Metals and their alloys are almost as old as the history of mankind and have had a lasting effect on our culture. For this reason, certain periods in the history of mankind have been named after the materials used, such as the Bronze Age or the Iron Age.
Metals are the chemical elements that, in their pure form, exhibit the following four material characteristics:
- electrical conductivity, which decreases with increasing temperature,
- high thermal conductivity,
- plasticity (ductility) and
- metallic sheen.
Metals are traditionally classified as heavy or light according to their density and as precious or base according to their reactivity.