【英语时差8,16】为什么天冷车窗会起雾？（上）

To get at what is going on here first we need to recall what the temperature of an object says about that object’s atoms. The atoms of any object are always in motion jiggling around, and the temperature of an object is a measurement of the average jiggling of that object’s atoms: the hotter the object the faster the average jiggling of its atoms. If the temperature of air is dropped below a specific temperature, called the dew point, then the water vapor¹ in that air condenses into a fog as the water molecules² jiggle around slower and slower and eventually clump³ together.

1 vapor   

n.蒸汽，雾气

参考例句：

• The cold wind condenses vapor into rain.冷风使水蒸气凝结成雨。
• This new machine sometimes transpires a lot of hot vapor.这部机器有时排出大量的热气。

2 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

3 clump   

n.树丛，草丛；vi.用沉重的脚步行走

参考例句：

• A stream meandered gently through a clump of trees.一条小溪从树丛中蜿蜒穿过。
• It was as if he had hacked with his thick boots at a clump of bluebells.仿佛他用自己的厚靴子无情地践踏了一丛野风信子。