Year 8 OCR Chemistry Teacher Guide & Lesson Plan Sharing | Year 8 OCR 化学：教师教学建议与教案分享

📚 Year 8 OCR Chemistry Teacher Guide & Lesson Plan Sharing | Year 8 OCR 化学：教师教学建议与教案分享

Teaching Year 8 Chemistry under the OCR framework requires a careful balance between introducing foundational concepts and nurturing scientific curiosity. This guide shares practical strategies, ready-to-use lesson plans, and assessment ideas that align with the Key Stage 3 programme of study, helping pupils build confidence in atoms, elements, reactions, and the periodic table. Whether you are an experienced teacher or new to the OCR pathway, the suggestions below aim to make lessons more interactive, enquiry-driven, and accessible for all learners.

在 OCR 框架下教授 Year 8 化学，既要打好基础概念，又要激发学生的科学好奇心。本文结合 Key Stage 3 课程要求，分享实用的教学策略、可直接使用的教案以及评估思路，覆盖原子、元素、化学反应和周期表等核心内容。不论您是经验丰富的教师，还是刚刚接触 OCR 课程，以下建议都能帮助课堂变得更互动、以探究为驱动，并照顾到每一位学生。

1. Understanding the Year 8 OCR Chemistry Scope | 了解 Year 8 OCR 化学知识范围

Before diving into lesson plans, it is essential to map the Year 8 content against the broader OCR KS3 Chemistry syllabus. The main topics usually include: atomic structure (protons, neutrons, electrons), elements and the periodic table, simple chemical reactions (oxidation, combustion, thermal decomposition), acids and alkalis, and an introduction to chemical formulae and equations. Teachers should also revisit and extend Year 7 concepts such as particle theory and states of matter, ensuring seamless progression into Year 9 topics like reactivity series and energy changes.

在深入教案之前，务必将 Year 8 内容与更广泛的 OCR KS3 化学大纲进行对照。主要课题通常包括：原子结构（质子、中子、电子）、元素与周期表、简单化学反应（氧化、燃烧、热分解）、酸与碱，以及化学式和方程式的入门。教师还应回顾并拓展 Year 7 的概念，比如粒子理论与物态变化，确保无缝衔接到 Year 9 的金属活动性顺序和能量变化等主题。

The OCR specification places a strong emphasis on ‘Working scientifically’, so every topic should be linked to practical skills such as making predictions, recording observations, and evaluating evidence. When planning a scheme of work, allocate at least one-third of teaching time to hands-on investigations. This not only meets syllabus requirements but also deepens conceptual understanding.

OCR 课程标准非常强调‘科学实践’，因此每个主题都应关联实验技能，如做出预测、记录观察和评估证据。在制订教学计划时，至少分配三分之一的教学时间用于动手探究。这不仅能满足大纲要求，还能深化概念理解。

2. Starting with Atoms: A Concrete to Abstract Approach | 从原子入手：由具体到抽象的教学方法

Atoms can feel invisible and intangible to 12–13-year-olds. Begin with a concrete activity: give each group a sealed box containing different numbers of marbles, then ask them to infer the contents without opening it – this mimics how scientists deduced atomic structure. Follow this with a simple diagram-drawing exercise where pupils label subatomic particles and note their relative charges and masses.

对于 12–13 岁的学生来说，原子是看不见摸不着的。先用一个具体的活动引入：给每组一个密封盒子，里面装有不同数量的弹珠，让他们在不打开盒子的情况下推断内容物——这模拟了科学家如何推断原子结构。接着进行简单的画图练习，让学生标注亚原子粒子，并记下它们的相对电荷和质量。

A common misconception is that electrons orbit the nucleus like planets around the sun. Address this early by explaining that the planetary model is simply a useful representation, not a photograph. Use the idea of electron shells and limited capacities (2, 8, 8) to draw atoms of the first 20 elements. Avoid introducing electron cloud models at this stage – keep it manageable.

