Nucleation of an embryo

As mentioned above, freezing does not proceed as a sudden total transformation of the whole liquid into solid ice instead, a small embryo (or nucleus) of the solid first forms by random motions of atoms and molecules in the liquid [4,5]. Such a coordinated random motion (somewhat of a contradiction in terms ) is termed a fluctuation. However, most of these embryos formed by fluctuation within hquid water are of higher energy than the liquid at the same volume. Therefore, they are not stable and melt back into liquid more easily than they are formed. 

We have aheady discussed in Chapter 2 that water exhibits a large number of anomalies at low temperature, below its freezing temperature. The properties of liquid water at low temperature may be explained qualitatively in terms of the existence of two disordered forms - the high-density liquid (HDL) and the low-density liquid (LDL). Our common water consists mostly of HDL. The freezing of ice seems to be intimately connected with these two forms. However, scientists are 

We now discuss the first successful simulation of the freezing of ice, which revealed a wealth of information about the freezing process, and also threw light on the difficulty of freezing water into ice. 

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