Ore is rock or mineral from which valuable metals can be extracted and refined. When miners dig iron ore out of the ground, they're pulling up chunks of rock that contain iron mixed with other materials. The ore itself isn't pure metal: it needs to be heated and processed to separate the useful iron from the less valuable rock around it.

Different ores contain different metals. Iron ore gives us iron for making steel. Copper ore provides copper for electrical wiring and pipes. Aluminum ore, called bauxite, is the source of aluminum for soda cans and airplane parts. Gold ore contains tiny particles of gold embedded in rock, often so small you can barely see them.

Mining and refining ore has shaped human civilization. The Bronze Age got its name because people learned to extract copper and tin from ore and combine them into bronze. The Iron Age began when civilizations mastered the tricky process of smelting iron ore at extremely high temperatures. Today, massive mines extract millions of tons of ore to supply the metals our modern world depends on: the steel in bridges and buildings, the copper in electronics, the aluminum in vehicles.