洗洁精，为什么能洗掉油？

Oil and water do not mix. 油和水本来是不相溶的。 Dish soap has special small molecules. 洗洁精里有特殊的小分子。 One end likes water, the other likes oil. 一头爱水，另一头爱油。 The oil end grabs the oil drops. 爱油的一头抓住油滴。 The water end holds the drops in water. 爱水的一头把油滴带进水里。 Then the oil is washed away. 这样油就被水冲走了。 That is why dishes get clean. 碗盘就这样被洗干净了。