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A Jed Rothwell quote from the Pure Energy Systems thread [21-7-04]
"People believe in things so firmly they come to imagine they can actually
observe -- or physically feel -- abstractions and generalizations. Someone
who indignantly told Chris Tinsley that he was sure energy is conserved
because he has watched it being conserved. He can feel it being conserved."
- Jed
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This reminded me of an incident that occurred early in my research career.
I had been using the Lab's 1000 ton Amsler to measure the full stress-strain
curves of a range of concretes. To achieve a sufficiently stiff machine
capable of following the descending stress-strain curve beyond the point of
maximum stress meant shunting most of the test machines load through a pair
of 6 square feet concrete blocks. The load on the specimen was measured
using a 12inch by 6inch square steel block covered with strain gauges.
Thus the steel load cell was the same size and shape as the concrete test
specimens. The strain of the concrete was measured using a long internal
strain gauge.
As I looked at the set up I mused that were the concrete stronger than
the steel I could be measuring the full stress strain curve of the steel
using the concrete as my load cell.
And then a Kekule like insight flashed before me. In fact, stress is
really just an alias for a strain and Force is an artefact, an alias,
a sheep in wolf's clothing. We don't need the concept of force at all.
We can replace it everywhere with strain.
A few days later we were having the usual discussions over our afternoon
cuppa and I thought I would try out my discovery on the latest Cambridge
Ph.D spending a few months at the lab on the way to higher things -
like administration no doubt. <g>
I said,
"Do you know - there's no such thing as Force.
It's just an alias for strain."
He rose to the bait and as he pushed his mug of tea across the table
with his forefinger said.
"There you are, I can feel the force."
I replied,
"No you can't. What you are feeling is the deformation of the end of
your finger. You are feeling strain. If your finger was not deforming
you wouldn't feel anything."
They say that people given a fleeting glance at a black king of hearts
suffer an emotional crisis when they are finally shown the card in
extenso. I wonder how many people will be similarly affected when
Mechanics suffers a conceptual meltdown into a much simpler system
as foreshadowed by Mark Buchanan in Ubiquity
Cheers
Frank Grimer
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Who is she that cometh forth as the morning rising
Fair as the moon
Bright as the sun
Terrible as an army set in battle array
- King Solomon -
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