MadSci Network: Physics |
A very trustworthy website with the information you seek is: http://wwwpdg.cern.ch/pdg/cpep/adventure_home.html This is the homepage for the Particle Adventure, produced by high energy particle physicists of the Particle Data Group at Lawrence Berkeley National Laboratory. If you want numbers, they give them: the size of an atom is about one angstrom (10E-10 m); the size of a nucleus inside an atom is a few femtometers (few 10E-15 m); the size of an electron is *less than* an attometer (10E-18 m). I highlight that "less than" because, as far as we can tell from current high energy particle experiments, the electron may have NO literal size (that is, its diameter may be ZERO). What it means for a particle to have mass and momentum without having size, I'll leave for a philosopher :) Using those numbers, we can calculate another pictoral model. Since the electron may have NO size, let's start with the nucleus. If we imagine a nucleus the size of a marble (say 1.5 to 2.5 cm), an atom would be something like 1.5 km (about one mile) across. The electrons would be smaller than 5 micrometers (5 times 10E-6 m)in size. Typical human hair is 50 to 100 micrometers, so the electrons would be smaller than a tenth of that. Remember, I always say "smaller than" because it could be that the electrons have no physical diameter at all!
Try the links in the MadSci Library for more information on Physics.