AS Biology 1.1 Practical Skills Written Assessment | AS 生物 1.1 实验技能笔试评估

📚 AS Biology 1.1 Practical Skills Written Assessment | AS 生物 1.1 实验技能笔试评估

The Practical Skills Written Assessment is a written examination component that evaluates your ability to plan experiments, record and present data, analyse results, and evaluate methods. It reflects the practical work you must complete during your AS course, but it is tested through written questions rather than hands-on tasks.

实验技能笔试评估是一种笔试考试组成部分，考查你规划实验、记录和呈现数据、分析结果以及评估方法的能力。它反映你在AS课程中必须完成的实验操作，但以书面问题而非动手操作的形式进行测试。

This assessment typically carries a significant proportion of the final grade. Questions are based on both familiar contexts, such as enzyme activity and osmosis, and unfamiliar contexts that require you to transfer your practical skills to new situations. In this revision article, we will walk through every core skill you need to master, with bilingual explanations and exam-focused guidance.

该评估通常在最终成绩中占有相当大的比重。题目既基于熟悉的情境（如酶活性和渗透作用），也基于不熟悉的情境，要求你将实验技能迁移到新场景中。在本复习文章中，我们将逐一梳理你需要掌握的各项核心技能，并附上双语解释和针对考试的指导。

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1. What Is the Practical Skills Written Assessment? | 什么是实验技能笔试评估

The written assessment is divided into several strands: planning, recording, presenting, analysing, and evaluating. Each strand addresses a different stage of the scientific method, and exam questions may combine multiple strands in a single scenario.

笔试评估分为几个板块：规划、记录、呈现、分析和评估。每个板块对应科学方法的不同阶段，考试题目可能在同一个情景中综合考查多个板块。

The planning strand requires you to design an experiment from scratch, including stating the aim, writing a hypothesis, identifying variables, selecting apparatus, and outlining a step-by-step procedure. The recording strand tests your ability to construct tables, record raw data with correct units, and handle repeats. The presenting strand covers graph construction, including axis labels, scales and best-fit lines. The analysis strand involves calculations, identifying trends, and drawing conclusions. Finally, the evaluation strand asks you to identify limitations and suggest improvements.

规划板块要求你从零开始设计实验，包括陈述目的、写出假设、识别变量、选择器材以及概述逐步操作流程。记录板块考查你构建表格、以正确单位记录原始数据以及处理重复测量的能力。呈现板块涵盖图表绘制，包括坐标轴标注、刻度选择和拟合曲线。分析板块涉及计算、识别趋势和得出结论。最后，评估板块要求你识别局限性并提出改进建议。

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2. Experimental Design and Planning | 实验设计与规划

When you are asked to plan an experiment, begin by writing a clear aim. For example, ‘To investigate the effect of temperature on the rate of amylase activity.’ The aim must identify both the independent variable and the dependent variable clearly, and it should be specific enough to guide the entire procedure.

当被要求规划实验时，首先要写出明确的目的。例如：”探究温度对淀粉酶活性的影响”。目的必须清晰地指明自变量和因变量，并且应足够具体以指导整个操作流程。

Next, formulate a testable hypothesis. A good hypothesis explains the expected relationship between the variables and is grounded in biological knowledge. For example, ‘As temperature increases from 10 °C to 40 °C, the rate of amylase activity will increase because molecules gain kinetic energy and collide more frequently; above the optimum temperature, the rate will decrease because the enzyme denatures.’

接下来，提出一个可检验的假设。好的假设解释变量之间的预期关系，并以生物学知识为基础。例如：”当温度从10°C升至40°C时，淀粉酶活性速率将增加，因为分子获得动能并更频繁地碰撞；超过最适温度后，速率将下降，因为酶发生变性。”

In your procedure, decide the range of values for the independent variable and the interval between them. For example, temperatures of 10, 20, 30, 40 and 50 °C create a sensible range that can reveal the optimum temperature. Avoid intervals that are too large, because trends may be missed; avoid intervals that are too small, because the experiment becomes time-consuming and the differences may be indistinguishable.

在操作步骤中，确定自变量的取值范围以及各值之间的间隔。例如，10、20、30、40和50°C的温度设置构成了一个合理的范围，能够揭示最适温度。避免间隔过大，因为可能会遗漏趋势；也避免间隔过小，因为实验会耗费时间且差异可能无法分辨。

Include at least three repeats for each treatment so that you can calculate a mean and identify anomalous results. Also state the total number of measurements and the time interval at which readings are taken. For example, ‘Measure the change in mass every 2 minutes for a total of 20 minutes.’

