The Onion Volcano
by Lori and Danny Gilmore, Steelville, MO

The concentric rings resulting from a sliced onion can be made into a model volcano for introducing topics on volcanology.

Materials: One large white onion, knife (electric knives make nice, even cuts), flat electric skillet, vegetable oil, ethyl alcohol (burner fuel), fireplace matches, goggles, and oven mits.

Safety Note: The liquids may not stay in the cone so be careful when lighting the vapors.

Procedure:
1. Preheat electric skillet. Put on the goggles.
2. Cut the onion in half. From one of the halves, cut a slice of onion approximately 1 to 1.5 cm thick.
3. Separate the rings.
4. Place the largest onion ring on the skillet. Stack the next largest ring on top of that and continue stacking until a cone with a hole in the top is made. The resulting structure should resemble a volcano.
5. Pour approximately 20 mL of vegetable oil into the volcano hole.
6. Pour approximately 10 mL of ethyl alcohol into the volcano hole.
7. Light a fireplace match and drop it into the volcano hole.
8. Turn off the room lights, and see flames shoot out of the top simulating an active volcano.

Extension: If you want orange flames, add NaCl to the alcohol or for red flames add LiCl to the alcohol.

Credit for this demonstration has to be given to our chef (name unknown) at Tanaka of Japan in Oahu, Hawaii. He did this for us on July 6, 1998 after we had finished our dinner. We were in Hawaii with Project LAVA.