Re: engineers and scientists was [TCML] Wireless Transmission Theory

[Jim Lux <jimlux@xxxxxxxxxxxxx>]

Ed Phillips wrote:
> Hi Bill,
>
> Most engineers I've encountered are not like that in any way. They are 
> about physics and they will look at the world through the eyes of our 
> physical universe and not limit themselves to "any" theory. I of course 
> have met a few engineers stuck in their ways and nothing was going to 
> change them. But most are not like that. Don't stereotype engineers. 
> There are both engineers and physicist set in their ways and there are 
> both engineers and physicist with a brain to look further.

I figure I'll throw my words in before Chip kills this off.

In my annual "career day" talk at my kid's schools I talk about what 
being an engineer is like.. and how engineers differ from scientists.
This is something I get to observe every day at work (JPL) and which 
interestingly, was also commented on by Steve Squyres in his book about 
the Mars Rovers.

Obviously, it's not a Manichean thing with one or the other, more of a 
continuum, but a bimodal one.

However.. Scientists are driven by wanting to understand. Engineers are 
driven by wanting to do.  The classic scientist might do experiments to 
better understand, but the goal is the understanding, not the doing the 
experiments.  The engineer strives to do something, typically requiring 
some understanding, but there are lots of engineers who work totally 
empirically.  Although, to me, what made engineering engineering (around 
the time of the Renaissance) was the change from doing it as a craft (do 
what worked before) was the use of a theoretical model to guide what you 
do next.  For instance, I'm pretty impressed by what Roman engineers did 
2000 years ago (aqueducts, bridges, the Pantheon), but I'm not totally 
convinced it was engineering in the modern sense.  It might have been 
how medieval cathedrals were built.. a collection of practical 
guidelines arrived at over many years of trial and error, without an 
understanding of why it works the way it does.

Consider, for instance, building an aqueduct like the Pont du Gard. 
Sure, the Romans were able to achieve amazing feats of controlling the 
grade and roughness to get the water flow to work right.  But, did they 
do this by applying experience (empiricism), essentially relying on 
trial and error.  Or, did they understand hydraulics, and have some 
theoretical basis for knowing why to choose a particular slope, 
roughness, and channel width, from first principles.

Likewise, consider the Pantheon in Rome: it's the largest self 
supporting dome in the world until Brunelleschi built the Duomo in 
Florence some 1500 years later.  And it's still standing.  An amazing 
feat, but, did they design it by analyzing stresses and figuring how 
thick to make the concrete, etc.  Or, was it just built by scaling up 
earlier designs, and when they collapsed, making it bigger.

An example of trial and error is pyramid building.  The pyramid of Zoser 
 in Maidun collapsed while the outer casing was being built.  The 
pyramid at Dashur was being built at the same time (but started some 
10-15 years later), and they thought the collapse was due to being too 
steep, so they reduced the angle midway up, producing the bent pyramid. 
 Later it was apparently determined that the problem was more how the 
courses of stone were laid (it couldn't resist the compressional 
loading, and essentially, the weight of the top courses squished the 
bottom courses out, like a watermelon seed between your fingers), so 
later designs essentially had the courses sloping rather than flat.

I don't know that pyramid architects actually figured this out by 
analyzing the forces, or by just doing some empirical experiments.


_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla