The formation of ice crystals on foreign surfaces or as a result of the growth of water clusters.

Critical stage in the process of the assembly of a polymer at which a small cluster of monomers aggregates in the correct arrangement to initiate rapid polymerization; more generally, the rate-limiting step in an assembly process.

the replating step in which a catalytic material, often a palladium or gold compound, is absorbed on a surface to act as sites for initial stages of deposition.

1) (homogeneous) the initiation of solid crystals from the liquid stage, or initiation of solid crystals from the liquid stage, or a new phase within a solid without outside interference - rarely occurs, 2) heterogeneous) foreign particles altering the liquid-solid interface energy during phase changes.

Any process in which the phase change of a substance to a more condensed state (such as condensation, deposition, and freezing) is initiated about a particle (nucleus) or at a certain locus.

the precipitation process involving the "birth of a new crystal" ie the initial formation of a crystal. Primary nucleation is nucleation in an unseeded system. Secondary nucleation is the process in which, as the crystals in a stirred precipitator rub past or bash into each other or the walls, fine chip-like particles are generated. These are used as seed crystals.

the initial stage in a phase transformation. It is evidenced by the formation of small particles (nuclei) of the new phase, which are capable of growing.

Phase change of a substance to a more condensed state initiated at a certain loci within a less condensed state.

The process of providing sites for 1) new bubbles to form in a liquid that is boiling or supersaturated with gas; 2) new droplets to condense from a supersaturated vapor, or 3) new crystals to form in a supersaturated solution. Nucleation sites can be scratches in a surface, dust particles, seed crystals, and so on.

The initial process that occurs in the formation of a crystal fom a solution, a liquid, or a vapour, in which a small number of ions, atoms, or molecules become arranged in a pattern characteristic of a crystalline solid, forming a site upon which additional particles are deposited as the crystal grows.

Nucleation is the onset of a phase transition in a small region. The phase transition can be the formation of a bubble or of a crystal from a liquid. Creation of liquid droplets in saturated vapour is also characterised by nucleation (see Cloud condensation nuclei).