Using the History of Research on Continental Drift to Promote Learning of the Nature of Science

Understanding the Nature of Science (NOS) is a foundational component of scientific literacy in geoscience education. A central NOS principle emphasized in the Next Generation Science Standards is that scientific knowledge is historically contingent and evolves through the refinement, rejection, and replacement of theories in response to new evidence and methods. However, students often perceive science as static and absolute. This paper presents a historically grounded instructional unit designed for an introductory physical geography course for pre-service secondary education majors. The unit integrates the historical development of continental drift and plate tectonics through early Earth theories, Alfred Wegener's continental drift hypothesis, and the later emergence of plate tectonics. Instruction emphasizes explicit historical framing, inquiry-based learning activities, and reflective writing tasks intended to support students' understanding of science as an evolving process of knowledge construction. A modified KWL framework is used to elicit students' prior conceptions and evaluate conceptual change. The paper describes the instructional design, assessment structure, and practitioner reflections from classroom implementation in an introductory undergraduate geoscience course and provides guidance for adapting the unit across instructional contexts.

INTRODUCTION

Nature of Science (NOS) understanding is widely recognized as a core component of scientific literacy and is explicitly emphasized in the Next Generation Science Standards (NGSS Lead States, 2013). A central NOS tenet is that scientific knowledge is not fixed but develops over time through iterative processes of evidence evaluation, theoretical refinement, and conceptual restructuring (Lederman, 2007; McComas, 2017). Despite its centrality in science education reform, research has consistently shown that NOS remains conceptually challenging for both students and instructors, with persistent conflations and ambiguities in how it is interpreted and taught (Abd-El-Khalick, 2012).

Geoscience is particularly relevant for NOS instruction because it is inherently a historical science in which understanding Earth processes depends largely on reconstructing past events through indirect evidence rather than direct experimental replication (Dodick & Orion, 2003; Nyarko & Rudge, 2022). This epistemological structure makes geoscience especially well-suited for examining how scientific knowledge is constructed, evaluated, and revised over time.

Despite this alignment, research in geoscience education indicates that students frequently view science as a collection of absolute and unchanging facts rather than as a dynamic and evolving process of knowledge construction (Libarkin & Kurdziel, 2006). More broadly, students often assume that scientific knowledge is fixed, universal, and context-independent. Research on learning in the geosciences further highlights persistent difficulties in reasoning about deep time, complex Earth systems, and inference from indirect evidence (Kastens & Manduca, 2012). Collectively, these epistemological assumptions can constrain students' understanding of science as historically and contextually situated, thereby limiting meaningful engagement with Earth system concepts that depend on reconstructing past processes from incomplete evidence.

Addressing these challenges requires instructional approaches that make the development of scientific knowledge explicit. One particularly effective approach is the use of historical case studies that situate scientific ideas within their developmental context and trace how they are refined over time in response to new evidence and methods. The integration of History of Science (HOS) into instruction has been widely identified as a productive strategy for supporting NOS learning by explicitly connecting scientific ideas to their historical evolution (Allchin, 2013).

In this context, the continental drift–plate tectonics transition provides a particularly powerful instructional case. It illustrates how scientific explanations are constructed, challenged, rejected, and ultimately refined into a unifying theory through advances in evidence, methodology, and instrumentation in the Earth sciences. Making this historical development explicit helps students recognize that scientific knowledge is not linear or fixed, but instead evolves through iterative processes of critique, revision, and integration of new evidence.

This paper addresses these challenges through the design and implementation of a historically grounded instructional unit that uses the development of continental drift and plate tectonics to explicitly support NOS learning alongside core geoscience content. The unit is designed to help students engage not only with scientific concepts, but also with epistemological processes through which scientific knowledge is constructed and revised over time.

The instructional design is aligned with the NGSS NOS framework, particularly the principle that, "Scientific knowledge has a history that includes the refinement of, and changes to, theories, ideas, and beliefs over time" (NGSS Lead States, 2013). This objective emphasizes that scientific theories are provisional explanatory frameworks that evolve as new evidence, tools, and analytical methods emerge. The instructional goal is to support students in recognizing science as a dynamic, historically situated process of knowledge construction rather than a static body of facts.

HISTORICAL BACKGROUND OF CONTINENTAL DRIFT AND PLATE TECTONICS

Early explanations for the distribution of continents and mountain building, including the contraction hypothesis and land bridge theory, preceded modern plate tectonic theory (Oreskes, 1999). The contraction hypothesis proposed that Earth cooled and contracted over time, producing surface deformation analogous to wrinkles on a shrinking object. In contrast, the land bridge hypothesis suggested that now-submerged land connections once linked continents but later disappeared due to subsidence. While both models attempted to account for fossil distribution and geological structures, neither adequately explained global-scale geophysical patterns nor the continuity of geological and paleontological evidence across oceans.

