Lesson: Dynamic Nature of Scientific Knowledge

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Area: General Science

Grade Level: 7 – 12 and college

Overview:

In this lesson, students develop an understanding and abilities of scientific inquiry through historical exploration of an unresolved research question that culminates with them contributing to current scientific knowledge. The lesson demonstrates the importance of repeatedly testing hypotheses and of using knowledge of related topics to investigate current questions. The question addressed is: Why do Daphnia, a.k.a water fleas, develop enlarged helmets and tail spines during some seasons of the year? As the scientific community has studied this question for more than a century, two alternative hypotheses have evolved: there is a chemical cue that triggers the morphological response that (a) originates from the predator or (b) originates from consumed prey. Students design their own experiments to explore these hypotheses and, upon completing their experiments, present their contributions at a classroom “conference.” Daphnia were chosen because they are readily available to instructors, the experiments run approximately a week and are relatively simple to conduct, researchers use organisms like Daphnia to study larger theories that are difficult to test on larger organisms, and the question has not been “answered.” Therefore, students have the opportunity to participate in the scientific debate. In addition to their experiment proposals and presentations, students are evaluated based on writing down and discussing what questions still remain (due to insufficient and/or weak data) and a theoretical experiment they would perform next to help address those questions. By exploring how the questions and knowledge of a current research topic have evolved through time and then participating in the debate themselves, the students can experience how science is conducted and its dynamic nature. This lesson can be modified for use in grades 7 through college.

Standards:

National Science Education Standards

STANDARD A. As a result of activities in grades 5 - 8 and 9 - 12, all students should develop
1. Abilities necessary to do scientific inquiry
2. Understandings about scientific inquiry
STANDARD G. As a result of activities in grades 5 - 8, all students should develop an understanding of
1. Science as a human endeavor
2. Nature of science
3. History of science
STANDARD G. As a result of activities in grades 9 - 12, all students should develop an understanding of
1. Science as a human endeavor
2. Nature of scientific knowledge
3. Historical perspectives
Dynamic Nature of Scientific Knowledge 1 Instructor Materials

 

Components
Lesson (pdf/doc)
Background (pdf/doc)
Procedure (pdf/doc)
Summary (pdf/doc)
Proposal (pdf/doc)
Proposal2 (pdf/doc)