how do tow trucks work? and other questions

I've been unlucky enough to require the services of two different tow trucks in the last five days, and lucky enough to have the resources enough to hire said tow trucks without ruining my budget completely.

while I waited for them and watched them hitch my poor car out of its paralysis, I pondered the winding tracks and ruts of specialization that make it so using huge, heavy machinery to tow paralyzed cars off the side of the interstate and back to town is the everyday work of some people and using books, libraries, and laptops to write (hopefully meaningful, possibly world-changing) sentences is the everyday work of other people.

the concept of a truck that tows other road vehicles makes some sense to me. I'm glad I know about these tools, and that I have indirect access to them. but I don't know what all the parts of a tow truck are called, I don't know at all how to operate such a truck, and I have no anticipation whatsoever of spending much time figuring these things out-- though I might be curious enough to go read the Wikipedia article about them. and their inventor. and this museum.

does Wikipedia have, in its intricate piles and piles of collected information, answers to any of the other random questions that have floated into my head lately?

for instance:

at what time or times of day do the proportions of one's shadow most precisely match the proportions of one's body? does that depend on latitude or anything? time of year? height? body shape? why would it be useful to know this (or would it?)

{ sun and shadow, fence, trees }

why is raucous applause such an ingrained and culturally dominant form of expressing satisfaction and approval after a performance or speech? is noise-making a universal element of that kind of expression, or are there societies (aside from deaf communities?) that express it totally differently, without sound?

can you train a fish? has anyone ever done it?

{ an aquarium at the National Zoo. }

someday I may try searching for other people's answers to all those questions.

speaking of searching-- I read this piece on user experience design a while back and decided that I am a searcher more than a browser in my interactions with websites. the other week after hearing a live concert on the radio and not remembering the performer's name at all, I tossed "des moines iowa social club violin live performance allan church Iowa public radio broadcast" all into Google and found it.

and speaking of other people's knowledge work-- I'm reading Yochai Benkler's The Wealth of Networks right now. it's both a technical and a philosophical book, with various political implications to go along with all its economic implications. Wikipedia features somewhat importantly in his description of how digital networks make possible new (more efficient?) ways of producing, sifting, and distributing knowledge. very worth reading for me in my current preparing-to-write-a-dissertation-prospectus phase, and of course worth reading for anyone else interested in all the cool ways computers are changing how we landscape our information environments.

postscript: people have indeed tried to train fish, apparently.