Liquid water (H2O) is often perceived to be ordinary as it is transparent, odorless, tasteless and ubiquitous. It is the simplest compound of the two most common reactive elements, consisting of just two hydrogen atoms attached to a single oxygen atom. Indeed, very few molecules are smaller or lighter.
However, liquid water is the most extraordinary substance. Although we drink it, wash, fish and swim in it, and cook with it (although probably not all at the same time), we nearly always overlook the special relationship it has with our lives. Droughts cause famines and floods cause death and disease. It makes up over about half of us and, without it, we die within a few days. It has importance as a solvent, a solute, a reactant and a biomolecule, structuring proteins, nucleic acids and cells and controlling our consciousness. Water is the second most common molecule in the Universe (behind hydrogen, H2) and fundamental to star formation. Life cannot evolve or continue without liquid water, which is why there is so much fuss about finding it on Mars and other planets and moons. It is unsurprising that water plays a central role in many of the World's religions.
Water is the most studied material on Earth but it is remarkable to find that its behavior and function are so poorly understood (or even ignored), not only by people in general, but also by scientists working with it everyday. The small size of its molecule belies the complexity of its actions and its singular capabilities. Water's unique properties and chameleonic nature seem to fit ideally into the requirements for life as can no other molecule.
A number of explanations of the complex behavior of liquid water have been published, many quite recently, with several stirring up great controversy. In this site, I have attempted to present these ideas in a self-consistent and balanced manner, which I hope will encourage both its understanding and further work.