Pyrotechnic chemistry drives the Vatican’s recipes for the black and white smoke used to announce papal election outcomes ...

But an overnight stay in the refrigerator results in the potassium chlorate crystals seen above. Fiery testing (seen below) lets him know the experiment worked. From here the product can be used ...

An easier, albeit vastly more expensive and dangerous alternative came in the 19th century when chemists discovered auto-ignition using a potassium chlorate mixture and sulfuric acid. This method ...