The science behind the Vatican’s smoke signal explained!

Habemus Papam!

A few days ago, the world’s eyes were on the copper chimney of the Sistine Chapel from which the release of black smoke signals that the 115 Cardinals voting to choose the new pope have not yet reached the two-thirds majority needed to secure a decision. On the 13^th of March, the smoke turned white… How do they make it black or white? 

Traditionally, the Vatican produced the different colours by burning wet straw for white and tarry pitch for black smoke. But why did the Vatican stop using this method? Mostly because it was noxious, as burning wet straw is full of sooty carbon particles that can overload the lungs and that are potentially carcinogenic. The decision to use a more reliable method based on chemical products was made during the last conclave in 2005. The Vatican has now revealed what these are. For black, it uses a mixture of potassium, perchlorate, anthracene and sulphur; white comes from potassium chlorate, lactose and the conifer resin called rosin, which is often rubbed on violin bows to increase friction.

Article by Mathilde & Pierre-Henri