Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Uncertainty Principle
Name: phoebe
Status: educator
Age: N/A
Location: N/A
Country: N/A
Date: 1999 


Question:
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.


Replies:
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.



Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory