📚 KS3 Activate 2 Science Revision: Core Concepts and Exam Skills | KS3 Activate 2 科学复习：核心概念与考试技巧
Welcome to this KS3 Activate 2 revision guide. It brings together the key ideas from the Activate 2 course, including health, ecosystems, chemistry, Earth science, electricity, and motion. Each section pairs an English explanation with a Chinese translation so you can check your understanding and build scientific vocabulary.
欢迎使用本 KS3 Activate 2 复习指南。它汇集了 Activate 2 课程中的核心概念，包括健康、生态系统、化学、地球科学、电学和运动。每一节都提供英文解释和中文对照，帮助你检查理解并积累科学词汇。
1. Working Scientifically | 科学探究方法
In every Activate 2 topic, you need to plan investigations, collect data, and draw conclusions. The independent variable is the one you change, the dependent variable is the one you measure, and control variables are kept the same to make the test fair.
在 Activate 2 的每个主题中，你都需要设计探究、收集数据并得出结论。自变量是你改变的变量，因变量是你测量的变量，控制变量则保持不变以确保实验公平。
When plotting a graph, put the independent variable on the x-axis and the dependent variable on the y-axis. Use a line of best fit only when the data show a clear trend; never join every point with a ruler if the points are scattered.
绘制图表时，将自变量放在 x 轴，因变量放在 y 轴。只有数据呈现明显趋势时才使用最佳拟合线；如果点分散，不要用直尺连接每一个点。
A scientific conclusion must refer back to the data. Say whether the results support the prediction, and describe the relationship in words such as 'as the independent variable increases, the dependent variable decreases'.
科学结论必须回到数据本身。要说明结果是否支持预测，并用语言描述关系，例如“随着自变量增大，因变量减小”。
In exam questions on working scientifically, look for clues about variables in the method. Always identify what is changed, what is measured, and what is kept constant before evaluating the quality of the data.
在科学探究方法的考题中，留意方法中关于变量的线索。在评价数据质量之前，始终先找清哪些是被改变的变量、哪些是被测量的变量、哪些是保持不变的变量。
2. Health and Lifestyle | 健康与生活方式
Health is not simply the absence of disease; it is a state of physical and mental wellbeing. In Activate 2, you study how nutrients, exercise, and drugs affect the body. Carbohydrates, proteins, and fats provide energy and building materials, while vitamins and minerals are needed in small amounts.
健康不仅仅是没有疾病；它是一种身体和心理的良好状态。在 Activate 2 中，你会学习营养素、运动和药物如何影响身体。碳水化合物、蛋白质和脂肪提供能量和构建材料，而维生素和矿物质需要量很小。
Digestion breaks large insoluble molecules into small soluble ones. Enzymes in the mouth, stomach, and small intestine speed up these reactions. The small intestine is where most absorption into the blood occurs.
消化将大分子不溶性物质分解为小分子可溶性物质。口腔、胃和小肠中的酶加速这些反应。小肠是大多数营养物质被吸收进入血液的地方。
Common exam questions ask you to interpret food tests or model gut data. Remember: Benedict's solution tests for reducing sugars, iodine tests for starch, and Biuret reagent tests for protein.
常见考题要求你解释食物测试或模拟肠道数据。记住：本尼迪克特溶液检测还原糖，碘液检测淀粉，双缩脲试剂检测蛋白质。
Lifestyle choices, such as smoking, poor diet, and lack of exercise, increase the risk of non-communicable diseases like heart disease and type 2 diabetes. These diseases cannot be passed from person to person.
生活方式的选择，如吸烟、不良饮食和缺乏运动，会增加患心脏病和 2 型糖尿病等非传染性疾病的风险。这些疾病不会在人与人之间传播。
3. Ecosystem Processes | 生态系统过程
Photosynthesis is the process by which green plants make glucose using light energy. The word equation is:
光合作用是绿色植物利用光能制造葡萄糖的过程。文字方程式为：
carbon dioxide + water → glucose + oxygen
二氧化碳 + 水 → 葡萄糖 + 氧气
Photosynthesis happens in chloroplasts, which contain chlorophyll. The rate is affected by light intensity, carbon dioxide concentration, and temperature.
光合作用发生在含有叶绿素的叶绿体中。光合作用速率受光照强度、二氧化碳浓度和温度的影响。
Aerobic respiration releases energy from glucose in the mitochondria of all living cells. Its word equation is:
有氧呼吸在所有活细胞的线粒体中将葡萄糖中的能量释放出来。其文字方程式为：
glucose + oxygen → carbon dioxide + water
葡萄糖 + 氧气 → 二氧化碳 + 水
Food chains show the transfer of energy from producers to consumers. Arrows point in the direction of energy flow, not in the direction of 'who eats whom'.
