What's the best way to set fire to a book?

Answers to your questions about the news.
Sept. 8 2010 5:16 PM

Burn Before Reading

What's the best way to set fire to a book?

Book burning. Click image to expand.
Open books burn more easily than closed ones.

The leader of a small, nondenominational Christian congregation in Gainesville, Fla., plans to host the first "International Burn a Quran" day this Saturday. Despite criticism from religious and political leaders around the world, the evangelical minister says he will go forward with the event, during which multiple holy texts will be set ablaze. If you wanted to engage in a ritual of gross religious intolerance, what would be the best way to burn a book?

Open it up. It's extremely challenging to ignite a closed book, even with repeated applications of lighter fluid. You may char the edges, but the flame that results will never grow large enough to consume an entire volume. For any chance at a sustained burn, it's necessary to open the offending book and fan out the pages as much as possible, so as to promote the circulation of air and heat exchange. The most efficient method would be to curl the pages in half lengthwise and tuck the outer edges into the binding and then to light the pages from the top or bottom and wait for the fire to spread.

If you're looking to burn a large pile of books in a headline-grabbing conflagration, you probably won't have time to fan out the pages of each one. But someone who wanted to burn a lot of books could just treat them like firewood. From a combustion perspective, a closed book behaves just like a log. They're both dense collections of cellulose.

Piling books in a loose configuration permits air to circulate and helps to sustain the blaze, so long as there isn't too much space between them.

To ignite a stack like this, you'd need to place a bunch of tinder—perhaps some ripped-out and crinkled pages—at the base of the heap and light it first. (Alternatively, you could get a roaring fire going using other fuel and just throw books on top of it.) Covers are typically made of wood-based materials as well. Leather-bound books may take a few extra seconds to ignite, but they won't change the temperature or burn time for the bonfire.

Why can you burn 100 closed books, but not one by itself? To sustain a fire, you have to get the outside of the book up to ignition temperature and keep it there. But two things happen when you apply flame to a book. First, heat is shunted into the middle of the volume, which prevents the outside from reaching ignition temperature. (The exact temperature required varies based on composition and conditions, Ray Bradbury's figure of 451 degrees Fahrenheit notwithstanding.) Second, a layer of char develops on the book cover, which serves to raise the ignition temperature. So, if you want to keep your books burning, you have to apply continuous heat to the surface by surrounding them with other burning books.  That's why it's so hard to burn a single log in your fireplace—without new heat coming in from adjacent burning wood, the energy dissipates and the fire dies.

However you burn books, you might want to stand upwind of the bonfire. Most book paper is bleached using chlorine, and burning it releases dioxins, which can cause skin lesions, liver damage, reproductive abnormalities, and cancer. You won't be affected by one International Burn a Quran Day, but make a habit of it and you're taking a chance.

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Brian Palmer is Slate's chief explainer. He also writes How and Why and Ecologic for the Washington Post. Email him at explainerbrian@gmail.com. Follow him on Twitter.