In 1912, Alfred Wegener proposed the continental drift hypothesis, arguing that Earth's continents were once joined in a single supercontinent, Pangaea, and have since drifted apart. Wegener supported this claim using multiple lines of evidence, including the geometric fit of continental margins (e.g., South America and Africa), continuity of mountain belts across continents, fossil correlations (e.g., Glossopteris), and paleoclimatic indicators such as glacial deposits in present-day tropical regions (Wegener, 1915). Despite the strength of this empirical evidence, the hypothesis was not accepted during his lifetime due to the absence of a plausible physical mechanism for continental movement.

Wegener proposed several potential driving forces, including tidal forces and centrifugal effects related to Earth's rotation. However, these mechanisms were considered insufficient to account for the movement of large continental masses across oceanic crust (Oreskes, 1999). In addition, disciplinary boundaries and institutional resistance contributed to skepticism, as Wegener was trained in meteorology rather than geology, and his hypothesis challenged dominant geological paradigms of the time.

By the mid-20th century, advances in oceanography, paleomagnetism, and seafloor mapping provided the empirical foundation for a new unifying theory. Key contributions included the development of seafloor spreading (Hess, 1962), the identification of magnetic striping patterns on the ocean floor (Vine & Matthews, 1963), and the recognition of global patterns of seismic activity and transform faulting (Wilson, 1965). Together, these findings established a mechanistic framework in which lithospheric plates move over the asthenosphere. Plate tectonics is now recognized as a unifying theory that explains continental movement, mountain building (orogeny), volcanism, and seismic activity. This historical progression provides a clear illustration of how scientific knowledge is refined, replaced, and reorganized over time in response to new evidence and methodological advances.

Our instructional unit was implemented in GEO 120 Physical Geography, an introductory course for pre-service secondary education majors. The unit was delivered over three 90-minute class sessions using a combination of lectures, guided discussions, collaborative activities, and reflective writing tasks.

Our instructional design was guided by three principles: (1) explicit integration of Nature of Science (NOS) learning objectives (Lederman, 2007), (2) use of historical case studies to support epistemological understanding (Allchin, 2013), and (3) inquiry-based and reflective learning experiences intended to promote deeper conceptual understanding of Earth system processes and the development of scientific knowledge (Posner et al., 1982).

Across the three sessions, students engaged in a progression of learning activities beginning with elicitation of prior conceptions through a modified KWL (What they Know, what they Want to know, and what they have Learned) framework, followed by structured exploration of the historical development of continental drift and plate tectonics, and culminating in reflective synthesis of NOS-related ideas. 

Instructional activities included guided analysis of geological, paleontological, and paleoclimatic evidence, collaborative discussion and interpretation of scientific ideas, digital geoscience exploration activities, and structured reflective writing tasks. Collectively, these activities were designed to help students make explicit connections between geoscientific content knowledge and the historical development, evaluation, and refinement of scientific theories. Our instructional unit includes structured materials such as a KWL-based diagnostic and summative assessment, guided discussion prompts, a scoring rubric, and activity worksheets aligned with the learning objectives of the unit (Due to space limitations, these materials are not included in full within this manuscript. However, the complete instructional package is available from the corresponding author upon request and may be adapted for use in secondary or undergraduate geoscience instructional contexts).

ASSESSMENT AND INSTRUCTIONAL ALIGNMENT

Our instructional unit was designed to support three primary learning goals: (1) developing an understanding of the NOS principle that scientific knowledge is historically evolving; (2) identifying and revising common misconceptions about continental drift and plate tectonics; and (3) recognizing how scientific theories develop through the accumulation and reinterpretation of evidence over time. Instruction was intentionally structured to align with these goals through inquiry-based learning, collaborative group work, structured discussion, digital geoscience exploration tools, and reflective writing tasks. These strategies were designed to support active engagement with both geoscientific content and NOS principles, with particular emphasis on the historical development of scientific ideas.

Assessment was embedded within instruction as part of routine classroom practice to support student reflection, guide classroom discussion, and monitor progress toward the unit learning goals. A modified KWL framework served as the central instructional tool, providing opportunities for students to articulate prior conceptions, reflect on evolving understandings, and connect geoscience content with broader NOS principles. The "K" component was used at the beginning of the unit to elicit students' prior conceptions and identify misconceptions, while the "L" component supported synthesis of learning and reflection at the conclusion of the unit.

Additional formative assessments occurred through collaborative discussion, written reflections, and instructor feedback during classroom activities. Throughout the unit, students completed open-ended reflective prompts designed to encourage connections between continental drift content and NOS principles. A three-level rubric (Excellent, Acceptable, Needs Improvement) was used to provide structured feedback on students' conceptual understanding and reflective reasoning.

INSTRUCTIONAL STRUCTURE: THREE - CLASS SEQUENCE 

Day 1: Eliciting Prior Conceptions and Historical Context: Students completed the "K" portion of a modified KWL assessment to identify prior knowledge and conceptions. Instruction introduced early Earth theories and the historical context of continental drift. Students engaged in spatial reconstruction activities (Pangaea modeling) and anticipatory questioning to surface initial thinking.