一个常见误解是电子像行星绕太阳一样绕核运行。要尽早说明，行星模型只是一种有用的表示方式，并非真实图像。利用电子层及其最大容纳数的概念（2, 8, 8）画出前 20 号元素的原子。现阶段不要引入电子云模型——保持内容易于掌握。

Relative charge and mass of subatomic particles

亚原子粒子的相对电荷与质量

Particle / 粒子	Relative charge / 相对电荷	Relative mass / 相对质量
Proton / 质子	+1	1
Neutron / 中子	0	1
Electron / 电子	-1	1/1836

3. Making the Periodic Table Memorable | 让周期表变得好记

Rather than treating the periodic table as a static chart, turn it into a puzzle. Print a blank table and give pupils a set of element cards with properties (melting point, density, reactivity) but no names. Challenge them to group the cards in a sensible way and deduce missing elements. This mirrors Mendeleev’s own process and embeds the logic behind the table’s layout.

不要把周期表当作一张静止的图表，而是将它变成一个拼图。打印一张空白表格，给学生一套写有性质（熔点、密度、活动性）但没有名称的元素卡片。让他们挑战以合理的方式分组，并推断缺失的元素。这模拟了门捷列夫自己的发现过程，并让学生理解周期表布局背后的逻辑。

Focus on the first 20 elements for Year 8. Pupils should be able to identify groups (1, 7, 0) and periods, and link group number to the number of electrons in the outer shell. Use a ‘dating profile’ activity: each pupil adopts an element and writes a short profile including its group, electron arrangement, and what it would ‘look for in a reaction partner’. This personalises the content and aids recall.

Year 8 重点学习前 20 号元素。学生应能识别族（1、7、0）和周期，并将族序数与最外层电子数联系起来。用“交友档案”活动：每位学生扮演一种元素，写一份简短的档案，包括所属族、电子排布以及它在反应中“寻找的伴侣”。这使内容人格化，有助于记忆。

Colour-coding is a practical tip: provide blank periodic tables and ask pupils to shade metals, non-metals and metalloids. For homework, they can research and annotate uses of everyday elements (e.g., lithium in batteries, chlorine in swimming pools) to connect abstract symbols with real life.

颜色编码是一个实用技巧：提供空白周期表，让学生用颜色区分金属、非金属和半金属。作为家庭作业，他们可以研究并标注日常生活中元素的用途（如电池中的锂、游泳池中的氯），将抽象符号与现实生活联系起来。

4. Demystifying Chemical Formulae and Equations | 揭开化学式和方程式的神秘面纱

Begin with the concept of a chemical symbol – a shorthand for an element’s name – and then build towards formulae. Use simple pairing exercises: give pupils cards showing sodium (Na) and chlorine (Cl) and ask them to combine to form NaCl, emphasising that the ratio is 1:1. Gradually introduce elements that need subscript numbers, such as MgCl₂, by using the crossover rule with ion charges.

从化学符号的概念开始——它是元素名称的简写——然后逐步构建化学式。使用简单的配对练习：给学生卡片，上面有钠 (Na) 和氯 (Cl)，让他们结合成 NaCl，强调比例为 1:1。逐步引入需要下标的元素，如 MgCl₂，利用离子电荷的交叉规则。

When teaching word equations, drill the pattern: ‘reactant A + reactant B → product C + product D’. Then introduce symbol equations as a more precise shorthand. Avoid balancing equations too early; first, ensure pupils can translate between word and symbol equations of simple reactions (e.g., magnesium + oxygen → magnesium oxide). Only when they are confident should you introduce the idea of conservation of mass and simple balancing with small whole numbers.

在教文字表达式时，反复练习模式：‘反应物 A + 反应物 B → 生成物 C + 生成物 D’。然后引入符号方程式作为更精确的简写。不要太早引入配平；首先要确保学生能够在简单反应（如镁 + 氧气 → 氧化镁）的文字表达式和符号方程式间转换。只有当他们有信心后，才引入质量守恒的概念，并用小整数进行简单配平。

A hands-on modelling kit – even coloured Lego blocks – can make abstract formulae tangible. Assign a colour to each atom (e.g., red for oxygen, white for hydrogen) and challenge pupils to build H₂O, CO₂, etc. This kinesthetic approach solidifies the idea that the subscript refers to the preceding atom only.

一套动手操作的模型——即使是彩色乐高积木——也能让抽象的化学式变得具体。为每种原子指定一种颜色（如红色代表氧，白色代表氢），让学生搭建 H₂O、CO₂ 等分子。这种动觉方法能巩固“下标仅指前一个原子”这一概念。

5. Teaching Reactions: Combustion, Oxidation and Thermal Decomposition | 教授反应：燃烧、氧化与热分解

Year 8 pupils often conflate physical and chemical changes. Start with a diagnostic question: ‘Is melting butter a chemical reaction?’ Discuss the evidence needed to decide – colour change, gas production, energy change, or formation of a new substance. Then introduce three reaction types in a structured sequence.

