Today, we wonder why people do experiments. 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 visited beautiful, baroque St.
Isaak's Cathedral in Leningrad back in 1972. The Soviet
Union was calling it a museum, not a church. They'd hung
a huge Foucault pendulum from the dome -- right in the
center. There was a certain violence in the way the
pendulum cut across the delicate lines of the
architecture. A lady in an official suit lectured
squadrons of little children about the experiment. She
explained how the pendulum holds its path while Earth
itself turns under it -- how the pendulum only seems to
move.
The Foucault pendulum is a dramatic demonstration of
Newtonian mechanics. But this wasn't science; this was a
not-so-subtle propaganda lesson for kids. It was a
sidewise way to tell them that life begins and ends in
the scientific mechanics of our being -- and that the
state is somehow the bedfellow of science.
Many fancy experiments confirm what we already know. For
example, a Stanford group has created an experiment to
check tiny changes in the direction of the axes of four
gyroscopes. They're in a satellite orbiting directly over
Earth's poles. The axes will point toward the star Rigel,
in Orion. As they move through Earth's gravitational
field, the axes will shift, just a little, as our gravity
fields bend space -- bend the line pointing toward Rigel.
Now, there're many reasons for doing the experiment.
Fortunately, when you get to the fine print, you learn
that there are aspects of relativity theory that're still
incomplete. But what the public hears is that the
experiment will prove Einstein's theory, and many people
are oddly content with the notion that we're trying to
verify something we already know is essentially true.
So we're back to that Foucault pendulum experiment, which
is no experiment at all. What it is is a
demonstration. Experiments sometimes do reveal
things dramatically. In the early nineteenth century the
French physicist Poisson attacked Fresnel's theory of
light. If Fresnel were right, he said, you'd see a spot
of light, under certain conditions, right in the middle
of the shadow cast by a disc. And that was silly. Then
Fresnel did the experiment, and the white spot appeared.
It surprised him as much as it did Poisson.
Experiments serve many purposes. We do have to look at
nature before we can form theories to describe it, and no
theory will stand up to even one counterexample. In 1887,
the famous
Michelson-Morely experiment was meant to show how
fast light traveled in the ether, which supposedly filled
space. The experiment actually demolished the ether
theory when it gave the wrong kind of result.
Once we're confident about a theory, experiments do start
looking like propaganda. We do many experiments to sell
our ideas to other people. That's an important part of
the business of science. But always remember: The
experiment that's really worth doing is the one that can
give us a result we don't want to see.
I'm John Lienhard, at the University of Houston, where
we're interested in the way inventive minds work.
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