From: "Gloria D. Rall" <gdrall@erols.com>
Subject: Modeling volcanoes
Date: Fri, 11 Jul 1997 20:09:21 -0700
We have been experimenting a lot with modeling volcanoes and we thought you might like to know what we've learned. We make our volcanoes with clay and with shallow craters. We give the students a very good picture of Olympus mons that really shows the shape of the volcano in a close-up view, and ask them to make the models as realistic as possible. That works fine, but we were unhappy with getting it to erupt. We used vinegar and baking soda. It works well but the action is much more like an eruptive volcano. Olympus mons is a shield volcano where the lava gently bubbled over the sides to give that gentle slope. We discovered that a tablespoon of water, enough cornstarch to thicken it, and an Alka Seltzer tablet works well. This bubbles like a shield volcano and the "lava" just spills over the sides. We add food coloring to make it more realistic. The cornstarch hardens rapidly, and if you do this several times you can see how the volcano shapes itself somewhat like Olympus mons.