Water plays an important role in life. It is the source of life and one of the indispensables and most important material resources for human survival and development. Human life is inseparable from water.

Water is one of the most common substances on the earth. About 71% of the earth's surface is covered by water. It is an important resource for all life including inorganic compounds and human beings, and it is also the most important component of organisms. Although its content in the air is small, it is an important component of the air.

There are many different understandings about the source of water on the earth, and each has its own reason, but the truth remains to be solved by scientists collecting more objective evidence. As we all know, 72% of the earth's surface is covered by water. However, where the water on the earth comes from remains an unsolved mystery.

According to an article in the journal Nature, scientists from the University of Munster, Germany, through isotope analysis of the meteorite from Tagish Lake British Columbia, Canada, and the earth's mantle rock samples, showed that water appeared on the earth much later than previously expected. To a large extent, this refutes the previous statement held by many scientists that "water was transformed from the ice layer on the surface of meteorites during the formation of the earth". The origin and formation time of water on the earth determine the direction of earth evolution and the time of life origin.

Water is necessary for normal metabolism of the human body. Under normal circumstances, the body should discharge about 1.5L of water through the skin, internal organs, lungs, and kidneys every day to ensure that toxins are discharged from the body. There is 80% water in children, 50%~60% in the elderly and 70% in normal middle-aged people.