Today, we wonder why people run 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 the beautiful,
baroque St. Isaac's Cathedral in Leningrad. The
Russians called it a museum. They'd hung a huge
Foucault pendulum from the dome -- right in the
center -- cutting through the delicate
architectural lines. A lady in a blue suit lectured
squadrons of little children. She explained that
the pendulum holds its path while the world turns
under it -- that the pendulum itself seems to
change direction as the day wears on.
The Foucault pendulum is a dramatic enough
demonstration of Newtonian mechanics. But this
wasn't science. It was a not-so-subtle propaganda
lesson for kids -- a sidewise way to tell them that
their lives were under the control of science and
the state.
A lot of fancy experiments do little more than
confirm what we already know. For instance: a
Stanford group has made a perfectly round sphere of
metal-coated quartz. It's about an inch in
diameter. An electrostatic field will hold it --
without letting it touch anything -- in a
satellite. It'll be set to spinning with its axis
pointing toward the star Rigel, in Orion. As it
moves through the earth's gravitational field, its
axis will shift -- just a little bit. The reason is
that our gravity field bends space. It'll bend the
line pointing to Rigel. The experiment will prove
Einstein's theory; but most people who understand
Einstein's theory believe it already.
Experiments sometimes do reveal things,
dramatically. The French physicist Poisson, for
example, attacked Fresnel's theory of light. If
Fresnel were right, he said, you'd see a spot of
light in the middle of the shadow cast by a disc --
under the right conditions. That didn't make sense.
But when Fresnel did the experiment, the white spot
appeared. It surprised him as much as it did
Poisson.
Experiments serve many purposes. After all, we have
to look at nature before we can form a theory to
describe it. And no theory will stand up to even
one counterexample. The famous Michelson-Morely
experiment was meant to show how fast light
traveled in a hypothetical ether that was supposed
to fill 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 the experiment that's really worth
doing is the one that can give us results we don't
want to hear.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
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