📚 Year 7 SQA Science: Key Points for Practical Assessments | Year 7 SQA科学：实验/实践考核要点
In SQA Science at Year 7, practical assessments are not just about following instructions — they test your ability to think like a scientist. You need to plan safe investigations, identify variables, collect reliable data, analyse patterns, and evaluate your method. This guide walks you through every essential skill you must demonstrate to succeed in your practical work and internal assessments, covering the key criteria used by teachers to award marks under the Scottish Curriculum for Excellence.
在SQA Year 7科学课程中，实践考核不仅仅是按步骤操作，更是测试像科学家一样思考的能力。你需要会设计安全的探究、识别变量、收集可靠的数据、分析规律并评估实验方法。本文带您逐一掌握在实验工作和校内评估中必须展现的所有核心技能，涵盖苏格兰卓越课程中教师评分的关键标准。
1. Understanding Safety in the Lab | 了解实验室安全
Safety is always the first thing an assessor observes. You must show that you can identify common hazards such as heat sources (Bunsen burner), corrosive chemicals (e.g. dilute HCl), and breakable glassware. Always wear safety goggles and a lab coat as personal protective equipment (PPE). Tie back long hair and tuck away neckties or loose sleeves. Before starting, check that you know where the fire extinguisher, fire blanket, eye-wash station and first aid kit are located.
安全永远是评估者观察的第一要素。你必须展示出能识别常见危险，如热源（本生灯）、腐蚀性化学品（如稀盐酸）和易碎玻璃器皿。始终要佩戴安全护目镜和实验服作为个人防护装备。长发要束好，并收好领带或宽松的衣袖。开始实验前，确认自己知道灭火器、灭火毯、洗眼器和急救箱的位置。
During the experiment, handle chemicals with care — never taste or directly sniff substances; waft the vapour towards your nose if needed. When heating a test tube, point it away from people. If a spill or accident occurs, report it to the teacher immediately. You will be assessed on how safely you work, not just on the final results. A well-practised safety routine shows you are ready for independent investigative work.
实验过程中，小心处理化学品——绝不可品尝或直接闻嗅；若需闻气味，用手扇动气体至鼻端。加热试管时，管口切勿朝向他人。万一发生溅出或意外，立即报告老师。你的安全操作本身会被评分，而不只看最终结果。一个熟练的安全流程表明你已做好了独立探究的准备。
2. Identifying Variables | 识别变量
Every fair investigation depends on correctly identifying three types of variables. The independent variable is the factor you deliberately change. The dependent variable is what you measure or observe as a result. Controlled variables are all the other factors that must stay the same to keep the test fair. For example, in 'How does light intensity affect the rate of photosynthesis in pondweed?', light intensity (distance of lamp) is independent, number of oxygen bubbles per minute is dependent, and CO₂ concentration, temperature, and pondweed length are controlled.
任何公平探究都依赖于正确识别三种变量。自变量是你有意改变的因素。因变量是你因此测量或观察的结果。控制变量是所有必须保持不变的因素，以保证测试公平。例如，在“光照强度如何影响水草的光合作用速率？”中，光照强度（灯的距离）是自变量，每分钟的氧气气泡数是因变量，而二氧化碳浓度、水温及水草长度则是控制变量。
In your plan, always list the independent, dependent and at least three important controlled variables. Stating how you will keep each controlled variable unchanged shows the assessor your understanding of a fair test. Without proper controls, any pattern you see could be caused by an unrelated factor — that makes your evidence invalid. Practice by taking everyday situations, such as 'Does adding salt affect boiling temperature?', and mentally list the variables.
在你的实验计划中，务必列出自变量、因变量以及至少三个重要的控制变量。说明你将如何保持每个控制变量不变，这会让评估者看到你对公平测试的理解。如果缺乏恰当的控制，你观察到的任何规律都可能由无关因素引起——这会使你的证据无效。可以通过日常情境来练习，比如“加盐会影响沸点吗？”，然后在心中列出各变量。
3. Writing a Clear Aim and Hypothesis | 撰写明确的目标与假设
Your aim should be a concise statement describing the purpose of the experiment. Start with 'To investigate ...' and include the independent and dependent variables. For example, 'To investigate how the concentration of salt solution affects the mass change of potato chips.' A hypothesis goes further — it is a testable prediction based on scientific knowledge, not a guess. Use an 'If ... then ... because ...' structure: 'If the salt concentration increases, then the potato mass will decrease because water moves out of the cells by osmosis.'
