What is the practical application of the experiment capacitor?
I believe there is a language problem with this question. Experiments do not have a practical application - they are for the purpose of demonstrating principles and phenomena. It may be possible that your intended question is how can an experiment be practically constructed that demonstrates the charge and discharge of a capacitor? You can make a capacitor from two sheets of metal and an insulating film, which could be thin plastic wrap. You would need to calculate the capacitance available with such a configuration (the top metal sheet - for which I would recommend printed circuit laminate due to its stiffness - could be hinged like a book cover to come down onto the bottom metal sheet, and sheets of plastic film could be placed between the two - with different numbers of plastic films creating larger (fewer layers) or smaller (more layers) capacitance. You could take the capacitor thus created (with a wire soldered to each of the two metal sheets) and create a circuit that would charge and discharge the capacitor (possibly a 555 relaxation oscillator), and display the waveforms on an oscilloscope display. However, I may have misjudged your intentions - please clarify them.