ABSTRACT
Consider what might seem to be a simple forensic example. A seized-drug analyst receives a single plastic bag containing a white powder. The analyst is tasked with determining if the powder contains a controlled substance, and if so, the weight of the powder. The measurement of interest here, the weight and weighing powders, is ostensibly a straightforward process. The powder is emptied into a preweighed or tared weighing dish, placed on an analytical balance, and the net weight of the powder is displayed. Suppose that the analyst follows standard laboratory procedure, works with care and good technique, and determines that the powder is methamphetamine that is greater than 99% pure. The analyst also obtains a net weight of 50.004 g using a reliable and properly functioning balance. If that were the end of the story, this would be a very short book.
