📚 Year 10 SQA Science: Key Knowledge Points Review | SQA 科学：核心知识点梳理
In Year 10 SQA Science, students explore fundamental ideas across biology, chemistry and physics, while building essential skills in scientific enquiry. This article brings together the core knowledge points to support your revision and deepen your understanding.
在 SQA 十年级科学课程中，学生们将探索生物、化学和物理的基础概念，同时培养科学探究的关键技能。本文汇总了核心知识点，帮助你高效复习并加深理解。
1. Scientific Inquiry & Variables | 科学探究与变量
Every well-designed experiment identifies three types of variables: the independent variable (what you change), the dependent variable (what you measure) and control variables (what you keep the same). This ensures a fair test.
任何一个设计合理的实验都会确定三种变量：自变量（你改变的因素）、因变量（你测量的结果）和控制变量（你保持不变的因素）。这样才能保证公平测试。
Reliability comes from repeating measurements and calculating an average; accuracy is improved by using instruments with a smaller scale division and avoiding systematic errors.
信度来自重复测量并计算平均值；准确度可以通过使用分度值更小的仪器并避免系统误差来提高。
Data should be presented clearly in tables and graphs. For line graphs, the independent variable goes on the x-axis and the dependent variable on the y-axis, with both axes labelled and units included.
数据应当用表格和图表清晰地呈现。绘制折线图时，自变量放在 x 轴，因变量放在 y 轴，两轴都要标上名称和单位。
2. Cells & Biological Molecules | 细胞与生物分子
All living organisms are made of cells. Animal and plant cells both have a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. Plant cells also have a rigid cell wall, a large permanent vacuole and chloroplasts for photosynthesis.
所有生物都由细胞构成。动物细胞和植物细胞都具有细胞核、细胞质、细胞膜、线粒体和核糖体。植物细胞还有坚硬的细胞壁、一个大液泡和进行光合作用的叶绿体。
Diffusion is the net movement of particles from a region of high concentration to a region of low concentration across a partially permeable membrane. Osmosis is specifically the diffusion of water molecules.
扩散是粒子从高浓度区域穿过半透膜向低浓度区域的净移动。渗透特指水分子的扩散过程。
ose + oxygen, using light energy absorbed by chlorophyll. The balanced symbol equation is:
光合作用可用文字方程式概括：二氧化碳 + 水 → 葡萄糖 + 氧气，需要叶绿素吸收光能。配平的符号方程式为：
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
3. DNA, Genes & Heredity | DNA、基因与遗传
DNA is a double helix molecule found in chromosomes inside the nucleus. A gene is a short section of DNA that codes for a particular protein and determines a characteristic. Different forms of a gene are called alleles.
DNA 是一种双螺旋分子，位于细胞核内的染色体上。基因是 DNA 上的一段短序列，编码特定的蛋白质并决定性状。基因的不同形式称为等位基因。
Alleles can be dominant or recessive. A dominant allele will be expressed even if only one copy is present, while a recessive allele is only expressed if two copies are present. Genetic diagrams, such as Punnett squares, help predict the probability of offspring inheriting certain traits.
等位基因可以是显性或隐性。显性等位基因只要有一个拷贝就会表现出来，而隐性等位基因则要在有两个拷贝时才会表达。遗传图解（如庞纳特方格）可以帮助预测后代继承某一性状的概率。
In a monohybrid cross, when a homozygous dominant (BB) and homozygous recessive (bb) individual reproduce, all first-generation offspring are heterozygous (Bb) and show the dominant trait.
在单性状杂交中，当纯合显性（BB）个体与纯合隐性（bb）个体交配时，第一代子代全部为杂合子（Bb）并表现出显性性状。
4. Ecosystems & Energy Flow | 生态系统与能量流动
An ecosystem is made up of a community of living organisms interacting with each other and their physical environment. Producers (green plants) capture light energy during photosynthesis and form the base of food chains.