实验目的应是描述实验意图的简明句子。以“探究……”开头，并包含自变量和因变量。例如：“探究盐水浓度如何影响土豆条的质量变化。”假设则更进一步——它是基于科学知识的可检验预测，而非胡猜。使用“如果……那么……因为……”的结构：“如果盐溶液浓度增加，那么土豆的质量会减少，因为水通过渗透作用从细胞中流出。”
Make sure your hypothesis clearly links the independent variable to the predicted change in the dependent variable. Avoid vague words like 'it might affect' — be specific about the direction and reason. A strong hypothesis can later be compared directly with your results. In SQA assessments, you are marked on whether your hypothesis is scientifically sound, even if the results do not fully support it — that shows honest scientific practice.
确保你的假设清晰地将自变量与因变量的预期变化联系起来。避免“可能会影响”这类模糊用语——要具体指出变化的方向和原因。一个有力的假设日后可直接与实验结果作比较。在SQA评估中，评分看的是你的假设在科学上是否合理，即使结果没有完全支持它——这反而展现了诚实的科学实践。
4. Designing a Reliable Procedure | 设计可靠的实验步骤
A reliable procedure is a step-by-step recipe that another scientist could follow and get similar results. Use numbered steps, indicate the sizes and types of apparatus (e.g. 'measure 50 cm³ of water using a 100 cm³ measuring cylinder'), and specify the range and intervals for the independent variable (e.g. 'test temperature at 20 °C, 30 °C, 40 °C, 50 °C, 60 °C'). Mention exactly how many readings you will take and how you will ensure repeatability — usually three trials for each condition.
一个可靠的实验步骤就像一份逐步进行的食谱，另一名科学家照着做也能得到相似结果。使用编号步骤，标明仪器的规格和类型（例如“用100 cm³量筒量取50 cm³水”），并明确自变量的范围和间隔（如“在20 °C、30 °C、40 °C、50 °C、60 °C下测试”）。准确说明你将记录多少个读数，以及如何确保可重复性——通常每个条件进行三次试验。
Include steps to minimise errors: zero the balance before use, stir the solution for the same length of time, and read the thermometer at eye level. Mention how you will record data immediately in a pre-drawn table to avoid memory errors. Assessors look for evidence that you have thought about the smooth running of the investigation, not just about the science concept. A well-planned procedure also saves valuable lab time and reduces stress on the day.
包括减少误差的步骤：使用天平前先归零，搅拌溶液的时间保持一致，并在眼睛水平位置读取温度计。提及如何立即将数据记录在预先画好的表格中，以免记忆出错。评估者寻找的是你对保障实验顺利进行的思考，而不仅仅是科学概念。一个精心设计的步骤还能节省宝贵的实验时间，减少当天的紧张感。
5. Selecting Apparatus and Making Measurements | 选择仪器并进行测量
Choosing the right instrument directly affects the quality of your data. For volume, use a measuring cylinder — if you need high precision, a pipette or burette. For temperature, use a glass thermometer (range -10 °C to 110 °C) or a digital probe. For mass, a digital balance reading to 0.01 g is ideal. For time, a stopwatch. Avoid using kitchen scales or clock dials if lab tools are available. State your choice in the equipment list and justify it briefly if asked.
选择合适的仪器直接影响数据的质量。测体积，用量筒——如需高精度则用移液管或滴定管。测温度，用玻璃温度计（量程 -10 °C 至 110 °C）或数字探头。测质量，精确到0.01 g的数字天平最为理想。测时间，用秒表。若实验室有专用器材，避免使用厨房秤或钟盘。在器材列表中标明你的选择，如有需要可简要说明理由。
When taking a measurement, read the scale correctly. Always look perpendicular to the scale to avoid parallax error. For analogue instruments, estimate the reading to half of the smallest division: if a thermometer has 1 °C marks, you should record to 0.5 °C. Record each value as it is measured — do not later change readings to fit your expectations. In practical assessments, you may be observed making these readings, so steady hands and a calm approach count.
