USING PROBLEM-BASED LEARNING (PBL) TO TEACH INTRODUCTORY EARTH SCIENCE

Many studies suggest that recent advances in technology demand new skills of today’s students. To this end, much curricular reform has been directed toward incorporating “active learning” pedagogies in upper level courses in science curricula. However, because many non-science majors may enroll in only one or two science courses during their college education, it is important that they gain some process skills (e.g., problem-solving and quantitative reasoning). Furthermore, many professional organizations and business leaders have recently emphasized the need for graduates with skills in teamwork, communication, and leadership, along with a desire and ability for lifelong learning.

At Macalester College the Dynamic Earth and Global Change course serves as an introduction to the composition, structure, and evolution of the Earth for both majors and non-science majors. Although the laboratory portion of the course utilized traditional exercises, many students realized the “concocted” nature of these problems and often failed to learn process skills. Using the “backward design” approach to course revision it became clear that the traditional lecture and laboratory approach to teaching introductory geology was not providing students with the necessary skills. If we want our students to think and work like scientists, they must learn by doing real science.

In problem-based learning, students learn by working cooperatively in groups to solve real-world problems. The problems are designed to be sufficiently complex to require group effort, decision-making, and judgment. Students begin by defining the problem, identifying what they do and don’t already know, and how to solve the problem. Students then work to solve the problem (collect and analyze data) and summarize their results (written and/or oral). The primary role of the instructor shifts to one of guiding the investigations and helping students monitor their own learning; lecture constitutes <20% of the course activities. Problems used in the course vary in scope, ranging from a single session focused on an important concept (e.g., fractional crystallization) to multi-week projects that require interdisciplinary approaches (e.g., locate a site for a new local landfill). Students are evaluated on the basis of individual and group performance.