How sensitive is an average person’s sense of the difference in weight between two items?

So I give you two weights, one being 10 lbs and the other being x lbs. How far from 10 does x need to be for an average person to detect that it is a different weight? For instance, I could easily tell that a 5 lb weight is different than a 10 lb weight, where does it start to get really blurry? via /r/askscience https://ift.tt/NlD3ktf