进行测量时，要正确读取刻度。始终从垂直于刻度的方向观察以避免视差误差。对于模拟式仪器，估读到最小刻度的一半：如果温度计每一格为1 °C，读数应记录到0.5 °C。测得每个数值即如实记录——切勿事后改动读数以迎合预期。在实践考核中，你可能在观察下完成这些读数，因此稳健的手法和沉着的心态也很重要。
6. Recording Data Effectively | 有效记录数据
Organise your raw data in a results table drawn with a ruler and pencil. The independent variable goes in the first column, with units in the header (e.g. 'Temperature (°C)'). The dependent variable occupies the next columns — if you are doing three trials, label columns 'Trial 1', 'Trial 2', 'Trial 3' and 'Average'. Every cell must have a measurement and unit; do not leave gaps. If a reading is missed, write a dash and note the reason in your evaluation.
用直尺和铅笔画出结果表来整理原始数据。自变量放在第一列，表头带单位（如“温度（°C）”）。因变量占据后续几列——如果你做三次试验，各列分别标注“试验1”、“试验2”、“试验3”和“平均值”。每个单元格必须有测量值和单位；不要留空。若遗漏读数，可画一短横线，并在评估中说明原因。
Here is a short example of a well-structured table. Temperature (°C) | Trial 1 (s) | Trial 2 (s) | Trial 3 (s) | Average (s). 20 | 120 | 118 | 122 | 120. 40 | 74 | 76 | 75 | 75. Always include a title above the table, for instance 'Table 1: Time taken for sugar to dissolve at different temperatures.' Neat presentation helps the assessor follow your logical thinking and allows you to spot any obvious outliers immediately.
以下是一个结构良好的简短表格示例。温度（°C） | 试验1（秒） | 试验2（秒） | 试验3（秒） | 平均值（秒）。20 | 120 | 118 | 122 | 120。40 | 74 | 76 | 75 | 75。表格上方始终要加标题，例如“表1：不同温度下糖溶解所需时间”。整洁的呈现有助于评估者理解你的逻辑思维，也让你自己即时发现明显的异常值。
7. Drawing and Interpreting Graphs | 绘制与解读图表
Graphs turn numbers into visual patterns. On graph paper, put the independent variable on the horizontal (x) axis and the dependent variable on the vertical (y) axis. Choose a scale that spreads your data points across at least half the grid in each direction — using multiples of 1, 2, 5 or 10 makes plotting easier. Label both axes with the variable name and unit, and give the graph a descriptive title.
图表将数字转化为可视的规律。在坐标纸上，将自变量放在水平（x）轴，因变量放在垂直（y）轴。选择能使数据点在每个方向上至少占满半张网格的刻度——使用1、2、5或10的倍数能让描点更轻松。两轴均标注变量名称和单位，并为图表加上描述性标题。
Plot each point with a small, neat cross (x). When all points are in place, draw a line or curve of best fit, which may be straight or smoothly curved. Do not join dot to dot in a zigzag. If a point lies far off the trend, circle it as an anomaly and do not let the best-fit line be dragged towards it. When interpreting the graph, describe the overall relationship — is it linear, directly proportional, or showing a plateau? Use correct terminology such as 'positive correlation' or 'as x increases, y decreases'.
用小而清晰的叉号（x）标出每个数据点。所有点就位后，画一条最佳拟合线或曲线，该线可以是直的或是平滑曲线。切勿逐点连成锯齿状。若某点远离趋势线，圈出作为异常值，且不要让最佳拟合线被它拉动。解读图表时，描述整体关系——是线性、正比关系还是出现平台？使用正确的术语，如“正相关”或“随着x增加，y减小”。
8. Analyzing Results and Identifying Patterns | 分析结果并识别模式
Analysis goes beyond reading the graph. Calculate averages correctly, and if you have time, work out the range of your repeats to see how consistent they were. A small range suggests good precision, while a large range points to random error. Identify any anomalous readings that break the established pattern and think about what might have caused them (e.g. a bubble blocked the delivery tube momentarily).
分析不单是读图表。正确计算平均值，若有时间，可计算重复试验的极差，判断数据的一致性。极差小说明精密度好，极差大则表明随机误差较大。识别任何打破已有规律的异常读数，并思考可能的原因（如气泡暂时堵住了导管）。
State the pattern you observe as a sentence linking the variables: 'As the temperature increased, the time taken for the sugar to dissolve decreased, showing a negative correlation.' If the data suggests a quantitative relationship, describe it — for instance, 'The mass decreased by a constant amount for every 10 °C rise.' Always refer back to your hypothesis: do the results support it? You do not lose marks for an unsupported hypothesis; you gain them for a thoughtful, evidence-based analysis.
