📚 Activate 1 Student Book: KS3 Science Core Concepts | Activate 1 学生用书：KS3 科学核心概念
Activate 1 is a KS3 science course that builds key ideas in biology, chemistry and physics. This revision guide walks through the main topics from the student book, including working scientifically, cells, particles, reactions, forces and space. It is useful for KS3 and Cambridge Checkpoint preparation.
《Activate 1》是一套 KS3 科学教材，帮助同学们建立生物、化学和物理的核心概念。本复习指南梳理学生用书中的主要主题，包括科学探究方法、细胞、粒子、化学反应、力和太空等内容。该指南也适用于 KS3 和 Cambridge Checkpoint 的备考复习。
1. Working Scientifically | 科学探究方法
Before studying content, you need to plan fair tests and handle data correctly. The independent variable is the one you change, the dependent variable is the one you measure, and control variables must be kept constant. A reliable experiment repeats readings and takes averages.
在学习科学内容之前，你需要学会设计公平实验并正确处理数据。自变量是你改变的变量，因变量是你测量的变量，控制变量则必须保持不变。可靠的实验需要重复读数并取平均值。
Safety is also central in the laboratory. Always wear eye protection when heating or using acids, tie back long hair, and report spills or breakages to a teacher immediately. You should also read labels and never taste or smell chemicals unless told to do so.
实验室安全同样非常重要。加热或使用酸液时要始终佩戴护目镜，扎起长发，如果发生泼洒或玻璃破损应立即报告老师。还应阅读标签，除非老师要求，否则不要品尝或直接闻化学药品。
When drawing graphs, put the independent variable on the x-axis and the dependent variable on the y-axis. Use a line of best fit to show patterns and identify anomalous results that do not fit the trend.
绘制图表时，将自变量放在 x 轴，因变量放在 y 轴。使用最佳拟合线来显示规律，并找出不符合趋势的异常结果。
2. Cells | 细胞
All living things are made of cells. Animal cells contain a nucleus, cytoplasm, cell membrane and mitochondria. Plant cells also have a cell wall, chloroplasts and a permanent vacuole, which support the cell, absorb light and store cell sap.
所有生物都由细胞组成。动物细胞含有细胞核、细胞质、细胞膜和线粒体。植物细胞还有细胞壁、叶绿体和中央大液泡，它们分别起到支持细胞、吸收光照和储存细胞液的作用。
The nucleus controls the cell and contains DNA. Mitochondria release energy by respiration, and chloroplasts absorb light for photosynthesis in plant cells. The cell membrane controls which substances enter and leave the cell.
细胞核控制细胞活动并含有 DNA。线粒体通过呼吸作用释放能量，叶绿体在植物细胞中吸收光能进行光合作用。细胞膜控制物质的进出。
ation. For example, a ×10 eyepiece and a ×40 objective give a total magnification of ×400.
观察细胞需要使用显微镜。总放大倍数等于目镜放大倍数乘以物镜放大倍数。例如，×10 的目镜和 ×40 的物镜，总放大倍数为 ×400。
total magnification = eyepiece magnification × objective magnification
Specialised cells such as root hair cells, sperm cells and red blood cells are adapted to their functions. Root hair cells have a large surface area to absorb water; sperm cells have a tail to swim; red blood cells carry oxygen by using haemoglobin.
根毛细胞、精子和红细胞等特化细胞都适应其特定功能。根毛细胞有较大的表面积以吸收水分；精子有尾部可以游动；红细胞利用血红蛋白运输氧气。
3. Structure and Function of Body Systems | 身体系统的结构与功能
Cells are organised into tissues, tissues into organs, and organs into organ systems. For example, muscle cells form muscle tissue, which forms the stomach, part of the digestive system. Organ systems work together to keep the body alive.
细胞组成组织，组织组成器官，器官组成器官系统。例如，肌肉细胞构成肌肉组织，肌肉组织构成胃，而胃是消化系统的一部分。各个器官系统相互配合以维持生命。
The skeleton supports the body, protects organs and allows movement. At joints, muscles pull bones; pairs of muscles such as the biceps and triceps work against each other. Antagonistic muscles allow smooth movement in opposite directions.
骨骼支撑身体、保护器官并使人运动。在关节处，肌肉牵拉骨骼；肱二头肌和肱三头肌等成对肌肉相互拮抗。拮抗肌使人体能够向相反方向平稳运动。
Breathing brings oxygen into the lungs, and the circulatory system carries oxygen and nutrients to cells. Gas exchange happens in the alveoli, where oxygen enters the blood and carbon dioxide leaves the blood.
