How a vinyl record makes sound: the groove under a microscope
The groove is a wiggly canyon and the needle just rides the bumps — the sound is the bumps. Good follow-up to the cicada recording.
Applied Science puts a slice of an LP and a stylus inside an electron microscope and shows, frame by stop-motion frame, the diamond needle tracing the groove. The wiggles cut into each groove wall are the sound wave itself; the needle's tiny side-to-side vibration becomes an electrical signal, which becomes what you hear.