生态系统由生物群落与其物理环境相互作用构成。生产者（绿色植物）通过光合作用捕获光能，成为食物链的基础。
Energy is transferred from producers to primary consumers (herbivores) and then to secondary consumers (carnivores). At each trophic level, about 90% of the energy is lost as heat, movement and undigested material, which limits the length of food chains.
能量从生产者传递到初级消费者（植食动物），再传递到次级消费者（肉食动物）。在每一个营养级，大约 90% 的能量以热量、运动和未消化物质的形式损失掉，这限制了食物链的长度。
Food webs show interconnected feeding relationships, while a pyramid of energy illustrates the decreasing amount of energy available at higher trophic levels. Decomposers, such as bacteria and fungi, break down dead organisms, returning nutrients to the soil.
食物网展示了相互交织的捕食关系，而能量金字塔则显示较高营养级可利用的能量逐渐减少。分解者（如细菌和真菌）分解死去的生物体，使养分回归土壤。
5. Atoms & the Periodic Table | 原子与元素周期表
An atom consists of a central nucleus containing protons and neutrons, surrounded by electrons in shells. Protons carry a positive charge, neutrons are neutral, and electrons are negatively charged.
原子由一个含有质子和中子的中央原子核以及核外分层排布的电子构成。质子带正电荷，中子不带电，电子带负电荷。
The atomic number equals the number of protons and determines the element. The mass number is the total of protons plus neutrons. Electrons are arranged in shells following the 2,8,8 rule for the first 20 elements.
原子序数等于质子数，决定了元素的种类。质量数是质子数与中子数的总和。前 20 号元素的电子按照 2,8,8 的规律排列。
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 outer-shell electrons. Periods are horizontal rows.
元素周期表按原子序数递增的顺序排列。族是纵列，同一族的元素因最外层电子数相同而具有相似的化学性质。周期是横排。
| Particle | Relative charge | Relative mass |
|---|---|---|
| Proton | +1 | 1 |
| Neutron | 0 | 1 |
| Electron | -1 | 1/1836 |
6. Chemical Bonding & Formulae | 化学键与化学式
Ionic bonding occurs between metals and non-metals. Metal atoms lose electrons to form positive ions (cations), while non-metal atoms gain electrons to form negative ions (anions). The strong electrostatic attraction between oppositely charged ions forms the ionic bond.
离子键形成于金属与非金属之间。金属原子失去电子形成阳离子，非金属原子得到电子形成阴离子。带相反电荷的离子之间的强静电吸引力构成了离子键。
Covalent bonding occurs between non-metal atoms. They share pairs of electrons to achieve a full outer shell. Single covalent bonds involve one shared pair, as in H₂, while double bonds involve two shared pairs, as in O₂.
共价键形成于非金属原子之间。它们通过共享电子对来达到满壳层结构。单共价键共享一对电子，如 H₂；双键共享两对电子，如 O₂。
Chemical formulae show the elements present and the ratio of atoms or ions. The formula of an ionic compound is the simplest whole-number ratio, such as NaCl (1:1) and CaCl₂ (1:2).
化学式表示化合物中所含的元素以及原子或离子的比例。离子化合物的化学式是最简整数比，如 NaCl（1:1）和 CaCl₂（1:2）。
7. Acids, Bases & Neutralisation | 酸、碱与中和反应
Acids are substances that produce hydrogen ions (H⁺) in aqueous solution; common laboratory acids include hydrochloric acid, sulfuric acid and nitric acid. Bases neutralise acids, and a soluble base is called an alkali, which produces hydroxide ions (OH⁻) in water.
