For 10 points, name this process that triggers the formation of a new phase, such as in crystallization.
The free energy barrier for this process is equal to 16 times pi sigma cubed over 3 times delta G squared. An equation for the rate of this process incorporates a constant known as the Zeldovich factor. The critical radius for this process is equal to negative 2 sigma over delta G. The Zimm-Bragg process determines whether helixes propagate or perform this other process. The Avrami equation assumes that this process occurs randomly. Spinodal decomposition occurs when there is no barrier to this process. In polymer chemistry, a theory named for John D. (*) Hoffmann characterizes this process. New microtubules undergo this process and are then organized by MTOCs. Boiling chips are added to solutions to add sites for this process, enabling smooth boiling without bumping. Silver iodide is added to clouds to provide a seed for the freezing form of this process. For 10 points, name this process that triggers the formation of a new phase, such as in crystallization.
The free energy barrier for this process is equal to 16 times pi sigma cubed over 3 times delta G squared.
nucleation [reverse-prompt on crystallization or crystal formation before mention]