Making Glass
For more than 4500 years, people have made glass from sand. The float-glass process shown below is used to make large sheets of glass for windows, while molds are usedto make glass bottles. Interpreting Diagrams How is air used in making glass bottles?
Colored glass
Metallic elements are mixed with the raw ingredients to produce colored glass. Iron or chromiumis added for green, copper or gold for red, and cobalt for blue.