What is fire?

Who's asking: Diane Lawlis, Amarillo, TX

Diane says that she had a high school science teacher who couldn't answer this question. It is more complicated than it seems, once you think about it; how would you describe fire to someone who'd never seen it? The Greeks considered it one of the four basic elements (earth, air, fire, water) for a reason.

The dictionary says that fire is a rapid, persistent chemical change that releases heat and light and is accompanied by flame.

Fire proves the laws of thermodynamics. The first of these says, in layman's terms, that energy is neither created nor destroyed, but converted from one form to another. The second says that nature favors disorder, and that transfers of energy are never 100% efficient -- some always gets dispersed.

When we strike a match, we use pressure to create friction that speeds up the movement of molecules, which we see in a spark of flame; the energy compressed into the sulfur on a match head is released (not produced) by the heat of the spark, and the whole thing burns.

Flames are a visible exothermic oxidation reaction -- the rapid combination of any other substance with oxygen in a manner that releases heat. The color of a flame depends on what's being burned, but a discussion of flame colors goes way beyond my expertise.

We had a kitchen fire when I was five or six years old, and for many years after that I was terrified of open flame. Now I have a not-entirely-healthy fascination with it. What we fear the most meets us halfway...

What I Read This Week

Will Thomas, The Hellfire Conspiracy. In their fourth adventure, Victorian enquiry agent Cyrus Barker and his assistant, Thomas Llewellyn, track down a serial killer of young girls who taunts his pursuers with limerick-style verse. I like these characters so much that I found myself impatient with the plot, which felt a little clunky and obvious. Still, this is among the best Sherlockian series going, and the end of this book makes me hopeful about the next one.

Laura Benedict, Isabella Moon. This first novel is a true old-fashioned Southern gothic, and it had been much too long since I'd read one. Kate Russell, a young woman with an obscure past, sees the ghost of a murdered girl who tells Kate where to find her body, which has been missing for two years. Kate brings this information to the sheriff of her small Kentucky town, setting in motion a series of events that ultimately reveals everyone's deadly secrets, including Kate's own. The book will be out in late September, just in time for a long night by the fire.

Karen Olson, Dead of the Day. Full disclosure: not only was this advance copy a gift from the author, but I was present at the book's christening. Karen and I were having drinks at last year's New England Crime Bake with Reed Coleman when she threw out the phrase and Reed said, "That's your title." Nevertheless, the third Annie Seymour novel is the best one yet, a complex tale of murder, immigration fraud, and bees. People write in to Karen to complain about Annie's language; Annie's a crime reporter for the New Haven paper, and talks like most other reporters I've met. If you're offended, skip those words. This book will be out in November.