The Water Cycle - USGS Water Science School

Earth's water is constantly moving, and the natural water cycle, also known as a hydrological cycle, represents a continuous movement of water above and below the surface of the earth. Water always changes state between liquids, water vapor, ice, and these processes happen in a matter of millions, in millions of years

Note: This table and information is "Public domain". That is, anyone can use it for any purpose. There is no need to obtain permission

For an explanation of the existence of the earth's water, please see the image below. Please note that the table below and the table below show the existence of the earth's water at some point, as we know that circulation of water so far represents the movement of water on the earth. Looking back at thousands or millions of years, there is no doubt that these numbers are different!

Total water supply in the world is about 322.5 million cubic miles, with over 96% salt water. In addition, more than 68% of the total freshwater is occupied by ice and glaciers. Another 30% of the freshwater is underground. Freshwater sources such as rivers and lakes are only about 22,300 cubic miles (93,100 cubic kilometers), accounting for about 1.150% of total water. However, rivers and lakes are the majority of the water people use every day.

Source: Igor / Cyclomanov Chapter "Freshwater Resources of the World", Peter H. Gleick (ed.), 1993, "Water Crisis: Guide to the World's Freshwater Resources" (Oxford University Press, New York)

For details of the water level of the earth, please see the data sheet below. Total water supply in the world is about 333 million cubic miles (1,386 million cubic kilometers), with more than 96% being saline. In addition, more than 68% of the total freshwater is occupied by ice and glaciers. Another 30% of the freshwater is underground. As a result, rivers and lakes supplying surface water to human water are only about 22,300 cubic miles (93,100 cubic meters), or about 0.007% of the total water bodies, but rivers are the source of water for most people.

The best starting point for massive general information on water science. What is water and its nature? How are they measured? How to use water How does USGS measure flow rate and collect water samples? Vocabulary, photo gallery, event center have many other functions. Connect the cartoons and download and print a series of nine posters introducing nine different water concepts such as coastal disasters, watersheds, hazardous waste, wetlands, water use, wastewater, navigation, groundwater, water quality, etc. Classroom activities for junior high school students are behind posters.

Through these educational resources of the USGS Water Academy, secondary and high school teachers and students can gain a deeper understanding of water and their characteristics. It is organized by category, such as the nature of water, water around water, chemical properties, water circulation, water science activity, and most materials are capillary phenomena, surface tension, conductivity, hardness, condensation, evaporation Provide background information to explain the concept of. Articles on each topic are hyperlinked to other USGS resources. Water science activities provide students with opportunities to enhance their understanding of water through actual / faulty testing of groundwater and water properties. Also, you can share your views on water problems through surveys (eg: What is the biggest water problem in the future? How to solve the water shortage problem?), You can ask questions (eg water volume discharged from drip tap) I will.