Date: Tue, 27 Oct 1998 05:48:41 -0800
From: Peter Geschke <peterg7@home.com>
To: Pinhole Listserv <pinhole@exploratorium.edu>
Subject: Halloween idea
We do a "flaming pumpkin" for our "trick" in Chemistry:
1. Carve pumpkin in a most creative fashion. Include a hole in the back big
enough to insert some rubber tubing. Put candle on pumpkin "floor".
2. Get some Lycopodium powder - very fine powder that's *really* combustible
in suspension.
3. Through use of a funnel, fill up a portion of the tube with the powder.
4. Insert tube through hole in back of pumpkin and aim the end to come out
near the candle - not too close to blow out candle.
5. Light candle. Move kids >10 feet away for safety.
6. Blow powder through tube. Flames come shooting out of the pumpkin!!
7. Kids will ask for repeat. Don't until they explain how the powder works.
The powder works because its very combustible and the particles are very fine
in suspension - so, when one particle burns, that generates enough heat to
burn a nearby particle. "And she told two friends, and so on, and so on."
Peter Geschke
Mission San Jose HS
Fremont, CA
510-657-3600x3528