Scottish Country Dance of the Day

Three quarks for Muster Mark!
Sure he hasn't got much of a bark
And sure any he has it's all beside the mark.

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~ James Joyce, Finnegans Wake

 

Physics Day is an unofficial holiday which began over 25 years ago, partnering the American Association of Physics Teachers with amusement parks, many of which  open their gates on a non-operating day, exclusively for physics students.   There is a great opportunity to study physics in action by examining the principles of roller coaster mechanics, but the physics of elementary particles is another scientific frontier, celebrated in a Scottish Country Dance referring to flavours of elementary particles known as quarks.

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The quark model was independently proposed by physicists Murray Gell-Mann and George Zweig, and the name, through a circuitous route, eventually took its spelling from the James Joyce quote from Finnegan's Wake.

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A quark is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei.

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Quarks have various intrinsic properties, including electric charge, mass, color charge, and spin. Quarks are the only elementary particles in the Standard Model of particle physics to experience all four fundamental interactions, also known as fundamental forces (electromagnetism, gravitation, strong interaction, and weak interaction), as well as the only known particles whose electric charges are not integer multiples of the elementary charge.

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There are six types of quarks, known as flavors: up, down, strange, charm, top, and bottom.

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From the wikipedia entry:

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The quark flavors were given their names for several reasons. The up and down quarks are named after the up and down components of isospin, which they carry. Strange quarks were given their name because they were discovered to be components of the strange particles discovered in cosmic rays years before the quark model was proposed; these particles were deemed "strange" because they had unusually long lifetimes.  In the past, bottom and top quarks were sometimes referred to as "beauty" and "truth" respectively, but these names have somewhat fallen out of use. While "truth" never did catch on, accelerator complexes devoted to massive production of bottom quarks are sometimes called "beauty factories."

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For an interactive tour of quarks, neutrinos, antimatter, extra dimensions, dark matter, accelerators, and particle detectors, click the quark graphic to visit "The Particle Adventure" from Lawrence Berkeley National Laboratory.