Another trick about flashlight bulbs is not to let the students lay their
hands on more than two dry cells. I was lax and naive on this and before I
knew it there were bulbs burning out in flashes of glory all over the
classroom as students connected 5 or 6 cells in series! That can get
expensive.
In one way or another let them know from the start they will be held
responsible if they blow bulbs frivolously.