The quarks : In 1964, Murray Gell-Mann and George Zweig suggested that hundreds of the particles known at the time could be explained as combinations of just three fundamental particles. Gell-Mann chose the name "quarks" for these three particles, a nonsense word used by James Joyce (1882-1941) in the novel Finnegan's Wake : "Three quarks for Muster Mark". http://fr.wikipedia.org/wiki/Finnegans_Wake There are six quarks, but physicists usually talk about them in terms of three pairs: up/down, charm/strange, and top/bottom. Also, for each of these quarks, there is a corresponding antiquark. Everything from galaxies to mountains to molecules is made from quarks and leptons. Physicists have developed a theory called "The Standard Model" that explains what the world is and what holds it together. It is a simple and comprehensive theory that explains all the hundreds of particles and complex interactions with only 6 quarks and 6 leptons. Protons contain two up quarks and one down quark : +2/3 +2/3 -1/3 = +1 Neutrons contain one up quark and two down quarks : +2/3 -1/3 -1/3 = 0 The electron is the best-known lepton. The photon is one of the "force carrier particles". http://www.ordiecole.com/physique.html ___________________________________________________________________ http://www.ordiecole.com/quarks.txt