📚 IGCSE Physics Experiment High-Frequency Topics and Answering Strategies | IGCSE物理实验高频考点与答题思路
Experiment questions are one of the most rewarding parts of IGCSE Physics: they test your practical skills, data handling and common sense. In the exam, you may be asked to describe a method, read an instrument or analyse a graph. This guide summarises the highest-frequency experiment topics and gives you a clear, step-by-step answering strategy.
实验题是 IGCSE 物理中最容易提分的部分之一：它考查实际操作思维、数据处理和常识判断。考试中，你可能会被要求描述实验步骤、读取仪器读数或分析图像。本文总结了最高频的实验考点，并给你一套清晰、可复制的答题思路。
1. Measuring Instruments and Readings | 测量仪器与读数
You must know the correct instrument for each physical quantity: metre ruler for length, measuring cylinder for volume, thermometer for temperature, stopwatch for time, balance for mass, ammeter for current and voltmeter for potential difference.
你必须知道每个物理量对应的正确仪器：长度用米尺，体积用量筒，温度用温度计，时间用秒表，质量用天平，电流用电流表，电压用电压表。
| Instrument 仪器 | Typical smallest division 常见最小刻度 | Reading note 读数注意 |
| Metre ruler 米尺 | 1 mm | Avoid parallax; keep eye vertical 避免视差，视线垂直 |
| Measuring cylinder 量筒 | 1 cm³ | Read the bottom of the meniscus 读凹液面底部 |
| Thermometer 温度计 | 1 °C or 0.5 °C | Bulb must be fully immersed 液泡完全浸没 |
| Stopwatch 秒表 | 0.01 s | Reaction time affects start and stop 反应时间影响启动和停止 |
When recording data, always include the unit and choose an appropriate number of decimal places. If a reading falls between two scale divisions, estimate the final digit to half a division if the scale is analogue.
记录数据时，一定要写单位并选择合适的小数位数。如果读数落在两个刻度之间，模拟式刻度要估读到最小刻度的一半。
2. Vernier Calipers and Micrometer Screw Gauge | 游标卡尺与千分尺
Vernier calipers measure lengths to 0.01 cm or 0.1 mm. To read them: write down the main scale value just before the zero of the vernier scale, then find the vernier line that exactly aligns with a main scale line and add it.
游标卡尺可以精确到 0.01 cm 或 0.1 mm。读数方法：先读出游标零刻度线之前最近的主尺刻度，再找出与主尺刻度对齐的游标刻度线，两者相加。
Reading = main scale + vernier aligned line × resolution
读数 = 主尺读数 + 对齐游标刻度 × 精确度
Example: main scale reads 2.3 cm and the 5th vernier line aligns. With a resolution of 0.01 cm, the reading is 2.3 + 5 × 0.01 = 2.35 cm. For a micrometer screw gauge, example: barrel shows 5.5 mm and the thimble scale shows 23, so total = 5.5 + 23 × 0.01 = 5.73 mm.
举例：主尺读数为 2.3 cm，游标第 5 条刻度线对齐，精确度为 0.01 cm，则读数为 2.3 + 5 × 0.01 = 2.35 cm。千分尺的例子：固定套筒读数为 5.5 mm，微分筒读数 23，则总读数为 5.5 + 23 × 0.01 = 5.73 mm。
Before using either instrument, check for zero error. If the reading is not zero with the jaws closed, subtract the zero error from every measurement.
使用这两种仪器前都要检查零误差。如果卡钳完全闭合时读数不为零，要在每次测量结果中减去零误差。
3. Density Measurement | 密度测量
Density is defined as mass per unit volume. The equation is shown below, where ρ represents density, m mass and V volume.
密度定义为单位体积的质量。公式如下，其中 ρ 表示密度，m 表示质量，V 表示体积。
ρ = m / V
For a regular solid, measure its mass with a balance and calculate volume from its dimensions using a ruler. For example, the volume of a rectangular block is length × width × height.
对于规则固体，用天平测量质量，用米尺测量长、宽、高等尺寸后计算体积。例如，长方体体积等于长 × 宽 × 高。
For an irregular solid, use the displacement method: record the initial water level in a measuring cylinder, fully immerse the object on a thin thread, then record the final level. The difference in levels equals the object’s volume. Remove air bubbles and read the meniscus at eye level.
对于不规则固体，使用排水法：先记录量筒中水的初始液面，用细线将物体完全浸没，再记录最终液面。两次液面之差就是物体的体积。要排开气泡，并让视线与凹液面齐平。
For a liquid, measure the mass of an empty measuring cylinder, add a known volume of liquid and measure again. Subtract the masses to find the liquid’s mass.
测量液体密度时，先称空量筒的质量，加入已知体积的液体后再称量，用两次质量之差得到液体质量。
4. Kinematics Experiments: Speed and Acceleration | 运动学实验：速度与加速度
In a ticker-tape experiment, a vibrating marker makes dots on a tape at a fixed time interval. If the frequency is 50 Hz, the time between adjacent dots is 0.02 s. To find the average speed, measure the length of a strip of dots and divide by the total time interval.
