据传有一年夏天,洋人宴请林则徐,其中一道甜点为冰激凌,因其上“白气”不断,林则徐以为必烫故以嘴吹之,谁知入口却冷,洋人笑以为柄.林则徐声色不动,过得几日,回请洋人,其中一道热汤刚刚煮沸,浮有厚油,无一丝“白气”冒出,林则徐热情请之,洋人一口吞下一勺,顿时龇牙咧嘴,哈哈有声,不停乱弹,出尽洋相.原来厚油将热汤覆盖住了,减慢了热汤中水的蒸发,所以看不到水蒸气液化形成的“白气”.这里就谈到了覆盖影响蒸发的 According to legend, one summer of the year, foreigners were invited to Lin Zexu. One of the desserts was ice-cream. Lin Zexu thought it was too hot because of the “white gas” Immobile, flies a few days, back to foreigners, one of the hot soup just boiled, floating thick oil, no trace of “white gas,” “emerge, Lin Zexu enthusiasm please foreigners swallow a spoon, suddenly stooped, Ha ha sound, stop chaos, out of the ocean. The original thick oil will cover the hot soup, slowing the evaporation of water in the soup, so do not see the formation of liquefied gas ”white gas." Here to talk about To cover the impact of evaporation