Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site decwrl.UUCP Path: utzoo!linus!philabs!prls!amdimage!amdcad!decwrl!dec-rhea!dec-regina!augeri From: augeri@regina.DEC (Mike Augeri) Newsgroups: net.physics Subject: Heisenberg Uncertainty Principle Message-ID: <3506@decwrl.UUCP> Date: Wed, 7-Aug-85 21:43:59 EDT Article-I.D.: decwrl.3506 Posted: Wed Aug 7 21:43:59 1985 Date-Received: Sun, 11-Aug-85 04:14:13 EDT Sender: daemon@decwrl.UUCP Organization: Digital Equipment Corporation Lines: 30 I imagine that these questions probably have been asked before, but I have not seen them during the time that I have been reading net.physics, so here goes. I can hear the experts saying "Oh boy, here we go again with some more dumb questions." In over-simplified terms Heisenberg's Uncertainty Principle says that we cannot know the simultaneous position and momentum of an individual elementary particle with unlimited accuracy. Yet, we are able to determine the simultaneous position and momentum of conglomerations of these elementary particles. That is, I can determine the position and momentum of my desk to a degree of accuracy limited only by the resolution of the measuring equipment I use, whereas the Uncertainty Principle says that no matter how accurate my measuring equipment, when it comes to the individual particles making up the desk, it is fundamentally impossible to even make the observation. What is different about the individual particles and groups of particles? Is it strictly a case of the measurement process itself disturbing the individual particle, or is something else going on here? For example, it seems to me that if it is simply a matter of the measurement process disturbing the particles we are trying to measure, then we just have to find a measurement process that uses small enough particles so that they won't disturb the particles we are trying to measure. I am not saying that such particles exist. But in my opinion saying that "in principle, it is impossible to measure the simultaneous position and momentum of a particle" is quite different than saying that "the means to measure the simultaneous position and momentum of a particle does not exist". The net result is the same, but the statements are different. Mike Augeri, DEC, Maynard MA USA