毛毛,科学的解释是加盐后降低冰雪的冰点儿。
这里一月,二月雪都不算多,不过一到三月就多了起来。几乎天天下。这里的居家可以交二百多块钱包一冬天免费清雪(只是Drive way 上)。相信城市道路也是如此,市政每一个冬天把一定的资金交给清雪公司。然后就只剩睡大觉了。
Colligative Properties and Freezing Point Depression
If you live in an area with a cold and icy winter, you have probably experienced salt on sidewalks and roads, used to melt the ice and snow and keep it from refreezing. Salt is also used to make homemade ice cream. In both cases, the salt works by lowering the melting or freezing point of water. The effect is termed 'freezing point depression'.
How Freezing Point Depression Works
When you add salt to water, you introduce dissolved foreign particles into the water. The freezing point of water becomes lower as more particles are added until the point where the salt stops dissolving. For a solution of table salt (sodium chloride, NaCl) in water, this temperature is -21°C (-6°F) under controlled lab conditions. In the real world, on a real sidewalk, sodium chloride can melt ice only down to about -9°C (15°F).
[ 本帖最后由 晔阳 于 08-3-16 12:23 编辑 ] |