Water is an inorganic compound with the chemical formula H2O. It is a transparent, tasteless, odorless, [c] and nearly colorless chemical substance. It is the main constituent of Earth's streams, lakes, and …

Apr 30, 2026 · Water, substance composed of the chemical elements hydrogen and oxygen and existing in gaseous, liquid, and solid states. It is one of the most plentiful of compounds and has the …

Welcome to the science section of the USGS Water Science School, where you can explore the many aspects of water. All of our information is available by browsing the various categories below.

All living things, from tiny cyanobacteria to giant blue whales , need water to survive. Without water, life as we know it would not exist. And life exists wherever there is water. All organisms, like animals and …

Jun 10, 2025 · Water is the most abundant molecule on Earth, but there are many facts about this substance you probably don't know.

Feb 5, 2026 · Water is essential to life on Earth. It has three phases (solid, liquid, and gas). In these three phases, water ties together the major parts of the Earth’s climate system — air, clouds, the …

Dec 23, 2025 · Water is in constant movement across our planet. The water cycle shapes our weather and climate patterns & provides freshwater that supports all life on Earth.Observing and monitoring …