Year 8 学生经常混淆物理变化和化学变化。从一个诊断性问题开始：‘黄油融化是化学反应吗？’讨论判断所需的证据——颜色变化、气体生成、能量变化或新物质生成。然后按结构顺序引入三种反应类型。

Combustion is best demonstrated with the classic burning candle in a gas jar over water to show that oxygen is used up and water rises. Pupils measure the water rise and deduce that about one-fifth of the air is oxygen. Follow with the magnesium ribbon burning experiment – emphasise safety (do not look directly at the bright light) – and guide pupils to write the equation: 2Mg + O₂ → 2MgO. Discuss why the mass increases (oxygen atoms are added).

燃烧最好通过经典实验来演示：将点燃的蜡烛放在水上的集气瓶中，显示氧气被消耗、水面上升。学生测量水面上升高度，并推断出空气中约五分之一是氧气。接着进行镁条燃烧实验——强调安全（不要直视强光）——并引导学生写出方程式：2Mg + O₂ → 2MgO。讨论为什么质量增加（纳入了氧原子）。

For oxidation, use rusting of iron as a familiar context. Set up a long-term investigation with nails in different conditions (water, salt water, oil, drying agent) and have pupils predict and observe over two weeks. This ties in with prior learning on variables and fair testing.

对于氧化，以铁生锈作为熟悉的背景。设置一个长期探究：将铁钉放在不同条件中（水、盐水、油、干燥剂），让学生预测并观察两周。这结合了先前学习的变量与公平测试知识。

Thermal decomposition can be safely explored with copper carbonate (CuCO₃) heating to produce black copper oxide (CuO) and carbon dioxide. Use limewater to test for CO₂. Pupils enjoy the colour change from green to black. Link back to the general equation: metal carbonate → metal oxide + carbon dioxide.

热分解可以通过加热碳酸铜 (CuCO₃) 生成黑色氧化铜 (CuO) 和二氧化碳来安全探索。用石灰水检验 CO₂。学生喜欢从绿色到黑色的颜色变化。回顾通式：金属碳酸盐 → 金属氧化物 + 二氧化碳。

6. Acids and Alkalis: A Practical Approach with Everyday Contexts | 酸与碱：结合日常情境的实践方法

Start by asking pupils what they associate with the word ‘acid’ – they often think of danger. Then introduce common acids found in the home (citric acid in lemons, acetic acid in vinegar, hydrochloric acid in the stomach). Safety is paramount: demonstrate correct handling, the use of pipettes, and the importance of wearing goggles.

先从提问开始：提到‘酸’学生联想到什么——他们通常想到危险。然后介绍日常生活中常见的酸（柠檬中的柠檬酸、醋中的乙酸、胃中的盐酸）。安全操作至关重要：演示正确的操作、滴管使用和佩戴护目镜的重要性。

pH scale and indicators come alive with a circus of activities. Set up stations: universal indicator paper, red and blue litmus, and homemade indicator made from red cabbage. Pupils test at least six substances (lemon juice, soap, milk, baking soda solution, soda water, tap water) and record pH values and colour changes. This generates rich discussion about precision – universal indicator gives a pH number, while litmus only shows acid or alkali.

通过一系列活动，pH 标度和指示剂变得生动起来。设置多个活动站：广泛指示剂试纸、红色和蓝色石蕊试纸、以及用红甘蓝自制的指示剂。学生至少测试六种物质（柠檬汁、肥皂、牛奶、小苏打溶液、苏打水、自来水），记录 pH 值和颜色变化。这引发关于精确度的丰富讨论——广泛指示剂给出 pH 数值，而石蕊仅显示酸性或碱性。

Neutralisation can be introduced as the reaction between an acid and an alkali to form a salt and water. Demonstrate with hydrochloric acid and sodium hydroxide, using phenolphthalein to show the colourless endpoint. Emphasise the general equation:

中和可引入为酸与碱反应生成盐和水。用盐酸和氢氧化钠演示，用酚酞指示无色的滴定终点。强调通式：

acid + alkali → salt + water

酸 + 碱 → 盐 + 水

Then give examples: HCl + NaOH → NaCl + H₂O. For a memorable lesson, let pupils make their own bath bombs – a mixture of citric acid and sodium bicarbonate – and discuss the neutralisation fizz.

