reliable and if there are any anomalies. Repeating measurements and calculating an average can improve reliability.
评估实验意味着判断结果是否可靠，是否存在异常值。重复测量并计算平均值可以提高可靠性。
Working safely in the laboratory involves wearing safety goggles, tying back long hair, standing up to carry out practical work and reporting any spills or breakages immediately. Always listen to your teacher’s instructions.
在实验室安全工作包括佩戴护目镜、扎起长发、站立进行实验操作，以及立即报告任何溢出或破损。务必听从老师的指导。
Writing a conclusion involves describing what the results show and linking back to scientific knowledge. Use scientific vocabulary and suggest improvements for future investigations.
撰写结论时需要描述结果所揭示的信息，并结合科学知识加以解释。要使用科学词汇，并提出对未来探究的改进建议。
Published by TutorHao | Science Revision Series | aleveler.com
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