GCSE WJEC Science: Last-Minute Revision Notes | GCSE WJEC 科学：考前冲刺笔记

📚 GCSE WJEC Science: Last-Minute Revision Notes | GCSE WJEC 科学：考前冲刺笔记

This guide covers essential concepts, equations and practical knowledge for the WJEC GCSE Science examinations. Use these concise, topic-by-topic notes to refresh your memory on physics, chemistry and biology, ensuring you can tackle any question with confidence.

本指南涵盖WJEC GCSE科学考试必考的核心概念、方程与实验知识。通过分主题的精简笔记快速重温物理、化学和生物要点，助你自信应对各类题型。

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1. Physics: Energy Stores and Transfers | 物理：能量储存与转移

Energy cannot be created or destroyed, only transferred between stores. The main energy stores are kinetic, gravitational potential, elastic potential, thermal, chemical and nuclear. Work done is a way of transferring energy mechanically.

能量不能被创造或消灭，只能在不同的储存之间转移。主要能量储存包括动能、重力势能、弹性势能、热能、化学能和核能。做功是机械转移能量的一种方式。

The kinetic energy of a moving object depends on its mass and speed. Use the formula Ek = ½mv², where m is mass in kg and v is velocity in m/s. Doubling the speed quadruples the kinetic energy.

运动物体的动能取决于质量和速度。使用公式 Ek = ½mv²，其中 m 为质量（kg），v 为速度（m/s）。速度加倍时，动能变为原来的四倍。

Gravitational potential energy is stored when an object is raised against gravity. It is calculated as Ep = mgh, with g = 9.8 m/s² on Earth. In WJEC papers, g is often taken as 10 m/s² for simplicity unless stated otherwise.

物体被举高克服重力时储存重力势能。计算公式为 Ep = mgh，地球上的 g 通常取 9.8 m/s²，但在 WJEC 试题中，未特别说明时常取 10 m/s² 以简化计算。

Energy can be dissipated as thermal energy to the surroundings, reducing the efficiency of a device. Efficiency = useful output energy transfer ÷ total input energy transfer, often expressed as a percentage.

能量会以热能形式散失到周围环境中，从而降低设备的效率。效率 = 有用的输出能量转移 ÷ 总输入能量转移，常用百分数表示。

Efficiency = (useful output ÷ total input) × 100%

效率 = (有用输出 ÷ 总输入) × 100%

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2. Physics: Forces and Motion | 物理：力与运动

Speed is a scalar quantity; velocity is speed in a given direction (vector). Average speed = total distance ÷ time, while acceleration = change in velocity ÷ time. The gradient of a distance-time graph gives speed, and the gradient of a velocity-time graph gives acceleration.

速率是标量；速度是带有方向的速率（矢量）。平均速率 = 总距离 ÷ 时间，而加速度 = 速度变化量 ÷ 时间。距离—时间图的斜率表示速率，速度—时间图的斜率表示加速度。

Newton’s First Law states that a resultant force is needed to change the velocity of an object. Newton’s Second Law relates force, mass and acceleration: F = ma. The unit of force is the newton (N).

牛顿第一定律指出，需要合力才能改变物体的速度。牛顿第二定律将力、质量和加速度联系起来：F = ma。力的单位是牛顿（N）。

Stopping distance = thinking distance + braking distance. Thinking distance is affected by tiredness, alcohol and distractions; braking distance is affected by speed, road conditions and tyre condition. Higher speed increases both components dramatically.

制动距离 = 反应距离 + 刹车距离。反应距离受疲劳、酒精和注意力分散影响；刹车距离受车速、路面状况和轮胎状态影响。车速越高，这两部分都会大幅增加。

Momentum is conserved in collisions. In WJEC science, you may need to recall that momentum = mass × velocity and understand how crumple zones, seatbelts and airbags increase impact time to reduce force.

碰撞中动量守恒。在 WJEC 科学中，你需要记住动量 = 质量 × 速度，并理解缓冲区、安全带和安全气囊如何通过延长碰撞时间来减小作用力。

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3. Physics: Waves and the Electromagnetic Spectrum | 物理：波与电磁波谱

Waves transfer energy without transferring matter. Transverse waves (e.g. light, water ripples) have oscillations perpendicular to the direction of energy transfer; longitudinal waves (e.g. sound) have oscillations parallel to the direction.

