📚 KS3 CIE Year 7 Waves Scheme of Work | KS3 CIE 七年级波的教学计划
Waves carry energy from one place to another without transferring matter. In Year 7, the CIE KS3 Science course introduces learners to the basic types, features and behaviours of waves, with a special focus on sound and light. This article provides a complete scheme of work, including key definitions, practical activities and common exam-style questions to help students master the topic.
波把能量从一个地方传递到另一个地方，而不会传递物质。在七年级，CIE KS3 科学课程向学生介绍波的基本类型、特征和表现，特别关注声音和光。本文提供完整的教学计划，包括关键定义、实验活动和常见考试题型，帮助学生掌握这一主题。
1. What Are Waves? | 什么是波？
A wave is a disturbance that transfers energy from one point to another. The material or field through which a wave travels is called the medium. Importantly, waves do not carry matter from place to place; they only carry energy.
波是一种将能量从一点传递到另一点的扰动。波传播所经过的材料或场称为介质。重要的是，波不会把物质从一个地方带到另一个地方；它们只传递能量。
For example, when a rope is shaken, a wave moves along the rope but the rope itself does not travel forward. Energy moves, while matter stays mostly in the same position.
例如，摇动绳子时，波沿着绳子传播，但绳子本身并没有向前移动。能量移动了，而物质基本停留在原位置。
2. Types of Waves: Transverse and Longitudinal | 波的种类：横波与纵波
Waves can be divided into two main types: transverse and longitudinal. In a transverse wave, the oscillations are perpendicular to the direction of energy transfer. Light waves and waves on a string are transverse.
波可以分为两大类：横波和纵波。在横波中，振动方向与能量传递方向垂直。光波和绳子上的波都是横波。
In a longitudinal wave, the oscillations are parallel to the direction of energy transfer. Sound waves are longitudinal, made up of compressions and rarefactions.
在纵波中，振动方向与能量传递方向平行。声波是纵波，由压缩区和稀疏区组成。
| Feature | 特征 | Transverse | 横波 | Longitudinal | 纵波 |
|---|---|---|
| Oscillation direction | 振动方向 | Perpendicular | 垂直 | Parallel | 平行 |
| Example | 例子 | Light, water waves | 光波、水波 | Sound | 声音 |
3. Key Features of a Wave | 波的关键特征
To describe a wave, we use several key terms. The wavelength is the distance between two matching points on a wave, such as two crests or two compressions. The amplitude is the maximum displacement from the rest position.
为了描述波，我们使用几个关键术语。波长是波上两个相同点之间的距离，例如两个波峰或两个压缩区之间的距离。振幅是偏离平衡位置的最大位移。
The frequency is the number of complete waves passing a point per second, measured in hertz (Hz). The period is the time taken for one complete wave, measured in seconds.
频率是每秒通过某一点的完整波的数量，以赫兹（Hz）为单位。周期是一个完整波所经过的时间，以秒为单位。
f = 1 ÷ T
seconds. For example, a wave with a period of 0.02 s has a frequency of 1 ÷ 0.02 = 50 Hz.
这里 f 是频率（赫兹），T 是周期（秒）。例如，周期为 0.02 秒的波，其频率为 1 ÷ 0.02 = 50 Hz。
4. Wave Speed and the Wave Equation | 波速与波动方程
n metres per second (m/s), f is frequency in hertz (Hz) and λ is wavelength in metres (m).
波速是波在介质中传播的快慢。它可以通过波动方程计算：速度 = 频率 × 波长。用符号表示为 v = f × λ，其中 v 是速度（米/秒，m/s），f 是频率（赫兹，Hz），λ 是波长（米，m）。
v = f × λ
0.68 m. Its speed is v = 500 × 0.68 = 340 m/s. This is roughly the speed of sound in air.
计算示例：一个声波的频率为 500 Hz，波长为 0.68 m。它的速度为 v = 500 × 0.68 = 340 m/s。这大约是声音在空气中的速度。
5. Sound Waves and How They Travel | 声波及其传播方式
Sound waves are produced by vibrating objects. These vibrations push and pull on nearby particles, creating a series of compressions and rarefactions. Sound is a longitudinal wave that requires a medium, such as air, water or a solid, to travel.
声波由振动的物体产生。这些振动推拉附近的粒子，形成一系列压缩区和稀疏区。声音是一种需要介质（如空气、水或固体）才能传播的纵波。
Sound cannot travel through a vacuum because there are no particles to vibrate. This is why astronauts in space cannot hear each other directly without radio communication.
声音无法在真空中传播，因为没有粒子可以振动。这就是为什么太空中的宇航员不能直接听到对方说话，必须依靠无线电通信。
6. The Ear and Hearing | 耳朵与听觉
The human ear converts sound waves into electrical signals that the brain interprets. The outer ear collects sound and funnels it down the ear canal to the eardrum. The eardrum vibrates, and these vibrations pass through three small bones to the cochlea.
人耳将声波转换成大脑可以解读的电信号。外耳收集声音并将其引导至耳道，到达鼓膜。鼓膜振动，这些振动通过三块小骨头传到耳蜗。
In the cochlea, tiny hair cells change vibrations into nerve impulses. Loud sounds can damage these hair cells, leading to hearing loss. Therefore, ear protection is important in noisy environments.
