Paul wrote:
wPhilip Winestone wrote:
> I have an intuitive feeling - totally
unsubstantiated - that the law of
> energy conservation is to energy, what Newton's
laws were to mechanics
> (or physics in general).
John Berry wrote:
> However this whole discussion is foolishness, you
can't get free energy
> from magnetic interactions.
I will show three examples that violate the
conservation of energy in terms of standard
physics, but not to insinuate such energy is being
created. Rather to demonstrate present
understanding of elementary physics is flawed.
The science community could greatly benefit by going
back to basics, to understanding
basic electromagnetism. Energy contained in a region
of magnetic field is claimed to be -->
E = V B^2 / (2 U0)
V = volume
B = magnetic field
U0 = permeability of free space
Therefore if the field doubles then the energy
quadruples.
Energy Violation #1:
Consider two lasers side by side, *slightly* inwardly
slanted so the two beams eventually
overlap and cross. Both lasers are in phase so the
fields nearly double when they overlap.
In that region of space it seems the field energy
quadruples. The field energy from four
lasers would increase by 16 times in that region, or
256 times from just 16 lasers.
You are neglecting the fact that the waves reinforce in some places and
cancel in others. You've "modeled" the lasers as producing perfect
plane parallel waves, and then you've assumed that by placing them close
together and turning the beams only slightly you can ignore the fact
that the wave fronts don't line up exactly. Neither assumption is correct.
Lasers are not magic; this exact scenario can be set up using water
waves in two dimensions rather than EM waves in 3.
If you work it out for any real case you'll find that wave energy is,
indeed, conserved. However, you can set up cases which are complicated
enough that you won't be able to arrive at an answer -- with that I
won't disagree! In the case of lasers, to get an exact answer you need
to take account of the diffraction of the beams (which results in the
collimation being imperfect) and the fact that the beams don't line up
perfectly. It's certainly complicated; too complicated to solve easily
and too complicated to model mentally with a simple picture.
Energy Violation #2:
Lets consider radio antennas. Consider an antenna that
radiates just a short pulse. A few
wavelengths away from that antenna is another antenna
with a load. The load collects some
energy from the wave. Now add another radiating
antenna on the opposite side of the
energy collecting antenna. So we have an energy
collecting antenna in the center of two
radiating antennas. Both radiators send a pulse. The
induced voltage (E-field) from the
entire pulse doubles across the energy collecting
antenna. Therefore the energy
collecting antenna collects four times as much energy.
Now place four radiating antennas
to form a circle around the energy collecting antenna.
This requires four times as much
energy, but the energy collecting antenna collects 16
times as much energy.
Once again you've neglected the fact that you've got "dead spots" in the
pattern where the waves cancel instead of overlapping. If you put
receiving antennas all around, rather than just putting one at the point
where you know all the waves reinforce, you'd find the power received at
some of them was dropping as you added more antennas. You are,
essentially, just focusing the pulse by adding more antennas.
And, of course, the total power received is still going to be _less_
than the total power radiated.
You can, again, imagine that you're using a parabolic reflector and
focusing "all" the energy on the receiver -- but again, that's just an
approximation. You can't get a plane parallel wave from an antenna any
more than you can from a laser (due to diffraction), and again you can't
line up the emitters in such a way that you get reinforcement everywhere.
Energy Violation #3:
Consider the intrinsic electron spin, which we'll call
ES. Ferromagnetic atoms have
unpaired ES, and therefore create a net appreciable
magnetic field outside the atom.
Consider two such atoms that are magnetically
unaligned. Now allow the two atoms to align.
We know from atomic scale experimentation from
companies such as IBM that during
avalanches the magnetic atoms rotate in magnetic
alignment. Typically this can take a few
nanoseconds in non-electrically conductive magnetic
materials, and much slower in
electrically conductive magnetic materials (due to
eddy currents). Understandably this
releases energy. On a larger scale, if we hold two
PM's (Permanent Magnets) that are
magnetically unaligned, we know they want to rotate so
they become magnetically aligned.
If we allow the two PM's to rotate they will gain
angular kinetic energy as they rotate.
In fact, if there's no friction the two PM's will
continue to vibrate back and forth due
to momentum and magnetic attraction. We gain kinetic
energy, but also note that the net
magnetic field actually increases as the two PM's
rotate and align. According to the above
equation, that also constitutes energy.
Interactions between permanent dipoles are conservative, as I've
observed before in this NG. The action of a magnetic field on a
permanent dipole can be described with a potential function.
Now replicate
the same PM experiments except use
air core coils generated by current. --->>>We get the
same results except we learn a
little something about where the energy comes
from.<<<--- While the two air coils are
rotating toward magnetic alignment there's an induced
voltage opposing the current in both
air coils. That drains energy from the source of power
that generates the current in the
air coils. Again, we gain kinetic energy ***and***
field energy (above equation).
And you can get the field energy back out again, too. In interactions
between electromagnets, electrical energy in (and out) and mechanical
energy out (and in) balance.
To
demonstrate that we gain field energy we can remove
the current source from the two air
coils, which will cause a EMP. If you place a load on
the both air coils you can collect
such energy. That's why pure inductors dissipate zero
energy; i.e., energy goes in the
inductor in the form of a magnetic field, but during
the other half of the cycle such
energy goes back to the source. Now in going back to
the original experiment regarding the
two ferromagnetic atoms one needs to ask, "Where is
the energy coming from when the two
ES's are rotating in magnetic alignment?"
> Again, we
> gain kinetic energy in addition to
> field energy. I have asked such a question to dozens
> of QM (Quantum Mechanics) physics. To
> date no QM physics can answer the question.
Again, in the case of a permanent magnet the action of the field can be
described with a potential function.
Almost nobody wants to be caught saying "The energy comes from the
magnetic field" because everybody knows magnetic fields aren't supposed
to do work, so you tend to get silence when you ask where the energy
comes from. I know at least one professional physicist who just flatly
says the energy comes from the B field, though, so there you go.
In any case the interaction is conservative -- the potential function
for a dipole "mu" in a magnetic field "B" is the dot product of the
dipole and the field strength, -<mu,B>. That correctly describes both
the force on the dipole due to nonuniformity in the field, and the
torque on the dipole due to misalignment with the field.
(Whether you can violate the _second_ law with permanent magnets is
something else again...)
The first example regarding lasers demonstrates how
the so-called B-field energy increases
exponentially relative to consumed energy from the
lasers. The second example regarding
antennas demonstrates how energy from the E-field
increase exponentially relative to
consumed energy from the antennas. The third example
demonstrates how elementary
particles seem to disregard such so-called energy, as
we know it.
Perhaps modern physicists should reconsider such
equations and the workings of elementary
physics. On the other hand, for most people such basic
stuff is no fun. Everyone seems to
love working on big stuff from black holes to super
strings, LOL. :-)
Regards,
Paul Lowrance
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