How do they produce the sounds in fireworks (apart from the bangs of course). Just went to a diplay in the UK where many of the ground based ones made all sorts of whistling noises. Are there whistles in the tube somehow?
I was in jointly charge of setting off the (large, expensive) fireworks at a home display recently- one of the roman candle-type devices had a whistle; while this was working, we observed a small jet of flame emanating from the top of the tube; clearly the gaseous products of combustion are being forced by a whistle mechanism, but in order for the whistle to survive this, I don’t think the hot gases are going through it - because this would necessitate using a durable material that, in the case of aerial fireworks, would be dangerous as it fell back to Earth.
I think it’s more likely that it’s done by passing the gases over the end of a tube that is sealed at the other end - like blowing across the top of a bottle - in the case of aerial charges, I expect the tube forms part of a shell that shortly afterward bursts open to release other stars/charges etc.
http://www.pyrouniverse.com/glossary.htm
Scroll to the bottom for “whistle” and “whistle mix”.
http://yarchive.net/explosives/whistle.html for discussion on how “whistle mix” actually works.
thanks for the links. I am a chemist but this pyrotechnics stuff is fascinating (and is what made me take up chemistry in the first place - making my own gunpowder)