I recently found an old cassette tape that unlocked many memories from when I was a kid. Music I used to listen to, the action of trying to record a song I liked from the radio station while hoping the radio host would remain silent for the whole time (it was rare), long hours tinkering with scissors and tape remixing songs from different tapes…
If someone born after 1990 ever visits this page (highly unlikely, I guess), you must know a cassette tape was used to store audio. Here is how it works:
When you play a cassette, the tape is run past a head that moves up and down from the charge on the tape. Just like a needle running over the etched sound waves on a vinyl record, the electromagnetic head of a cassette moves from the sound waves recorded on the tape. The movement of the receptor is translated into electromagnetic waves which are then sent to your speakers.
Analog: How do Audio Cassettes Work.
For more information, check the Encyclopedia entry about Cassette Tapes. Oh, and as the Analog quote mentions vinyl records, you are going to need to read this Sounds et al. post, too: How do Vinyl Records Work?
And here is the cassette tape I found: