Happy New Year – and whistle while you work!

 

 

Following New Year celebrations, there are plenty of great web articles on fireworks – for example, http://ms.spr.ly/612175Bof5 and http://ms.spr.ly/612105Bofi

At school we burned many chemicals to examine their spectra, including some that whistled loudly as they went up in flames.

What were they? Answers below, please, to put me out of my misery!