Metallurgy is the science and craft of working with metals: extracting them from rocks, purifying them, mixing them together, and shaping them into useful objects. A metallurgist might figure out how to make steel stronger for building bridges, or create a new aluminum alloy that makes airplanes lighter and faster.

For most of human history, metallurgy was one of the most important technologies on Earth. Ancient metallurgists discovered how to extract copper and tin from ore and combine them to make bronze, which was hard enough for tools and weapons. Later, metallurgists learned to work with iron, which required much hotter furnaces. These discoveries were so important that historians name entire eras after them: the Bronze Age and the Iron Age.

Modern metallurgy involves complex chemistry and engineering. Metallurgists study how metals behave under extreme heat or pressure, how to prevent rust and corrosion, and how to create special alloys for everything from surgical tools to spacecraft. When engineers needed a material that could withstand the intense heat of rocket engines, metallurgists developed new titanium alloys. The smartphone in a person's pocket contains tiny amounts of dozens of different metals, each chosen by metallurgists for specific properties.