Teachers of earth science in Minnesota and North Dakota have a wide range of preparational backgrounds. To provide insight into factors influencing preparation, we have administered an essay test to inservice and preservice teachers, geology majors, and members of the student body at Minnesota State University Moorhead. This test is not primarily a test of factual knowledge, but rather evaluates conceptual understanding and creative thinking on questions that might arise in an 8th grade or high school classroom, particularly as relevant to teaching investigative science or addressing student questions. These concepts are commonly taught in introductory college earth science. The test was validated by a panel of geoscience educators ranging from 8th grade to college instructors and scored independently by two graders who followed a scoring rubric.

We consider correlations to several factors, including number of courses taken in earth science, courses taken in other sciences, whether courses are introductory or advanced, and whether they were traditional (classroom and lab) or nontraditional (workshop or online course). Teaching experience was also taken into account. Results indicate that introductory courses, even when they specifically address the material tested, are generally insufficient to provide a conceptual understanding sufficient to teach earth science at the junior high or high school. Teaching experience is the most significant factor correlated to conceptual understanding, but only when that experience builds on traditional classroom experiences. Workshops and online courses, when taken without prior traditional foundation in earth science, provide no statistically significant improvement in understanding of the discipline.

We conclude that tracking student exposure to a set of "content standards" is an inadequate means to confirm proper preparation of teachers. Instead, future teachers benefit from a 'synergistic' exposure to broader disciplinary material outside the standards and repeated exposure to material more advanced than they are required to teach.