Water is an inorganic compound with the chemical formula H2O. It is a transparent, tasteless, odorless, and nearly colorless chemical substance, and it is the main constituent of Earth's hydrosphere and the fluids of all known living organisms. It is vital for all known forms of life, despite not providing food energy or organic micronutrients. Its chemical formula, H2O, indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. In liquid form, H2O is also called "Water" at standard temperature and pressure.
Water
This pillow basalt on the seafloor near Hawaii was formed when magma extruded underwater. Other, much older pillow basalt formations provide evidence for large bodies of water long ago in Earth's history.
Specific heat capacity of water
High tide
The color of water varies with the ambient conditions in which that water is present. While relatively small quantities of water appear to be colorless, pure water has a slight blue color that becomes deeper as the thickness of the observed sample increases. The hue of water is an intrinsic property and is caused by selective absorption and scattering of blue light. Dissolved elements or suspended impurities may give water a different color.
When water is in small quantities (e.g. in a glass) it appears colorless to the human eye.
An indoor swimming pool appears cyan from above, as light reflecting from the bottom of the pool travels through enough water that its red component is absorbed. The same water in a smaller bucket looks only slightly cyan, and observing the water at close range makes it appear colorless to the naked eye.
Large bodies of water such as oceans manifest water's inherent blue color.
From space, oceans appear so dark as to be almost black. This is an image taken by the MODIS instruments of the Gulf of Mexico.
