A Super Old (1936) Film Explains How Gears Work In A Car Transmission.   

Something is so fundamentally basic such as using tons of levers yet is so mesmerizing. For example, in the video right after the break, a simple explanation of how leveraging smaller gears to move much bigger gears and allows us to innovate tons of things such as creating a transmission in a car and so forth. Although the video right after the break is super old since it was filmed in 1936, I find it to be super easy to make me understand the topic of using levers to move gears in a car's transmission. With this idea, I surmise that a jet engine is probably using the concept of levers to move gears too.