A simulator for rewiring batteries and capacitors and watching them charge and discharge. In the circuit panel, set each of the battery and the capacitor to a single unit, in series, or in parallel, then enter the electromotive force, the capacitance, the resistance and the plate gap.
Press charge and electrons run along the wires, collecting on the plates. As they collect, the current thins out and the field lines between the plates grow in number. Switch to discharge and the flow reverses; disconnect and the charge simply stays.
The readings panel shows the combined capacitance, the time constant RC, the current, the total charge and the stored energy. The waveform panel shows how the voltage and the current change over time.
Set the playback speed to suit the time constant. The time constant is resistance times capacitance, so some combinations charge in an instant and others hardly move at all.