Electricity is a form of energy. We know what it is by what it does. It is important that the student understand that the atom is composed of electrically charged parts. The separation, frictional or chemical, of these parts creates an attraction or flow as a result of the particles re-uniting. This electron-proton flow thus creates a flow.
Electrons are the smallest particles of electricity.
Electricity is not as awesome and difficult as we are led to believe. Think word charge. Moving with a force towards some goal. Static electricity to the sixth grader is a tangible, realistic concept that they can relate to with their experiences. For instance, lightning, shocks from wool carpets, balloons that stick to walls and static cling.