Connecting Science Pedagogy with Complex Earth Systems Thinking: A Non-Linear, Sensitive-Dependent Journey
Eric Pyle, James Madison University
When I contemplate the nature of complex Earth systems, I am immediately drawn to both the philosophical aspects of their descriptions as well as the instructional opportunities that they represent. When I was a high school science teacher in the late 1980s and early 1990s, I recount being profoundly dissatisfied with both the curriculum for Earth science my instruction was expected to adhere to as well as lack of utility provided by the available instructional materials that were purportedly intended to support learning by the students. Materials were either at too low or too high a level, but in both cases were characterized by discrete chunks or knowledge, with the main difference being the grain-size of those chunks. Having had rich learning opportunities in the geosciences myself, this type of curriculum simply could not convey the richness of Earth systems in a manner that students could appreciate. When the textbook discussed "global warming," for example, the text only mentioned generalities that left students with the impression that things would simply be warmer by 2-3 degrees. Trying to describe how increased warming would make global climates increasingly unstable by adding more energy to the atmospheric system, I was rewarded by blank stares. Retrospectively, I believe more could have been done if I had only had the right tools for supporting student learning, or had a more organized framework for constructing them myself.
Integrating the Secondary School Science Curriculum
In my first faculty position, at West Virginia University, I was almost immediately engaged in an environment that had embraced, in large part, an interdisciplinary approach to science curricula, particularly at the crucial middle school juncture, when so many students are turned-off to mathematics and science. An NSF-funded Teacher Enhancement project, Coordinated and Thematic Science (Project CATS), had driven the reorganization the curriculum in grades 6-10 and provided the necessary professional development to teachers in those grades to provide instruction that was rich, longitudinally coordinated, and promoted the interaction of science concepts to broader situations. In the funding life span of this project, approximately seven years, positive changes in student performance in science were being realized, closing the gap between West Virginia students and their peers in other states. Sadly, many portions of what had become a successful program were dismantled when the funding expired, driven by teachers in upper grades who wished to return to a disciplinary focus, since their prior training and materials were oriented in this manner.
When I started teaching at James Madison University in 2005, I found there in several of the faculty not only the well-thought out framework that I sought to organize my own thinking, but also a suite of learning experiences that could be adapted to a broader student audience, at least in the Earth sciences. Drs. Lynn Fichter and Steve Baedke had already organized coursework for geology majors and non-majors alike. Interacting with them and other faculty members, it became clear to me that this was the feedstock for the reorganizing of Earth science curriculum and instructional materials. Organized into a relatively simple framework, these elements include (a) small changes in systems are cumulative and drive a system from equilibrium; (b) patterns in the behavior of Earth systems are describable with a greater degree of satisfaction than any deterministic outcome; (c) these patterns are repeated at a range of scales; (d) the frequency of input from forces that drive changes in system patterns are inversely exponentially related to the energy input, and (e) patterns in Earth systems often represent one equilibrium condition or another, and that change form one pattern to another is often rapid and dramatic.
Pedagogical Theory & Practice in Support of Earth Systems Thinking
Philosophically, these factors captured much of my thinking, but there remained the dilemma of their instructional significance in pre-college science settings. A paper in the Journal of Research in Science Teaching in 2005, by Assaraf and Orion, spoke directly to this problem. Outlining eight separate "stages" of student thinking on Earth systems, they not only documented something of a learning progression for students, but they also identified prerequisites and barriers to Earth systems thinking that needed to be addressed. The factors they identified were:
- The ability to identify the components of a system and processes within the system;
- The ability to identify relationships among the system's components;
- The ability to organize the systems' components and processes within a framework of relationships;
- The ability to make generalizations;
- The ability to identify dynamic relationships within the system;
- Understanding the hidden dimensions of the system;
- The ability to understand the cyclic nature of systems; and
- Thinking temporally: retrospection and prediction.
Through their research with middle school students, they determined that students are often lacking in their understandings of each of these components. In tracking students' learning towards these components, they found a strong hierarchical component, such that 70% of students could identify system components and processes, while only about half could identify dynamic relationships between system components. Less than a third of students could identify networks of relationships, make generalizations, or suggest predictions of the system. Until such time as students were able to understand each of these elements, significant barriers to students understanding of Earth systems would remain.
Another important aspect of Earth systems appealed to me, and that was the way in which systems have and do evolve over time. It was clear, however, that the prevailing definition of evolution focused on biology was not adequate to the task. Biological evolution is an elaborating process, but understanding the evolution of Earth systems over time also requires an understanding of the evolution of self-organizing systems as well as evolution that fractionatesEarth materials. Indeed, this expanded definition of evolution allows for a richer discussion of everything from the development of stream channels and rocks to the geologic history of other planets. In both a philosophical as well as an instructional sense, concepts are summarized in two articles that have been recently accepted by the Journal of Geoscience Education: (a) Expanding Evolutionary Theory Beyond Darwinism with Elaborating, Self-Organizing, and Fractionating Complex Evolutionary Systems; and (b) Strategies and Rubrics for Teaching Chaos and Complex Systems Theories as Elaborating, Self-Organizing, and Fractionating Evolutionary Systems. (Steve Whitmeyer from JMU serves as the third author on both of these manuscripts.)
