From: utzoo!decvax!yale-com!leichter Newsgroups: net.physics Title: Re: Millikan oil drops Article-I.D.: yale-com.965 Posted: Fri Feb 25 00:39:05 1983 Received: Fri Feb 25 07:46:55 1983 References: floyd.1212 Millikan found some oil drops that didn't give reasonable values, so he threw them out. He was pretty careful about justifying which ones he threw out, I think. What you may have heard being discussed was more recent attempts to look for 1/3-charge particles, using a much more sensitive version of the Millikan experiment. (Instead of oil drops, the exprimenters use tiny niobium spheres, cooled to super-conductivity and floated in a magnetic field. They have much tighter control over what's going on and can use a single ball for hours (days?) on end, adding and removing charge, or letting cosmic rays do their stuff.) I seem to recall that someone looked back at Millikan's original data and found some cases that were consistent with a 1/3 charge; however, it's only if you are looking for this pattern that you'd notice these against the other "noisy" data. The current trend in particle physics is to believe that quarks really are bound permanently inside leptons and baryons. There is now some good reason to believe the theories that exist require this. If anyone actually found a particle of charge 1/3, either quark theory would need rethinking, or it would be of a whole new class, or both. -- Jerry decvax!yale-comix!leichter PS - just to make it clear: What I said about Millikan's 1/3 charge (and other "inconsistent" results) is based on vague memory; if anyone can find a reference & prove me wrong, I won't be too shocked.