食物链显示能量从生产者到消费者的传递。箭头指向能量流动的方向，而不是“谁吃谁”的方向。
A common misconception is that plants only respire at night. In fact, plants respire all the time, but during the day photosynthesis usually produces more oxygen than respiration uses.
一个常见的误区是植物只在夜间呼吸。事实上，植物时刻都在呼吸，但在白天光合作用产生的氧气通常多于呼吸作用消耗的氧气。
4. Adaptation and Inheritance | 适应与遗传
Organisms have adaptations that help them survive in their environment. For example, camels have wide feet to spread their weight on sand, and cacti have thick stems to store water.
生物体具有帮助它们在环境中生存的适应性特征。例如，骆驼有宽大的脚掌以分散在沙地上的重量，仙人掌有粗厚的茎来储存水分。
Natural selection explains how species change over time. Individuals with advantageous traits are more likely to survive and reproduce, passing those traits to their offspring.
自然选择解释了物种如何随着时间发生变化。具有有利特征的个体更有可能生存和繁殖，并将这些特征传给后代。
Genetic information is carried by DNA in the nucleus. A gene is a section of DNA that controls a characteristic. In KS3, you do not need the full structure of DNA, but you should know that genes are passed from parents to offspring during reproduction.
遗传信息由细胞核中的 DNA 携带。基因是控制某一特征的 DNA 片段。在 KS3 阶段，你不需要掌握 DNA 的完整结构，但应该知道基因在生殖过程中由父母传给后代。
Variation within a species can be caused by genetic factors, environmental factors, or a combination of both. For example, height is influenced by genes and by diet.
物种内部的变异可能由遗传因素、环境因素或两者共同引起。例如，身高既受基因影响，也受饮食影响。
5. The Periodic Table | 元素周期表
All substances are made from elements. An element contains only one type of atom. Compounds form when two or more different elements chemically combine, such as water (H₂O) and carbon dioxide (CO₂).
所有物质都由元素组成。元素只含有一种原子。当两种或多种不同元素发生化学结合时形成化合物，例如水（H₂O）和二氧化碳（CO₂）。
The Periodic Table arranges elements in order of increasing atomic number. Metals are on the left and in the centre, while non-metals are on the right. Group 1 elements are the alkali metals, Group 7 are the halogens, and Group 0 are the noble gases.
元素周期表按原子序数递增的顺序排列元素。金属位于左侧和中间，非金属位于右侧。第 1 族是碱金属，第 7 族是卤素，第 0 族是稀有气体。
Chemical reactions can be represented by word equations. Reactants go on the left, products on the right, and an arrow shows the direction of change. No atoms are lost or made, so the total mass is conserved.
化学反应可用文字方程式表示。反应物写在左边，产物写在右边，箭头表示变化方向。原子不会消失或产生，因此总质量守恒。
When you see a chemical formula such as CO₂, the subscript 2 tells you there are two oxygen atoms in one molecule. If there is no subscript, there is only one atom of that element.
当你看到 CO₂ 这样的化学式时，下标 2 表示一个分子中有两个氧原子。如果没有下标，则表示该元素只有一个原子。
6. Separation Techniques | 分离技术
Mixtures contain two or more substances that are not chemically joined. Unlike compounds, the parts of a mixture can be separated by physical methods because each substance keeps its own properties.
混合物含有两种或多种没有化学结合的物质。与化合物不同，混合物的各组分可以通过物理方法分离，因为每种物质保持自身的性质。
| Technique | Used to separate | Key idea |
|---|---|---|
| Filtration | Insoluble solid from liquid | Solid stays in filter paper |
| Evaporation | Soluble solid from solution | Water evaporates, solid remains |
| Distillation | Solvent from solution | Evaporate then condense the solvent |
| Chromatography | Different coloured solutes | Solutes move at different speeds |
This table summarises the four main separation techniques you need to describe and choose in exam questions. Always link the method to the properties of the substances in the mixture.
该表总结了你在考试中需要描述和选择的四种主要分离技术。始终将方法与混合物中各物质的性质联系起来。
For example, filtration is used to separate sand from water because sand is insoluble. Distillation is better than evaporation when you need to collect the liquid as well as the solid.
例如，过滤用于分离沙子和水，因为沙子不溶于水。当你既需要收集液体又需要收集固体时，蒸馏比蒸发更合适。
7. Metals and Acids | 金属与酸
Metals react with acids to produce a salt and hydrogen
Published by TutorHao | KS3 Revision Series | aleveler.com
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