📚 Year 7 AQA Science: Core Knowledge Review | Year 7 AQA 科学：核心知识点梳理
In Year 7 AQA Science, students begin to build a strong foundation across biology, chemistry and physics. This article summarises the essential core knowledge you will encounter, from cells and forces to atomic structure and experimental skills. Use it as a checklist to consolidate your understanding and prepare for assessments.
在 Year 7 AQA 科学课程中，学生开始建立生物学、化学和物理学的坚实基础。本文梳理了你将接触到的核心知识点，从细胞、力到原子结构和实验技能。把它当作一份清单，用来巩固理解并为评估做准备。
1. Cells and Organisation | 细胞与组织结构
All living organisms are made of cells, which are the basic units of life. A microscope magnifies tiny structures so we can observe cell parts.
所有生物都是由细胞构成的，细胞是生命的基本单位。显微镜能放大微小的结构，让我们观察到细胞的组成部分。
Animal cells usually contain a nucleus, cytoplasm, cell membrane and mitochondria. Plant cells have these plus a rigid cell wall, chloroplasts for photosynthesis, and a large permanent vacuole.
动物细胞通常含有细胞核、细胞质、细胞膜和线粒体。植物细胞除了具备这些，还有坚硬的细胞壁、进行光合作用的叶绿体和一个大的永久液泡。
Unicellular organisms, such as bacteria and amoeba, consist of a single cell, while multicellular organisms like humans have cells specialised to perform different functions. Specialised cells include red blood cells (carry oxygen), root hair cells (absorb water), and nerve cells (transmit signals).
细菌、变形虫等单细胞生物仅由一个细胞构成，而人类等多细胞生物则拥有特化执行不同功能的细胞。特化细胞包括红细胞（运输氧气）、根毛细胞（吸收水分）和神经细胞（传递信号）。
2. States of Matter and Changes | 物质的状态与变化
Matter exists as solid, liquid or gas, depending on the arrangement and movement of particles. Solids have a fixed shape and volume because particles are tightly packed in a regular pattern and only vibrate.
物质以固态、液态或气态存在，取决于粒子的排列方式和运动状态。固体有固定的形状和体积，因为粒子紧密排列成规则结构，只在原位振动。
Liquids have a fixed volume but take the shape of their container; particles are close together but can move past each other. Gases have no fixed shape or volume; particles are far apart and move rapidly in all directions.
液体有固定的体积但会随容器改变形状；粒子彼此靠近但能相对滑动。气体既无固定形状也无固定体积；粒子相距很远，快速向各个方向运动。
Changes of state are physical changes: melting (solid to liquid), freezing (liquid to solid), boiling/evaporation (liquid to gas), condensation (gas to liquid), and sublimation (solid to gas directly). Mass is conserved because the number of particles does not change.
状态变化属于物理变化：熔化（固态→液态）、凝固（液态→固态）、沸腾/蒸发（液态→气态）、冷凝（气态→液态）以及升华（固态直接变为气态）。由于粒子总数不变，质量守恒。
| Change | Process |
|---|---|
| Solid → Liquid | Melting |
| Liquid → Solid | Freezing |
| Liquid → Gas | Boiling / Evaporation |
| Gas → Liquid | Condensation |
3. Atoms, Elements and Compounds | 原子、元素与化合物
All matter is made of tiny particles called atoms. An element is a pure substance made of only one type of atom. Metals, like iron and copper, and non-metals, like oxygen and carbon, are examples of elements.
所有物质都由称作原子的微小粒子构成。元素是只由一种原子组成的纯净物。诸如铁、铜等金属以及氧、碳等非金属都是元素的例子。
Compounds form when two or more different elements chemically combine in fixed proportions. The properties of a compound are different from the elements it contains. For instance, water (H₂O) is a liquid, yet it is made from hydrogen and oxygen gases.
当两种或多种不同的元素以固定比例发生化学结合时，便形成化合物。化合物的性质不同于构成它的元素。比如水（H₂O）是液体，但它由氢气和氧气两种气体化合而成。
toms are lost or made during a chemical reaction; this is the law of conservation of mass.
化学反应可用文字方程式或符号方程式表示。例如：氢气 + 氧气 → 水，或 2H₂ + O₂ → 2H₂O。化学反应中没有原子生成或消失，这就是质量守恒定律。
4. Acids and Alkalis | 酸与碱
Acids are substances with a pH less than 7. They taste sour (though never taste in a lab) and turn blue litmus paper red. Common laboratory acids include hydrochloric acid (HCl), sulfuric acid (H₂SO₄) and nitric acid (HNO₃).