然后举例：HCl + NaOH → NaCl + H₂O。为让课程难忘，让学生自制沐浴气泡弹——柠檬酸和碳酸氢钠的混合物——并讨论中和反应产生的气泡。

7. Differentiating Lessons for Mixed-Ability Groups | 在混合能力班级中进行差异化教学

Every Year 8 class contains a wide range of abilities. For chemistry, differentiation can be achieved through tiered worksheets, targeted questioning, and flexible grouping. Low-attaining pupils benefit from gap-fill exercises and pre-printed diagrams for labelling; high-attaining pupils can be stretched with open-ended enquiries, such as ‘Design an experiment to find out which indigestion tablet neutralises the most acid per gram’.

每个 Year 8 班级都包含能力各异的学生。在化学中，差异化可以通过分层工作单、有针对性的提问和灵活分组来实现。能力较弱的学生受益于填空练习和预先打印的标注图；能力强的学生可以通过开放式探究进行拓展，比如‘设计一个实验，找出哪种消食片每克能中和最多的酸’。

Support EAL learners by displaying key vocabulary on the board with pictorial prompts. For example, a ‘combustion’ display might show a flame next to the word. Pre-teach critical terms such as ‘particle’, ‘compound’, ‘electron’ before lessons. Provide sentence starters for writing conclusions: ‘As the concentration increased, the reaction rate ________ because ________’.

为英语作为附加语言的学习者提供支持：在黑板展示关键词汇并配图。例如，“燃烧”展示区可配火焰图片。课前预先教授‘粒子’、‘化合物’、‘电子’等关键术语。为书写结论提供句子开头：‘随着浓度增加，反应速率 ________，因为 ________’。

Practical work offers natural differentiation: low-attaining pupils can focus on making careful observations, while higher-attaining pupils calculate means, plot graphs, and suggest improvements. Always pair a strong practical student with a strong thinker to foster peer tutoring.

实验工作天然具有差异化特点：能力较弱的学生可以专注于细致观察，而能力较强的学生可计算平均值、绘制图表并提出改进建议。始终将动手能力强的学生与思维缜密的学生配对，以促进同伴互助。

8. Embedding Working Scientifically Skills | 融入科学实践技能

OCR KS3 Chemistry insists that ‘Working Scientifically’ skills are embedded, not taught in isolation. When planning the thermal decomposition lesson, explicitly teach how to record observations in a table: do not just say ‘write what you see’, but model a table with columns for ‘before heating’, ‘during heating’, ‘after heating’, including space for unexpected results.

OCR KS3 化学要求‘科学实践’技能必须融入教学，而非孤立教学。在设计热分解课时，明确教授如何用表格记录观察：不要只说‘记下你看到的’，而要示范一个表格，包括‘加热前’、‘加热中’、‘加热后’三列，并留下记录意外结果的空间。

Graph drawing is a skill that needs scaffolding. Provide pre-drawn axes with labelled scales for the cooling of stearic acid experiment. Pupils plot data points in pencil, then a line of best fit. Discuss what the flat sections represent (change of state). Challenge misconceptions: ‘Is energy still being released during the plateau?’ Use particle diagrams to explain.

绘制图表是需要搭建支架的技能。在硬脂酸冷却实验中，提供带有标注刻度的预绘坐标轴。学生用铅笔描点，然后画一条最佳拟合线。讨论平台期代表什么（状态变化）。挑战误解：‘在平台期，能量是否仍在释放？’用粒子图进行解释。

Teach evaluation as a positive habit, not criticism. After the acid-alkali titration, ask: ‘What made it difficult to stop at exactly the endpoint?’ and ‘How could you improve your method next time?’ Pupils learn to identify sources of error and suggest realistic improvements, such as using a burette instead of a pipette for larger volumes.

将评估作为一种积极习惯来教授，而非批评。在酸碱滴定后提问：‘什么使得恰好停在终点变得困难？’以及‘下次你可以如何改进方法？’学生学习识别误差来源并提出切实的改进建议，例如在大量液体时使用滴定管代替移液管。

9. Assessment for Learning: Quick Checks and Formal Tests | 学习评估：快速检查与正式测试

Use exit tickets at the end of every third lesson: a small slip of paper with one key question, e.g., ‘Why does mass increase when magnesium burns?’. This gives immediate feedback on understanding and highlights who needs re-teaching. To make it efficient, sort tickets into ‘got it’, ‘partial’, ‘didn’t get it’ piles and adapt the next starter accordingly.

