📚 Year 7 AQA Science: Key Points for Experiments and Practical Assessments | Year 7 AQA 科学：实验/实践考核要点
In Year 7 AQA Science, practical work is not just about following instructions—it is about understanding how to investigate scientifically. You will be assessed on your ability to design experiments, collect and present data, and evaluate your findings. This guide covers the essential skills you need to succeed in your practical assessments.
在 Year 7 AQA 科学中，动手实践不仅仅是按步骤操作——更是要理解如何进行科学探究。你需要展示设计实验、收集和展示数据以及评估结果的能力。本指南涵盖了你通过实践考核所需的各项关键技能。
1. Understanding Variables | 理解变量
Every experiment has variables: factors that can change. You must identify the independent variable (the one you change), the dependent variable (the one you measure), and the control variables (the ones you keep the same).
每个实验都有变量：即可以改变的因素。你必须确定自变量（你改变的量）、因变量（你测量的量）和控制变量（保持不变的量）。
For example, if you are testing how temperature affects the rate of dissolving sugar, the temperature of the water is the independent variable, the time it takes for the sugar to dissolve is the dependent variable, and the volume of water, type of sugar, and stirring speed are control variables.
例如，若测试温度如何影响糖的溶解速率，水温是自变量，糖溶解所需时间是因变量，而水的体积、糖的种类和搅拌速度都是控制变量。
It is good practice to write your variables in a clear sentence before starting, such as 'I will change the temperature, measure the time taken to dissolve, and keep the mass of sugar and volume of water the same.'
好的做法是在开始前用清晰的句子写出变量，如：“我将改变温度，测量溶解所需时间，并保持糖的质量和水的体积不变。”
2. Forming a Hypothesis | 形成假设
A hypothesis is a testable statement that predicts the relationship between the independent and dependent variables. It is often written as 'If … then … because …'.
假设是一个可检验的陈述，预测自变量和因变量之间的关系。通常写成“如果……那么……因为……”。
For instance: 'If the temperature of the water is increased, then the sugar will dissolve faster because particles move more quickly and collide more often.' The 'because' part shows your scientific reasoning.
例如：“如果水温升高，那么糖会溶解得更快，因为粒子运动更快，碰撞更频繁。” “因为”部分展示了你的科学推理。
Your hypothesis should be based on prior knowledge, not a wild guess. In Year 7, you are expected to link your prediction to ideas about particles, forces, or energy.
你的假设应基于已有知识，而不是胡乱猜测。在 Year 7，你需要将预测与粒子、力或能量等概念联系起来。
3. Planning a Fair Test | 设计公平实验
A fair test is one where only the independent variable is changed, all control variables are kept constant, and the dependent variable is measured accurately. This ensures that any effect observed is due to the variable you changed.
公平实验是指只改变自变量、所有控制变量保持不变并且准确测量因变量的实验。这确保观察到的任何效应都是由你改变的变量引起的。
You should list all the equipment you need and think about how to use it safely. Also consider the range and interval of your independent variable—for example, measuring temperature every 10 °C from 20 °C to 80 °C gives a good spread of data.
你应该列出所需的所有器材，并考虑如何安全使用。同时要考虑自变量的范围和间隔——例如，从 20 °C 到 80 °C 每隔 10 °C 测量一次，可获得分布良好的数据。
Repeating measurements is part of a fair test. Taking at least three readings for each condition helps to spot anomalies and calculate a mean.
重复测量是公平实验的一部分。每个条件下至少读取三次数据，有助于发现异常值并计算平均值。
4. Safety and Risk Assessment | 安全与风险评估
Before any practical, you must identify potential hazards and describe how to minimise risk. A hazard is anything that could cause harm, and a risk is the chance of that harm occurring.
在任何实验之前，你必须识别潜在的危险源，并说明如何降低风险。危险源是任何可能造成伤害的东西，风险是伤害发生的可能性。
Common hazards in Year 7 include hot liquids, glassware, Bunsen burners, and chemicals like acids. You should wear safety goggles, tie back long hair, and handle hot apparatus with tongs.
Year 7 常见的危险源包括热液体、玻璃器皿、本生灯和酸类化学品。你应该佩戴护目镜、束起长发，并用坩埚钳夹取热的器具。
Write a simple risk assessment in your plan, e.g., 'Bunsen burner: risk of burns – tie hair back, use safety flame when not heating, stand up during the experiment.'
