Hi all, I'm still trawling my way through the equipment needed to teach physics year 11 next year, and trying to organise a set of capacitors so that the pupils can observe them charging and discharging. I first ordered some excellent electrolytic capacitors (470uF), and these work really well - they take roughly a minute to charge with the suggested circuit, and the pupils could see the voltage slowly creeping up as they charge (and the current slowly decreasing also). I've since found out that they can explode if not connected with the correct polarity, and therefore seem to me to be completely un-usable in a classroom (my year 11s would probably take it as a challenge to make them explode). I really want to do this as a class practical and not a demo behind a screen, so I sourced some ceramic capacitors, however their capacitance is much lower (47pF) and so they charge pretty much instantly - the pupils would therefore not see much of anything happening. I was wondering if anyone out there uses capacitors in the classroom, and if they do: Do you use electrolytic or non-electrolytic? If you use electrolytic how do you manage safety? If you use non-electrolytic, how do you manage to use them so that they have a reasonably long charging time (I've already set my resistance to 470 kiloOhms and it can't go any higher)?