📚 Year 7 SQA Science Practical Assessment Key Points | 七年级SQA科学实验/实践考核要点
In Year 7 SQA Science, practical assessments are a key part of your learning. You are expected to plan, carry out, and evaluate experiments safely and accurately. This guide covers the essential skills you need to succeed in practical assessments, from identifying variables to drawing conclusions and evaluating your methods.
在七年级SQA科学课程中，实践考核是你学习的重要组成部分。你需要安全、准确地计划、实施并评价实验。本指南涵盖你在实践考核中获得成功所需的关键技能，包括识别变量、记录数据、绘制图表、得出结论以及评价方法。
1. Understanding Variables | 理解变量
In any experiment, you must identify three types of variables: independent, dependent, and controlled. The independent variable is the factor you change deliberately. The dependent variable is the factor you measure or observe. Controlled variables are all other factors that must be kept constant to ensure a fair test. For example, in an experiment to investigate how light intensity affects the rate of photosynthesis in pondweed, the independent variable is light intensity (distance from lamp), the dependent variable is the number of oxygen bubbles produced per minute, and controlled variables include temperature, carbon dioxide concentration, and the type of pondweed.
| Variable Type | Definition | Example (Photosynthesis) |
|---|---|---|
| Independent | The factor you change | Light intensity (distance) |
| Dependent | The factor you measure | O₂ bubbles per minute |
| Controlled | Kept constant for a fair test | Temperature, CO₂ level, pondweed species |
在任何实验中，你必须识别三种变量：自变量、因变量和控制变量。自变量是你故意改变的因素。因变量是你测量或观察的因素。控制变量是必须保持不变的所有其他因素，以确保公平测试。例如，在研究光照强度如何影响水草光合作用速率的实验中，自变量是光照强度（灯的距离），因变量是每分钟产生的氧气气泡数，控制变量包括温度、二氧化碳浓度和水草的种类。
2. Writing a Hypothesis | 撰写假设
A hypothesis is a testable prediction based on scientific knowledge. It often follows an "If... then..." format. For example: "If the temperature of the water increases, then the time taken for the sugar to dissolve will decrease, because particles have more kinetic energy." Your hypothesis should clearly state the relationship between the independent and dependent variables and give a scientific reason.
假设是基于科学知识的一种可检验的预测。它通常遵循“如果……那么……”的格式。例如：“如果水温升高，那么糖溶解所需的时间将减少，因为粒子具有更多的动能。”你的假设应明确陈述自变量和因变量之间的关系，并给出科学依据。
3. Planning an Experiment | 设计实验
A well-planned experiment includes a clear method, a list of apparatus, and consideration of safety. Your method should be written in numbered steps, using imperative verbs (e.g., "Pour 100 ml of water into the beaker"). You must identify risks and how to control them. Also, think about how you will record results and how many repeats you need for reliable data. A pilot experiment can help test your plan.
一个精心设计的实验包括清晰的方法、设备清单和安全考量。你的方法应按编号步骤书写，使用祈使动词（例如：“将100毫升水倒入烧杯中”）。你必须识别风险及控制措施。同时，思考如何记录结果以及需要多少次重复以获得可靠数据。预实验有助于检验你的计划。
4. Making Measurements | 进行测量
Accurate measurements are crucial in science. Use appropriate instruments, such as a ruler, thermometer, measuring cylinder, or stopwatch. Read scales at eye level to avoid parallax error. Record measurements with the correct number of significant figures and units. For example, the mass of a substance should be recorded to the nearest 0.01 g if using a digital balance. Always repeat measurements and calculate a mean to improve reliability, excluding any anomalous results.
精确测量在科学中至关重要。使用合适的仪器，如直尺、温度计、量筒或秒表。在读取刻度时视线应与刻度平行，避免视差误差。记录测量值时要有正确的有效数字和单位。例如，如果使用数字天平，物质的质量应记录到最接近的0.01克。始终重复测量并计算平均值以提高可靠性，排除异常结果。
5. Recording Data | 记录数据
Present your data clearly in a results table. The table should have headings that include the quantity and unit, such as "Time (s)" or "Temperature (°C)". Independent variable is placed in the first column; dependent variable in subsequent columns. All entries should be aligned and neat. If you take repeats, include a column for each repeat and a column for the mean.