每个处理至少重复三次，以便计算平均值并识别异常结果。还应说明测量的总次数以及读取读数的时间间隔。例如：”每2分钟测量一次质量变化，总共持续20分钟。”

Finally, specify the apparatus required and give a step-by-step method that is logical, precise and reproducible. A control experiment should be described where appropriate, removing the variable being tested to provide a comparison. For example, in an enzyme experiment, the control might use boiled enzyme to show that no reaction occurs without active enzyme.

最后，明确所需器材，并给出逻辑清晰、精确且可重复的逐步操作方法。在适当情况下，应描述对照实验：去掉被测试的变量，以提供比较基准。例如，在酶实验中，对照可以使用煮沸的酶，以表明没有活性酶时不会发生反应。

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3. Variables: Independent, Dependent and Controlled | 变量：自变量、因变量和控制变量

An independent variable is the factor you deliberately change in an experiment. A dependent variable is the factor you measure, which responds to changes in the independent variable. Controlled variables are all other factors that must be kept constant so that they do not affect the dependent variable.

自变量是你在一项实验中刻意改变的因素。因变量是你测量的因素，它随自变量的变化而响应。控制变量是必须保持恒定的所有其他因素，以免它们影响因变量。

For example, in an osmosis experiment using potato cylinders, the independent variable is the concentration of sucrose solution (e.g., 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 mol dm⁻³). The dependent variable is the change in mass of the potato cylinder. Controlled variables include temperature, the surface area of each cylinder, the volume of solution, and the time the cylinders remain in the solution.

例如，在土豆条渗透实验中，自变量是蔗糖溶液的浓度（如0.0、0.2、0.4、0.6、0.8和1.0 mol dm⁻³）。因变量是土豆条的质量变化。控制变量包括温度、每条土豆条的表面积、溶液体积以及土豆条在溶液中浸泡的时间。

When stating controlled variables in an exam, be specific about how each variable is controlled. Avoid simply writing ‘temperature’ — instead write ‘kept at 25 °C using a water bath’. Similarly, instead of ‘surface area’, write ‘cut all cylinders to the same length using a cork borer and a ruler’.

在考试中陈述控制变量时，务必具体说明如何控制每一个变量。避免只写”温度”，而应写”使用水浴锅保持在25°C”。同样，不要只写”表面积”，而应写”用打孔器和直尺将所有土豆条切成相同的长度”。

Some variables are difficult to control completely, such as pH in an unbuffered solution. In such cases, mention that a buffer solution should be used to maintain a constant pH. In planning questions, the examiner rewards specific, practical methods of control rather than vague statements.

有些变量难以完全控制，例如无缓冲溶液中的pH值。在这种情况下，应提到使用缓冲液来维持恒定的pH。在规划题中，考官更青睐具体、可操作的控制方法，而不是模糊的陈述。

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4. Health and Safety in the Laboratory | 实验室健康与安全

A hazard is a potential source of harm, while risk is the likelihood that harm will occur and its severity. In the laboratory you must be able to identify hazards and describe how to reduce the risk. In the written paper, questions often ask you to suggest precautions for a named procedure.

危害是潜在的伤害来源，而风险是伤害发生的可能性及其严重程度。在实验室中，你必须能够识别危害并描述如何降低风险。在笔试中，题目通常会要求你为指定的操作步骤提出预防措施。

Common biology hazards include corrosive chemicals such as hydrochloric acid and sodium hydroxide, flammable solvents such as ethanol, biological materials such as blood or microorganisms, and sharp instruments such as scalpel blades or needles. Extreme temperatures, such as a boiling water bath, also present a scalding hazard.

生物实验室常见的危害包括盐酸和氢氧化钠等腐蚀性化学品、乙醇等易燃溶剂、血液或微生物等生物材料，以及解剖刀刀片或针头等锐利器械。沸水浴等极端温度也存在烫伤风险。

Precautions may include wearing safety goggles, gloves and a lab coat, using a water bath or electric heater instead of a naked flame, cutting away from the body when using a scalpel, and disinfecting work surfaces before and after handling biological materials. If a chemical is corrosive, state that it must be handled with care or in a fume cupboard if fumes are hazardous.

预防措施可能包括佩戴护目镜、手套和实验服，使用水浴锅或电加热器代替明火，使用解剖刀时朝远离身体的方向切割，以及在处理生物材料前后对工作台面消毒。如果化学品具有腐蚀性，应说明必须小心操作；如果产生有害烟雾，则应在通风橱中进行。

In your written answer, always link the precaution to the specific hazard. For example: ‘Wear safety goggles to protect the eyes from acid spl

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