Go to "On Fire" Flash required On Fire By Rick Groleau Whether it's in the form of burning tobacco or a raging forest fire, combustion is merely some material rapidly combining with oxygen. Well, maybe that's stating it too simply. Combustion turns out to be a complex interaction between molecules -- even the burning of a simple five-atom molecule can involve more than 100 individual chemical reactions. And if you take a look at the burning of organic matter such as tobacco and wood, which contain long molecules of intricately arranged atoms, the interactions are substantially more involved. This feature lets you explore the basics of combustion, including how a fire ignites, how a molecule's atoms rearrange themselves during combustion, and what a flame is made of. On Fire (95K) Requires Flash On Fire (non-Flash version) Rick Groleau is managing editor of NOVA Online. Anatomy of a Cigarette | "Safer" Cigarettes: A History | The Dope on Nicotine | On Fire Resources | Teacher's Guide | Transcript | Site Map | Search for a Safe Cigarette Home Search | Site Map | Previously Featured | Schedule | Feedback | Teachers | Shop Join Us/E-Mail | About NOVA | Editor's Picks | Watch NOVAs online | To print PBS Online | NOVA Online | WGBH © | Updated October 2001