How do those second hands keep ticking off the minutes, and minute hands the hours, and hours the days? The same way they have since long before this 1949 explanatory video was made: gears, springs, and so much more.

I'm having a hard time deciding which I like more, the biggie-sized watch innards model or the fact that our narrator likely went on to voice his share of Cold War-era Atom bomb safety videos. [OnFocus via Kottke]