First, the salt content of fresh water and salt water is different:
Fresh water:
1, almost salt-free water or almost unpolluted water.
Salt water:
1, salt water, usually seawater or NaCl solution. Generally, the content of dissolved salt in seawater is 35,000 mg/L (3.5%), of which chloride is 20,000 mg/L, mainly table salt, and there are other kinds of brines, some of which contain 300,000 mg/L of dissolved salt.
Second, the distribution of fresh water and salt water storage areas is different:
Fresh water:
1, the total amount of water on the earth is1400 million cubic kilometers. There is a lot of water on the earth, and the fresh water reserves only account for 2.53% of the global total water, of which 68.7% belong to solid glaciers, which are distributed in the mountains and polar regions that are difficult to use, and some fresh water is buried deep underground and difficult to exploit.
2. Only groundwater, lake fresh water and river bed water can be directly utilized by human beings, and the sum of the three accounts for 0.77% of the total water volume of the earth. At present, the amount of fresh water resources used by human beings is increasing. Except the deep groundwater that can't be exploited, the water that humans can actually use only accounts for about 0.26% of the total water of the earth.
Salt water:
It mainly exists in the ocean, Pacific Ocean, Pacific Ocean, Indian Ocean and other sea areas, and the water quality is salty water with very high salt content.
Extended data:
The functions of salt water are very diverse:
1. When there is dust or dirt in the house, sprinkle some salt water in the dirty place to achieve the sterilization effect. The principle is to use the osmotic pressure of salt water to make bacteria lose water. In addition, if you sprinkle some salt water in the corner when cleaning at home, you can also avoid the invasion of mosquitoes such as cockroaches. So you don't have to buy pesticides, and it seems to have the effect of preventing global warming.
2, gargling with salt water can eliminate the odor in the mouth and achieve a clean effect. It is said that drinking a glass of salt water when the stomach is uncomfortable can eliminate gastric acid and achieve acid-base neutralization. In fact, it may be that salt water dilutes gastric acid instead of neutralizing gastric acid, because the salt in salt water is mainly neutral sodium chloride.
References:
Baidu encyclopedia-danshui
References:
Baidu encyclopedia-salt water