酸是在水溶液中产生氢离子（H⁺）的物质；实验室常见的酸有盐酸、硫酸和硝酸。碱能中和酸，可溶性的碱被称为碱，它在水中产生氢氧根离子（OH⁻）。
The pH scale runs from 0 (strongly acidic) to 14 (strongly alkaline), with 7 being neutral. Universal indicator gives a range of colours across the scale.
pH 标度从 0（强酸性）到 14（强碱性），7 为中性。通用指示剂在不同 pH 值下会呈现一系列不同的颜色。
During neutralisation, hydrogen ions react with hydroxide ions to form water:
H⁺ + OH⁻ → H₂O
This reaction is exothermic and explains why mixing an acid and an alkali produces a salt and water only.
中和反应中，氢离子与氢氧根离子结合生成水：这个反应是放热的，这也解释了为何酸与碱混合只会生成盐和水。
8. Motion, Forces & Energy | 运动、力与能量
Speed is the distance travelled per unit time, while velocity is speed in a given direction. Acceleration is the change in velocity per unit time. The key formulas are:
速度是单位时间内移动的距离，而速率是特定方向上的速度。加速度是单位时间内速度的变化量。核心计算公式为：
v = d / t and a = (v – u) / t
Newton' d Law relates force, mass and acceleration: F = m × a. Forces are measured in newtons (N).
牛顿第一定律指出，除非受到非平衡力的作用，物体将保持静止或匀速直线运动状态。第二定律将力、质量和加速度联系在一起：F = m × a。力的单位是牛顿（N）。
nergy cannot be created or destroyed, only transferred or transformed. Power is the rate of energy transfer, calculated as P = E / t or P = W / t, measured in watts (W).
能量有多种形式：动能（由运动产生）、重力势能（由高度产生）和储存在燃料中的化学能。能量既不能创生也不能消灭，只能转移或转化。功率是能量传递的速率，计算公式为 P = E / t 或 P = W / t，单位是瓦特（W）。
9. Electricity & Circuits | 电与电路
An electric current is a flow of charge; in a metal wire, it is the movement of free electrons. Current (I) is measured in amperes (A), voltage (V) in volts (V) and resistance (R) in ohms (Ω). Ohm's law links them:
电流是电荷的流动；在金属导线中，它是自由电子的定向移动。电流（I）的单位是安培（A），电压（V）的单位是伏特（V），电阻（R）的单位是欧姆（Ω）。欧姆定律将三者联系起来：
V = I × R
In a series circuit, the current is the same at all points, but the total resistance increases as more resistors are added. In a parallel circuit, the voltage across each branch is the same, and adding more branches reduces the total resistance.
在串联电路中，各处电流相等，但增加电阻会使总电阻增大。在并联电路中，各支路两端的电压相同，增加支路会降低总电阻。
Common circuit symbols include a cell, battery, switch, lamp, resistor and variable resistor. When drawing circuits, use straight lines for wires and ensure the circuit is closed for current to flow.
常见电路符号有电池、电池组、开关、灯泡、电阻和可变电阻。绘制电路图时，用直线表示导线，并确保电路闭合才能使电流通过。
10. Waves & the Electromagnetic Spectrum | 波与电磁波谱
Waves transfer energy without transferring matter. Transverse waves (e.g. light, water waves) oscillate perpendicular to the direction of energy transfer; longitudinal waves (e.g. sound) oscillate parallel to it.
波传递能量而不传递物质。横波（如光波、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。
The wave equation relates speed (v), frequency (f) and wavelength (λ):
v = f × λ
⁸ m/s). In order of decreasing wavelength, it includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays.
电磁波谱是一系列横波，它们在真空中以相同的速度（3 × 10⁸ m/s）传播。按照波长递减的顺序，包括无线电波、微波、红外线、可见光、紫外线、X 射线和伽马射线。
Different parts of the spectrum have different uses and dangers. Radio waves are used for communication, X-rays for medical imaging, and gamma rays for sterilising equipment; however, ultraviolet, X-rays and gamma rays are ionising and can damage cells.
波谱的不同部分有着不同的用途和危害。无线电波用于通信，X 射线用于医学成像，伽马射线用于设备灭菌；而紫外线、X 射线和伽马射线具有电离能力，会损害细胞。
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