在耳蜗中，微小的毛细胞将振动转化为神经冲动。响亮的声音可能损伤这些毛细胞，导致听力下降。因此，在嘈杂环境中保护耳朵很重要。
7. Light Waves and Reflection | 光波与反射
Light is a transverse wave that can travel through a vacuum. Unlike sound, light does not need a medium. Light travels in straight lines, which explains why shadows form and why we can use ray diagrams to model reflection.
光是一种可以在真空中传播的横波。与声音不同，光不需要介质。光沿直线传播，这解释了为什么会有阴影，以及为什么我们可以用光线图来模拟反射。
The law of reflection states that the angle of incidence equals the angle of reflection. This law applies to smooth surfaces such as mirrors; rough surfaces scatter light in many directions.
反射定律指出入射角等于反射角。这一定律适用于镜子等光滑表面；粗糙表面则会把光散射到许多方向。
angle of incidence = angle of reflection
8. Comparing Sound and Light | 声音与光的比较
It is useful to compare sound and light to avoid confusion. Sound is a longitudinal wave, needs a medium, travels at about 340 m/s in air, and is detected by the ears. Light is a transverse wave, can travel through a vacuum, travels at about 300,000,000 m/s in a vacuum, and is detected by the eyes.
比较声音和光有助于避免混淆。声音是纵波，需要介质，在空气中的传播速度约为 340 m/s，由耳朵检测。光是横波，可以在真空中传播，在真空中的速度约为 300,000,000 m/s，由眼睛检测。
Because light is much faster than sound, we see lightning before we hear thunder during a storm, even though both are produced at the same moment.
由于光比声音快得多，暴风雨时我们先看到闪电，后听到雷声，尽管两者是同时产生的。
9. Practical Skills and Investigations | 实验技能与探究
A typical practical for this topic involves using a slinky to demonstrate transverse and longitudinal waves. Students can stretch the slinky on the floor and move one end side to side for transverse waves, or push and pull for longitudinal waves.
本主题的典型实验是用螺旋弹簧演示横波和纵波。学生可以在地板上拉长弹簧，左右移动一端来产生横波，或者推拉一端来产生纵波。
he echo, then use speed = distance ÷ time. The distance is twice the distance to the wall.
另一个探究实验利用响亮的拍手声和墙壁的回声来测量声速。学生记录拍手声与回声之间的时间间隔，然后用速度 = 距离 ÷ 时间计算。距离是到墙壁距离的两倍。
When recording results, students should use a table with clear headings and repeat measurements to improve reliability.
记录结果时，学生应使用带清晰表头的表格，并重复测量以提高可靠性。
10. Common Misconceptions | 常见误区
Many learners believe that waves carry matter, or that in a sound wave particles travel all the way from the source to the ear. In fact, particles only vibrate back and forth; energy passes, matter does not.
许多学生误以为波传递物质，或者认为声波中的粒子从声源一直跑到耳朵。实际上，粒子只是来回振动；能量传递了，物质没有。
Another common error is thinking that larger amplitude means faster wave speed. Amplitude affects loudness or energy, but wave speed depends only on the medium for sound.
另一个常见错误是认为振幅越大波速越快。振幅影响响度或能量，但声波的波速只取决于介质。
Students also sometimes write 'Hz' as a unit for wavelength. The correct unit for wavelength is the metre. Frequency is measured in hertz, not wavelength.
学生有时把 "Hz" 写成长度的单位。波长的正确单位是米。频率的单位是赫兹，而不是波长。
11. Exam-style Questions | 考试题型示例
Question 1: A wave has a frequency of 20 Hz and a wavelength of 2 m. Calculate its speed.
问题 1：一个波的频率为 20 Hz，波长为 2 m。计算它的速度。
Answer: v = f × λ = 20 × 2 = 40 m/s.
答案：v = f × λ = 20 × 2 = 40 m/s。
Question 2: Explain why sound cannot travel through a vacuum.
问题 2：解释为什么声音不能在真空中传播。
Answer: Sound is a longitudinal wave that requires particles to vibrate. A vacuum contains no particles, so the vibrations cannot be passed on.
答案：声音是一种需要粒子振动的纵波。真空中没有粒子，因此振动无法传递下去。
12. Revision Checklist | 复习清单
Before the test, make sure you can define a wave, compare transverse and longitudinal waves, label wavelength and amplitude, use the wave equation, explain how sound and light travel, describe the law of reflection, and state why sound cannot travel through a vacuum.
考试前，请确保你能够定义波，比较横波和纵波，标出波长和振幅，使用波动方程，解释声音和光的传播方式，描述反射定律，并说明为什么声音不能在真空中传播。
Practise drawing ray diagrams for reflection and drawing a waveform with labelled crest, trough, wavelength and amplitude. Try past paper questions and check your answers using the mark scheme.
练习绘制反射光线图，并画出标注了波峰、波谷、波长和振幅的波形图。尝试做历年真题，并用评分标准检查答案。
Published by TutorHao | Physics Revision Series | aleveler.com
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