Re: Heisenberg's uncertainty principle
Does the position/velocity concept pertain only to electrons and to
other sub-atomic particles, or, can it apply to other measurable
things in the real world like trains or planes? This may sound
idiotic, but in Greene's book, he says the "ideas directly apply to
all constituents of nature." Are man-made things considered "con-
stituents of nature"? Probably not...I'm not a scientist...clearly.
Yes, the uncertainty principle applies to all objects. There is no
distinction between natural and man-made things. However, it works so that
the uncertainty in the product of position and momentum is a constant small
number. For small objects like electrons, this can mean a considerable
uncertainty in its position, or in its velocity. However, momentum is the
product of mass and velocity. For more massive objects, a small uncertainty
in momentum makes for very little uncertainty in velocity. For all
practical purposes, uncertainty is insignificant for macroscopic objects.
Richard E. Barrans Jr., Ph.D.
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Update: June 2012