Quarks and the Scale of Things
While we know for sure that quarks and electrons are smaller than 10 (-18)
meters, it is possible that they have no
size at all. It is also
possible that quarks and electrons are not fundamental but are composites of
more fundamental particles. (Yikes! Will it never end?)
In summary, we know that atoms are made of protons, neutrons, and
electrons. Protons and neutrons are made of quarks, which are
possibly made of more fundamental particles...
...but, we hope not.