波传递能量而并不传递物质。横波（如光、水波）的振动方向与能量传递方向垂直；纵波（如声波）的振动方向与能量传递方向平行。

Wave speed = frequency × wavelength (v = fλ). Period T = 1/f. On a WJEC exam, you may need to measure wavelength from a diagram and calculate speed or frequency.

波速 = 频率 × 波长（v = fλ）。周期 T = 1/f。在 WJEC 考试中，可能需要从示意图中测量波长并计算波速或频率。

The electromagnetic spectrum, from longest wavelength to shortest, is: radio, microwave, infrared, visible, ultraviolet, X-ray, gamma. All EM waves travel at the same speed in a vacuum (3.0 × 10⁸ m/s). Each region has distinct uses and hazards.

电磁波谱从长波到短波依次为：无线电波、微波、红外线、可见光、紫外线、X 射线、伽马射线。所有电磁波在真空中的速度相同（3.0 × 10⁸ m/s）。各波段有特定的用途和危害。

Infrared radiation is emitted and absorbed by all objects. Black, matte surfaces are best absorbers and emitters; shiny, light surfaces reflect more. This is tested in the context of cooling and the greenhouse effect.

所有物体都会发射和吸收红外辐射。黑色、粗糙的表面是最好的吸收体和发射体；光亮、浅色的表面反射更多。这一知识点常在冷却过程和温室效应情境中考查。

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4. Chemistry: Atomic Structure and the Periodic Table | 化学：原子结构与元素周期表

Atoms consist of protons and neutrons in the nucleus, with electrons in energy levels. Proton number (atomic number) determines the element. The relative charge of a proton is +1, neutron 0, electron −1; relative masses are 1, 1 and negligible respectively.

原子由原子核内的质子和中子以及核外分层排布的电子构成。质子数（原子序数）决定了元素种类。质子的相对电荷为 +1，中子为 0，电子为 −1；相对质量分别为 1、1 和可忽略不计。

Isotopes are atoms of the same element with different numbers of neutrons. They have identical chemical properties because electron configuration is the same. Mass number = protons + neutrons.

同位素是同一元素具有不同中子数的原子。因为电子排布相同，它们的化学性质完全相同。质量数 = 质子数 + 中子数。

The modern periodic table arranges elements by increasing atomic number. Groups have the same number of outer electrons; periods have the same number of electron shells. Group 1 (alkali metals) are very reactive, Group 7 (halogens) are reactive non-metals, and Group 0 (noble gases) are unreactive.

现代周期表按原子序数递增排列元素。同一族元素的最外层电子数相同；同一周期元素的电子层数相同。第1族（碱金属）很活泼，第7族（卤素）是活泼的非金属，第0族（稀有气体）极不活泼。

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5. Chemistry: Bonding and Structure | 化学：化学键与结构

Ionic bonding occurs between metals and non-metals, where electrons are transferred to form positive and negative ions. Giant ionic lattices have high melting points and conduct electricity when molten or dissolved because ions are free to move.

离子键存在于金属和非金属之间，通过电子转移形成阳离子和阴离子。巨型离子晶格具有高熔点，在熔融或溶于水时可导电，因为离子能自由移动。

Covalent bonding is the sharing of electrons between non-metal atoms. Simple molecular substances like H₂O and CO₂ have low melting points and do not conduct electricity. Giant covalent structures (diamond, graphite, silicon dioxide) have very high melting points.

共价键是非金属原子间共享电子。简单分子如 H₂O 和 CO₂ 熔点低，不导电。巨型共价结构（金刚石、石墨、二氧化硅）具有极高的熔点。

Graphite is unusual: each carbon atom bonds to three others in layers with delocalised electrons, allowing it to conduct electricity and act as a lubricant. Diamond, with each carbon bonded tetrahedrally, is incredibly hard and an electrical insulator.

石墨很特殊：每个碳原子与其余三个碳原子成键，形成层状结构并拥有离域电子，因此能导电并用作润滑剂。金刚石中每个碳原子以四面体方式成键，极其坚硬且不导电。

Metallic bonding involves a regular lattice of positive ions surrounded by a sea of delocalised electrons. This explains why metals are good conductors, malleable and ductile.

