Final answer:
A Compact Disc (CD) is a form of digital optical disc storage that contains data stored as tiny pits and bumps read by a CD player's laser. CDs once revolutionized data and audio storage by providing a high capacity alternative to tapes and vinyl but have since been overtaken by streaming services.
Step-by-step explanation:
A Compact Disc (CD) is a digital optical disc data storage format. A typical CD has a diameter of about 6 inches and is made principally of polycarbonate plastic. The disc contains data stored in the form of tiny, laser-created pits and bumps near its surface. This data is encoded digitally, meaning in binary form, as a sequence of ones and zeros.
The density and precision of these pits allow a CD to store a considerable amount of information despite its physical size; for instance, it can contain an entire encyclopedia. A CD player utilizes a laser beam to read these pits. As the disc rotates, an inexpensive solid-state infrared laser beam scatters from the pits, translating the reflected light into digital information that can be processed and transformed into its intended form, such as audio or computer data.
Despite their previous popularity, CDs have been largely supplanted by streaming services and other storage methods. Nevertheless, they marked a significant advancement from earlier forms of storage like vinyl records and audio cassette tapes, offering higher capacity and durability.