Fire book trick...?

Question

how do science teachers do that trick where they open the book and its on fire....

Answer 1

there could be several answers from an electical ignitor, or a misch metal "flint" like magicians use to a pyrophoric substance like white phosphorous. All of the ones I see in my quick web search are electrically ignited. Probably something along the lines of a giant zippo lighter out of a book.

There are chemicals that when exposed to air spontaneously combust, but these are pretty dangerous to just lug around in highly flammable package.