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Re: Particle Position



Jim,
I would propose that it is that the very concepts of position and
momentum are human constructs fashioned from our experience with
everyday macroscopic reality, and that these concepts do not literally
apply to sub-microscopic reality.

The Heisenberg uncertainty principle is an instance of what happens
when human understanding tries to force sub-microscopic reality into the
categories of everyday macroscopic human experience.

Bob Sciamanda
Physics, Edinboro Univ of PA (em)

trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
From: Jim Green <JMGreen@SISNA.COM>
To: <PHYS-L@LISTS.NAU.EDU>
Sent: Sunday, May 09, 1999 10:03 PM
Subject: Particle Position


We all understand that the position and momentum of a particle must
satisfy
the Heisenberg Uncertainty Principle. But what does this mean? Is
it
that _I_ can not know x & p with better precision? --- that the
infinitesimal _particle_ "knows" exactly where it is and how fast it
is
going but an observer can not -- ie that the particle does indeed
have an
exact locations and velocity, but the observer just can't know what it
is?
OR does it mean that the particle is of finite size such that it
takes up
a space of delta x?

Consider a particle in a 1 d box -- say of length L: How many
locations
along L can the particle occupy? Assume any needed additional
information.

Likewise, consider a 3 d box of sides L: how many places in the box
can the
particle occupy?

Just me over here in my little corner.

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen