EXPLOSIVE VOLCANIC ERUPTION EXERCISE: A WAY TO GET STUDENTS COLLECTING DATA, WORKING TOGETHER AND INTERPRETING THE PLOTTED VALUES

This introductory geology exercise for elementary education majors generates a large amount of excitement, entertainment and dialogue. To begin students are asked to compare a bottle of cola possessing a hole in the cap and a volcano prior to rapid degassing the cola using an ultrasonic cleaner. Multiple liquid nitrogen fueled simulated volcanic eruptions from large barrels of water are conducted with deliberate variations between repeated events. Discussions of observations after each volcanic demonstration leads to enhanced interpretations. The class is divided into two equal groups and simulated non-lethal tephra (rubber ducks) are added to the remaining barrels of water and erupted. Students are intentionally given limited instructions, a set of tape measures and a few hints of how to work as a group and collect the data representing the distribution of volcanic ejecta. The numbers of ducks landing in several semi circles in each quadrant is used for a simplified mapping application. Data is averaged, plotted on graph paper and the shape of the graph is interpreted. The two groups share data and everyone must discuss the similarities and differences between the eruptions and what is controlling these variations.

An alternative apparatus using a vertical air cannon and mini marshmallows can be used when the logistics and safety considerations make the liquid nitrogen volcano impractical. A simple clinometer made from a protractor and weighted string can be used for peak altitude measurement. Safety considerations, mistakes and successful techniques are also presented.