酸是 pH 值小于 7 的物质。它们尝起来是酸味（但绝不可在实验室品尝），并且能使蓝色石蕊试纸变红。常见的实验室用酸包括盐酸（HCl）、硫酸（H₂SO₄）和硝酸（HNO₃）。
Alkalis are soluble bases; they have a pH greater than 7, feel soapy, and turn red litmus paper blue. Sodium hydroxide (NaOH) and potassium hydroxide (KOH) are typical alkalis.
碱是可溶性的碱；它们 pH 值大于 7，有滑腻感，并使红色石蕊试纸变蓝。氢氧化钠（NaOH）和氢氧化钾（KOH）是典型的碱。
acid + alkali → salt + water. This reaction is used to treat acidic soils and indigestion.
当中和反应发生时，酸和碱反应生成盐和水。总方程式为：酸 + 碱 → 盐 + 水。该反应可用于改良酸性土壤和缓解胃酸过多。
5. Forces and Motion | 力与运动
A force is a push or pull that can change an object's shape, speed or direction. Forces are measured in newtons (N) using a forcemeter. Contact forces, like friction and tension, require objects to touch; non-contact forces, like gravity and magnetism, act over a distance.
力是能改变物体形状、速度或方向的推或拉。力用牛顿（N）为单位，使用测力计测量。摩擦力、拉力等接触力需要物体相互接触；重力、磁力等非接触力则在一定距离处产生作用。
Balanced forces mean the object remains stationary or moves at constant speed. Unbalanced forces cause acceleration, deceleration or a change in direction. Friction slows moving objects and produces heat.
平衡力意味着物体保持静止或以恒定速度运动。非平衡力会导致加速、减速或方向改变。摩擦力使运动的物体减速并生热。
Speed can be calculated using: speed = distance ÷ time (v = d / t). Distance– nt speed, a horizontal line means stationary, and a steeper line indicates a faster speed.
速度可用公式计算：速度 = 距离 ÷ 时间（v = d / t）。距离-时间图可以描述运动；直线表示匀速，水平线表示静止，越陡峭的线条代表速度越快。
6. Energy Transfers and Stores | 能量转移与储存
Energy cannot be created or destroyed, only transferred or stored. The main energy stores are kinetic, gravitational potential, elastic potential, thermal, chemical, nuclear, and magnetic.
能量不能被创造或消灭，只能被转移或储存。主要的能量储存形式有动能、重力势能、弹性势能、热能、化学能、核能和磁能。
Energy transfers occur through heating, waves, electric current or forces. For example, when a ball is thrown upwards, kinetic energy is transferred to gravitational potential energy; when it falls, the reverse happens.
能量通过加热、波、电流或力等途径进行转移。例如，当向上抛球时，动能转化为重力势能；球下落时，则发生相反的转化。
Fossil fuels (coal, oil, gas) are non-renewable energy resources that originally stored chemical energy from ancient organisms. Renewable resources include solar, wind, tidal, wave and hydroelectric power.
化石燃料（煤、石油、天然气）是不可再生的能源，它们最初储存了远古生物的化学能。可再生能源包括太阳能、风能、潮汐能、波浪能和水力发电。
7. Electricity | 电学基础
An electric circuit needs a complete loop for current to flow. Current is the flow of electric charge and is measured in amperes (A) using an ammeter connected in series. Voltage (potential difference) is the push that drives current, measured in volts (V) with a voltmeter in parallel.
电路需要完整回路才能使电流流动。电流是电荷的流动，用串联在电路中的安培表测量，单位为安培（A）。电压（电位差）是驱动电流的“推力”，用并联在电路中的伏特表测量，单位为伏特（V）。
Conductors, like metals, allow charge to flow easily because they have free electrons. Insulators, such as rubber and plastic, prevent current flow. Series circuits have one path; if one component breaks, all go off. Parallel circuits provide separate paths, so other branches stay lit.
像金属这样的导体容易让电荷通过，因为它们拥有自由电子。橡胶、塑料等绝缘体则阻止电流流动。串联电路只有一条路径，一个元件损坏，所有灯都熄灭。并联电路提供独立支路，因此其他支路仍能工作。
Resistance slows down current and is measured in ohms (Ω). Components like lamps and motors have resistance. When electrons collide with ions in a wire, electrical energy is transformed into heat.
