Water is a transparent liquid that is the major component of streams, lakes, oceans, rain, and living things. A water molecule consists of two hydrogen atoms bonded to one oxygen atom. On Earth, water exists as a liquid under standard conditions but also as a solid (ice) and gas (water vapor). Water covers 71% of the Earth's surface and is essential for all life as we know it. It has a variety of important uses including agriculture, drinking, washing, transportation, firefighting, recreation, industrial processes, and food preparation.