law of diminishing returns. A concept in economics that if one factor of production (number of workers, for example) is increased while other factors (machines and workspace, for example) are held constant, the output per unit of the variable factor will eventually diminish.
History of glass. The history of glassmaking can be traced back to 3500 BCE in Mesopotamia, but Mesopotamians may have created second-rate copies of glass objects from Egypt, where this complex craft actually originated. Other archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Egypt.
The earliest precursor to what we call the styrofoam cup was invented in Germany in the 19th century. Today, however, when we enjoy a hot drink that stays hot or a cold drink that stays cold, holding it in a hand that stays dry and at normal body temperature, we are actually using a different type of foamed plastic called polystyrene. Styrol.