在你的计划中写一个简单的风险评估，例如：“本生灯：烧伤风险——束起头发，不加热时使用安全火焰，实验时站立。”
5. Making Accurate Measurements | 进行精确测量
Accuracy means how close a measurement is to the true value. You should choose the most appropriate measuring instrument and use it correctly. For volume, use a measuring cylinder and read the bottom of the meniscus at eye level.
准确性指测量值与真实值的接近程度。你应选择最合适的测量仪器并正确使用。测量体积时，使用量筒并在视线水平处读取弯月面的底部。
For length, a ruler is fine, but a digital caliper gives more precision. Always record the unit and the resolution of the instrument (the smallest scale division). For a standard ruler, the resolution is 1 mm.
测量长度时，直尺即可，但数字卡尺精度更高。务必记录单位和仪器的分辨率（最小刻度）。对于标准直尺，分辨率为 1 mm。
Repeat measurements improve reliability. If you get a result that does not fit the pattern, it might be an anomaly. You should exclude it when calculating a mean only if you have a clear reason, such as a known mistake.
重复测量可提高可靠性。如果你得到一个不符合规律的结果，它可能是异常值。只有在有明确理由（如已知错误）时，才应在计算平均值时将其排除。
6. Recording Data in Tables | 用表格记录数据
Data tables must be clear and well organised. Draw them with a ruler and pencil, and include headings with units. The independent variable goes in the left column, and the dependent variable in the right column(s).
数据表必须清晰、条理分明。用直尺和铅笔画表格，并包含带单位的表头。自变量放在左列，因变量放在右列。
For example, a table for the dissolving experiment might have columns: 'Temperature of water (°C)' and 'Time taken to dissolve (s)', with rows for each temperature tested and repeats.
例如，溶解实验的表格可能有以下几列：“水温 (°C)”和“溶解时间 (s)”，每行对应一个测试温度及重复实验数据。
Leave space to record the mean and any observations. Always write numbers to the same number of decimal places that your instrument can measure.
留出空间记录平均值和任何观察结果。始终将数字写到仪器可测量的相同小数位数。
7. Drawing Graphs | 绘制图表
Graphs help you see patterns in your data. In Year 7, you mainly draw bar charts and line graphs. Use a sharp pencil, label both axes with the variable name and unit, and give the graph a title.
图表有助于你观察数据中的规律。在 Year 7，你主要绘制条形图和折线图。用尖铅笔绘制，在坐标轴上标出变量名称和单位，并给图表加上标题。
For a line graph (when the independent variable is continuous, like temperature), plot the points carefully with small crosses, then draw a line of best fit. This line may be straight or curved and does not have to go through every point.
对于折线图（当自变量是连续量，如温度时），用小十字号仔细描点，然后画出最佳拟合线。这条线可以是直线或曲线，不一定通过所有数据点。
paper. Avoid awkward scales like 1 square = 3 units; use 1, 2, 5, or 10 multiples instead.
选择能够使数据占据坐标纸一半以上的刻度。避免使用别扭的刻度，如 1 格 = 3 个单位；使用 1、2、5 或 10 的倍数。
8. Identifying Patterns and Relationships | 识别规律与关系
Once the graph is drawn, describe the trend. Use phrases like 'as the temperature increases, the time to dissolve decreases', or 'the graph shows a linear relationship'.
图表画好后，描述其趋势。使用诸如“随着温度升高，溶解时间减少”或“图表显示线性关系”等表述。
You may be asked to read a value from the graph. If the value lies between two plotted points, you use interpolation. If it lies outside the range of your data, you use extrapolation, but be cautious—extrapolation can be unreliable.
你可能需要从图中读取数值。若数值位于两个已描点之间，使用内推法。若数值超出数据范围，使用外推法，但需谨慎——外推法可能不可靠。
Look for direct proportion (a straight line through the origin) or inverse proportion (a curve that shows one variable increasing as the other decreases). Use numbers from the graph to support your description.
观察正比例关系（过原点的直线）或反比例关系（一个变量随另一个增大而减小的曲线）。用图表中的数字支持你的描述。
9. Writing a Conclusion | 撰写结论
A conclusion states what you found out and whether the results support your hypothesis. It should refer to the data, not just repeat the prediction.
