You probably can detect a weight difference between a 50-g envelop and a 100-g envelope.But if you pick up a 2000-g package,you'd probably need another package that weighs at least 2100 g before detecting a difference between them.This description illustrates:

Question

Quizplus · Accepted Answer

Weber's law states that the threshold for noticing a difference between two stimuli is proportional to the magnitude of the stimuli. In other words, a larger difference is required to detect a change in weight for larger objects than for smaller ones. This is exactly what is described in the scenario given, where a larger weight difference is needed to detect a change in a heavier object compared to a lighter object.

You Probably Can Detect a Weight Difference Between a 50-G