One variety of this property defines eight different types of gluons; hadrons with that type of this property cannot be isolated or directly observed due to confinement.  
One variety of this property defines eight different types of gluons; hadrons with that type of this property cannot be isolated or directly observed due to confinement.  Unlike that "color" type, the more common type of this causes a point to be accelerated in proportion to it by the Lorentz force. Its conservation is assumed by Kirchoff's first circuit rule, and the Millikan oil-drop experiment measured the "elementary" one. For 10 points, name this property measured in coulombs, whose rate of change is current and which can be positive or negative.
One variety of this property defines eight different types of gluons; hadrons with that type of this property cannot be isolated or directly observed due to confinement.  
electric charge [accept color charge until "color" is read]