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.
Generally, writable DVD discs come in 12 cm (120 mm) and 8 cm (80 mm) diameter sizes. The most commonly used is the larger 12 cm type which has the same physical dimension as most commercial video, audio, computer software and game console DVDs. 8 cm discs are less common and are typically used in portable consumer electronic devices such as digital video camcorders.