Water covers about 70 percent of the surface of the earth, and the largest concentrations of it are in the Pacific, Atlantic and Indian Oceans. Water also makes up a large percentage of the composition of the human body. Hydrogen and oxygen are the two chemical components of water.
Two atoms of hydrogen and one atom of oxygen are the chemical components of water, and the latter is often referred to scientifically as H20. Water in its purest state has no smell or taste. The two basic types of water bodies on earth are fresh water and salt water.
Water comes in three forms: liquid, solid and gas. Ice is the name of the solid form, and steam, or water vapor, is the name of the gas form. Water expands up to a certain point as it freezes, and it vaporizes when it becomes very hot. The sun is one source of water vaporizing, and it evaporates around a trillion tons of water every day.
Water is critical to the survival of many life forms. Whereas humans may survive up to a month without food, they can perish in less than a week, or even in days through over-exertion in harsh conditions, without water.