📚 Year 10 WJEC Physics Key Experiment and Practical Skills | Year 10 WJEC 物理实验与实践考核要点
Practical work is at the heart of WJEC GCSE Physics. In Year 10, you will carry out a range of experiments that build your understanding of key concepts and prepare you for the practical assessment. This article summarises the essential experimental skills and the most common practical tasks you need to master, from planning an investigation to analysing data and evaluating results.
实验是 WJEC 物理课程的核心。在十年级，你将进行一系列实验，加深对重要概念的理解，并为实践考核做好准备。本文总结了必备的实验技能和最常见的实验任务，从规划调查、分析数据到评估结果，帮助你全面掌握实验要点。
1. Planning Investigations | 规划实验调查
A good experiment starts with a clear plan. You need to identify the independent variable (the thing you change), the dependent variable (the thing you measure) and at least two control variables (things you keep the same). Always state your aim and write a hypothesis linking the variables.
一个好的实验始于清晰的计划。你需要确定自变量（你改变的量）、因变量（你测量的量）以及至少两个控制变量（保持相同的量）。始终要陈述实验目的，并写出连接这两个变量的假设。
When planning, describe the equipment, draw a labelled diagram, and explain how you will measure each variable. State the range of measurements and the intervals you will use. For example, if you investigate how the length of a wire affects its resistance, you might choose wire lengths from 10 cm to 100 cm in 10 cm steps.
规划时，要描述所用器材，画标注的示意图，并说明如何测量每个变量。还要说明测量的范围和间隔。例如，如果你研究导线长度如何影响电阻，你可能会选择从10厘米到100厘米的长度，以10厘米为步长。
Always include a risk assessment: identify hazards (such as hot objects, sharp edges, electrical risks) and explain how you will control them (e.g. use low voltage, wear goggles, avoid touching hot surfaces).
始终要进行风险评估：识别危险（例如热物体、锋利边缘、电气风险），并解释如何控制它们（如使用低电压、佩戴护目镜、避免触摸热表面）。
2. Making Measurements and Using Equipment | 进行测量和使用器材
tal balance (resolution typically ±0.01 g). For time, a stopwatch is common, but human reaction time (±0.1 s– mperature, use a thermometer with a suitable scale, reading to the nearest 0.5 °C or 1 °C.
精确的测量是基础。测量长度时，使用直尺（分辨率为±1毫米）或游标卡尺以获得更高精度。测量质量时，使用电子天平（分辨率通常为±0.01克）。测量时间时，秒表是常用的，但必须考虑人的反应时间（±0.1秒至0.3秒）。测量温度时，使用合适量程的温度计，读出最接近的0.5°C或1°C。
In electrical experiments, ammeters and voltmeters must be connected correctly: ammeters in series, voltmeters in parallel. Always choose an appropriate scale to get the most accurate reading. When using a multimeter, ensure you select the right function (DC voltage, resistance, etc.).
在电学实验中，电流表必须串联，电压表必须并联。始终选择合适的量程以获得最准确的读数。使用万用表时，确保选择正确的功能（直流电压、电阻等）。
Record raw data in a table as you go. Each column should have a clear heading with the unit, e.g. "Length / cm", and values should be written to the same number of decimal places consistent with the instrument's resolution.
边实验边将原始数据记录在表格中。每一列应有清晰的表头并注明单位，例如“长度 / cm”，且数值应根据仪器的分辨率保持相同的小数位数。
3. Repeats and Reliability | 重复实验与可信度
To improve reliability, take repeat readings and calculate a mean. Usually three measurements are sufficient. If one reading is anomalous (does not fit the pattern), ignore it when calculating the mean. Anomalous results can arise from misreading an instrument, a change in conditions, or a simple mistake.
为了提高可信度，应进行重复读数并计算平均值。通常三次测量足够。如果某个读数是异常值（不符合规律），在计算平均值时将其剔除。异常值可能源于读错仪器、条件变化或简单的失误。
Repeats help reduce random errors. However, they cannot eliminate systematic errors, which occur when there is a fault in equipment or a consistent bias in measurement (e.g. a balance that is not zeroed).
