一般说来,水温降到0℃,水就会结成冰。那么,是否所有的水其温度降到0℃,就一定会结冰呢? 不一定。气象学家在观测云的时候,发现有一种云叫混合云,云的中上部温度已经达到-20℃至-30℃,甚至-40℃,还有许多并没有冻结的雨滴。据说,有的科学家成功地使纯净无瑕的水冷却到-70℃仍未冻结成冰。这种温度低于0℃还不冻结的水叫过冷却水。 In general, when the water temperature drops to 0°C, the water will form ice. Then, will all the water fall to 0°C and it will certainly freeze? Not necessarily. When meteorologists observed the cloud, they discovered that there was a cloud called a hybrid cloud. The temperature in the middle and upper part of the cloud had reached -20°C to -30°C, and even -40°C. There were many raindrops that did not freeze. It is said that some scientists have succeeded in cooling pure and unblemished water to -70°C and have not yet frozen into ice. The water that does not freeze when the temperature is lower than 0°C is called supercooled water.