Student Submitted - The chemistry of papal smoke

Today's post was submitted by Katelynn J, one of my AP chemistry students. As a sub assignment after the AP chemistry exam, I had students submit two posts for this blog. I'll be posting them over the next few weeks.

Following the death of Pope Francis, a new pope now needs to be chosen. 16-20 days after the mourning period for Francis, elections have now begun and ended, and cardinal Robert Prevost, now Pope Leo XIV, has been chosen. During this selection period, all cardinals under the age of 80 travel to the Vatican to vote, and they are isolated from society until a decision is made. In order to keep the outside world updated, after every vote, ballots are burned and either black {indicating no decision has been made} or white {indicating a pope has been elected} smoke “billows” from the chimney of the Sistine Chapel. Interestingly, the longest conclave took 3 years, following the death of Pope Clement IV in 1268.

But fire only produces one color of smoke, normally. So how are the two colors created? Originally, white smoke was made by the burning of the ballots and the addition of dry grass for a lighter smoke color, and black smoke was made by ballots, wet straw, and rosin to darken the smoke. In modern times (after 2005), a mix of chemicals are used for each color. Chemicals listed here.

This chemical cocktail works because of the state of matter changes that occur. When a substance, like the chemicals used, is vaporized (fire does that!), the particles will recondense in the air, blocking light and only allowing some colors through, the color of smoke that we see.

Learn more about how other non-white/black colors of smoke are made at this link.

The chemistry of pyrotechnics (loooong)

Today you get four long videos about fireworks. The above is an episode of Nova from PBS on the history and chemistry of fireworks. I fully assume that I'll have to refind it eventually because Nova tends to be pretty good about deleting their episodes from YouTube when they're posted whole like this.

The chemistry of pyrotechnics (shorts)

After the fireworks video a couple of weeks ago, I went hunting more videos to explain the chemistry of pyrotechnics, and I found a bunch of them.

We'll start this week with the shorter videos.

The one above is the most comprehensive of the short (10 min or less) videos I've found. It explains a bit of history, some of the structure of, the chemical reactions taking place in, and the colors produced in common fireworks.

Start with that one. 

It isn't, however, a very pretty video. It's a lecture with an animated hand writing and drawing on a digital white board. Not the most exciting of the videos.

How Professional Fireworks Work

Probably twenty years ago I took a week long workshop "Chemistry of Pyrotechnics" at Miami University in the summer. It was a great explanation of the science that goes into creating everything from tiny backyard sparklers all the way up to giant fireworks shells.

The course was taught by people who normally taught science to fireworks makers, and they said that the workshop was their first time teaching the fireworks side to people who already knew the science. That made for a really interesting cross-educational experience.

Coincidentally, it turns out that Ed Escudero and Beth Eddy - both of whom I would later work with through ASM - took the same class.

The above video takes you through more of the mechanics of a large, professionally made pyrotechnics shell than it does the chemistry of pyrotechnics (I'm going to look for that video in a minute), but the mechanics includes a bunch of chemistry from controlling the rate of a reaction to producing the various colors. 

And I just put in a request to get a copy of this textbook from the University of Akron library. Thank you, OhioLink.