What makes the popes smoke white

White smoke for pyrotechnics is more commonly — and reliably — made by burning zinc dust with the organic solvent hexachloroethane and zinc oxide added. It is widely used for military training exercises. In any event, the smoke system now leaves little to chance. But perhaps the Vatican is missing a trick by being unimaginatively monotone. Why stop at a mere two-colour signalling system? The lurid rainbow smokes used in aerial displays like those of the Red Arrows are simply tinted with bright pigments and dyes such as indigo and rhodamine.

If you would like to comment on this article or anything else you have seen on Future, head over to our Facebook page or message us on Twitter. The smoke is black if no pope has been elected. The smoke is white if a pope has been elected. For example, the smoke was black today after the first round of votes, which means no consensus has been reached among the voting Cardinals yet. First, the chimney is connected to two stoves inside the chapel.

The conclave uses cartridges filled with different chemicals to produce either white or black smoke, according to the Times. It is still not known what those chemicals are. The director of a smoke-machine supplier in England, Ben Baxter , gave the Times a few suggestions as to what the chemicals are:. The principal chemical was most likely potassium chlorate, which ignites easily — a 9-volt battery will do — and produces fine white particles as it burns.

A black cartridge probably uses potassium chlorate too, he said, along with a dye to coat the particles. A two-thirds plus one majority is required to elect the Pope. The whole process is extremely well-guarded. The color has to be just right, or millions of onlookers will be fooled.

The color of that smoke depends on what those particles are made of," Robert Krampf, a science educator who calls himself the Happy Scientist, told CBS News via email. White smoke is usually more complex, made up of fuel vapor, water vapor or mineral ash. Originally, the Roman Catholic Church burned wet straw with the paper ballots to give the smoke its dark color -- which worked for a while. The incomplete burning produces the particles of carbon needed for dark colored smoke," said Krampf.

This has sometimes led to quite a bit of confusion, with people thinking that a new Pope had been selected if the dark smoke was not dark enough.