A: Thomas Paine believed that the American army would become the strongest in the world, that America would achieve independence from Britain with a strong ar... Full Answer > Filed Under:
How DVDs Work. DVDs are of the same diameter and thickness as CDs, and they are made using some of the same materials and manufacturing methods. Like a CD, the data on a DVD is encoded in the form of small pits and bumps in the track of the disc. A DVD is composed of several layers of plastic, totaling about 1.2 millimeters thick. Each layer is created by injection molding polycarbonate plastic.
As with CD and DVD, Blu-ray Disc media comes in pre-recorded, recordable and rewritable variants. The pre-recorded disc is called BD ROM, and usually contains movies or re-issued TV shows in High Definition format. The recordable disc is called BD R, and can be used for archival of huge amounts of data or video.