金属键中，正离子按规则排列，浸没在离域电子的“海洋”中。这解释了金属为何是良导体，且具有延展性和可塑性的原因。

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6. Chemistry: Chemical Reactions and Energy Changes | 化学：化学反应与能量变化

During chemical reactions, atoms are rearranged and bonds are broken and made. The law of conservation of mass states that total mass of reactants equals total mass of products. Some reactions may appear to lose mass if a gas is produced and escapes.

在化学反应中，原子重新排列，化学键断裂并形成。质量守恒定律指出反应物的总质量等于生成物的总质量。如果有气体产生并逸出，称量质量可能会减少。

Exothermic reactions release energy to the surroundings (e.g., combustion, neutralisation). Endothermic reactions absorb energy (e.g., thermal decomposition, citric acid + sodium hydrogencarbonate). Energy changes can be shown on reaction profiles.

放热反应向周围环境释放能量（如燃烧、中和反应）。吸热反应则吸收能量（如热分解、柠檬酸与碳酸氢钠反应）。能量变化可用反应进程图表示。

Balanced symbol equations use state symbols: (s) solid, (l) liquid, (g) gas, (aq) aqueous. E.g., 2Mg(s) + O₂(g) → 2MgO(s). You must be able to balance equations and interpret information from ionic equations.

配平的符号方程需标示物质状态：(s) 固体, (l) 液体, (g) 气体, (aq) 水溶液。例如：2Mg(s) + O₂(g) → 2MgO(s)。你必须掌握配平方程并能解读离子方程中的信息。

Reactivity series: potassium, sodium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver, gold. Metals above hydrogen react with acids, and a more reactive metal displaces a less reactive metal from its compound.

金属活动性顺序：钾、钠、钙、镁、铝、（碳）、锌、铁、（氢）、铜、银、金。排在氢前面的金属能与酸反应，较活泼金属能将较不活泼金属从其化合物中置换出来。

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7. Biology: Cell Biology and Organisation | 生物：细胞生物学与组织层次

All living organisms are made of cells. Eukaryotic cells (plant and animal) have a nucleus and membrane‑bound organelles. Prokaryotic cells (bacteria) are smaller, lack a nucleus, and have circular DNA and plasmids.

所有生物都由细胞构成。真核细胞（植物和动物）有细胞核和膜包被的细胞器。原核细胞（细菌）更小，没有细胞核，DNA 呈环状，并且含有质粒。

Plant cells have a cellulose cell wall, a large permanent vacuole, and chloroplasts for photosynthesis. Animal cells lack these. Both have cell membrane, cytoplasm and mitochondria where aerobic respiration occurs.

植物细胞有纤维素组成的细胞壁、一个大型中央液泡和进行光合作用的叶绿体。动物细胞则没有这些结构。两者都有细胞膜、细胞质以及进行有氧呼吸的线粒体。

Specialised cells are adapted for their function: sperm cells have a tail for movement; root hair cells have a large surface area for water uptake; xylem cells are hollow and strengthened with lignin to transport water.

特化细胞在结构上适应其功能：精子具有鞭毛以运动；根毛细胞有极大表面积用于吸收水分；木质部细胞中空且木质化加厚，用以运输水分。

Tissues, organs and organ systems form a hierarchy. In the digestive system, for example, glands produce enzymes, the stomach churns food, and the small intestine absorbs soluble products. Enzymes are biological catalysts that speed up reactions.

组织、器官和器官系统构成层级体系。以消化系统为例，腺体分泌酶，胃搅拌食物，小肠吸收可溶性产物。酶是生物催化剂，能加快化学反应速率。

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8. Biology: Photosynthesis and Respiration | 生物：光合作用与呼吸作用

Photosynthesis takes place in chloroplasts, using carbon dioxide and water to produce glucose and oxygen. The overall word equation: carbon dioxide + water → glucose + oxygen (in the presence of light and chlorophyll).

光合作用在叶绿体中进行，利用二氧化碳和水生成葡萄糖和氧气。总文字方程：二氧化碳 + 水 → 葡萄糖 + 氧气（需要光和叶绿素）。

The rate of photosynthesis is affected by light intensity, carbon dioxide concentration and temperature. Limiting factors can be identified from graphs. In WJEC, you might be asked to interpret data from pondweed experiments counting oxygen bubbles.

