Re: "and gloves were forbidden"
My chemistry teacher once went to demonstrate what a stochiometric mixture is, by filling an empty paint tin with natural gas. The tin has a small hole in the bottom and one in the lid, so that gas escaping from the hole in the lid is replenished with air through the bottom hole.
You light the gas coming out of the hole in the lid, then wait for the gas/air mixture to become stochiometric. At which point the flame will ignite the gas mixture, and the lid will pop off.
Or at least, that's the theory. If you use a small tin and reasonably-sized holes.
In this case, the holes were quite small and the tin, well, one-fifth its size would have been a better choice.
Due to the volume and the small holes, the mixture was slow to reach its kaboom point, so the experiment was put aside to do its thing while other experiments were demonstrated. And with no-one paying much attention any more, the kaboom caused a lot more consternation than it normally would have.