Today, we worry about good and bad technical
information. The University of Houston's College of
Engineering presents this series about the machines
that make our civilization run, and the people
whose ingenuity created them.
The gap between our
technical literacy and the things we have to know
in today's world is growing. We're heaped with
technical information. Some of it's accurate; some
of it's terribly wrong; some of it's just
innocently off-base.
A mechanic tells us a part in our car failed
because it crystallized. He thinks that because
fatigue-failures run along the grain of metals.
Failure reveals a crystal structure that was there
all along. Now there's no real harm in talking
about crystallization. But we're surely better off
knowing that metal doesn't mysteriously go bad with
age and change its structure.
I was more worried by an ophthalmologist who said I
should have laser surgery. "A laser," he explained,
"carries both light and heat." Actually lasers are
used in retinal surgery because they carry no heat
whatsoever. The energy of a laser beam is all
coherent light. It passes right through the optic
fluid. It's transformed to heat only when it hits
the retina. But optic fluid absorbs heat radiation.
If there were any heat in a laser, it would be
absorbed in the eyeball instead of the retina. The
consequences of that are too horrible to think
about. To this day, I don't know whether he
actually knew how his laser worked or not.
We run into the same thing with some
aluminum-siding and storm-window salesmen. It's
fascinating to imagine a thermodynamics book based
on some of their theories of heat.
But who am I to complain? As a joke, we start one
chapter in our Heat Transfer book with a tall tale.
It goes like this:
When I was a lad, winter was really cold. It
would get so cold that if you went outside with a
cup of hot coffee, it would freeze. I mean it would
freeze fast. That coffee would freeze so fast that
it was still hot after it froze. Now that's
cold!
When someone looks me straight in the
eye and says, "Gosh, I didn't know it could get that
cold," then I have to repent my own sins.
We live in a technology-dense world. The engines of
our ingenuity are everywhere, and we're
terrifyingly naked when we don't know elementary
things about how they work -- a little about the
flow of electricity or fluids -- something about
chemical reactions -- or the insides of our
automobiles.
A world unknown is a world we can't cope with. It's
not a nice place to live. You've heard people tell
you with authority that hot water freezes faster
than cold water, or that storm windows let heat
flow only one way. We're in trouble if we don't
have the tools to test statements like these. None
of us can know everything we'd like to know. But we
have to be educated well enough to be proper
skeptics. We need the confidence at least to
question the things so many people are telling us.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
(Theme music)
