John, Corby asked:
Are there any health effects from firing off lots of fireworks in a confined space?
Chris - There would be if you were to breathe in all the smoke. The way in which fireworks make their nice pretty colours is by exploiting an effect that Bunsen of Bunsen burner fame discovered about 150 years ago. The science of spectroscopy: he realized that when you look at something, say a distant star, you can work out what the chemicals are in the star because different chemicals absorb light and they produce light at specific fingerprint wavelengths. You can exploit that fact. If you heat up an element it will emit light in one wavelength. You can get different colours from each chemical. Each chemical has its own unique flame colour. You give the elements some energy by heating it up in a firework and it glows a pretty colour. To get those nice colours in your fireworks you have to put lots of metals in. Strontiumís a good choice for making red colours. Barium can make pretty green colours and so can copper salts. They can make greeny-blue colours. Thatís how you get the colours. The problem is that all those things can be toxic in big doses. The reassuring thing is that Disney have done some studies where they have Disney World in Florida and Disney Land in California where they jettison thousands of pounds worth of fireworks in their displays. Over 20 years of doing this they have never detected any significant heavy-metal poisoning in their waters in the water features where they let their fireworks off. Cynics would say thatís because all the people at the fireworks displays have gone home with the heavy metals inside them. I didnít say that Ė I just heard it!