31 October 2009
Arbitrariness - charges
It can be confusing to many physics and/or chemistry students that the flow of current is generally defined to be the way positive charges move, but in reality, what's usually actually moving is a series of electrons - negative charges. The seemingly logical solution to this would be to have labelled electrons as being positive, thereby having all charges flipped from what they currently are. Is there a clear answer as to the reason that charges are defined positive or negative as they are? There doesn't seem to be any actual physical reason for it; nothing about positive or negative actually makes a difference, only the oppositional nature of the two seems to actually be required.
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I learned about this and it was arbitrary. It actually is because Ben Franklin randomly chose one charge to be positive (glass rubbed with silk) and one to be negative (amber rubbed with fur) - but then later when we figured out which charges were the ones that moved we found out it was backwards but by that time the convention was already too set so it was too late to switch.
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