A Compact Disc (CD) is made from a 1.2 mm thick disc of almost pure
polycarbonate plastic. The surface of a CD is reflective because the disc is coated with a thin
layer of aluminum or sometimes gold. The shiny metal layer reflects the
laser that is used to read or write to the device. A layer of lacquer is spin-coated onto the CD to protect the metal.The label print is applied to the top of
that surface. A Digital Versatile Disc (DVD) is made from essentially the same material but can store up to 6 times the data.