光合作用的速率受光照强度、二氧化碳浓度和温度的影响。可通过图表识别限制因素。在 WJEC 考试中，可能会要求解读水草实验计数氧气泡的数据。

Aerobic respiration releases energy from glucose in the presence of oxygen: glucose + oxygen → carbon dioxide + water (+ energy). It occurs in mitochondria and is used for processes such as muscle contraction and maintaining body temperature.

有氧呼吸在有氧条件下从葡萄糖中释放能量：葡萄糖 + 氧气 → 二氧化碳 + 水（+ 能量）。该过程在线粒体中进行，用于肌肉收缩、维持体温等生命活动。

Anaerobic respiration in muscles produces lactic acid, causing cramp and an oxygen debt. In yeast and plants, anaerobic respiration produces ethanol and carbon dioxide (fermentation). Both forms release less energy than aerobic respiration.

肌肉中的无氧呼吸产生乳酸，导致痉挛和氧债。酵母和植物的无氧呼吸则生成乙醇和二氧化碳（发酵）。这两种形式释放的能量均少于有氧呼吸。

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9. Biology: Ecology and the Environment | 生物：生态与环境

An ecosystem includes all the organisms in a habitat and the physical environment. Interdependence means changes in one population affect others. Food chains show the transfer of energy; arrows indicate direction of energy flow.

生态系统包括栖息地中的所有生物及其物理环境。相互依存意味着一个种群的变化会影响其他生物。食物链展示能量的转移；箭头表示能量流动的方向。

The carbon cycle describes how carbon moves between the atmosphere, organisms and the Earth. Photosynthesis removes CO₂; respiration, decomposition and combustion release it. Deforestation and burning fossil fuels upset the balance.

碳循环描述了碳在大气、生物体和地球之间的循环。光合作用消耗 CO₂；呼吸作用、分解作用和燃烧释放 CO₂。森林砍伐和燃烧化石燃料破坏了这一平衡。

Biodiversity refers to the variety of species and ecosystems. Pollution, habitat destruction and climate change reduce biodiversity. Conservation methods include breeding programmes, protected areas and replanting hedgerows.

生物多样性指物种和生态系统的多样性。污染、栖息地破坏和气候变化导致生物多样性下降。保护措施包括繁殖计划、设立保护区和重植绿篱等。

In fieldwork, quadrats and transects are used to estimate population sizes and distribution. Systematic sampling along a transect can show zonation. You must be able to calculate mean, median and mode, and describe reliability of data.

现场调查中，样方和样线用于估算种群大小和分布。沿样线进行系统采样可以显示分带现象。你必须能够计算平均值、中位数和众数，并描述数据的可靠性。

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10. Practical Skills and Data Analysis | 实验技能与数据分析

WJEC Science papers include questions on practical procedures. You should know how to measure variables accurately, identify control variables, and assess risks. A correct method is reproducible and reduces random and systematic errors.

WJEC 科学试卷包含实验程序相关的题目。你需要知道如何准确测量变量、识别控制变量并评估风险。正确的方法应当可重复，并能减少随机误差和系统误差。

When plotting graphs, always label axes with quantity and unit, use an appropriate scale, and draw a line of best fit. For rate experiments, the initial rate is found from the steepest part of the curve. Calculate the gradient to find rate of reaction.

绘制图表时，务必标注坐标轴名称和单位，使用合适比例，并画出最佳拟合线。在速率实验中，初始速率取曲线最陡段。通过计算斜率即可求出反应速率。

Drawing conclusions involves describing patterns and using scientific knowledge to explain them. Evaluate data by identifying anomalies, considering whether repeats improved reliability, and suggesting improvements. Use terms like ‘repeatable’ and ‘reproducible’ correctly.

得出结论包括描述规律并运用科学知识加以解释。评价数据时需找出异常值，判断重复实验是否提升可靠性，并提出改进建议。正确使用“可重复”和“可重现”等术语。

Remember to convert units consistently, especially for mass (g to kg), volume (cm³ to dm³) and time (seconds). An error of a factor of 1000 is a common mistake; for concentration calculations, ensure mol/dm³ is used when working with volumes in dm³.

请务必统一换算单位，特别是质量（g→kg）、体积（cm³→dm³）和时间（秒）。差一个千倍因子是常见错误；计算浓度时，若体积使用 dm³ 则单位应为 mol/dm³。

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