The quality of a cast item is influenced by a variety of factors. This is valid especially for porosity. Some times the effect of a factor is predictable with almost mathematical precision. However, in most cases there is only a statistical relationship. At the worst the behavior seems unpredictable. In common sense we call it chaotic. In science a effect is called chaotic when e.g. a small accidental change in starting conditions can change the final result in a fundamental and not foreseeable scale.

Author: Dieter Ott