Every year on New Year’s Eve, I head over to some friends’ house here in the Atlanta area. They have the best party around — Possum Drop — and I’ve been going for nearly a decade now. As midnight approaches, the newly-crowned Possum Queen leads the countdown. The possum is lowered slowly onto the fire and then erupts in an explosion flames and sparks.
Don’t worry. It’s not a real live possum. It’s a giant possum made of chicken wire, papier-mÃ¢ché, fabric, and other scavenged materials… and it’s stuffed full of fireworks!
How much heat can you get from a Christmas tree?
Naturally, the backyard bonfire is fueled by Christmas trees, an abundant fuel source in the days leading up to Possum Drop. So you might wonder, how many Christmas trees does it take to burn the possum?
And once you ask that question, you’ve started thinking like a 19th century scientist… sort of. Take Thomas Tredgold and Nicolas Clément, for example. Both worked on a similar problem: relating a quantity of fuel to a result of burning that fuel. Both came up with similar definitions.
According to Dan Holohan, who is famous for helping to carry 18th century steam heating knowledge into the 21st century, Tredgold is credited with inventing the British Thermal Unit, or BTU. In his article The Origin of the British thermal Unit, Holohan quoted from Tredgold’s book: “I take as the measure of the effect of a fuel, the quantity, in pounds avoirdupois, which will raise the temperature of a cubic foot of water one degree of Fahrenheit’s scale.”
The definition has evolved a bit since then, though. Now we define it thus: One BTU is the amount of…