Working within a mental framework of complex Earth systems has been an instructional playground, allowing me to develop and disseminated, or recognize the application of, a wide range of instructional materials. For example, an examination of prevailing wind patterns on an overhead transparency led to a layering of transparencies containing the different elements that drive these winds as well as the impact that these winds have on currents and weather. Different system elements can be added or subtracted, and allow students to access the hidden elements of the global climate system in a simple manner. Discussions on igneous rock fractionation first led to a colored-bead model of partial melting, in which a basaltic parent collection of beads is left enriched in mafic elements by the extraction of a string of beads enriched in more felsic minerals. This next led to the development of an activity where students "construct" analogical igneous rocks by fusing crushed hard candy of various colors, in specific proportions. Taken to a larger scale, fractionation of Earth materials, combined with the evolution of continents in the Wilson cycle led to the development of a classroom poster of the Wilson cycle, with an accompanying teacher's guide that describes the process of fractionation in the context of place and time and is inclusive of all three major rock types. It is a graphical representation of a plate tectonics rock cycle. Two of the activities and the poster/teacher's guide are currently being produced and marketed by a major supplier of educational materials, where they enjoy steady sales.
In a classroom setting, students are well exposed to different cycles of matter and energy through systems. Indeed, this is mandated in the current language of the National Science Education Standards. Yet despite having had a parade of cycles throughout school, starting with the water cycle in elementary schools, relatively little of this knowledge either retained or capitalized on by students, as was shown by Assaraf & Orion's research. In an effort to impact this difficulty, I've used a simple activity with classes that not only demonstrates the interactions between cycles but also allows for a demonstration of the dynamic nature of these interactions. Called the "Web-o-Cycles," groups of students are each assigned a different matter cycle to become deeply familiar with not only the internal components and interactions, but also possible connections to other cycles. For example, volcanic activity in the rock cycle also discharges sulfur into the atmosphere, which turn interacts with the water cycle in cloud formation. Connections such as these are made between posters of the cycles using colored yarn, hooked on the appropriate nodes on each cycle and labelled by the nature of the interaction. In a short period of time, the classroom is a web of yarn, connecting each cycle to the others.
The next element of this activity attempts to capture elements of complex Earth systems, especially the concepts of equilibrium, hysteresis, power law relationships, and sensitive dependence. All lines connecting the cycles are held taut, representing an equilibrium condition. Small shifts in one cycle are compensated for by consequent shifts in other cycles. Selecting one of the interconnecting strands, tension is in introduced, first in small pulls which accumulate to imbalance and shift the cycles slightly. A single large pull in one strand, to the point of breaking the yarn, causes some lines to slacken, perhaps to the point that they cannot be easily restored to tautness without dramatic shifts in the connected cycles. Re-tightening the connections causes a shift in the cycles, which takes place quickly and assumes a slightly different but at least familiar pattern. Having students then share their observations of the process of pattern description-imbalances-shifts-new equilibrium allows them to recognize the dynamic nature of Earth systems interactions as well as to seek deeper understanding of hidden elements within the Earth system.
The Challenges Ahead, or "Why Aren't We There Yet?"
What remains for future challenges to teaching about complex Earth systems is already being addressed, at least in part. The Earth Science Literacy Initiative of 2009 directly focuses on the curricular aspect, such that one cannot fully appreciate how the Earth works until one grasps complex interactions that define the flow of matter and energy in the Earth system, and how this system is subject to change from a variety of sources and has evolved over time. The ESLIframework one of the documents being reviewed as revisions to the National Science Education Standards are being conceptualized. Once revisions are in place, instructional materials will consequently change. What has not been addressed fully, though, is once curriculum changes, assessment will also have to change. It is preferable from a resource and coherence standpoint that assessment be considered contemporaneously with curriculum. Past history, however, indicates that assessment lags far behind curriculum in development. When assessment becomes high-stakes, there is a risk of the assessment driving the curriculum and consequently instruction. Such a condition is not conducive to deep understanding by students, who are "taught to the test."
With respect to participation in this Cutting Edge workshop, I wish to accomplish four things: (a) deepen my understanding of the elements of complex Earth systems as described above, to better incorporate them into instruction, (b) share the instructional materials development that I have engaged in with other faculty who seek these materials; (c) discuss the best approaches to ensure that complex Earth systems are incorporated into pre-college science education standards, curricula, and teacher preparation and professional development; and (d) integrate information from previous Cutting Edge workshops on Teacher Preparation and Assessment to ensure that the curriculum-instruction-assessment chain is reinforced at all educational levels.