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.
Most DVDs are of the same dimensions as compact discs (CDs) but store more than six times as much data. Variations of the term DVD often describe the way data is stored on the discs: DVD-ROM has data which can only be read and not written, DVD-R and DVD+R can only record data once and then function as a DVD-ROM.