The six flavors of quarks

[brightrosefox]

http://xkcd.com/474/

(Alt-text: Supercollider? I 'ardly know 'er!)

There are six different types of quarks, usually known as flavors: up, down, charm, strange, top, and bottom. The charm, strange, top, and bottom varieties are highly unstable, and are believed to have decayed within a fraction of a second after the Big Bang – though they can be briefly recreated and studied by scientists. However, the "up" and "down" varieties are abundant and are distinguished by (amongst other things) their electric charge. It is this which makes the difference when quarks clump together to form protons or neutrons: a proton is made up of two "up quarks" and one "down quark", yielding a net charge of +1, while a neutron contains one "up quark" and two "down quarks", yielding a net charge of 0.
-http://en.wikipedia.org/wiki/Quark