Occasionally I have students turn pennies into silver and gold using zinc powder and 4 mol/L sodium hydroxide solution. Some years ago when I first did this, the excess wet zinc powder was wrapped in paper toweling and thrown into the garbage. An hour later the garbage pail burst into flames! I later discovered that this powder is especially susceptible to oxidation as it dries out and the trapped heat was enough to ignite the paper towel.
Learning by Accident – Zinc Dust
Categories: General Interest