Voda

One molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom. It is the most abundant substance on the surface of Earth and the only common substance to exist as a solid, liquid, and gas on Earth's surface. Under standard conditions water is primarily a liquid, unlike other analogous hydrides of the oxygen family, which are generally gaseous. This is due to hydrogen bonding. Naturally occurring water is almost completely composed of the neutron-less hydrogen isotope protium.

Geosmin and 2-methylisoborneol are the major biological causes of muddy odor and flavor in drinking water worldwide. Geosmin has a very low odor detection threshold in water, ranging from 0.006 to 0.01 micrograms per liter. Dimethyl sulfide is emitted over the oceans by phytoplankton. It has a characteristic odor commonly described as cabbage-like, and it contributes to the characteristic odor of sea air. Petrichor is the earthy scent often associated with rain falling on dry soil or rock, and geosmin is a contributor to it.

Liquid water has weak absorption bands at wavelengths of around 750 nm, which cause it to appear blue. Liquid water is densest at about 4 °C. It is described as the universal solvent. It is miscible with methanol, ethanol, propanol, isopropanol, acetone and glycerol. Only 155 ppm of naturally occurring water includes deuterium, a hydrogen isotope with one neutron. Deuterium oxide is called heavy water because of its higher density.

Explore all seven extraits in the Discovery Set.

—

Related: Airy Note · Aluminum · Helional · Industrial Glue · Ozone Acetaldehyde · Plastic · River Notes · Steam Accord