When I was a kid I asked my dad what the big thing connecting the two rear wheels of a pick up truck was (You know, the bit with a bulge in the middle). He told me it was the differential. He said it was a thing that let the rear wheels turn at different speeds. I did not think to ask why that was important but the idea was intriguing. How could a mechanism letting two different shafts turn at different speeds work?
It was not until I was well into trade school that I got more than a glimmer of understanding as to what exactly enabled the different speeds. Even opened up and seeing it work, differentials don’t make much sense. If I had seen this video I would have understood when I was a kid!
I love the old school instructional videos. This one does a good job covering all the bases. The video has a long intro. If you get bored skip to 1:50.