电阻会减慢电流，单位为欧姆（Ω）。灯泡和马达等元件具有电阻。当电子与导线中的离子碰撞时，电能转化为热量。
8. Reproduction in Plants and Animals | 动植物的繁殖
Reproduction ensures the continuation of a species and can be sexual or asexual. Sexual reproduction involves the joining of male and female gametes, producing offspring that are genetically different from the parents.
繁殖确保了物种的延续，可分为有性繁殖和无性繁殖。有性繁殖涉及雄配子和雌配子的结合，产生的后代与亲代在遗传上存在差异。
In humans, the male gamete is the sperm (produced in testes) and the female gamete is the egg (produced in ovaries). Fertilisation occurs in the oviduct, and the fertilised egg develops into an embryo in the uterus. The placenta provides oxygen and nutrients while removing waste.
在人类中，雄配子是精子（由睾丸产生），雌配子是卵子（由卵巢产生）。受精发生在输卵管，受精卵在子宫内发育成胚胎。胎盘提供氧气和营养物质，并移除废物。
Flowering plants reproduce sexually. Pollen (male gamete) from the anther is transferred to the stigma of a flower (pollination). The pollen tube grows down to the ovary, and fertilisation forms seeds. Seed dispersal methods include wind, water, animals and explosion.
开花植物进行有性繁殖。花药中的花粉（雄配子）被传到花的柱头上（传粉）。花粉管向下生长到达子房，受精后形成种子。种子传播的方式包括风力、水力、动物传播和弹射传播。
9. The Periodic Table Basics | 元素周期表基础
The Periodic Table arranges elements in order of increasing atomic number. Groups are vertical columns; elements in the same group have similar chemical properties because they have the same number of electrons in their outer shell.
元素周期表按原子序数递增排列。族是纵列；同一族的元素具有相似的化学性质，因为它们的最外层电子数相同。
Group 1 elements are the alkali metals (e.g., lithium, sodium, potassium). They are soft, react vigorously with water, and become more reactive as you go down the group. Group 7 elements are the halogens (e.g., fluorine, chlorine), non-metals that become less reactive down the group.
第 1 族是碱金属（例如锂、钠、钾）。它们质地柔软，与水剧烈反应，且越往下反应性越强。第 7 族是卤素（例如氟、氯），是非金属元素，越往下反应性越弱。
Group 0 (or 8) are the noble gases (helium, neon, argon). They are unreactive because they have a full outer shell of electrons. Metals are found on the left and centre, non-metals on the right.
第 0 族（或第 8 族）是稀有气体（氦、氖、氩）。它们非常不活泼，因为最外电子层已排满。金属位于周期表左侧和中间，非金属位于右侧。
10. Practical Skills and Safety | 实验技能与安全
All practical work in Year 7 follows strict safety rules. Always wear safety goggles, tie back long hair, and never eat or drink in the lab. Know the hazard symbols for corrosive, flammable, toxic and irritant substances.
Year 7 所有实验操作都遵循严格的安全规则。始终佩戴护目镜，扎起长发，绝不在实验室饮食。须熟知腐蚀性、易燃、有毒和刺激性物质的危险标识。
Measurements must be taken accurately using appropriate instruments: a measuring cylinder for volume, a balance for mass, a thermometer for temperature, and a stopwatch for time. Read the measurement at eye level and record units.
测量时必须使用合适的仪器准确读取：量筒测体积，天平测质量，温度计测温度，停表测时间。在视平面高度读数，并记录单位。
When drawing graphs, label the axes with the variable and unit, use a sensible scale, and plot points with a sharp pencil. Identify independent, dependent and control variables when planning an investigation.
绘制图表时，用变量和单位标记坐标轴，选用合理的比例，并用尖铅笔描点。设计探究实验时，要识别自变量、因变量和控制变量。
Common techniques include using a Bunsen burner safely, filtering to separate an insoluble solid from a liquid, and evaporation to obtain a soluble solid from a solution. Chromatography can separate mixtures of coloured substances.
常用技术包括安全使用本生灯、用过滤法分离不溶性固体与液体、用蒸发法从溶液中获取可溶性固体。色谱法可以分离有色物质的混合物。
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