[extropy-chat] Magnetic field shoves heat sideways & Massless ghosts of the nanoworld
Terry W. Colvin
fortean1 at mindspring.com
Mon Jan 16 23:51:19 UTC 2006
Forwarding permission was given by William R. Corliss
< http://www.science-frontiers.com >
SCIENCE FRONTIERS, No. 163, Jan-Feb 2006, p. 4
PHYSICS
No. 1
Magnetic field shoves heat sideways
Here is an anomaly only a physicist could love.
Normally, when one applies heat to the edge of a flat plate, the heat flows
directly across to the opposite cold edge of the plate. It's elementary
physics.
But if the experimenter also applies a magnetic field through the plate---
top to bottom---it gives the heat a sideways push toward one of the edges.
But the plate here is electrically *nonconducting*.
This effect is analogous to the well-known Hall effect in which a similarly
applied magnetic field makes electrons flowing in a *conducting* plate
swerve sidewards. Since magnetic fields are admitted to affect the
motion of electrons, the Hall effect is nonanomalous.
But the heat in the *nonconducting* plate is transported by phonons
(quantum vibrations) rather than electrons. The phonons being
uncharged electrically should not be affected by the applied
magnetic field. So an anomaly is born.
(Cho, Adrian; "Magnetic Fields Give Heat a Curious Sideways Shove,"
*Science*, 310:420, 2005)
No. 2
Massless ghosts of the nanoworld
In the realm of the very small---the nanoworld---weird phenomena occur
often. Most of these weird events cannot [be] termed "anomalous"
because quantum mechanics explains them handily. (Of course,
understanding quantum mechanics is another matter.)
Anyway, a most interesting effect happens in carbon sheets only one
atom thick. Electrons moving in this ultrathin sheet move as if they
possess *no* mass! They zip along at speeds much faster than they
do in semiconductor sheets of comparable thickness.
In the quantum-mechanical explanation the apparent loss of mass
occurs when the quantum waves of the confined electrons meet and
cancel one another out.
Now, technologists foresee thin carbon sheets---conducting high-speed
electrons in electronic devices---as potentially increasing their
operating frequencies a thousandfold.
(Weiss, P.; "Ghostly Electrons," *Science News*, 168:309, 2005)
SCIENCE FRONTIERS is a bimonthly collection of scientific anomalies in
the current literature. Published by the Sourcebook Project, P.O. Box
107, Glen Arm, MD 21057 USA. Annual subscription: $8.00.
--
"Only a zit on the wart on the heinie of progress." Copyright 1992, Frank Rice
Terry W. Colvin, Sierra Vista, Arizona (USA) < fortean1 at mindspring.com >
Alternate: < fortean1 at msn.com >
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