Haven’t you ever wondered how many trees were cut down to produce those cardboard mailers for CD’s? How much fuel is used taking them to the Post Office, then delivering them to your mailbox. (Yes, I know, the letter carrier might be stopping by anyway.)
Did you think CD’s grow on trees? First you dig a hole in the ground, to extract oil for plastic; aluminum; and maybe some silver or gold. Then you build an airtight room where no dust is allowed.
Raw Materials
A compact disc is a deceptively simple looking device considering the technology required to make it. CDs consist of three layers of materials:
A base layer made of a polycarbonate plastic.
A thin layer of aluminum coating over the polycarbonate plastic.
A clear protective acrylic coating over the aluminum layer.
Some manufacturers use a silver or even gold layer instead of the aluminum layer in the manufacture of their compact discs.
The Manufacturing Process
Compact discs must be manufactured under very clean and dust free conditions in a "clean room," which is kept free from virtually all dust particles. The air in the room is specially filtered to keep out dirt, and occupants of the room must wear special clothing. Because an average dust particle is 100 times larger than the average pit and land on a CD, even the smallest dust particle can render a disc useless.
Read more: http://www.madehow.com/Volume-1/Compact-Disc.html#ixzz8DtZPRKAr