每三节课的末尾使用‘出口票’：一小张纸条，上面有一个关键问题，如‘为什么镁燃烧时质量增加？’。这能立即反馈理解情况，并显示出谁需要重新教学。为提高效率，将票分为‘已掌握’、‘部分掌握’、‘未掌握’三叠，并相应调整下一节的开场活动。

Summative assessment should mirror the style of OCR end-of-topic tests. Include multiple-choice questions to check knowledge, short-answer questions to test application, and a six-mark extended response that assesses experimental design or data interpretation. For Year 8, a suitable six-mark question might be: ‘Describe how you would obtain a sample of pure, dry sodium chloride from a mixture of sand and sodium chloride solution.’ Provide a mark scheme and model answer for self-assessment.

终结性评估应模仿 OCR 单元末测试的风格。包含检验知识的选择题、测试应用能力的简答题，以及评估实验设计或数据解析的六分拓展题。对于 Year 8，合适的六分题可能是：‘描述你如何从沙子和氯化钠溶液的混合物中获取一份纯净、干燥的氯化钠样品。’提供评分标准和标准答案，供学生自评。

Self- and peer-assessment builds metacognition. After a practical session, give pupils a ‘practical skills checklist’ (e.g., Did I wear goggles? Did I record results in a table? Did I state a conclusion?). They tick and comment on their own or a partner’s work. This encourages responsibility for learning and reduces marking load.

自评与互评能培养元认知。实验课结束后，给学生一份‘实验技能检查表’（如：我戴护目镜了吗？我将结果记录在表格中了吗？我陈述结论了吗？）。他们对自己的或同伴的作品打勾并评论。这能培养学习的责任感，并减轻批改负担。

10. Using Digital Tools and Simulations | 善用数字工具与模拟实验

PhET simulations (University of Colorado Boulder) offer excellent virtual labs for atomic structure, balancing equations, and pH scale, which are ideal for homework or revision. For example, the ‘Build an Atom’ simulation lets pupils add protons, neutrons, and electrons and see how the element changes. Set a specific challenge: ‘Build an atom with 6 protons, 6 neutrons, and 6 electrons. What element is it?’

PhET 模拟实验（科罗拉多大学博尔德分校）为原子结构、化学方程式配平和 pH 标度等提供了优秀的虚拟实验室，非常适合家庭作业或复习。例如，“构建一个原子”模拟实验让学生添加质子、中子和电子，并观察元素如何变化。设置具体挑战：“构建一个有 6 个质子、6 个中子和 6 个电子的原子。它是什么元素？”

Video clips can bring reactions to life, especially those too dangerous for the classroom. A slow-motion video of alkali metals reacting with water helps pupils see the vigour of the reaction without the risk. Always clip and embed the video in a lesson slide with a purpose: ‘Watch the video and note three observations that suggest a chemical reaction is happening.’

视频片段能让反应栩栩如生，尤其是那些对课堂来说过于危险的反应。碱金属与水反应的慢动作视频，能帮助学生观察反应的剧烈程度而无风险。务必将视频剪辑嵌入课堂幻灯片，并带有目的性：‘观看视频，并记下三个表明发生化学反应的观察结果。’

For those with access to data loggers, use them to plot temperature changes during neutralisation or cooling curves. They save time, produce neat graphs, and allow pupils to focus on interpretation rather than manual plotting. However, ensure that pupils also occasionally draw graphs by hand to develop the skill.

对于有条件使用数据记录器的学校，可以用它来绘制中和反应中的温度变化或冷却曲线。它们节省时间、生成整洁的图表，并让学生专注于解读而非手工绘图。不过，也要确保学生时常手绘图形，以培养技能。

11. Sample Lesson Plan: Introduction to the Periodic Table (60 minutes) | 教案示例：周期表入门（60 分钟）

Starter (10 min): On entry, pupils receive a card with a symbol and atomic number. They must find three classmates and arrange themselves in ascending order of atomic number. This spatial activity pre-teaches the foundation of periodicity. Plenary discussion: ‘What did you notice about elements with similar symbols?’

