Noble metals are generally resistant to corrosion and found in nature in raw form. Term dates back to late 14th century. Odling published first noble metals table in 1864
Alum was known since 5th century BCE for dyeing and medicinal purposes. Alum became international commodity during Middle Ages. Renaissance scientists recognized alum as salt of new earth. Aluminium metal was discovered by Ørsted in 1825
Platinum is a silver-white, highly unreactive transition metal. It is malleable, ductile, and highly resistant to corrosion. Pure platinum is lustrous and ductile, but less malleable than gold
Conductor allows electric current flow in one or more directions. Current flows through momentum transfer between mobile charge carriers. Metals are ideal conductors due to delocalized electron sea
Whitcomb L. Judson patented the first zipper design in 1892. The name "zipper" came from B.F. Goodrich's rubber boots in 1923. Gideon Sundbäck improved the design in 1917 with ten teeth per inch. The "S-L" machine was developed by Sundbäck for continuous zipper production
Metal is a naturally occurring chemical element found in Earth's crust. Steel is an alloy of iron with varying carbon content (0.5-1.5%). Steel is not a pure metal but a variation on one