Hah! I remember doing this back in my high school physics class with mechanical pencil lead and smaller power supplies. We even impaled some Gummy Bears onto the lead before we lit some of them up. (Yes, this was actually a teacher approved experiment!) BTW, burning pencil lead stinks pretty bad. Keep away from nose, and anything flammable.
_________________________
“Hiking is just walking where it’s okay to pee. Sometimes old people hike by mistake.” — Demitri Martin