C25 SCALES SCALING AND SCALE-UP 1 Much engineering practice involves the manipulation and understanding of scales. The existence of scales seem to intrinsically evident from observations. But it is also evident that scales has a highly elastic meaning that is at the least a barrier for communication among disciplines and at the most is a source of error. This presentation reviews the idea behind scales and what they mean to petrophysical properties. There are 4 central ideas all related. The first idea the motivation for the remainder of the presentation is that all petrophysical properties seem to depend on scale