Today, I want to pit you against your machines. 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.
I ask you to do an
experiment. I ask each one of you to run up several
flights of stairs as fast as you can. Use your
watch to measure how long it takes to do it. Say
you run up three flights, and it takes you twenty
seconds.
Now multiply the height of the stairs by your
weight. If you weigh 150 pounds, and the three
flights go up 40 feet, then you've done 6,000
foot-pounds of work in 20 seconds. That's 300
foot-pounds a second. A horsepower is 550
foot-pounds a second, so you've generated just over
half a horsepower.
If you're in good shape, you can generate a whole
horsepower in a short burst like that. But what if
you climb all day? Can you climb a 6000-foot
mountain in 8 hours? That's only about thirty
foot-pounds a second -- about a twentieth of a
horsepower.
This gets interesting when you compare your power
with the machines that serve you. Suppose human
beings had to power the generator that supplied a
150-watt light bulb. It would take 15 people doing
five-man eight-hour shifts to keep that light
burning. An automobile engine that generates 100
horsepower does the work of 2000 people. But when
those people have to rest at the end of eight
hours, the automobile keeps right on going. If
everyone in America worked like a galley slave,
they'd generate barely enough electricity to power
a small city.
The engines of our ingenuity are big and powerful,
and we're no match for them. We've become
absolutely dependent on huge supplies of power. But
the very magnitude of our power plants threatens
our well-being. If they burn fossil fuel, they
don't just spoil the air around the plant, they
endanger the whole planet. If they use nuclear
fuel, we can't figure out what to do with their
waste. Solar collectors, in any form, eat up huge
amounts of real estate.
So try my experiment -- time yourself running up
the stairs. You'll see what an astonishing
difference in scale we've created between our
machines and ourselves. We're like mice directing
the movements of elephants. Too many of our
machines can crush us with a wrong step. The
difference in scale is increasing. And the greater
it is, the more dangerous our machines become.
In the end, our only protection from those great
beasts is restraint -- restraint in the use of
energy -- restraint in our wants -- restraint in
the use of our ingenuity. Run up the stairs and
measure your power output. Take a long close look
at the enormous gulf between us and our machines.
Learn how to view those machines with a
well-balanced mixture of fear and respect.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
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