ABSTRACT
Many of the changes occurred especially in the early times when people had minimal or no knowledge about chemistry, but they empirically developed new materials and uses without knowing that they were made possible by chemical processes. The cavemen did not understand that fire is a chemical process but figured out that to maintain it, wood had to be used and that the fire was better if the wood was dry and did not contain moisture. While the first use of wood was for primitive purposes, i.e., heating the cave, creating a weapon to hunt for meat, then searing it, without any modification, it quickly became one of the most important construction material replacing the cave. Wood is the most abundant energy source, which can be renewed utilizing the sun's energy through photosynthesis. While small amount of copper was available in metallic form, its use was rare other than for some jewelry.
