What materials are used to make a compact disk and how is music stored on one?

A compact disk (CD) is an optical storage medium that is used to store digital data, such as music and video. CDs are made of a plastic material, such as polycarbonate, and have a reflective layer of aluminum or gold. The data is stored on the CD in the form of microscopic pits and lands. The pits represent binary 1s, while the lands represent binary 0s.

To read the data from a CD, a laser is used to scan the disk. The laser reflects off of the lands, but it is absorbed by the pits. The reflected light is then detected by a photodiode, which converts it into an electrical signal. The electrical signal is then processed by a computer, which interprets the data and plays the music or video.

The storage capacity of a CD is determined by the number of pits and lands that can be stored on the disk. The more pits and lands that can be stored, the more data can be stored on the disk. The standard capacity of a CD is 700 megabytes (MB), but there are also high-capacity CDs that can store up to 900 MB of data.

CDs are a popular storage medium for music because they are relatively inexpensive and easy to use. They are also very durable and can last for many years. However, CDs are becoming less popular as a storage medium for video, as they cannot store as much data as DVDs or Blu-ray discs.