I literally witnessed a demonstration of that two days ago. Every semester or so, the chemistry department at my university does a chemical magic show. Despite having seen the tricks a million times, I still love chemical magic. Like all good science propaganda, it was full of dramatic flames and explosions. The finale involved exploding hydrogen balloons. After setting a particularly large balloon full of hydrogen alight with a tiki torch, which opened the heavy auditorium doors every so slightly, a smaller balloon with 2:1 hydrogen-oxygen mix was set off that blew them wide open. The advice to cover our ears was heeded, and much appreciated.
