Materials that can be pulled into wires are called ductile. Many metals are ductile, including aluminium, copper, iron and tin. Ductile metals have commercial applications. For example, wires of aluminum and copper are used for carrying electric current. Gold and silver are also ductile but very expensive.
Not all metals are ductile. Some metals break on application of tensile stress and cannot be pulled into wires. Lead is an example of a soft metal that cannot be pulled into wires.
Ductility in metals decreases with an increase in temperature. The property of ductility is due to the formation of bonds in metals at the atomic and molecular levels. Most ductile metals are also malleable and can be beaten into sheets.