Inside is a metal clicker, once the pack cools to room temperature, crystallization of sodium acetate (an exothermic process) is triggered by the clicker, which gives the sodium acetate a nucleation ...

Water's freezing point is generally accepted to be 32 degrees Fahrenheit. But that is due to ice nucleation—impurities in everyday water raise its freezing point to this temperature. Now ...

This is a fixed point on the Celsius temperature scale ... near Hamburg has now succeeded in precisely measuring the nucleation of supercooled liquids. The experiments took place in a vacuum ...

In both cases no special care is taken with regard to nucleation and the parameter of time.