Colored flame tricks that make use of methanol and various metal ions are old hat–and a source of in-class accidents—but one does not often see the use of zinc oxide, which is the main ingredient of Ihle’s paste, some foot powders and many diaper rash ointments. The electron transitions of zinc ion are very sensitive to different flame temperatures, and the emissions are beautiful.
ZnO is red between 568 to 704 degrees Celsius
ZnO is green between 704 to 948 degrees Celsius.
The sparks that are seen are ZnO particles that have fallen into the solution then were lifted with the flame, the methanol evaporated out of them and just like any dust particle they produced a spark.(Thanks to student Veronica Chudzinski for digging this up)
Earlier in this school year, I came in early to film this demo hoping that one day people would get so exhilirated from watching its emissions that it would eliminate the need for recreational drugs!
Here it is:
Some Safety Precautions:
(1) Add sand to the beaker. Although this precautionary trick is not fail proof, it lowers the probability of getting broken glass and burning methanol all over the place.
(2) Cut the methanol’s concentration to 50% (dilute with water)
(3) Methanol is not only highly flammable, it is also poisonous. Perform this demo in a fume hood.Bulletin of the National Research Council Volume 5