YouTuber Andy Elliott (mist8k) stumbled upon an awesome DIY project. While "tinkering with a small electric engine," he describes in his video, "my audio jack accidentally came in contact with the engine...and started randomly playing music." Elliott unknowingly built his own speaker.
Fascinated by the idea, he broke down this accidental discovery into a step-by-step guide on how to make a simple, very simple speaker. All that's required is a magnet, copper wire, some tape, a plastic cup, and also some gator clips if you have some lying around. Coil the wire on the bottom of the cup, attach clips, and drop the magnet, that's all it takes. Elliott explains how it works:
The electrical current running down the jack is being magnetized by the coil of wire in the same way as an electromagnet. When combined with a neodymium magnet, the coil causes the air to vibrate in such a way that it creates a sound wave.
Granted, this speaker won't be replacing any fancy multi-channel setup or any decent bluetooth speaker you might have at home, but it's a fun, fundamental look at how those pieces of technology work. [Youtube/Mist8k]