📚 Year 7 CIE Science: Key Points for Practical Assessments | Year 7 CIE 科学：实验/实践考核要点
Practical work is a vital part of Year 7 CIE Science, where you learn how scientists investigate the world. These assessments test your ability to plan, carry out experiments safely, record data, analyse results, and draw conclusions. This guide covers the key points you need to master for practical success.
实验工作是 Year 7 CIE 科学的重要组成部分，你将学习科学家如何探究世界。这些考核评估你规划、安全地开展实验、记录数据、分析结果和得出结论的能力。本指南涵盖了你需要掌握的关键要点，助你在实践考核中取得成功。
1. Safety in the Laboratory | 实验室安全
Always wear a lab coat and safety goggles to protect your skin and eyes from spills or splashes. Tie back long hair and tuck in loose clothing to avoid catching fire or dipping into chemicals.
始终穿着实验服并佩戴护目镜，以保护皮肤和眼睛免受泼溅伤害。将长发扎起并塞好宽松衣物，防止着火或接触化学品。
Never eat, drink or taste any chemicals in the lab. Wash your hands thoroughly after handling materials. Report any accident, breakage or spill immediately to your teacher.
切勿在实验室中进食、饮水或品尝任何化学品。接触材料后务必彻底洗手。发生任何事故、器皿破损或溢出应立即报告老师。
2. Common Apparatus and Their Uses | 常用仪器及其用途
Familiarity with basic laboratory equipment is essential. Below is a table of apparatus you will frequently use and their functions.
熟悉基本实验仪器至关重要。下表列出你常用的仪器及其功能。
| Apparatus | Use |
|---|---|
| Measuring cylinder | Measures volume of liquids accurately |
| Beaker | Holds, mixes or heats liquids (approximate volumes) |
| Conical flask | Mixing by swirling without spilling |
| Thermometer | Measures temperature |
| Stopwatch / timer | Measures time intervals |
| Electronic balance | Measures mass |
| Ruler / metre stick | Measures length or distance |
Always choose the instrument with the appropriate precision for your measurement. For example, use a measuring cylinder rather than a beaker when you need an accurate volume.
始终选择精度合适的仪器。例如，当需要准确体积时，应使用量筒而非烧杯。
3. Measuring Length, Mass and Volume | 测量长度、质量和体积
When measuring length with a ruler, align the zero mark with one end of the object and read the scale at the other end. Record the reading to the nearest millimetre (mm).
使用直尺测量长度时，将零刻度对准物体一端，然后在另一端读取刻度。读数精确到最接近的毫米（mm）。
For mass, place the empty container on the electronic balance and press the 'tare' or 'zero' button before adding the substance. This ensures you measure only the mass of the substance, not the container.
测量质量时，先将空容器放在电子天平上，按“去皮”或“归零”键，然后加入待称量物质。这样可以确保只测量物质的质量，而不包括容器。
For liquid volume, place the measuring cylinder on a flat surface and read the bottom of the meniscus at eye level. Record the volume in cm³ or mL.
测量液体体积时，将量筒置于平坦桌面，视线与液面凹液面的最低点保持水平。以 cm³ 或 mL 为单位记录体积。
4. Measuring Temperature and Time | 测量温度和时间
Immerse the thermometer bulb fully in the substance without touching the sides of the container. Wait for the reading to stabilise before recording. Never use a thermometer as a stirrer.
将温度计的感温泡完全浸入待测物中，但不要接触容器壁。待读数稳定后再记录。切勿用温度计当作搅拌棒。
When using a stopwatch, start timing as soon as you add or mix reactants. Record time in seconds (s) and, if needed, perform repeats to improve reliability.
使用秒表时，加入或混合反应物的瞬间开始计时。以秒（s）为单位记录时间，必要时进行重复测量以提高可靠性。
5. The Bunsen Burner and Heating | 本生灯与加热
To light a Bunsen burner safely, first close the air hole, then light a match and hold it just above the barrel before turning on the gas tap. A yellow safety flame appears. Then adjust the air hole to produce a blue, roaring flame for heating.
安全点燃本生灯的方法是：先关闭气孔，点燃火柴并放在灯管口上方，然后打开燃气阀。此时会出现黄色安全火焰。接着调节气孔，产生蓝色的强烈加热火焰。
When heating substances, always point the open end of a test tube away from yourself and others. Use a test tube holder and move the tube gently through the flame to heat evenly.
加热物质时，始终将试管开口端远离自己和他人。使用试管夹，并轻轻将试管在火焰中来回移动以均匀加热。
6. Recording Data in Tables | 在表格中记录数据
Design a results table before starting the experiment. The first column usually lists the independent variable (what you change), and the second column lists the dependent variable (what you measure). Subsequent columns can hold repeat readings or calculated averages.
在实验开始前设计好数据记录表格。第一列通常列出自变量（你改变的变量），第二列列出因变量（你测量的变量）。后续列可以记录重复读数和计算出的平均值。
Each column heading must include both the quantity and its unit, for example 'Time (s)' or 'Temperature (°C)'. Record raw data neatly and immediately during the experiment.
每列的标题必须同时包含物理量和单位，例如“时间（s）”或“温度（°C）”。实验过程中要整洁、即时地记录原始数据。
7. Constructing Graphs | 绘制图表
Plot the independent variable on the horizontal x-axis and the dependent variable on the vertical y-axis. Label each axis with the quantity and unit, and choose a scale that makes your data spread over more than half the graph paper.
将自变量标在横轴（x 轴），因变量标在纵轴（y 轴）。为每个轴标注物理量和单位，并选择使数据点占据大半张坐标纸的比例尺。
neat cross (×) or dot with a circle. If there is a pattern, draw a smooth line of best fit — which may be a straight line or a curve — not a dot-to-dot join.
用细小清晰的叉号（×）或带圆圈的圆点绘制每个数据点。如有规律，画一条平滑的最佳拟合线（可以是直线或曲线），而不要逐点连接。
Give your graph a descriptive title, such as 'Graph of Temperature against Time for the heating of water'.
为图表起一个描述性的标题，例如“水加热时温度对时间的变化曲线”。
8. Interpreting Graphs | 解读图表
Look for the overall trend: is the line going up (positive correlation), down (negative correlation), or staying flat? Describe the relationship using phrases such as 'As the time increases, the temperature increases steadily'.
观察整体趋势：线条是上升（正相关）、下降（负相关）还是持平？用短语描述关系，例如“随时间增加，温度稳步上升”。
If the graph shows a straight line passing through the origin, it indicates a directly proportional relationship. You can then write a simple equation: y ∝ x, or for a specific case, distance = constant × time.
如果图表显示一条通过原点的直线，说明两者成正比关系。此时你可以写出简单关系：y ∝ x，或在特定情况下写成：距离 = 常数 × 时间。
Identify any anomalous points that do not fit the line. Do not ignore them — note them for the evaluation.
找出任何偏离曲线的异常点。不要忽略它们——应在评估部分加以记录。
9. Drawing Conclusions | 得出结论
Your conclusion must answer the original aim or question. State clearly what you found out, and support your statement with data from the table or graph. For example: 'The temperature increased by 15°C every 2 minutes, showing a steady heating rate.'
结论必须回答最初的实验目的或问题。清晰陈述你发现了什么，并用表格或图表中的数据作为支持。例如：“每2分钟温度升高15°C，说明加热速率稳定。”
Always refer to the pattern shown by the data, not what you expected to happen. Be precise and avoid vague language like 'it got hotter'.
始终根据数据显示的规律下结论，而不是你期望发生什么。表述要精确，避免使用“它变热了”这样模糊的语言。
10. Evaluating the Experiment | 评估实验
Evaluation involves discussing how reliable your results are. If you repeated measurements, did you obtain similar values? Discuss repeatability and the spread of data.
评估包括讨论结果的可靠性。如果你重复了测量，读数是否相似？讨论重复性和数据的离散程度。
Identify sources of error. For instance, heat loss to the surroundings can affect temperature readings, or a reaction started before the stopwatch was pressed. Classify errors as random (e.g. reading a scale slightly differently each time) or systematic (e.g. using a ruler with a worn end).
识别误差来源。例如，向周围环境散热会影响温度读数，或还没按下秒表反应就已开始。将误差分类为随机误差（例如每次读取刻度时略有不同）或系统误差（例如使用了末端磨损的直尺）。
Suggest specific improvements. Instead of saying 'be more careful', propose using a lid to reduce heat loss, or take more repeat readings and calculate a mean.
提出具体的改进建议。不要说“更小心”，而应建议使用盖子减少热量损失，或进行更多次重复测量并计算平均值。
11. Planning a Fair Test | 设计公平测试
A fair test means changing only one variable at a time (the independent variable), keeping all other variables the same (control variables), and measuring the effect on the dependent variable.
公平测试意味着每次只改变一个变量（自变量），保持所有其他变量相同（控制变量），并测量对因变量的影响。
List the control variables explicitly in your plan, for example: 'Keep the volume of water constant at 100 cm³, use the same Bunsen burner flame setting, and start timing at the same moment.'
在你的计划中明确列出控制变量，例如：“保持水的体积恒定为100 cm³，使用相同的本生灯火焰设置，并在同一时刻开始计时。”
Write a step-by-step method that another person could follow to repeat your experiment exactly. Include safety precautions within the method.
写出分步操作步骤，使其他人能够完全重复你的实验。在方法中包括安全注意事项。
Published by TutorHao | Science Revision Series | aleveler.com
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