The temperature above 100 degrees is gas, below 0- 100 degrees is liquid and below 0 degrees is solid.
Water exists in nature in three forms: solid, liquid and gas. Specifically, solids include ice, snow, frost and hail; Liquid state includes clouds, rain, fog and dew; The gaseous state is mainly water vapor.
Water cycle refers to the continuous movement of water in nature through various links in hydrosphere, atmosphere, lithosphere and biosphere. There are three forms of water cycle: the cycle between ocean and land (land-sea cycle is a big cycle), the cycle between land and land (inland cycle) and the cycle between ocean and ocean (ocean cycle).
Land circulation (large circulation) mainly includes evaporation (water vapor), water vapor transport (clouds and fog), precipitation (rain, dew, snow, frost and hail) and runoff (surface and underground); Inland circulation is mainly: evaporation and plant transpiration, precipitation; Ocean circulation mainly includes evaporation and precipitation.
The water cycle is of great significance to the earth, mainly including:
1, keep all kinds of water bodies constantly updated?
2. Maintain the dynamic balance of global water resources.
3. Promote the material movement in nature?
4. Is it the connection between land and sea?
5, shaping the surface morphology
Extended data
The importance of water:
All life activities originate from water. On earth, where there is water, there is life. Water in human body accounts for about 65% of body weight.
Without water, nutrients in food can't be absorbed, waste can't be excreted, and drugs can't reach the effective parts. Once the human body is short of water, the consequences are very serious. Lack of water 1%-2%, feeling thirsty; Lack of water 5%, dry mouth, wrinkled skin, unconsciousness, and even hallucinations; Water shortage 15% is often more than hunger.
Without food, people can live for a long time (some people estimate that it is two months). If there is no water, they can live for a week at most.
For people, water is the most important substance after oxygen. In adults, 60~70% of the mass is water. The proportion of water in children is even greater, reaching nearly 80%.
If a person doesn't eat, he can live for a month only by storing nutrients in his body or consuming his own tissues. But if you don't drink water, it will be difficult for a week. Water loss in the body 10% is a threat to health. If you lose 20% water, your life will be in danger, which shows the importance of water to life.
Water also has the function of treating common diseases, such as: a cup of cold boiled water in the morning can treat pigmentation; Drinking water for half an hour after a meal can be used to lose weight; The massage function of hot water is a powerful tranquilizer, which can relieve insomnia; Drinking a lot of water can relieve constipation; A glass of water before going to bed is good for the heart; You can induce vomiting with salt water when you are nauseous.
Water plays an important role in our life. It is the source of life and one of the most important material resources for human survival and development. People cannot live without water for a moment. Water is the most important substance in people's lives.
Baidu encyclopedia-water
People's Network-The importance of water is ignored. Drinking water also has a set of "health classics"