http://www.finishing.com/faqs/howworks.html
How electroplating works
http://www.ae.iastate.edu/Ae573_ast475/Physical_Treatment-Theory.htm
Sedimentation
http://liftoff.msfc.nasa.gov/Shuttle/USML2/science/DPM.html
Comparison of force strengths in fluids
http://www.sciam.com/1998/0198issue/0198amsci.html
A kitchen centrifuge
http://www.ebtx.com/ntx/orgnchrg.htm
The origin of electric charge