Question: What interests you the most about fireworks?

Kieren Bradley answered on 20 Mar 2014:

I went to a couple of talks about fireworks and there are a number of interesting things to do with fireworks. For example, the loud bang you hear is usually the cardboard tube exploding under the pressure of the gas built up from the gunpowder burning rather than the gunpowder itself exploding. The whizzing sound some fireworks make that starts of high pitch and goes down to low pitch is also to do with the cardboard tube, the air rushing out of it vibrates and the pitch of the vibration is to do with the length of the tube and how the tube empties of powder as it burns, try blowing over the top of a bottle and you’ll get a nice note, then you drink some of the liquid try again and you get a lower note. The firework is constantly doing this so the sound changes. Finally there is the colour of the fireworks, different chemicals burn with different colours, usually it is metals that give nice bright colours. Tuning the colours and finding clever ways of mixing them really appeals to me and maybe one day I’ll get a chance to work with them.