Study of the Relationship between Magma Viscosity and the Shape of a Volcanic Edifice: A Simple Experiment Using Slime and Its Educational Effectiveness

Abstract

We report the educational effectiveness and the results of a volcanology class conducted in a junior high school in Kobe, Japan. The aim of the class was to show the relationship between the viscosity of magma and the shape of a volcanic edifice by using slime made with polyvinyl alcohol (PVA), water, and sodium borate (borax) as an educational tool. Slime, of different viscosities, can be obtained by changing the ratio of laundry starch (PVA) and water. The resulting slime can be easily piled up to model a volcanic edifice. Students can learn about the formation process of a natural composite volcano and the relationship between the viscosity of magma and the shape of the volcanic edifice by observing a volcanic model made of the slime. An improvement in the learning effect achieved by using a volcanic model in the class was documented by a comparison of the pre- and post-test results of the students. The slime used can be made inexpensively with equipment at hand, and shows a good overall learning effect.