在打点计时器实验中，振动的打点器以固定时间间隔在纸带上打点。如果频率是 50 Hz，相邻两点之间的时间间隔就是 0.02 s。要测量平均速度，可以测量一段纸带的长度，再除以对应总时间。
To find acceleration from a ticker tape, calculate the speeds in two separated intervals and use a = (v − u) / t, or plot a velocity-time graph and measure its slope.
要在纸带实验中求加速度，可以计算两个间隔内物体的速度，再用 a = (v − u) / t，或者作出速度-时间图像并求斜率。
Light gates are more accurate because they remove reaction time. A card of known length passes through a gate; the timer records how long the card takes to pass, so speed = card length ÷ time. Two gates can measure two speeds and the distance between them, giving acceleration.
光电门更精确，因为它避免了反应时间。让一个已知长度的遮光片通过光电门，计时器记录遮光时间，则速度 = 遮光片长度 ÷ 时间。两个光电门可以测量两处速度和它们之间的距离，从而求出加速度。
5. Thermal Experiments: Heating Curves and Specific Heat Capacity | 热学实验：加热曲线与比热容
To measure specific heat capacity, an electric heater is placed inside or around a metal block of known mass. The ammeter, voltmeter and stopwatch give electrical energy E = IVt, while the thermometer gives the temperature rise ΔT.
测量比热容时，将电加热器放入或包裹住已知质量的金属块。电流表、电压表和秒表可以求出电能 E = IVt，温度计可以测出温升 ΔT。
E = IVt = mcΔT
c = IVt / (mΔT)
The main source of error is heat lost to the surroundings. Improvements include insulating the block, stirring the liquid, heating for a shorter time, and recording a cooling correction after switching off the heater.
实验的主要误差来源是向周围环境散热。改进方法包括：给金属块加保温层、搅拌液体、缩短加热时间，以及关闭加热器后记录冷却修正值。
A cooling curve is obtained by heating a liquid and then recording temperature every 30 seconds as it cools. The steeper the cooling curve, the faster heat is lost. A lid or insulation makes the curve shallower.
冷却曲线通过先把液体加热，然后每 30 秒记录一次温度得到。冷却曲线越陡，说明散热越快。加盖子或保温层会使曲线变得更平缓。
6. Optics Experiments: Reflection, Refraction and Lenses | 光学实验：反射、折射与透镜
For reflection, direct a ray box at a plane mirror and mark both the incident and reflected rays. Measure the angles to the normal using a protractor. The result should show that the angle of incidence equals the angle of reflection.
反射实验：让光线射向平面镜，标出入射光线和反射光线，用量角器测量它们与法线的夹角。实验结果应说明入射角等于反射角。
For refraction, pass a narrow ray through a semicircular glass block. Measure incident angle i and refracted angle r for several angles. Snell’s law can be checked using the ratio below. If i increases beyond the critical angle, total internal reflection occurs.
折射实验：让细光束射入半圆形玻璃砖，多次测量入射角 i 和折射角 r。可以用下面的比值验证折射定律。当入射角超过临界角时，会发生全反射。
n = sin i / sin r
For a converging lens, place an object in front of the lens and move a screen until a sharp image forms. Record object distance u and image distance v. The focal length can be found from the lens formula below, or by placing the object at 2f so that the image is the same size as the object.
凸透镜实验：将物体放在透镜前方，移动光屏直到出现清晰像，记录物距 u 和像距 v。可以用薄透镜公式求焦距，也可以把物体放在二倍焦距处，此时像与物等大。
1/f = 1/u + 1/v
7. Electricity Experiments: Circuits and I-V Characteristics | 电学实验：电路与伏安特性
To measure the resistance of a component, connect an ammeter in series with it and a voltmeter in parallel with it. A variable resistor controls the potential difference. For each setting, record current I and voltage V, then calculate R = V / I.
测量元件电阻时，将电流表与元件串联，电压表与元件并联。用滑动变阻器调节电压。在每种设置下记录电流 I 和电压 V，再计算 R = V / I。
R = V / I
For a metallic resistor at constant temperature, the I-V graph is a straight line through the origin. For a filament lamp, the graph curves because the filament becomes hotter and its resistance increases with current.
定值金属电阻在温度不变时，I-V 图像是过原点的直线。对小灯泡，图像会弯曲，因为灯丝温度升高，电阻随电流增大而增大。
In the exam, remember to open the switch when not taking readings to prevent the circuit from heating up. Choose suitable meter ranges and turn the variable resistor to maximum resistance before switching on.
考试中要注意：不读数时断开开关，防止电路过热；选择合适的电表量程；闭合开关前把
Published by TutorHao | IGCSE Physics Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导Cancel reply