* Static electricity : static cling of clothes out of dryer; lightning; * Walk across carpet and touch get a shock touching metal doorknob – friction of shoes against carpet cause you acquire static electric charge * Static charge – electric charge at rest, stays on and eventually discharged or lost to other objects/air * Discharge – remove excess static charge so the object is neutral * Static charge last long when air is dry * Electrostatics – study of static electric charge
* Benjamin Franklin demonstrated lightning is a form of electricity by flying a kite during a thunderstorm * Kite made out of silk and had pointed wire tip 30cm to draw “electric fire” * Flew kite using piece of twine tied to ground & metal key tied to twine by silk *
* 2 types of charge: positive & negative * Object with no net charge is neutral (equal amounts of positive & negative) * Law of Electric Charges – like charges repel and unlike charges attract * Benjamin Franklin imagined an electric charge was a type of fluid and believed every object contained “natural amount” of the fluid * When rubbed against another, one lost some fluid and one gained some * Positive indicate an object had more than the natural amount * Charges could easily been called red and green; positive & negative makes adding up the total charge easier
Atomic Structure and Electric Charge * Atoms made up of smaller particles * Protons – positive charge, large mass (2000x larger than electron) * Electrons – negative charge, tiny mass * Neutrons – no charge, similar mass as proton * Protons and neutrons in nucleus of atom and do not move when atom becomes charged * Electrons move around outside of nucleus and can be easily added/removed from an atom * Atom with same number of protons and electrons is neutral; unequal number has an electric charge * Ion – atom that