Burning paper towels soaked in various metal nitrates

Igniting paper towels that have been soaked in concentrated potassium nitrate and allowed to dry yields a flame reminiscent of that produced by guncotton. Repeating this experiment with other metal nitrates produces flames with different colors, plus a few other chemical surprises! This series of experiments is fascinating and connects to a wide variety of chemical topics including combustion, redox reactions, chemical thermodynamics, and flame tests. You don't want to miss this one!

The Empirical Formula of Magnesium Oxide Lab: A Successful Failure, Next Steps—and an Important Lesson

Michael Jansen reflects on a very common empirical formula lab that asks students to determine the empirical formula of MgxOy. He then explains how he continues to use it as a "successful failure", how he demonstrates an alternate procedure and leads his students to an important lesson.