重复实验有助于减少随机误差。但它们无法消除系统误差，系统误差是由于仪器故障或测量中持续存在偏差（例如天平未调零）而产生的。
4. Controlling Variables and Fair Testing | 控制变量与公平测试
A fair test means that only the independent variable is deliberately changed; all other variables that might affect the dependent variable are kept constant. This allows you to confidently link any changes in the dependent variable to the changes in the independent variable.
公平测试意味着只有自变量被有意改变，所有其他可能影响因变量的变量都保持不变。这样，你就可以确信因变量的任何变化都是由自变量的变化引起的。
For example, when investigating the effect of force on the extension of a spring, you must use the same spring each time and avoid exceeding its elastic limit. Temperature can affect the spring's stiffness, so keep the temperature constant. In circuit investigations, the temperature of components can drift; briefly switch off between readings to minimise heating effects.
例如，在研究力对弹簧伸长的影响时，每次必须使用同一弹簧，且不能超过其弹性极限。温度会影响弹簧的刚度，因此要保持温度恒定。在电路实验中，元件的温度可能会漂移；在每次读数之间短暂关闭电路以减少热效应。
5. Graph Drawing and Data Presentation | 绘图和数据呈现
Graphs are a powerful way to display results. Use graph paper or software; label axes clearly with quantity and unit, e.g. "Voltage / V". The independent variable goes on the x‑axis, the dependent on the y‑axis.
图表是展示结果的有力方式。使用坐标纸或软件；清晰地标注轴，写上物理量和单位，例如“电压 / V”。自变量画在x轴上，因变量画在y轴上。
Choose a scale that uses more than half of the grid in both directions; use sensible intervals like 1, 2, 5, or 10 per large square. Plot points accurately with small crosses. Draw a line of best fit, which may be a straight line or a smooth curve. Do not join the dots with straight segments. If the line should go through the origin, make sure it does.
选择一种比例，使两个方向都用到超过一半的格子；使用合理的间隔，如每大格代表1、2、5或10。用小叉号精确描点。画出最佳拟合线，它可能是直线，也可能是光滑曲线。不要用直线段连接各点。如果线应该经过原点，确保它经过。
When the graph is a straight line through the origin, the dependent variable is directly proportional to the independent variable. You can use the gradient to find constants such as resistance (V–I graph) or spring constant (force–extension graph).
当图形是一条通过原点的直线时，因变量与自变量成正比。你可以利用斜率求出如电阻（V–I图）或弹簧常数（力–伸长图）等常量。
6. Key Experiment: Investigating Density | 关键实验：测量密度
uler). For an irregular solid, use a displacement method: fill a measuring cylinder partly with water, note the initial volume, then gently lower the solid into the water and note the new volume; the difference is the volume of the solid.
要测量固体的密度，先用天平测质量。对于规则形状，用直尺测量长度、宽度和高度并计算体积（长×宽×高）。对于不规则固体，使用排水法：在量筒中加入适量水，记录初始体积，然后轻轻放入固体，记录新的体积；两次体积差即为固体的体积。
unit is g/cm³ or kg/m³. For a liquid, measure mass of an empty measuring cylinder, then pour in the liquid, measure total mass, and subtract to get the liquid's mass. The volume is read directly from the cylinder.
密度ρ的计算公式为 ρ = m / V。单位是g/cm³或kg/m³。对于液体，先测量空量筒的质量，倒入液体后测量总质量，相减得到液体的质量。体积直接从量筒读出。
Improve accuracy: use a more precise balance; for irregular solids, use a smaller measuring cylinder if the object is small; avoid air bubbles on the object; take repeat readings.