用一句话陈述你所观察到的规律，将变量联系起来：“随着温度升高，糖溶解所需时间减少，呈负相关。”如果数据提示定量关系，可以如此描述：“每升高10 °C，质量减少一恒定数值。”始终回看你的假设：结果支持它吗？即使假设不被支持也不会丢分；相反，你基于证据进行深思熟虑的分析才能得分。
9. Evaluating Sources of Error | 评估误差来源
A solid evaluation distinguishes between systematic and random errors. Systematic errors affect all readings in the same direction — for example, a thermometer that always reads 1 °C too high, or starting the stopwatch too late each time. Random errors cause readings to be spread out unpredictably, like slight variations in reaction time when pressing a stopwatch or small temperature fluctuations in the room.
一份扎实的评估能区分系统误差与随机误差。系统误差会使所有读数朝同一方向偏离——例如，温度计始终偏高1 °C，或每次都较晚启动秒表。随机误差导致读数不可预测地分散，如按下秒表时反应时间的轻微差异，或室温的微小波动。
Identify at least two likely errors in your experiment and explain how they affected the results. Then, suggest realistic improvements: 'Use a water bath to keep the temperature constant instead of heating directly with a Bunsen burner,' or 'Use a light gate to measure time instead of a hand-held stopwatch.' Show that you understand the difference between 'something went wrong' and a real source of measurement error. The best evaluations also mention how you could extend the investigation with a related research question.
找出实验中至少两处可能的误差，并解释它们如何影响结果。然后，提出切实可行的改进建议：“使用水浴保持温度恒定，而非用本生灯直接加热”，或“采用光栅门测时以代替手持秒表”。要展示你明白“哪里出了错”与真正的测量误差来源之间的区别。最好的评估还会提及如何延伸这一探究，提出一个相关的研究问题。
10. Drawing Conclusions | 得出结论
Your conclusion is the final answer to the initial aim. Start by stating whether the hypothesis was supported or not. Then back it up with specific data: 'The hypothesis was supported because as the salt concentration increased from 0% to 10%, the average potato mass decreased from 5.2 g to 4.1 g, which is a drop of 21%. This matches the prediction that water would leave the cells by osmosis.' Avoid vague phrases like 'the experiment worked well' — let numbers do the talking.
结论是对初始实验目的的最终回答。首先阐述假设是否得到支持，然后用具体数据佐证：“假设得到支持，因为随着盐浓度从0%增至10%，土豆的平均质量从5.2 g降至4.1 g，降幅达21%。这与水分通过渗透作用离开细胞的预测相符。”避免“实验进行顺利”之类的模糊表述——用数字说话。
If the results conflict with the hypothesis, do not say the hypothesis was 'wrong'. Instead, state that the evidence did not support it and suggest why, based on your scientific understanding and evaluation. Link the conclusion to the scientific theory behind the investigation — such as particle theory, osmosis, or energy transfer. A good conclusion also acknowledges any limitations, showing maturity in scientific thinking.
如果结果与假设相矛盾，不要说假设“错了”。而是陈述证据没有支持该假设，并依据你的科学理解和评估，解释可能的原因。将结论与探究背后的科学理论联系起来——如粒子理论、渗透或能量转移。一个优秀的结论还会承认各种局限，展示出成熟的科学思维。
11. Improving the Experiment | 改进实验
Improvement is not about scrapping the whole method — it is about targeted tweaks. If the data showed poor repeatability, suggest increasing the number of trials to five or six. If temperature control was a problem, propose a thermostatically controlled water bath. If measuring colour change by eye was subjective, recommend using a colorimeter or a standard colour chart. Each suggested improvement must address a specific weakness identified in your evaluation.
改进实验并非要全盘推翻原有方法，而是进行有针对性的微调。如果数据的重复性不佳，建议将试验次数增至五到六次。如果温度控制是难题，提出使用恒温控制水浴。如果目测颜色变化带有主观性，推荐使用色度计或标准比色卡。每条改进建议
Published by TutorHao | Year 7 Science Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图