Scientists at the University of Bristol in the UK and Tokyo University in Japan have explained the anomalous properties of water, which she is at cooling and freezing.
To do this, the researchers using computer simulations have made changes to the structure of the H2O molecule, giving it new features, the newspaper reports Science Alert.
Usually liquid with decreasing temperature become more dense, but water reaches its maximum density at four degrees Celsius. Below this point the density again decreases, with the result that ice floats on water surface. In addition, water has a high surface tension, yielding a liquid form of mercury, high boiling point and is a good solvent.
Such physical features are explained by hydrogen bonds that form between water molecules. The latter are connected to each other and form a tetrahedron (triangular pyramid).
The researchers used a supercomputer to create different models of the molecular structure of water. For this, they varied the parameter λ, called the potential of Stillinger-Weber, which is used to describe the physical properties of materials with tetrahedral arrangement of molecules. The researchers have traced how the changes in capacity affect the density of a substance and the number of chemical bonds between atoms (two state model). This allowed to calculate for which values of λ appear anomalous properties of water.
It turned out that when the capacity of Stillinger Weber anomalous properties of water related to density, become weaker. As a result the maximum density is shifted towards the phase transition liquid-ice, the solid form of water loses buoyancy. With decreasing λ the properties predicted by the model of two States, also weaken.