结论应陈述你发现了什么，以及结果是否支持你的假设。它应引用数据，而不仅仅是重复预测。
For example: 'The results show that as temperature increased from 20 °C to 80 °C, the mean dissolving time decreased from 120 s to 25 s. This supports the hypothesis that sugar dissolves faster at higher temperatures because particles move faster.'
例如：“结果表明，当温度从 20 °C 升至 80 °C 时，平均溶解时间从 120 s 降至 25 s。这支持了糖在较高温度下溶解更快的假设，因为粒子运动更快。”
If the data does not fully support the hypothesis, say so. Science is about honest reporting. Suggest a revised hypothesis if appropriate.
如果数据不完全支持假设，就照实说。科学在于诚实地报告。如果恰当，可提出修改后的假设。
10. Evaluating the Experiment | 评估实验
An evaluation looks at how well the experiment worked. You should identify any sources of error or limitations in your method. Distinguish between random errors (e.g., human reaction time) and systematic errors (e.g., a faulty thermometer).
评估审视实验进行得如何。你应指出方法中的任何误差来源或局限性。区分随机误差（如人的反应时间）和系统误差（如有故障的温度计）。
Comment on the reliability of your results: 'The repeats were close together, so the data is reliable' or 'There was a wide spread of repeats for 40 °C, which might be due to inconsistent stirring.'
评论结果的可靠性：“重复实验数据很接近，因此数据可靠” 或 “40 °C 时重复数据分散度大，可能是因为搅拌不均匀”。
Suggest realistic improvements. For example, 'Use a data logger with a temperature probe to record the exact moment the sugar dissolves, instead of relying on a stopwatch manually.' This shows higher-order thinking.
提出切实可行的改进建议。例如，“使用带温度探头的数据记录器来记录糖溶解的准确时刻，而不是手动依赖秒表。” 这体现了高阶思维能力。
11. Using Scientific Vocabulary | 使用科学词汇
Examiners expect you to use key scientific terms correctly. Words like 'dissolve', 'particle', 'soluble', 'force', 'reaction', and 'accurate' must be used in the right context.
考官期望你正确使用关键科学术语。像“溶解”、“粒子”、“可溶的”、“力”、“反应”和“精确的”这些词必须在正确的上下文中使用。
Practice writing full sentences that incorporate these terms. For example, instead of 'the stuff disappeared', write 'the solute dissolved in the solvent to form a solution'.
练习写包含这些术语的完整句子。例如，不要写“那东西不见了”，而应写“溶质溶解在溶剂中形成溶液”。
Be careful not to confuse everyday meanings with scientific ones. 'Weight' is a force measured in newtons, not the same as 'mass' in kilograms, even though people often use them interchangeably in daily life.
注意不要混淆日常含义和科学含义。“重量”是以牛顿为单位的力，不同于以千克为单位的“质量”，尽管日常生活中人们常混用。
12. Common Practical Tasks in Year 7 | Year 7 常见实验任务
Typical Year 7 practicals you might be assessed on include: investigating the factors that affect dissolving, measuring the force needed to stretch a spring, observing cells under a microscope, testing for acids and alkalis using indicators, and separating mixtures by filtration or chromatography.
可能考核的 Year 7 典型实验包括：探究影响溶解的因素、测量拉伸弹簧所需的力、用显微镜观察细胞、用指示剂检测酸和碱，以及通过过滤或色谱法分离混合物。
For each of these, you need to know the key variables, the correct use of equipment, safety precautions, and how to present and analyse the results. Practise writing full experiment plans, including a hypothesis, method, and risk assessment.
对于每一个实验，你需要知道关键变量、设备的正确使用、安全预防措施，以及如何呈现和分析结果。练习撰写完整的实验计划，包括假设、方法和风险评估。
Remember that practical skills are not only tested in the lab—you may get written questions asking you to identify errors in a method, choose the right graph, or suggest improvements. So learn to think like a scientist.
记住，实验技能不仅在实验室中考核——你可能会在笔试中遇到要求你找出方法中的错误、选择正确的图表或提出改进意见的题目。因此要学会像科学家一样思考。
Published by TutorHao | Science Revision Series | aleveler.com
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