TECH 101: CD (Compact Disc)
A compact disc is a portable storage medium that can be used to record, store and play back audio, video and other data in digital form. A standard compact disc measures 4.7 inches, or 120 millimeters (mm), across, is 1.2 mm thick, weighs between 15 grams and 20 grams, and has a capacity of 80 minutes of audio, or 650 megabytes (MB) to 700 MB of data.