呼吸将氧气带入肺，循环系统将氧气和营养物质输送到细胞。气体交换发生在肺泡中，氧气进入血液，二氧化碳从血液中排出。
The digestive system breaks down large food molecules into small soluble molecules. Enzymes help to speed up digestion, and the small intestine absorbs nutrients into the bloodstream.
消化系统将大分子食物分解为小分子可溶性物质。酶有助于加快消化速度，小肠将营养物质吸收到血液中。
4. Reproduction | 生殖
In human reproduction, sperm and egg cells fuse during fertilisation to form a zygote. The zygote divides and becomes an embryo, which develops in the uterus. The placenta supplies oxygen and nutrients to the fetus and removes waste.
在人类生殖过程中，精子和卵细胞在受精时融合形成受精卵。受精卵分裂并发育成胚胎，在子宫内发育。胎盘为胎儿提供氧气和营养物质，并排出废物。
During pregnancy, the amniotic fluid protects the developing fetus from knocks and bumps. After about nine months, contractions of the uterus lead to labour and birth. After birth, the baby obtains milk for nourishment and immunity.
怀孕期间，羊水保护发育中的胎儿免受撞击。约九个月后，子宫收缩引发分娩和出生。出生后，婴儿通过吸吮乳汁获得营养和免疫物质。
The menstrual cycle prepares the female body for possible pregnancy. The uterus lining thickens, and if fertilisation does not occur, the lining is shed during menstruation. Ovulation is the release of an egg from an ovary.
月经周期使女性身体为可能的怀孕做好准备。子宫内膜增厚，如果没有受精，内膜就会在月经期间脱落。排卵是卵子从卵巢中释放的过程。
Flowering plants reproduce by pollination, fertilisation and seed dispersal. Pollen from the anther reaches the stigma, and seeds form in the ovary. Seeds can be dispersed by wind, water, animals or explosive mechanisms.
开花植物通过传粉、受精和种子传播进行繁殖。花药中的花粉到达柱头后完成传粉，子房中形成种子。种子可以通过风、水、动物或弹射机制传播。
5. Particles and Their Behaviour | 粒子及其行为
The particle model explains solids, liquids and gases. Solid particles are closely packed in a regular pattern and vibrate in fixed positions; liquid particles are close but can move past each other; gas particles are far apart and move quickly in all directions.
粒子模型能解释固体、液体和气体的性质。固体粒子排列紧密且有规则，只在固定位置振动；液体粒子相互靠近但能滑动；气体粒子相距很远并快速向各个方向运动。
Changing state requires energy. Melting, evaporating and boiling absorb energy, while freezing and condensing release energy. Mass is conserved during changes of state because no particles are created or destroyed.
物态变化需要能量。熔化、蒸发和沸腾吸收能量，而凝固和冷凝释放能量。物态变化过程中质量守恒，因为粒子不会凭空产生或消失。
Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration. Diffusion occurs faster in gases than in liquids because gas particles move more quickly.
扩散是粒子从高浓度区域向低浓度区域的运动。气体中的扩散比液体中快，因为气体粒子运动得更快。
Gas pressure is caused by particles colliding with the walls of a container. Increasing the temperature makes particles move faster, so they collide more often and with more force, raising the pressure.
气体压力由粒子撞击容器壁产生。温度升高使粒子运动加快，因此它们碰撞得更频繁、更有力，从而使压力升高。
6. Elements, Atoms and Compounds | 元素、原子和化合物
All substances are made of atoms. An element contains only one type of atom, and its symbol is shown on the periodic table. Examples include oxygen (O), carbon (C) and iron (Fe).
所有物质都由原子组成。元素只含一种原子，其符号列在元素周期表中。例如氧（O）、碳（C）和铁（Fe）。
A compound is formed when two or more different elements chemically combine. Properties of a compound are different from the elements that make it. For example, water has the formula H₂O, and carbon dioxide has the formula CO₂.
化合物由两种或两种以上不同元素通过化学结合形成。化合物的性质不同于组成它的元素。例如，水的化学式为 H₂O，二氧化碳的化学式为 CO₂。
water: H₂O | carbon dioxide: CO₂
Chemical formulae use symbols and small subscript numbers to show the ratio of atoms. A mixture is not chemically combined and can be separated by physical methods such as filtration, distillation or chromatography.
化学式用元素符号和下角数字表示原子的比例。混合物没有发生化学结合，可以用过滤、蒸馏或色谱法等物理方法分离。
The periodic table arranges elements in order of increasing atomic number. 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的顺序排列元素。同一族的元素具有相似的化学性质，因为它们的原子最外层电子数相同。
7. Reactions | 化学反应
A chemical reaction makes new substances and is often difficult to reverse. Signs of a reaction include colour change, gas bubbles, temperature change and the formation of a precipitate. Physical changes, by contrast, do not make new substances.
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