Cordilleran Section - 115th Annual Meeting - 2019

Paper No. 35-7
Presentation Time: 10:15 AM


CARLSON, Steve, Geology, Portland State University, PO Box 751, Portland, OR 97201

This activity driven demonstration uses marshmallows and gum drops to build the Bowen’s Reaction. I start the activity, depending on class size, with each student making a model of a SiO2 molecule from tooth picks and dried marshmallows. Then the students pair up and collectively make tetrahedra, single chains, double chains, and sheet structures. The class ends up making a sheet of mica.

It’s of course not “scientifically accurate in scale” but they get the idea! I have made "egg carton kits" to go with the activity with both discontinuous fe/mg, and the continuous series of feldspar minerals. At each point in the activity, we talk about the temperature, pressure changes and curie points that are happening as the magma chamber cools. Accompanying the Bowens simulation, I made a set of "egg carton kits" of igneous rocks, that fits next to the mineral kit, and ask the students to find those mineral crystals in the matrix. When they finish they really start looking at identification based on composition and texture!