Aqua Incognita. Why ice floats on water and Galileo 400 years on.

Preamble. We remembered that 400 years ago, on October 2, 1611 AD, Cosimo II de’ Medici, Grand Duke of Tuscany and patron of the arts and sciences, sponsored a debate on the topic: Why Ice Floats on Water. The then young Galileo led this famous debate. Cardinal Barberini, a great admirer of Galileo the soon to become Pope Urban VIII – who eventually put him under house arrest – in a tragedy too well known to recount, was there. We could not let the occasion pass. So a small group of us, research scientists, took upon ourselves to organise a different kind of small meeting, in Florence, July 15-19, 2013 to commemorate the occasion. The motivation derived too from our observation that at practically all scientific meetings these days, mutual incomprehension is almost mandatory. The focus seems always on specialised technical minutae of our disciplines, physical, colloid surface chemistry, and more. It is the same for all fields of science and technology. The reader may be surprised to learn that the answer to the ice question is still unresolved. So are the answers to a myriad questions about water. In the simpler terminology of an older world, our discussions would be about water, salt, air and light. And biology. And geology and, and … From that perspective we are all at sea. It is an extraordinary and not widely recognised fact that our present, classical, theories that underpin the entire enabling disciplines of physical, colloid and surface chemistry lack predictability, from biology to earth sciences and chemical engineering. These theories are undergoing a paradigm shift from the beginnings up. The same is true in many other disciplines like cosmology and particle physics. It is true also for molecular biology. We wanted to have an overview debate and discussion between scientists at the cutting edge from around the world, on where we are now on WATER. And to record the situation. Hence, on Aqua Incognita, Galileo 400 years on. Some technical topics that we addressed included: 1. water, its properties and structure, and in biology 2. solutions of electrolytes in water and non-aqueous solvents 3. specific ion effects in the bulk and at interfaces, particularly in medicine and biology 4. effects of light and magnetic fields on water and processes in water dispersion 5. dissolved gases, how they affect aqueous media 6. hydration and, in general, solvation and crystallisation 7. challenges to the foundations and the emerging new theories in physical chemistry But the enquiry expanded to a more eclectic collection of papers, on Fresco restoration, on metaphysics and Galileo’s problems, on chirality, on the history of water throughout civilisation, on promising advances in desalination, and deep sea water, and human sweat and touch!