Day 2: Evidence-Based Reasoning and Concept Development: Students examined geological, fossil, and paleoclimatic evidence supporting continental drift. Inquiry-based digital activities and collaborative discussions supported evidence integration and explanation development. Students also completed reflective writing tasks addressing possible mechanisms of continental movement.

Day 3: Conceptual Synthesis and NOS Reflection: Students completed formative review activities followed by the "L" portion of the KWL assessment. This allowed comparison of pre- and post-instruction responses to evaluate conceptual change. A final discussion emphasized the historical development of scientific theories and the emergence of plate tectonics as a unifying framework.

IMPLEMENTATION NARRATIVE AND PRACTITIONER REFLECTION

The unit has been implemented over multiple semesters in introductory geoscience courses for pre-service secondary education majors. Across implementations, I observed consistently high student engagement with the historical narrative of continental drift, particularly during discussions of Wegener's hypothesis and the scientific resistance it initially faced. Students were often most engaged when confronted with the tension between strong empirical evidence and the absence of a convincing mechanism, which appeared to challenge their expectations of how scientific knowledge is validated.

In reflective writing and class discussions, many students shifted from describing science as a collection of established facts to describing it as a process shaped by evidence, revision, and debate. Several students expressed surprise that Wegener's ideas were not immediately accepted despite substantial supporting evidence, revealing a growing awareness that scientific acceptance depends not only on evidence accumulation but also on explanatory mechanisms and broader scientific consensus.

From an instructional standpoint, the modified KWL framework was particularly useful for making student thinking visible early in the unit. In practice, the first author who created this unit plan and used it in her class, found that many students initially assumed that scientific theories are either immediately accepted or rejected based solely on evidence accumulation. This misconception persisted even after initial instruction and required repeated revisiting through discussion and reflection activities.

One consistent instructional challenge was helping students distinguish between the strength of evidence and the process of theory acceptance within scientific communities. To address this difficulty, additional scaffolding was incorporated through guided questioning and whole-class discussion comparing Wegener's evidence with later developments in plate tectonic theory. While most students were able to recount key evidence supporting continental drift, fewer initially understood why the theory was not accepted in its time. This required additional scaffolding during discussion sessions, particularly when transitioning from Wegener's evidence to the development of plate tectonics.

Overall, these classroom experiences suggest that the unit has strong potential to support both conceptual understanding and NOS-related epistemological reflection. However, they also indicate that explicit instructional emphasis on the social and methodological dimensions of scientific theory acceptance may further strengthen student understanding.

ADAPTATION FOR OTHER INSTRUCTIONAL CONTEXTS

This instructional unit is designed to be flexible across a range of instructional settings while maintaining its central focus on NOS learning. In college-level geography courses that do not specifically serve pre-service secondary education majors, the unit can be readily integrated into introductory physical geography, Earth science, or environmental science courses. In these contexts, instructors may adjust the level of scaffolding and the emphasis on pedagogical reflection while preserving the core structure of historical case analysis, evidence evaluation, and reflective writing. 

The unit is particularly well suited for courses addressing Earth system processes, as it provides a structured framework for linking scientific concepts to their historical development. In large-enrollment university courses, collaborative activities may be adapted into digitally mediated inquiry modules or structured online discussion prompts to maintain engagement while accommodating instructional scale.

In secondary science classrooms, the unit may be adapted by simplifying inquiry tasks into structured learning stations, reducing the number of historical episodes examined, and providing more guided support for interpreting geological and fossil evidence. Instructional emphasis can be placed on collaborative discussion and teacher-facilitated questioning to support students' developing understanding of how scientific theories change over time.

In time-constrained instructional settings, the unit may be condensed by focusing primarily on (i) Alfred Wegener's continental drift evidence and (ii) the subsequent development of plate tectonics as a unifying theory of Earth system processes. Even in abbreviated formats, maintaining structured reflective prompts (such as the modified KWL framework) is recommended, as these elements are central to eliciting and supporting NOS-related conceptual change.

CONCLUSION

This paper presented a historically grounded instructional unit that integrates the development of continental drift and plate tectonics into introductory geoscience instruction to support Nature of Science (NOS) learning. The unit uses a sequence of inquiry-based activities, collaborative learning, and reflective assessment to engage students with both scientific content and the historical development of scientific ideas.

The instructional design incorporates a modified KWL framework and structured historical case analysis to elicit prior conceptions, support evidence-based reasoning, and encourage reflection on how scientific knowledge evolves over time. The unit is designed for flexible implementation across a range of instructional contexts in undergraduate geoscience education.

Overall, the approach illustrates one way that historical case studies can be embedded within geoscience instruction to support NOS-focused learning goals.

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