There was this really boring winter I spent.....(uh I won't say where cause I don't know the statue of limitations)......where we made our own hydrogen and filled balloons with it.....just to see them float, you understand. I wouldn't know for sure, but if they were to ignite I assume from the poor quality of our hydrogen they'd make a large yellow fireball. As I said I wouldn't know for sure.
I do know if you take about 10 feet of the old Scotch tape.....the old, non-transparent, yellow kind and tape it to the balloon.....uh for ballast, of course, and accidentally light it, it won't blow out very easily and burns at a modest rate.
I definitely wouldn't recommend doing this just off the end of a runway....a USAF runway.....at 2am in the morning.
Well it WAS a boring winter
.....up until then.
Well, what do you know.
A group of us, 5 or 6, aged about 15 or 16 discovered that a local surplus shop was selling balloons that had been part of a pilot survival kit.
They came with the balloon and a canister of caustic soda, I think it was.
The balloon was intended to have an antenna attached to haul it up high so a distress signal could be sent.
Attach the balloon to the canister, submerge it in water and it generated hydrogen to fill the balloon.
We each managed to score a couple before they were all gone.
We tried to get glorious explosions from them but never got anything satisfactory. It was daytime and we figured we just couldn't see the flames

We did send a large paper bag full of ice cubes aloft on a warm breezy summer day with 1200 ft of kite twine. Ice melted, bag got soggy and there was a nice shower of ice, but we missed anything exciting.
What we did do with them was one evening we had 5 aloft with flashlights tied below them and sent them up on our kite twine. As they got up high, they would twist in the wind and the lights would appear to be turning off and on..
We were doing it in the street of a cul-de-sac and all the folks in the circle were out with us watching.... till two or three police cars showed up. The officers were very nice but had us haul the balloons in....seems their switchboard was flooded with UFO sighting calls.
One didn't make it down. Jack Blackwell, the Mad Scientist of our group, had securely fasten a plastic cottage cheese container with a mouse in it to send up. Well, he ran the twine through the plastic container and the mouse chewed through it (the working theory) and, no doubt, had an unsuccessful re-entry and landing. The balloon, however, with flashlight attached continued on, the light visible off and on as it got tossed end over end by the wind.
Cops stayed with us to watch it go up out of sight and relay to us that the phone calls were now reporting that several of the UFOs had landed but one was heading home....
Our balloons never did fly again...and we couldn't get any of those to go in a blaze of glory as they were retired from service.
Circa 1963.