by
DR » Tue Oct 03, 2006 12:55 pm

Fun with jets:
Once in a biology lab, people were flame sterilizing tweezers (dip in a sm. beaker MeOH, pass through flame of an alcohol lamp, MeOH burns off is a second or two).
A TA noticed that one of the many sm. beakers was about empty. He failed to notice that it was the only nearly empty one, failed to ask himself why it might be the only empty one, failed to remember that MeOH flames have no color... He decided to refill it from a 1L flask of MeOH. There was a dinner plate sized black spot on the wall opposite where he started to pour into the beaker as the flame shot up the stream and jetted 3 feet to the wall when it hit the MeOH saturated vapor at the opening of the flask.
(nobody was injured)
Then there was the time I was student teaching and I wanted to do the self-inflating balloon demo.
I added some calcium carbide chips and water to a balloon, tied it off and clamped it to the top of a ring stand several yards from anything.
Once the balloon was inflated, I lit a match that I had taped to the end of a yard stick so that I could detonate the gas in the balloon.
Instead of popping and exploding, the balloon developed a pinhole and broke loose from the clamp. It did one short lap around the center of the room before heading for the curtains at the head of a 2 foot flame. Fortunately, it ran out of gas just before it got to the window. I made a note to limit that demo to open, muddy fields in the future.