The 8-track is a music format which first appeared in the 1960s. It is a tape format which was created so people could play music in their cars. Unlike cassettes, 8 tracks are a continuous loop of tape. They did not need to be turned over to keep playing. There were four programs of music on each tape with two tracks on each program to create stereo sound. When the track was over, a very thin piece of metal in the tape would be sensed. This would cause the part of the player that read the tape (the "head") to start reading the next track. 8 tracks became very popular in the early 1970s. They were used both in the home and car.