How a car's differential works


Originally published at:


The differential is integral to the car’s function.


I’m going to have to look up who this Kottke person is.


The marching music was a hoot too!


It’s nice that they explained the differential’s integration by parts.


After seeing one of these videos I want to add the knowledge to the list of things to know when traveling back in time.


Nitpick: isn’t a gram literally and exactly the weight of 1 cc of water at some standard set of conditions, not “about the weight of 1cc of water?”

I also question how my back in time society is milling a sufficiently perfect vessel to hold an cubic centimeter of water. While being unable to create a weight to act as the standard gram.


This poster has been around for a long time. Perhaps there have been updates made to recent publications. I think that being in the now we would have known if someone had used the poster to change history or standard measurements. Or would we?


Having looked it up: the litre is an unofficial SI unit, defined as 1 cubic decimetre. It has always been defined in these terms. The kilogram used to be defined as the weight of 1 litre of water at the temperature of melting ice but redefinitions mean that the relation is no longer exact.


I remember those.
Good times!


I bought the T-shirt, and my biggest problem with it by far is that “You can do a neat trick with C20H26O2!” would be an utterly useless piece of advice even to chemists today, i.e. since there is an astronomical number of compounds that fit that description. But eh, it looks cool, and a useful synthesis for progesterone from Dioscorea probably won’t fit conveniently anyway.


That stentorian voice!


Produced by The Jam Handy Organization…?



Haven’t you ever watched MST3k?


Ha! Back when large corporations actually thought there was something to be gained by consumers being smarter! What a hoot, how quaint.


Came here to quote Cory quoting the Kattke quote; satisfied upon arrival. And good on you for drilling down beneath the Google AMP crap to make good links. Looking forward to seeing this post again in 2021 (tho by then it might be titled “This Is How Differential Gears Worked Back When They Were Still A Thing” ; -).


Is that available in tattoo form? Some time travel happens without a machine.





Are there any more videos in this series?


But what about limited slip differentials?