【英语时差8,16】在冬季，听声音的季节变换

For those of us who live in the northern part of the country, arguably no other season transforms the environment quite as much as winter. Snow makes the world over so that it's hardly recognizable.   The scenery isn't the only thing that changes during the winter season, though. Today's Moment of Science is about how winter transforms the way the environment sounds.

Before that first snowfall, when the ground has hardened from the cold temperatures, sound experiences its first winter makeover. Just as smooth, hard surfaces like glass reflect light, the smoother and harder a surface, the better it reflects sound. The harder ground of the early winter season absorbs less sound. Thus, acoustic¹ waves retain more of their energy when they reflect off the ground. As a result, early winter sounds are louder and clearer. Pay attention, and you might notice that everything sounds a little bit crisper.

After the first snow, sound is made over again. The porousness³ of snow makes it absorb sound. Specifically, snow tends to absorb higher frequency acoustical⁴ waves. As a result, sound becomes quieter and somewhat distorted. Without looking out your window, you might know it snowed simply from noticing how bird calls or passing cars are slightly muffled⁵.

If the snow lingers or it is topped with rain, winter sound will be made over once more. As snow hardens, it becomes smoother, less porous². As you can probably guess, this means that the snow will, like the hardened ground that preceded it, reflect sound well. Sound will once again be crisp and clear.

This winter, see if you can hear how the season transforms sound, as well as the scenery.  

 

1 acoustic   

adj.听觉的，声音的；(乐器)原声的

参考例句：

• The hall has a fine acoustic.这个大厅的传音效果很好。
• Animals use a whole rang of acoustic, visual,and chemical signals in their systems of communication.动物利用各种各样的听觉、视觉和化学信号来进行交流。

2 porous   

adj.可渗透的，多孔的

参考例句：

• He added sand to the soil to make it more porous.他往土里掺沙子以提高渗水性能。
• The shell has to be slightly porous to enable oxygen to pass in.外壳不得不有些细小的孔以便能使氧气通过。

3 porousness   

多孔性

参考例句：

4 acoustical   

adj. 听觉的，声学的，音响学的

参考例句：

• This system can set up acoustical resonances. 这种系统能产生共鸣。
• The relevance of acoustical principles is by no means limited to sound and hearing. 声学原理并不仅仅适用于声音和听觉。

5 muffled   

adj.（声音）被隔的；听不太清的；（衣服）裹严的；蒙住的v.压抑，捂住( muffle的过去式和过去分词 )；用厚厚的衣帽包着（自己）

参考例句：

• muffled voices from the next room 从隔壁房间里传来的沉闷声音
• There was a muffled explosion somewhere on their right. 在他们的右面什么地方有一声沉闷的爆炸声。 来自《简明英汉词典》