将你的数据清晰地呈现在结果表格中。表格应有包含数量和单位的标题，例如“时间 (s)”或“温度 (°C)”。自变量放在第一列，因变量放在后续列中。所有条目应对齐整洁。如果进行了重复实验，应包括每次重复的列以及平均值列。
6. Drawing Tables and Graphs | 绘制表格与图表
ertical). Label both axes with the quantity and unit. Choose a suitable scale that uses most of the graph paper. Plot points with small crosses (×) and draw a line of best fit (a smooth curve or straight line) that shows the trend. Do not connect dot-to-dot unless instructed. If the data suggest a proportional relationship, the line passes through the origin.
图表可帮助你直观地发现数据规律。自变量放在x轴（水平），因变量放在y轴（垂直）。为两条轴标注数量和单位。选择合适的比例，充分利用图纸。用小叉号（×）标出数据点，并绘制一条显示趋势的最佳拟合线（平滑曲线或直线）。除非有要求，否则不要逐点连接。如果数据表明比例关系，直线将通过原点。
7. Identifying Patterns and Trends | 识别模式和趋势
Look at your graph or table and describe what you see. Use phrases such as "As the independent variable increases, the dependent variable increases/decreases steadily." Identify whether the relationship is linear, directly proportional, or non-linear. Also note any outliers that do not fit the pattern. For example, "The number of bubbles increased as light intensity increased, but at very high light intensities the rate levelled off."
观察你的图表或表格，描述所见。使用“随着自变量增加，因变量稳定增加/减少”等语句。判断关系是线性、正比还是非线性。同时注意任何不符合模式的异常值。例如，“产生的气泡数量随光照强度增加而增加，但在很高光照强度下，速率趋于平稳。”
8. Drawing Conclusions | 得出结论
Your conclusion should state whether your results support the hypothesis. Summarise the relationship between variables using data evidence. For example, "The results show that the higher the concentration of acid, the faster the reaction. This supports the hypothesis because an average of 35 cm³ of gas was produced at 2 M acid compared to 20 cm³ at 1 M." If the results do not support the hypothesis, explain possible reasons.
你的结论应说明结果是否支持假设。用数据证据总结变量之间的关系。例如，“结果显示，酸浓度越高，反应越快。这支持了假设，因为在2 M酸中平均产生35 cm³气体，而在1 M酸中为20 cm³。”如果结果不支持假设，解释可能的原因。
9. Evaluating an Experiment | 评价实验
Evaluation involves assessing the reliability and validity of your experiment. Identify sources of error, such as measurement uncertainties or control variables that were difficult to keep constant. Suggest improvements to the method, for example, using a water bath to control temperature more precisely. Also comment on the quality of the data – were there any anomalous results? If you had limited repeats, suggest more repeats to increase reliability.
评价涉及评估实验的可靠性和有效性。识别误差来源，如测量不确定性或难以保持不变的控制变量。提出改进方法，例如使用水浴更精确地控制温度。还要评论数据质量——是否有异常结果？如果重复次数有限，建议增加重复次数以提高可靠性。
10. Safety in the Lab | 实验室安全
Safety is always the priority during practical work. Follow your teacher's instructions, wear appropriate personal protective equipment (PPE) such as safety goggles and a lab coat. Tie back long hair, tuck away loose clothing, and never eat or drink in the lab. Know the location of the fire extinguisher, fire blanket, and eye wash station. Always report spills or breakages immediately. Read hazard symbols on chemicals and understand the risks.
安全始终是实验过程中的首要事项。遵循老师的指导，穿戴合适的个人防护装备（PPE），如护目镜和实验服。扎起长发，整理好宽松衣物，不在实验室饮食。了解灭火器、灭火毯和洗眼器的位置。一旦发生溢出或破损，立即报告。阅读化学品上的危险标志，了解风险。
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