Year 7 Cambridge Biology: Key Points for Experimental / Practical Assessments | 七年级剑桥生物：实验与实践考核要点

📚 Year 7 Cambridge Biology: Key Points for Experimental / Practical Assessments | 七年级剑桥生物：实验与实践考核要点

Practical work is the heart of biology. In your Year 7 Cambridge course, you will be assessed not only on what you know but on how well you can plan, carry out and think about experiments. This guide brings together the most important practical skills and common assessment targets to help you perform confidently in lab tasks and written papers about practical work.

实践操作是生物学的核心。在七年级剑桥课程中，不仅考查你的知识，更看重你计划、实施和反思实验的能力。本指南汇总了最重要的实践技能和常见考核目标，帮助你在实验室任务和涉及实验的笔试中自信地表现。

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1. Laboratory Safety Rules | 实验室安全规则

Always wear safety goggles and a laboratory coat to protect your eyes and clothing from spills or splashes. Never perform an experiment without them if instructed.

始终佩戴安全护目镜和实验服，以保护眼睛和衣物免受溅出的化学品伤害。如果要求佩戴，切勿在不穿戴的情况下操作实验。

Tie back long hair and remove loose jewellery, scarves or ties. These can catch fire on a Bunsen burner or become caught in equipment.

将长发束起，取下悬垂的首饰、围巾或领带。这些物品容易在本生灯上着火，或被设备卷住。

Never eat, drink or chew gum in the laboratory. Wash your hands thoroughly after handling any biological material or chemicals.

实验室内严禁饮食或嚼口香糖。接触任何生物材料或化学品后，都要彻底洗手。

Report any accident, spill or broken glassware to your teacher immediately, even if it seems minor. Know the location of the fire extinguisher, fire blanket and first‑aid kit.

任何意外、溢出或破损玻璃器皿都必须立即报告老师，即使看起来很轻微。要熟知灭火器、灭火毯和急救箱的位置。

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2. Using a Light Microscope | 使用光学显微镜

Place the slide securely on the stage using the stage clips. Always begin with the lowest‑power objective lens (usually 4× or 10×) to locate the specimen easily and avoid crashing the lens into the slide.

用压片夹将载玻片牢固地放置在载物台上。始终从最低倍物镜（通常为 4× 或 10×）开始，以便轻松找到标本，并避免镜头压碎载玻片。

While looking from the side, use the coarse focus knob to raise the stage until the slide is just below the objective lens. Then look through the eyepiece and slowly lower the stage using the coarse knob until the image comes into focus. Sharpen the image with the fine focus knob.

从侧面观察，用粗准焦螺旋升高载物台，直到玻片刚好在物镜下方。然后通过目镜观察，用粗准焦螺旋缓慢降低载物台，直到图像出现，再用细准焦螺旋把图像调清晰。

total magnification = eyepiece magnification × objective magnification

总放大倍数 = 目镜放大倍数 × 物镜放大倍数

For example, a 10× eyepiece combined with a 40× objective gives a total magnification of 400×. Always record the magnification used on any drawing.

例如，10× 目镜与 40× 物镜组合，总放大倍数为 400×。在任何绘图中都要记录所使用的放大倍数。

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3. Making Accurate Biological Drawings | 绘制准确的生物图

Always use a sharp HB pencil for biological drawings. Draw clear, continuous outlines—do not sketch or make feathery lines. The specimen should be large enough to show all important details.

绘制生物图始终使用削尖的 HB 铅笔。画出清晰、连续的轮廓线——不要素描或用毛糙的线条。标本应画得足够大，以显示所有重要细节。

Do not use shading or colouring. To indicate darker areas, use stippling (small dots). Only draw what you actually see, even if it is not a perfect textbook specimen.

不要使用阴影或涂色。如需表示较暗区域，可使用点描法。只画你实际看到的结构，即使与教科书上的完美标本不同。

Label the structures using a ruler to draw straight label lines. Write the labels horizontally in pencil or black ink. Avoid arrows or crossing lines.

用直尺画出直的标准指示线，并用铅笔或黑色墨水笔水平书写标签。避免使用箭头，也不要让指示线交叉。

Write a title beneath your drawing that states the specimen viewed and the magnification, for example “Onion epidermal cells, ×100”.

在图下方写上标题，说明所观察的标本和放大倍数，例如 “洋葱表皮细胞，×100″。

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4. Measuring Length, Mass and Temperature | 测量长度、质量和温度

When using a ruler, line up the zero mark exactly with the edge of the object. Position your eye directly above the scale to avoid parallax error, and record the measurement in millimetres (mm) or centimetres (cm).

使用直尺时，将零刻度对准物体的边缘。眼睛正对刻度，避免视差，并以毫米 (mm) 或厘米 (cm) 记录数值。

For a liquid‑in‑glass thermometer, keep the bulb immersed in the substance while taking the reading. Wait until the liquid column stops moving, then read at eye level. Express temperature in degrees Celsius (°C).

使用液体玻璃温度计时，读数时保持感温泡浸在物质中。待液柱停止移动后，在眼睛水平高度读数，温度以摄氏度 (°C) 表示。

When using an electronic balance, place it on a level surface and press the tare (zero) button before placing the object on the pan. Record mass in grams (g) and always use a weighing boat or paper for loose substances.

使用电子天平时，放置在水平桌面上，放物体前按下归零键。质量以克 (g) 记录，称量散装物质时务必使用称量纸或称量舟。

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5. Using a Bunsen Burner Correctly | 正确使用本生灯

Connect the gas tubing securely to the gas tap. Close the air hole completely, light a splint or match, and hold it just above the barrel before turning on the gas. A yellow “safety flame” should appear.

将气管牢固地连接在煤气龙头上。完全关闭气孔，点燃木条或火柴，然后将其放在灯管口上方，再打开煤气。应看到黄色的 “安全火焰”。

For heating, slowly open the air hole until you obtain a blue, roaring flame, which is much hotter and less sooty. Always return to a yellow flame when not actively heating, so it remains clearly visible.

需要加热时，缓慢打开气孔，直到出现蓝色的、咝咝作响的火焰，这种火焰温度更高且不易产生黑烟。不进行加热时，务必将火焰调回黄色，使其清晰可见，防止意外。

Never leave a lit Bunsen burner unattended. Tie back hair and tuck in any loose clothing before you light it. Turn off the gas tap completely after use.

点燃的本生灯绝不可无人看管。点燃前系好长发，塞好宽松衣物。使用后完全关闭煤气龙头。

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6. Planning Investigations: Asking Scientific Questions | 设计探究：提出科学问题

A good investigation starts with a testable question that links two variables. For example: “How does temperature affect the germination of cress seeds?” The wording makes it clear what you will change and what you will measure.

好的探究始于一个将两个变量联系起来的可测试问题。例如：”温度如何影响水芹种子的萌发？” 这个问法清楚地表明了你要改变什么和测量什么。

Avoid questions that are too vague, such as “What makes seeds grow best?” Instead

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