声音通过材料传播
Sound Travels Through Materials
认识到声音的振动需要通过介质（固体、液体或气体）传到耳朵
Recognise that vibrations from sounds travel through a medium (solid, liquid, or gas) to the ear
学习证据 / Evidence
- 解释声音的振动需要介质（材料）才能传播，不能在真空中传播
- 举出声音通过不同介质传播的例子，如空气、水、固体
- 描述土电话（绳子电话）的工作原理：说话声使杯子振动，振动沿着绳子传到另一个杯子
- Explain that sound vibrations need a material (medium) to travel through — they can't travel in a vacuum
- Give examples of sound travelling through different media: air, water, solid objects
- Describe how a string telephone works: voice vibrates the cup, vibrations travel along the string to the other cup
评估问题 / Assessment
{{name}}能解释为什么隔着墙能听到别人说话，以及为什么在水下游泳时还能听到声音吗？
Can {{name}} explain why you can hear someone talking through a wall, and why sound travels through water when you're swimming underwater?