提高精确度：使用更精密的天平；对于不规则固体，若物体较小，使用更细的量筒；避免物体表面有气泡；进行重复读数。
7. Key Experiment: Hooke's Law and Springs | 关键实验：胡克定律与弹簧
Suspend a spring from a clamp. Attach a mass hanger and add slotted masses one at a time. Measure the spring's length for each load using a ruler. The extension is the difference between the stretched length and the original unstretched length. Ensure the ruler is vertical and read at eye level to avoid parallax error.
将弹簧悬挂在铁架上。加上砝码挂架，并逐个增加槽码。用直尺测量每次加载后弹簧的长度。伸长量是拉伸后长度与原始未拉伸长度的差值。确保直尺竖直，并在视线水平处读数以避免视差误差。
Plot force (weight of masses, F = mg) on the x‑axis and extension on the y‑axis. A straight line through the origin shows Hooke' much mass, the spring will be permanently deformed - the elastic limit has been exceeded.
将力（砝码的重量，F = mg）画在x轴上，伸长量画在y轴上。通过原点的直线表明遵守胡克定律：F = kx，其中k是弹簧常数（图线斜率，单位N/m）。如果加载过重，弹簧会永久变形——已超过弹性极限。
A common mistake is measuring from the end of the spring, which might slip; always use a pointer attached to the bottom of the spring to take readings from the ruler. Take repeat readings for each mass and check that the spring returns to its original length after removing the loads.
常见错误是从弹簧末端测量，而那里可能滑动；始终使用固定在弹簧底部的指针，从直尺上读数。每个质量重复测量，并在移除负载后检查弹簧是否恢复原长。
8. Key Experiment: I-V Characteristics | 关键实验：电流-电压特性
Set up a circuit with a power supply, ammeter in series, and a voltmeter in parallel across the component being tested. Use a variable resistor (rheostat) to change the current, or vary the supply voltage. Measure pairs of current and voltage.
搭建电路，包括电源、串联的电流表以及与待测元件并联的电压表。使用可变电阻器（变阻器）改变电流，或改变电源电压。测量一组组电流和电压。
For a fixed resistor at constant temperature, the I-V graph is a straight line through the origin, showing it is ohmic. For a filament lamp, the line is curved because the filament heats up and its resistance increases with temperature. For a diode, current flows only in one direction; the forward bias needs about 0.6V before significant current flows.
在恒定温度下，定值电阻的I-V图是一条通过原点的直线，表明其是欧姆导体。对于白炽灯，图线弯曲，因为灯丝发热，其电阻随温度升高而增大。对于二极管，电流仅在一个方向流过；正向偏置电压约0.6V时才会有明显电流。
Always include a protective resistor in series with the diode to limit current. Take many readings near the origin and at higher voltages. Switch off between readings to keep the component cool.
始终与二极管串联一个保护电阻以限制电流。在原点附近和较高电压处多记录几组读数。在读数之间关闭电源以保持元件冷却。
9. Key Experiment: Waves on a String / Ripple Tank | 关键实验：弦上的波/水波槽
length by measuring the length of several half-wavelengths with a metre ruler and dividing. The wave speed v can be found using v = fλ.
对于弦上的波：使用连接是信号发生器的振动器。调整频率直至形成驻波。用米尺测量几个半波长的长度并除以相应数目以计算波长。波速v可以用v = fλ求出。
In a ripple tank, create circular or plane waves. Illuminate the tank with a stroboscope to freeze the wave pattern. Measure wavelength from the projected image and frequency using the count of waves per second or from the signal generator settings.
在水波槽中，产生圆形波或平面波。用频闪灯照亮水波槽使波形“定格”。从投影图像测量波长，并利用每秒的波数或信号发生器的设置来获得频率。
Accuracy tips: for the string, ensure the string is horizontal and the pulley is friction-free; for ripple tank, measure a distance spanning several wavelengths then divide, rather than just one wavelength, to reduce percentage error.
提高精度技巧：对于弦，确保弦水平且滑轮无摩擦；对于水波槽，测量跨越几个波长的距离后再除以波长的个数，而不是只测量一个波长，以减少百分比误差。
10. Handling Errors and Uncertainties | 处理误差与不确定度
is ± the last digit (unless specified otherwise). When you take repeat readings, the spread of the values gives an idea of random uncertainty; you can calculate the range (max − min) and use half the range as an estimate.
