5,000 years ago, humanity transitioned from the Stone Age to the Bronze Age through the advent of metallurgy. The process involves heating copper ore in a stone or ceramic pot to separate it from impurities. Although there are no documents detailing how metallurgy was born, it is believed that the ancients came up with the idea of blowing air through hollow bars to increase furnace temperature and release molten metal. This primitive blacksmith did not realize that carbon in wood reacted with oxygen in ore, converting it to CO2 and releasing copper.
Bronze was a suitable metal for creating new tools and weapons that were much better than stone. Copper hardened when struck with a hammer and could be melted and poured into molds to make standard items. Additionally, copper could be improved by mixing it with tin, forming a new alloy. This alloy was not only harder than pure copper when struck with a hammer but also melted at a lower temperature, making casting easier. The widespread use of this mixture around 3000 BC marked the beginning of the Bronze Age – an era when many alloys were created as people experimented with adding zinc and other metals to copper. New alloys continue to appear today with many useful applications.
The technological advances of the Bronze Age fueled the rise of some of the world’s most powerful civilizations. However, this era eventually ended when humans discovered how to smelt iron from rock, creating an even more useful material and ushering in the Iron Age. Initially, ancient furnaces could not reach high enough temperatures to melt iron, so blacksmiths had to work with wrought iron – material obtained by separating it from slag produced during firing process. Around 300 BC, Chinese metalworkers invented a blowpipe that created a flame hot enough to melt iron. While iron is not as hard as copper-tin alloy, objects made from iron are often of lower quality than those made from this alloy due to its abundance compared to tin’s scarcity