This is an interesting and (mostly) easy-to-understand explanation of the technical history of filmmaking through frame rate. Why is this important? Other than being interesting, there is a new unit if time launched by Facebook, called the “‘Flick” which will make it easier to align and standardize video and sound for smoother effect. Interesting how many different frame rates evolved along with the evolution of video.
This gets a little hairy (it is a technical narration, after all) and runs about 15 minutes, but it is worth the watch: