Sea water, river water, and undergr

Sea water, river water, and underground water together make up the continuous water of the earth, which we call the hydrosphere. The vast sea in the sun's irradiation, constant evaporation of water molecules from the sea. This water vapor condenses when it cools in the air and falls to the ground as rain, snow, and hail. They then wash through the soil, wash away rocks, dissolve substances, and eventually return to the sea. This is how water circulates: the ocean -- the air -- the earth -- each time the ocean circulates, it carries away a lot of soluble material in the rocks. It has been calculated that the world's rivers carry up to 3 billion tons of material from land to sea each year. In other words, every 25, 000 years water breaks down and carries to the ocean a layer about a metre thick. Water plays a very important role on the earth. Its chemical formula is H2O, and it's one of the most widespread substances on Earth. There are 1.37 billion cubic kilometers of water in the world! Water is of great significance to the history of geology. This is why there is a hydrogenic hypothesis in geology. This hypothesis states that all rocks on the earth grow out of water. The other ignetic hypothesis holds that rocks on Earth solidified when molten material from underground was sprayed onto the surface. These two hypotheses were fiercely debated, but we now know that both water and volcanoes were involved in rock formation.