第五课

5. Sound transmission声音的传播

1．Why can we hear the bell in different parts of the school?为什么我们在学校的不同地方都能听到铃声？

2．Material package材料包

3．Stone, paper cups, cotton, wool, wire, copper wire, etc.  石块、纸杯、棉线、毛线、铁丝、铜丝等。

4．Activity process活动过程

5．What objects can sound propagate in?声音可以在哪些物体中传播?

6．In which direction does the sound travel?声音向哪个方向传播呢?

7．Data Card资料卡

8．1.When the object reports sound, it will cause the surrounding air to vibrate, forming the sound "wave ".物体报动发声时，会引起用围的空气也跟着振动，形成声音的“波浪”。

9．2.Just as water waves can travel far away, so can sound waves.像水波可以向远处传播一样，声波也可以向远处传播。

10．Sound can be transmitted in all directions in the gas, liquid, and solid声音可以在气体、液体和固体中向各个方向传播。

11．Playing "earth phone" is better than using what kind of material to spread sound.玩一玩“土电话”，比一比用哪种材料传播声音的效果更好。

12．The length of the line should be the same.线的长短要一样。

13．Try another material.换一种材料再试试。

14．Outreach activities拓展活动

15．Review the information for the cause of the echo. 查阅资料，了解回声产生的原因。