KS3 CIE Electromagnet Graph Question Mark Scheme | KS3 CIE 电磁铁图形题评分标准

📚 KS3 CIE Electromagnet Graph Question Mark Scheme | KS3 CIE 电磁铁图形题评分标准

In KS3 CIE Science, electromagnet graph questions often ask you to plot experimental data, describe the relationship between current and magnetic strength, and use the graph to make predictions. The mark scheme rewards accurate graph skills, correct scientific language, and the ability to interpret a best-fit line.

在 KS3 CIE 科学中，电磁铁图形题通常要求你描点绘制实验数据、描述电流与磁力之间的关系，并利用图形进行预测。评分标准对准确的作图技能、正确的科学语言以及解读最佳拟合线的能力给予奖励。

1. Understanding the Experiment | 理解实验

A common investigation changes the current in a coil and counts the number of paperclips the electromagnet can pick up. The current is the independent variable and the number of paperclips is the dependent variable.

常见的探究实验改变线圈中的电流，并数出电磁铁能够吸起的回形针数量。电流是自变量，回形针数量是因变量。

The circuit includes a power supply, an ammeter connected in series, a variable resistor and a coil around an iron core. Changing the variable resistor alters the current flowing through the coil.

电路包括电源、串联的电流表、可变电阻和绕在铁芯上的线圈。改变可变电阻可以改变流过线圈的电流。

You should also keep control variables constant, such as the number of coils, the core material and the paperclip size, so the test is fair.

你还需要保持控制变量不变，例如线圈匝数、铁芯材料和回形针的大小，以确保测试公平。

• Independent variable: current / A | 自变量：电流 / A
• Dependent variable: number of paperclips | 因变量：回形针数量
• Control variables: number of turns, core type, paperclip type | 控制变量：匝数、铁芯类型、回形针类型

2. Plotting the Graph | 绘制图形

Plot current on the x-axis and number of paperclips on the y-axis. Marks are given for accurately placing each data point with a small neat cross.

将电流标在 x 轴，回形针数量标在 y 轴。准确放置每个数据点并用小而清晰的十字标记可得分。

For example, a data table might show 0 A gives 0 paperclips, 1 A gives 4 paperclips, 2 A gives 8 paperclips, and so on. Plot each pair carefully.

例如，数据表可能显示 0 A 对应 0 个回形针，1 A 对应 4 个回形针，2 A 对应 8 个回形针，以此类推。仔细描出每一对数据。

Do not use large dots because they can hide the exact position. If you make an error, erase cleanly and plot again.

不要使用大圆点，因为它们会遮盖准确位置。如果画错了，擦干净后重新描点。

3. Labelling Axes and Units | 坐标轴标签与单位

The mark scheme checks that both axes are labelled with the quantity and unit. Write ‘Current / A’ on the x-axis and ‘Number of paperclips’ on the y-axis.

评分标准检查两个坐标轴是否标出了物理量和单位。在 x 轴写 ‘Current / A’，在 y 轴写 ‘Number of paperclips’。

The unit is written after a forward slash, for example A for amps. If the unit is missing, one mark is usually lost, even if the graph is correctly plotted.

单位写在斜杠后面，例如 A 表示安培。如果缺少单位，即使图形绘制正确，通常也会扣掉一分。

The label must match the data table heading exactly. If the table says ‘Current in amps’, write ‘Current / A’ on the axis.

标签必须与数据表标题完全一致。如果数据表写的是 ‘Current in amps’，那么轴上应写 ‘Current / A’。

4. Choosing a Sensible Scale | 选择合理刻度

The scale should increase in equal steps and use at least half of the graph grid. For current values from 0 to 5 A, a scale of 2 cm = 1 A is suitable.

刻度应按等间距递增，并至少使用图纸网格的一半。

Published by TutorHao | KS3 Revision Series | aleveler.com

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