The lead image is from three photos on Wikipedia's article on flame testing, which lists a variety of flames with helpful photos to match flame color to their probable contents. The flames above are, left to right, lead, arsenic, and copper.
For those of you working on educational materials, Aus-e-tute also has a nice activity/lesson for identifying flame spectra:
http://www.ausetute.com.au/emissions.html (this has been referenced before)
This is similar to some of the work done by Stu Williams in Australia: http://publiclab.org/notes/straylight/10-14-2012/classroom-flame-spectroscopy
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