In reply to ChemE Stewart's message of Sat, 8 Mar 2014 17:48:13 -0500: Hi, >That one is easy, it's flour power
:) [snip] >> Normally a charge imbalance arises when different materials are rubbed >> together. (eg. amber and fur) >> Since all the grains are made from same the material a charge imbalance >> should not occur and no voltage should arise >> ...hence the mystery. >> >> harry >> When grains made of long chain molecules rub against one another molecules can be broken (this should happen with some plastics too). When a molecule breaks, it can either form two neutral molecules, or a pair of ions. The latter constitute opposing charges on two separate grains (each gets part of the original molecule). Breaking into two charged ions may be more likely in molecules containing atoms such as Oxygen which tend to hold onto excess electrons, thus retaining a negative charge. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html