每一次测量都存在一定的不确定度。对于单次读数，不确定度至少是最小刻度的一半。对于数字仪器，一般是±最后一位数字（除非另有说明）。当你进行重复读数时，数值的分布范围给出了随机不确定度的概念；你可以计算极差（最大−最小），并用极差的一半作为估计。
es. For product or quotient, add percentage uncertainties. Always quote your final result with the appropriate uncertainty, e.g. R = 15.0 ± 0.5 Ω.
当物理量由两个或更多测量值计算得出时，你需要合成不确定度。加减运算时，将绝对不确定度相加。乘除运算时，将百分比不确定度相加。最后的结果务必加上相应的不确定度，例如 R = 15.0 ± 0.5 Ω。
In your evaluation, comment on the main sources of error in your experiment and suggest how to reduce them. Common improvements: use a data logger to reduce reaction time error, use a longer measurement distance to reduce percentage error, or screen the apparatus from draughts.
在评价中，评论实验的主要误差来源，并建议如何减小它们。常见的改进方法：使用数据记录仪以减少反应时间误差，使用更长的测量距离以降低百分比误差，或遮挡装置避免气流。
11. Conclusion and Evaluation | 结论与评价
Your conclusion should refer back to the hypothesis and the data. State the relationship between variables in words, and back it up with evidence from the graph or table. If the data supports a direct proportion, say so and quote the gradient where appropriate.
你的结论应回顾假设和数据。用文字陈述变量之间的关系，并用图或表格中的证据支持。如果数据支持正比关系，要明确指出，并在适当的时候给出斜率。
The evaluation must discuss the reliability and accuracy of results. Did repeats show consistency? Were points close to the line of best fit? Mention any anomalies and explain possible reasons. Then propose specific, realistic improvements to the method - avoid vague statements like "be more careful".
评价部分必须讨论结果的可靠性和准确性。重复测量是否显示了一致性？数据点是否靠近最佳拟合线？提及任何异常值并解释可能的原因。然后提出具体、可行的改进方法——避免诸如“更加小心”之类的含糊说法。
A strong evaluation shows scientific thinking. For instance, " e of uncertainty was reading the analogue voltmeter; a digital multimeter would give readings to ±0.01 V, reducing the error."
一个出色的评价体现了科学思维。例如：“各点几乎落在通过原点的直线上（R² = 0.99），证实电流与电压成正比。不确定度的主要来源是读取模拟电压表；数字万用表可读到±0.01 V，从而减小误差。”
12. Practical Exam Tips and Common Pitfalls | 实验考核技巧与常见失误
During the practical assessment, read the instructions carefully. Plan your time: set up the apparatus, take trial readings, then record data systematically. Never rush to dismantle the equipment – you may need to recheck a reading.
在实验考核中，仔细阅读说明。规划好时间：搭建器材，进行试读，然后系统记录数据。千万别匆忙拆掉装置——你可能需要重新核对某个读数。
Common pitfalls include: not zeroing instruments (balance, newton meter), connecting ammeter in parallel, forgetting to set the variable resistor correctly, taking readings over too narrow a range, and using an inappropriate scale on a graph. Always label the axes with units and use a sharp pencil for plotting.
常见失误包括：未将仪器调零（天平、弹簧秤），将电流表并联连接，忘记正确设置变阻器，读数范围过窄，以及图表标度选用不当。始终在坐标轴上标明单位，并用尖铅笔绘图。
Finally, in the written exam, questions about practicals often ask you to describe how you would investigate a relationship or to explain why a certain technique is used. Practise answering these by referring to specific apparatus and details – the examiners want to see that you have actually done the experiments.
最后，在笔试中，实验相关题目常常要求你描述如何调查某个关系，或解释为什么使用某种技术。练习回答这类问题时，要提及具体器材和细节——考官希望看到你真正做过实验。
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