开场（10 分钟）：学生入场时领到一张写有元素符号和原子序数的卡片。他们需要找到三位同学，并按照原子序数升序排列。这个空间活动为周期律打下基础。全班讨论：“关于具有相似符号的元素，你注意到了什么？”

Main 1: Element detective (20 min): Teacher presents a blank periodic table on the interactive whiteboard with only group and period numbers. Pupils work in pairs, each receiving a set of element clue cards (e.g., ‘I am a gas at room temperature, I have 8 electrons in my outer shell, I am used in light bulbs’ – argon). They deduce the element and place it on the table. Teacher circulates and questions.

主体 1：元素侦探（20 分钟）：教师在互动白板上展示一张空白周期表，仅标有族序数和周期数。学生两人一组，每组收到一套元素线索卡片（如：我是室温下的一种气体，最外层有 8 个电子，用于灯泡——氩）。他们推断出元素后放在表上。教师走动提问。

Main 2: Group trends (15 min): Teacher demonstrates (or shows video of) lithium, sodium, and potassium reacting with water, emphasising safety. Pupils complete a table of observations and deduce the trend in reactivity down Group 1. They learn that reactivity increases as the outer electron is further from the nucleus and more easily lost.

主体 2：族规律（15 分钟）：教师演示（或播放视频）锂、钠、钾与水的反应，强调安全。学生完成观察表格，并推断出第 1 族从上到下活动性增强的规律。他们学到，随着最外层电子离原子核越来越远、越来越容易失去，活动性增强。

Plenary (15 min): Rapid fire quiz using mini-whiteboards. Questions: ‘Which element has the electron arrangement 2,8,1?’, ‘Name a halogen.’, ‘Why are noble gases unreactive?’. For exit ticket, each pupil writes one sentence explaining why the periodic table is called ‘periodic’.

总结（15 分钟）：使用迷你白板快速问答。问题：‘哪种元素具有 2,8,1 的电子排布？’、‘说出一种卤素。’、‘为什么稀有气体不活泼？’。作为出口票，每位学生写一句话解释为什么周期表被称为‘周期’表。

12. Managing Practical Work and Safety | 管理实验操作与安全

Chemistry practicals require meticulous safety planning. Before any lesson involving heating or chemicals, complete a model risk assessment and share it with your technician. Teach the ‘CLEAPSS’ student safety code: wear eye protection, tie back long hair, stand up to work when using Bunsen burners, and never taste chemicals.

化学实验需要周密的安全规划。在任何涉及加热或化学试剂的课前，完成一份示范风险评估，并与实验员共享。教授‘CLEAPSS’学生安全守则：佩戴护目用具，束起长发，使用本生灯时站立操作，绝对不可品尝化学试剂。

Organise equipment by allocating a labelled tray per group. Use a ‘lab coat manager’ role to ensure coats are worn, a ‘goggles monitor’ to check everyone before starting, and an ‘equipment officer’ to count out and return items. These roles build responsibility and reduce chaos. Practise a ‘Stop, drop and roll’ routine if clothing catches fire, even though the risk is minimal.

通过为每组分配一个贴有标签的托盘来组织设备。设立‘实验服管理员’角色确保实验服穿戴，‘护目镜监督员’在开始前检查每个人，‘设备官’负责清点和归还物品。这些角色培养了责任感并减少混乱。即使衣物着火的风险极低，也要练习‘停止、趴下、翻滚’的应急程序。

Never underestimate the power of a clear, visual method sheet. For the magnesium combustion practical, provide a step-by-step guide with icons: ‘1. Measure mass of crucible and lid (balance icon). 2. Add magnesium ribbon, measure again. 3. Heat strongly (Bunsen icon, with eye protection symbol). 4. Allow to cool, weigh.’ This ensures even less confident readers can follow safely.

切勿低估一份清晰、可视化方法说明的力量。对于镁的燃烧实验，提供带有图标的步骤指南：‘1. 称量坩埚和盖子的质量（天平图标）。2. 加入镁条，再次称量。3. 强热加热（本生灯图标，配护目镜符号）。4. 冷却后称重。’这能确保即使阅读能力稍弱的学生也能安全操作。

Published by TutorHao | Chemistry Revision Series | aleveler.com

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Year 8 OCR Chemistry Teacher Guide & Lesson Plan Sharing | Year 8 OCR 化学：教师教学建议与教案分享