Their energies need direction, a path, so does the electron flow which we will call the current. Since current, in general terms, means a flow whether we are talking about wind, water or electricity, the path is called a circuit. With electricity, the end result may be music, pictures or some kind of work being done for us. Current electricity works for people. In order to conduct electricity, atoms must have electrons that are free to move from atom to atom.
Metals make good conductors because only the electrons move in metal conductors.
Now we have established that the charge is the moving factor in electricity. As something is needed to force these parts to move, we will call this the electromotive force. We are reminded that a force is a push or pull. The children know this fact if nothing else. Electric current in a circuit works much like a long hose with water.